Documents published in 2022 : Scipedia

RECYCLED FIBERS INTEGRATION IN AUTOMOTIVE COMPONENTS MANUFACTURED BY INJECTION
S. García-Arrieta, C. Elizetxea, A. Calle, O. Ollo, M. Múgica, E. Goikuria, E. Sarlin, M. García

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 161

Abstract
In the last decade, a great effort has been made to achieve a transition from the current linear economy to a circular economy. This transition also affects the composites sector, which, due to the intrinsic complexity of recycling, requires the implementation of recovery and remanufacturing processes that will be technically, economically and environmentally feasible. This challenge was addressed within the FiberEUse project, in which one of the working lines was based on waste recycling from wind and aeronautical sectors. Both glass and carbon fiber were recovered by pyrolysis. Subsequently, the recycled fiber was treated and processed with thermoplastic matrices used in automotive applications. The technologies used and the results obtained throughout the value chain, from the waste to the part, are presented in this paper. Formulations with different recycled fibers, with and without sizing treatments and with different matrices, were manufactured by compounding-injection. These materials were mechanically analysed and tested with the aim of selecting three formulations. The reinforced materials were validated in three real automotive prototypes: a pedal bracket, a front-end and a cowl top support. As a result, the prototypes were manufactured, tested and validated by the automotive companies.
Abstract
In the last decade, a great effort has been made to achieve a transition from the current linear economy to a circular economy. This transition also affects the composites [...]
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"TORRESPRINT3D® - NEW ADDITIVE MANUFACTURING PROCESS FOR LARGE COMPONENTS"
V. Forte, J. Vidal, A. Cerezuela, P. Alzórriz

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 163

Abstract
Additive manufacturing (AM) for large volume parts is a rising technology with the potential to reduce the fabrication costs and lead times for components. It has practical applications in multiple industrial fields. AM technology can be instrumental in producing large pieces with complex geometries, especially for tooling and ancillary equipment. Despite these advantages, several technological aspects limit the use of AM for massive manufacturing. One of the limitations is the need to maintain the part and the working area at an elevated temperature using heating systems. Another critical limitation is the size of the 3D printing system, limiting the size of the components that can be produced using this technology and imposing some restrictions regarding the components’ geometry and thickness. Research has been carried out to solve these primary issues, and specific solutions have been developed and matured. The solution shown on this article comprises: 1. A system that can alter the required temperature locally without using a heated working environment 2. A moving base that supports the part during the manufacturing process eliminates the part dimension’s limits, allowing for the manufacture of large -“infinite”- parts 3. The material applying process design allows depositing the material increased flexibility and perfect control of the thickness and layer overlap. These new technologies have been tested extensively by manufacturing and testing large industrial molds obtaining excellent results. The fields of application of this technology are limitless. The principal industries that can benefit from immediate uses are the aerospace, wind energy, naval, and railway sectors. This technology will revolutionize the mold manufacturing industry, allowing the curing mold manufacturers to produce large curing molds at a low cost and shorter delivery times.
Abstract
Additive manufacturing (AM) for large volume parts is a rising technology with the potential to reduce the fabrication costs and lead times for components. It has practical [...]
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Mechanical evaluation of different repair concepts in thermoplastic and thermoset materials
P. Luna, K. Muñoz, M. Jiménez, M. Iglesias, B. Nicolás, B. Fantina, E. Lorenzo-Villafranca

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 174

Abstract
The repair process of thermoplastic and thermoset polymeric matrix composite materials is being increasingly demanded in the aeronautic industry for the need to know, in relation to the performed approximation, the recovery of residual strenght. To ensure the security and the viability of the repair processes, as well as its durability throughout its life cycle, it is necessary to perform the validation of the mechanical properties of structural elements after the repair process to eliminate defects and damages. The aim of this work is to validate, after aging, different damaged composite repaired coupons that have undergone different repair processes. The analyzed repair concepts are named as “Prepreg”, “Dry” and “Hybrid” for the thermoset material, and “Reconsolidation” and “Pre-consolidated patch” for different integration techniques of thermoplastic materials. Test coupons have reached H/W conditions according to applicable specifications. Additionally, different protections have been performed on the specimens to faithfully simulate ageing conditions. Furthermore, for each type of material and configuration, a reference test series meaning undamaged and unrepaired specimens has been tested to monitore in each case the level of recovered structural capacity. This activity is part of the CERES (Advanced Rear End Structural test program – low level tests) project, which is framed under Clean Sky 2 JU.
Abstract
The repair process of thermoplastic and thermoset polymeric matrix composite materials is being increasingly demanded in the aeronautic industry for the need to know, in relation [...]
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3D PRINTING OF BIO-INSPIRED CORES FOR OUT-OF-AUTOCLAVE SANDWICH STRUCTURES
I. Sukia, A. Esnaola, U. Morales, L. Aretxabaleta, J. Aurrekoetxea

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 164

Abstract
The design and manufacture of sandwich structures allow for many variants related to core and skin types, but their fabrication is very limited with conventional technologies. Recent advances in 3D printing are creating new design possibilities, such as bio-inspired structures with more complex cellular units than the current ones, functional gradients, and curved panels. The present work has focused on two aspects; 1) the efficiency of the core inspired by the trabecular structure of beetle wings versus the conventional honeycomb, and 2) the feasibility of integrating these new cores with carbon fiber/epoxy prepreg skins for out-of-autoclave curing. The results show that the ONYX® 3D printing cores obtained by filament extrusion technology and the skins manufactured by out-of-autoclave curing show good skin/core adhesion. On the other hand, the results of the flexural tests have shown that the stiffness of the sandwich panel with the trabecular structure is better than that of one of the honeycombs and the strength in both cases is similar. However, where substantial differences have been found between the two types of cores is in the quasi-static puncture resistance, that of the trabecular structure being 60% higher.
Abstract
The design and manufacture of sandwich structures allow for many variants related to core and skin types, but their fabrication is very limited with conventional technologies. [...]
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Allowables Evaluation for the Design of a Thermoplastic Fuselage
K. Muñoz, M. Jiménez, M. Mesa, R. Cabrera, S. Anaya, R. Elices, K. Fernández, J. Cuenca

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 173

Abstract
Carbon fibre reinforced polymers are commonly used in the primary and secondary structures of aircraft, mainly due to their excellent specific mechanical properties. Currently, there is a growing interest in the use of carbon fibre and thermoplastic resin composite materials in aeronautical applications, since they offer multiple advantages compared to thermosetting equivalents. This study presents the results of the mechanical tests carried out at the coupon and element levels for the characterization of the properties of a thermoplastic composite that will form a fuselage panel. In addition to standardized tests, tests are carried out to evaluate the behaviour of critical areas of the panel, such as the radius of the frames, the stringers, and the joint between the frame and the skin around the stringers (mouse-hole). In these latest tests, experimental procedures are developed for their execution, including the design of the necessary tools to reproduce the representative boundary conditions. As a result of this research, the allowables have been obtained for the design of the curved thermoplastic fuselage panel. This work is developed as part of the European project DELTA, within the framework of the Clean Sky 2 JU program. The objective of this project is to develop and execute innovative experimental test procedures that allow the validation of thermoplastic composite aircraft fuselage panels, in order to apply these solutions in medium and long-range aircraft (LPA). The ultimate goal of this project will be achieved through the execution of a curved thermoplastic fuselage panel test under representative load conditions.
Abstract
Carbon fibre reinforced polymers are commonly used in the primary and secondary structures of aircraft, mainly due to their excellent specific mechanical properties. Currently, [...]
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Development of polymeric composite materials and prototypes with cork for large format additive manufacturing
P. Burgos-Pintos, I. Romero-Ocaña, A. León, F. Delgado, D. Moreno-Sánchez, D. Moreno-Nieto, J. Relinque, M. Mata, N. Fernández-Delgado, M. Herrera, . D.L.Sales, S. Molina

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 171

Abstract
The ADICORK project is associated with an agreement between the Ministry of Agriculture, Livestock, Fisheries and Sustainable Development of the Junta de Andalucía and the INNANOMAT research group of the University of Cádiz. It is oriented to the development of industrial applications with polymer-based composite materials based on cork, which allow the manufacture of innovative value-added products, using the technology of Large Format Additive Manufacturing. This technology makes it possible to manufacture high-volume industrial products, compared to the usual additive manufacturing technologies. Some of the polymer bases studied to develop the composite materials presented in this communication, within the framework of the indicated project, are ABS, PET-G, PLA and ASA. The incorporation of cork in the form of a microparticulate powder, properly processed, has made it possible to achieve improvements in certain properties of the composite materials and, in some cases, after carrying out a screening, in the particle size. Among the properties that have been improved, the mechanical and thermal ones stand out. With the methodology developed, it has been possible to obtain recyclable and more sustainable composite materials than the starting polymeric material. This type of technology has made it possible to obtain attractive and differentiated products of complex geometries, based on and inspired by the territorial and natural origin of cork and its collection, which by other types of manufacturing processes could be impossible or very expensive to create. The sectors in which these developments make sense are varied and in this communication we will focus on the presentation of prototypes developed with the composite materials developed for the furniture, lighting and habitat sectors.
Abstract
The ADICORK project is associated with an agreement between the Ministry of Agriculture, Livestock, Fisheries and Sustainable Development of the Junta de Andalucía [...]
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Determination of the flexural and shear moduli in curved section specimens by means of bending tests
I. Adarraga, F. Mujika, F. De Caso

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 177

Abstract
In recent years, wooden and concrete poles are replacing by others made of fiberglass-reinforced polyester. The advantages of this material compared to traditional ones are its low weight, ease of transport and resistance to corrosion, fire and weather. Due to the great variability in the mechanical properties provided by manufacturers, it may be useful to define a bending test procedure to characterize the material using specimens obtained from poles. Since these specimens have a curved section, it is necessary to analyze the influence of shear when the width and length of the specimen vary. In this study, the effect of shear is analyzed to obtain the flexural and shear moduli by means of bending tests with different lengths of the specimen.
Abstract
In recent years, wooden and concrete poles are replacing by others made of fiberglass-reinforced polyester. The advantages of this material compared to traditional ones are [...]
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Study of an insulating hemp-based bio-material: mechanical, thermal and acoustic properties
B. Martinez, L. Gil, E. Bernat

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 158

Abstract
Currently there is a need to develop more sustainable and renewable materials compromised with the environment. From these needs, hemp stalk has great potential because it is mostly a waste material. Moreover, hemp shives are a lightweight material with a high insulating property. This study aims to increase the knowledge in a material made solely from stalk and ECF (elementary chlorine free) bleached eucalyptus kraft pulp and a second 100% recycled material where the kraft pulp is replaced by recycled cardboard fiber, also a vegetable coating is added to protect against moisture. The hemp/fiber ratio influence is studied. Samples are evaluated in terms of mechanical behaviour (compression and shear), thermal and acoustic insulation. To study the thermal insulation, a testing camera is used where the heat transfer through the material is measured in order to study the thermal resistance. A Kundt tube is used in the acoustic insulation study to calculate the absorption of sound waves in a range from 0 to 6500 Hz. The results show that by increasing the percentage of hemp, the mechanical properties increase (compression and shear). Also, the eucalyptus pulp acts as a binder between the shives; nevertheless, if there is not enough, the material is not stable. Therefore, a maximum of 70 wt.% of hemp is recommended. In the case of thermal insulation, better thermal resistance is obtained in the case of 60 wt.% of hemp, while in acoustic insulation a higher percentage of hemp have a high performance, reaching attenuation values greater than 0.8 for frequencies greater than 1000Hz. The carboard sample improves the shear and acoustic insulation performance. The coating improves the thermal resistance but worsens the acoustic insulation.
Abstract
Currently there is a need to develop more sustainable and renewable materials compromised with the environment. From these needs, hemp stalk has great potential because it [...]
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Optimization of thermoplastic matrix composite materials of renewable origin with pine fiber reinforcement
M. Morcillo, J. Gomez-Caturla, L. Sánchez-Nacher, D. Garcia-Garcia, D. Garcia-Sanoguera

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 168

Abstract
In recent years, there has been a significant increase in social awareness of environmental problems related to high waste generation, oil scarcity and the growing need to reduce the carbon footprint. In this context, polymers from renewable sources can successfully reduce the use of fossil resources. This research work presents the study of polymer matrix composites from high density polyethylene of renewable origin (bioHPDE) and fibers extracted from the strobili of the common pine (Pinus halepensis) typical of the Mediterranean area, characterized by its high percentage of cellulose, and for being very abundant in the natural and economic environment. The research has focused on the influence of a compatibilizing agent based on polyethylene grafted with maleic anhydride on the final performance of the composite material. The resulting composites have been processed by extrusion and subsequent injection molding and a characterization focused on mechanical and thermal properties has been carried out. The results have demonstrated the optimization of the performance of the composite by using the compatibilizer, offering a significant improvement of the fiber-matrix interaction and thus validating its use in this type of composites. The result is a wood plastic composite (WPC) with a wide range of properties depending on the filler content used, providing a highly versatile material with applications in various industrial sectors.
Abstract
In recent years, there has been a significant increase in social awareness of environmental problems related to high waste generation, oil scarcity and the growing need to [...]
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A new tool to simulate ground shaking and earthquake losses
F. Lopez Hidalgo, M. Navarro, S. Molina

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (3), 35

Abstract
The main purpose of this suite is Planning and Management of Seismic Emergencies before and after future damaging earthquake. This tool is written in ArcGIS software executing a fast and efficient determination of the estimated shakemaps and damage scenarios. The tool allows to select the earthquake source parameters through a defined database; moreover ground motion prediction equations can be chosen and they can be combined according to the study area features. The local site effects are characterized from Vs30 values, which have been achieved by topographic slope as a proxy (even with local correlations) obtained from digital elevation model. The elements exposed to risk are incorporated from the cadastral database after inputs has been refined through an automated analysis. Vulnerability and estimated losses can be determined either empirically (EMS-98 scale and Vulnerability Index, Iv) or analytically (Capacity spectrum). Additionally, a vulnerability modifier is implemented to account soil-structure resonance. Epistemic uncertainties are quantified in the input parameters using a logic tree. This tool has been validated through a representative seismic scenario: the 1910 Adra earthquake (southern Spain) with moment magnitude (Mw) 6.3 and macroseismic intensity VIII (EMS-98 scale) proving the reliability of this program.
Abstract
The main purpose of this suite is Planning and Management of Seismic Emergencies before and after future damaging earthquake. This tool is written in ArcGIS software executing [...]
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Improvement of the mechanical properties of PLA/coffee residue biocomposites from the liquor industry
E. Delicado, L. Carrilllo, J. Martínez, N. Muñoz, L. Nácher

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 162

Abstract
This work deals with the revaluation of coffee bean residues from the coffee liquor industry with the aim of developing eco-efficient composite materials with a polymeric matrix of polylactic acid (PLA). The coffee residue is incorporated in a proportion of 20% to the PLA by extrusion. After a grinding process, they are processed by injection to obtain standardized test pieces for their characterization. In order to improve the mechanical properties, as well as the toughness and compatibility between the biopolyester and the lignocellulosic particles of the coffee residue, two oligomers of lactic acid (OLA2 and OLA2mal functionalized with maleic anhydride) are added, together with the particles of the coffee residue during the extrusion process. These "Green composites" show that the incorporation of coffee residue particles from the manufacture of coffee liquor considerably increases the ductility of the samples analyzed by practically 280% due to their high content of oils present in the lignocellulosic residue. In addition, the incorporation of the OLA2 and OLA2mal oligomers contribute to improve the tensile strength of the composite materials studied, by 35% and 60%, respectively. These interesting results show the wide possibilities of this eco-efficient and sustainable material made of PLA and coffee residue. These are biodegradable materials, respectful of the environment and that allow the revaluation of coffee bean residues from the agri-food industry such as coffee liquor.
Abstract
This work deals with the revaluation of coffee bean residues from the coffee liquor industry with the aim of developing eco-efficient composite materials with a polymeric [...]
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Minimally intrusive nonlinear Model Order Reduction
R. Rossi, R. Bravo, J. Hernández, C. Roig

Mechanistic Machine Learning and Digital Twins for Computational Science, Engineering & Technology (MMLDT-CSET 2021) Conference (2021). San Diego, USA (virtual conference). 26-29 September 2021
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From Linear Mappings to Deep Learning for Model Reduction of Numerical Simulations of Industrial Interest:
R. Bravo, R. Rossi, J. Hernández, C. Roig

Computational Science and AI in Industry (CSAI 2021) Conference. (2021). Trondheim, Norway (virtual conference). 7-9 June 2021
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A Local POD-HROM framework for fast and accurate numerical simulations
R. Bravo, R. Rossi, J. Hernández

XI International Conference on Coupled Problems in Science and Engineering (COUPLED 2021), (2021). Chia Laguna, Italy (virtual conference). 13-16 June,2021
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Clustering Techniques for Enhanced Reduced Order Model Simulations in Structural Mechanics
R. Bravo, R. Rossi, J. Hernández

XVI International Conference on Computational Plasticity (COMPLAS 2021) (2021). Barcelona, Spain. 07-09 September 2021
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A comparison between “rod counting” and “box counting” methods in linear fractal dimensions measurements
C. Acosta, F. Peñuñuri, O. Carvente, G. Rivadeneyra, I. Martín

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (3), 27

Abstract
In this work, the “rod counting” method is reviewed in comparison with the “box counting” method applied to linear measurements on irregular figures. Both methods are applied in measurements of fractal dimension of some knowing fractals. Results shows that the “rod counting” method is more accurate in linear measurements. Later the method is applied in a Mandelbrot fractal figure to measure its perimeter fractal dimension.
Abstract
In this work, the “rod counting” method is reviewed in comparison with the “box counting” method applied to linear measurements on irregular figures. [...]
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Cost evaluations due to seismic damage to concrete buildings
C. Castillo-Castillo, J. Valdés-González, F. Bañuelos-García

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (3), 34

Abstract
The study of earthquake losses in structures has been traditionally addressed for a single seismic intensity, but this could be unrealistic since throughout the life of a building it can be subjected to several earthquakes with different intensities. This paper analyzes the relations between the seismic intensities with the corresponding damage costs. Three nonlinear analytical models of reinforced concrete were analyzed. Each model differs in dynamic characteristics and was designed by scaling the design spectrum for three amplification factors. A firm soil earthquake was analyzed, which was scaled to 22 intensities and with this results, dynamic capacity curves of the studied models were constructed. From the analyses it was obtained interstory drift and maximum accelerations, with which the following seismic damage costs were estimated: structural and non-structural damage, contents replacement, income and profits, injuries and deaths. The results show different types of relations between intensity and each type of loss. They also justify the importance of introducing amplification factors at the design stage to minimize the cost of a particular type of damage.
Abstract
The study of earthquake losses in structures has been traditionally addressed for a single seismic intensity, but this could be unrealistic since throughout the life of a [...]
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ADDITIVE MANUFACTURING OF SURLYN SPECIMENS WITH A NANO-REINFORCEMENT OF CARBON NANOTUBES.
R. Calderón-Villajos, L. Peponi, A. Bosque, M. Sanchez, A. Ureña

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 165

Abstract
This paper explores the self-healing abilty of the ionomer called Surlyn® 8940 (manufactured by DuPont), a partially neutralised poly(ethylene-co-methacrylic acid) (EMAA) ionomer copolymer, and the improvement of the mechanical properties after adding a nano-reinforcement of multiwall carbon nanotubes (MWCNTs) to the structure of the polymer. It begins with the manufacture the nanocomposite material, based on Surlyn® 8940 as raw material, and the mixture process with MWCNTs. Afterwards, an extrusion process was optimized to obtain a homogeneous reinforced filament, which was subsequently used to manufacture the final test samples by means of a 3D printing machine. Specimens with different concentrations of MWCNTs (0.0, 0.1, 0.5, 1.0 % wt.) were manufactured, in order to test the mechanical properties and self-healing ability of unreinforced and nano-reinforced samples. The results show that nano-reinforced samples had an increase of their self-healing ability (increase for 0.5 y el 1% wt. of MWCNTs) and mechanical properties (σTS 18.35, 25.91, 26.92, 28.02 MPa to 0, 0.1, 0.5 y 1 % wt. de MWCNTs respectively). Specimens of 5% of MWCNTs have also been manufactured with different mixing times in the extrusion chamber to study the conductivity of the polymer. Electrical conductivity values for 8 and 10 minutes of mixing times reached S/m units order have been obtained.
Abstract
This paper explores the self-healing abilty of the ionomer called Surlyn® 8940 (manufactured by DuPont), a partially neutralised poly(ethylene-co-methacrylic acid) (EMAA) [...]
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Ligthweigth (Talgo) high speed rodal frame. Composites in high responsability rail components
F. Piñeiro*, J. Valverde, V. Meroño, F. García Piñeiro

Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 169

Abstract
Nowadays, the railway sector demands new lighter designs in the structural components of rolling stock that compensate for its increase due to the incorporation of new technologies, to improve passenger comfort and experience, as well as to face new environmental challenges (reduction emissions, energy consumption, increased capacity, etc.). With this objective, Talgo introduces a frame in high-performance composite material (CFRP) in its rolling elements (wheels) for high-speed trains, traditionally made of metal (steel), which allows weight saving of over 45%. However, the introduction of new materials is subject to overcoming certain challenges: compliance with fire requirements, adaptation of existing regulations, ballast impact behavior, direct cost increase, etc. This project consists of different phases: a) design, in accordance with the requirements demanded by current standards, b) manufacture of prototypes, c) process of characterization and verification of properties of non-standard materials, d) testing of component validation equivalent to what is required of a conventional frame (static resistance and fatigue test up to 10 million cycles in accordance with existing regulations), and, finally, e) track tests.
Abstract
Nowadays, the railway sector demands new lighter designs in the structural components of rolling stock that compensate for its increase due to the incorporation of new technologies, [...]
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Pre-processing of dam data coupled with behavior analysis through machine learning
A. Conde, F. Salazar

F. Salazar's Conference proceedings (2021). 3

Abstract
A predictive study framework for dams is proposed using Machine Learning (ML) algorithms programmed in R. This study is capable of estimating the relationship between dam response and internal properties or external forces. For a better efficiency of the analysis with predictive models, a previous step has been developed consisting of database cleaning and expansion processes. An interactive interface for each of the two phases has been developed using the Shiny package with the aim of making these processes accessible also to professionals who do not possess knowledge of laborious programming scripts.
Abstract
A predictive study framework for dams is proposed using Machine Learning (ML) algorithms programmed in R. This study is capable of estimating the relationship between dam [...]
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Adaptive analysis of multistage down-hole throttling and optimization design of process parameters in Sulige gas field
W. Yijun, Y. Wu, X. Zheng, Y. Li, X. Lu, C. Liu, X. Li

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (2), 23

Abstract
The Sulige Gas Field mainly adopts down-hole throttling production technology. For gas Wells with high bottom-hole pressure and productivity and low pressure drop in the testing process, it is difficult to reduce the wellhead pressure to the ideal value by installing a single-stage down-hole throttle, which cannot meet the needs of existing middle and low-pressure gas gathering technology in Sulige Gas field. Therefore, it is proposed to adopt down-hole multi-stage throttling technology, which not only makes full use of the residual pressure and heat of the well bore, but also ensures the safety of the surface gathering and transportation process system and the normal production of gas wells. In this paper, the optimization design method and theory for the technological parameters of the down-hole multi-stage throttling system of gas wells are established. According to the constraint of low-pressure gas collection mode in a temperature and pressure of wellhead safety to determine the number of down-hole choke and the process parameters. Discuss the applied conditions of down-hole multi-stage throttling, and provide theoretical support for the selection of the down-hole choke technology of the Sulige gas well and the safe and stable production of the gas well. It has important guiding significance for gas field quality and efficiency improvement and fine management.
Abstract
The Sulige Gas Field mainly adopts down-hole throttling production technology. For gas Wells with high bottom-hole pressure and productivity and low pressure drop in the testing [...]
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Sectoral Analysis of the Fundamental Criteria for the Evaluation of the Viability of Wave Energy Generation Facilities in Ports—Application of the Delphi Methodology
R. Cascajo

Sectoral Analysis of the Fundamental Criteria for the Evaluation of the Viability of Wave Energy Generation Facilities in Ports—Application of the Delphi Methodology (2022).

Abstract
Nearly 40% of the world’s population lives within 100 kilometres of the coast with the risk that this implies in terms of exposure to the effects of climate change. Ocean energy, according to the IPCC (Intergovernmental Panel on Climate Change) in 2019, has been identified as one of the measures for mitigating these effects. In addition, ocean energy can play an essential role in achiev‐ ing some of the SDGs (Sustainable Development Goals) set at the Paris Climate Summit in 2015, namely SDG 7 (clean and affordable energy) and SDG 13 (climate action) and could have a substan‐ tial impact on others such as SDG 1 (poverty eradication), SDG 2 (end hunger), SDG 5 (gender equality), SDG 6 (universal energy access), SDG 8 (promote sustainable economic growth), SDG 9 (build resilient infrastructure), SDG 14 (sustainable conservation of oceans and seas) and SDG 17 (promote sustainable development cooperation). There are several projects under development around the world aimed at extracting energy from waves. However, to date, no technology has been found that, in general terms, is superior to others. There are several conditioning factors that prevent this type of energy from reaching the level of maturity of other marine renewable energies. These are mainly economic, technological, environmental, and regulatory, to mention the most important. This article aims to analyse the approaches that other researchers have adopted to evaluate wave energy projects and, through a prospective method of expert consultation such as the Delphi meth‐ odology, will present the most generally accepted criteria for successful wave energy projects. Sub‐ sequently, the validity of these results will be analysed for the case of the use of the energy produced for self‐consumption in ports.
Abstract
Nearly 40% of the world’s population lives within 100 kilometres of the coast with the risk that this implies in terms of exposure to the effects of climate change. [...]
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An introduction to Digital Economy, Part 2
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 12
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Automatización de textos periodísticos en la televisión brasileña: Estudio de caso del sistema AIDA (Globo-Brasil)
J. Canavilhas

Doxa Comunicación (2019). Essenfelder, R.; Canavilhas, J.; Maia, H. C. y Pinto, R. J. (2019). Automatización de textos periodísticos en la televisión brasileña: Estudio de caso del sistema AIDA (Globo-Brasil). Doxa Comunicación, 29, pp. 255-274.

Abstract
Los avances tecnológicos han creado un ecosistema mediático en el que el periodismo tradicional ve su existencia fuertemente amenazada por el surgimiento de nuevos actores. Las redes sociales han creado un entorno competitivo que, ya sea por su dispersión o por su capilaridad, relegaron los mainstream media a un rol secundario en el ecosistema mediático. Irónicamente, las tecnologías que amenazan el periodismo tradicional son asimismo aquellas que pueden salvarlo, siempre que se utilicen correctamente. El periodismo, debilitado por los efectos de la crisis económica y con redacciones cada vez más reducidas, tiene en la inteligencia artificial una oportunidad de recuperar cierta centralidad en el ecosistema de los medios. En este trabajo se estudia AIDA, un proyecto de la televisión brasileña Globo. Este proyecto buscó en la automatización una respuesta para evitar errores y ambigüedades en las noticias. El estudio del caso AIDA, complementado con entrevistas, presenta los desafíos para lograr la automatización en la lectura y presentación de datos de sondeos electorales
Abstract
Los avances tecnológicos han creado un ecosistema mediático en el que el periodismo tradicional ve su existencia fuertemente amenazada por el surgimiento de [...]
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CONTEÚDOS VIRAIS NO FACEBOOK: estudo de caso na pré-campanha das eleições presidenciais brasileiras de 2018
J. Canavilhas

Brazilian Journalism Research (2019). Canavilhas, J.; Bittencourt, M.; Andrade, M.A.A.; (2019). Conteúdos virais no Facebook: estudo de caso na pré-campanha das eleições presidenciais brasileiras de 2018. Brazilian Journalism Research, Vol. 15 - N. 3, pp. 598-625

Abstract
Neste trabalho coletamos e analisamos conteúdos manipulados com o objetivo de se tornarem virais no Facebook e, dessa forma, influenciarem a opinião pública durante o período pré-eleitoral no Brasil. Ao longo de 2017, foram recolhidos os posts de 10 páginas do Facebook de organizações brasileiras conotadas com a produção de notícias falsas ou manipuladas, tendo sido selecionadas 50 publicações que correspondem às mais partilhadas em cada uma das páginas. Os resultados permitem verificar que os posts com mais compartilhamento têm algumas características comuns em três quesitos: formato de conteúdo, estratégia de linguagem e fonte de informação. Foram também identificados em textos, vídeos e fotografias, formatos habitualmente usados com esta finalidade de propagação, o recurso às frases de impacto, a utilização descontextualizada de figuras públicas comentando fatos políticos e a abordagem sensacionalista.
Abstract
Neste trabalho coletamos e analisamos conteúdos manipulados com o objetivo de se tornarem virais no Facebook e, dessa forma, influenciarem a opinião pública [...]
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Desinformación en las elecciones presidenciales 2018 en Brasil: un análisis de los grupos familiares en WhatsApp
J. Canavilhas

El profesional de la información (2019). Canavilhas, J.; Colussi, J.; Moura, Zita-Bacelar (2019). “Desinformación en las elecciones presidenciales 2018 en Brasil: un análisis de los grupos familiares en WhatsApp”. El profesional de la información, v. 28, n. 5, e280503

Abstract
This investigation aims to verify what kind of contents was most shared in WhatsApp family groups during the 2018 Brazilian presidential campaign and which percentage contained false information. The relevance of this study is justified
Abstract
This investigation aims to verify what kind of contents was most shared in WhatsApp family groups during the 2018 Brazilian presidential campaign and which percentage contained [...]
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Mobile phones in young people everyday life: case study with Portuguese and Brazilian students
J. Canavilhas, V. Piñeiro-Naval

Revista Famecos (2020). Canavilhas, João, Pellanda, Eduardo, Piñeiro-Naval, Valeriano & Nunes, Ana Cecília Bisso (2020). Mobile phones in young people everyday life: case study with Portuguese and Brazilian students, Revista Famecos, Vol. 27, pp. 1-23.

Abstract
Mobile phones have become commonplace everyday objects in almost all societies regardless of their development stage. The presence of these devices has become a constant on any latitude, as shown by the penetration rate figures for 2018: 65.9%. These numbers, already surprising on their own, reach even higher values among young people. Thus, this paper studies the use of mobile phones, in particular smartphones, by young Portuguese and Brazilian university students. For this purpose, an app that registered all the uses made by the youngsters in their mobile devices, was employed. This methodology allows data collection in a daily context without the participants feeling controlled. A total of 317,938 interactions, registered in the participants devices, shows that the main use given to these devices is as a platform for access to social networks, followed by the sending of messages and the variable “second uses” of the device (watch, calendar, camera, calendar and calculator). Although this is a study in progress, at this stage it is safe to state that the data confirm previous studies (FORTUNATI; TAIPALE, 2014) in which smartphones assert themselves as a verbal written communication platform in opposition to their genesis based on orality.
Abstract
Mobile phones have become commonplace everyday objects in almost all societies regardless of their development stage. The presence of these devices has become a constant on [...]
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A tétrade de McLuhan na pesquisa em comunicação: revisão sistemática de aplicações no Brasil e em Portugal
J. Canavilhas

Matrizes (2020). Dall’Agnese, C. W., Canavilhas, J., & Barichello, E. (2020). A tétrade de McLuhan na pesquisa em comunicação: revisão sistemática de aplicações no Brasil e em Portugal. MATRIZes, 14(1), 221-239.

Abstract
This article presents the results of an exploratory work to map the application of McLuhan’s tetrad, in communication studies in Brazil and Portugal. The methodology used was the systematic review of the literature in the last decade (2009-2019). For such mapping, academic works (theses, dissertations, articles and chapters) were located from indexing systems, public repositories and specialized search engines. The goal was to discover how the tetrad has been applied and to which purposes. Finally, the potentialities of this tool, called McLuhan’s “exploratory probe”, are pointed out.
Abstract
This article presents the results of an exploratory work to map the application of McLuhan’s tetrad, in communication studies in Brazil and Portugal. The methodology [...]
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A produção ciberjornalística colaborativa e internacional como experiência de ensino em universidades iberoamericanas
J. Canavilhas

REBEL - Revista Brasileira de Ensino de Jornalismo (2021). Larrondo Ureta, A., Fernandes Teixeira, J., Luiz Martins, G., Peña Fernández, S., Canavilhas, J. & Zamith, F. (2021). A produção ciberjornalística colaborativa e internacional como experiência de ensino em universidades iberoamericanas. Revista Brasileira De Ensino De Jornalismo, 11(28), 3-21.

Abstract
This paper analyses the possibilities for innovation in the teaching of web journalism based on two international cooperative projects involving a convergence of programs and methodologies. This article examines how, in their most advanced stage, Brazilian, Portuguese and Basque students organized themselves in working groups to cooperate and jointly develop, in English, in-depth journalistic and multimedia coverage, some of them, even with a transmedia perspective. The results allow us to evaluate the advantages and difficulties of cooperative and virtual teachinglearning processes that seek to promote the internationalisation of media and communication students in Ibero-America.
Abstract
This paper analyses the possibilities for innovation in the teaching of web journalism based on two international cooperative projects involving a convergence of programs [...]
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Funcionalidades e affordances como bases para classi cação de apps jornalísticas destinadas a smartphones
J. Canavilhas

(2021). Canavilhas, J. e Empinotti, M. (2021). Funcionalidades e affordances como bases para classificação de apps jornalísticas destinadas a smartphones. Em Carlos Ortiz (Org.), Convergências da comunicação: Olhares à cultura digital, pp. 237-261. Aveiro: Ria Editorial

Abstract
A centralidade adquirida pelos telefones celulares no cotidiano global transformou estes dispositivos em objetos de interesse para diversas áreas, entre as quais o jornalismo. A evolução tecnológica destes aparelhos, com o constante surgimento de novas valências, alterou as rotinas de produção jornalística, mas também as formas de relacionamento entre o jornalismo e o seu público. Por isso, atualmente é impossível falar de jornalismo sem referir o papel dos celulares em alguma das suas fases de produção, circulação e consumo.
Abstract
A centralidade adquirida pelos telefones celulares no cotidiano global transformou estes dispositivos em objetos de interesse para diversas áreas, entre as quais o [...]
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LA RADIO EN EL ECOSISTEMA MEDIÁTICO DEL SIGLO XXI: ESTUDIO DE CASO EN PORTUGAL
J. Canavilhas

Index Comunicación (2020). Canavilhas, J. (2020). La radio en el ecosistema mediático del siglo XXI: estudio de caso en Portugal. index.comunicación, 10(3), 263-281.

Abstract
Desde que aparece la televisión, la muerte de la radio se anuncia como cercana. A pesar de todas las amenazas, el medio continúa vivo e, incluso, gana nuevos públicos en un escenario hostil para un medio centenario. La realidad muestra que la radio transformó sus debilidades en fuerzas y se adecuó al nuevo ecosistema de una forma más rápida que cualquier otro medio. Las razones de esta veloz y exitosa adaptación están relacionadas con la simplicidad del soporte y con el lenguaje unisensorial usado, pero también con una capacidad inaudita para el reajuste a nuevas situaciones. En este trabajo se identifican los rasgos que hacen de la radio una superviviente y se analiza la forma como se adaptó al nuevo ecosistema, ilustrando cada caso con ejemplos de programas radiofónicos portugueses
Abstract
Desde que aparece la televisión, la muerte de la radio se anuncia como cercana. A pesar de todas las amenazas, el medio continúa vivo e, incluso, gana nuevos [...]
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Fake News Explosion in Portugal and Brazil the Pandemic and Journalists’ Testimonies on Disinformation
J. Canavilhas, T. Jorge

Journalism and Media (2022). Canavilhas, João, and Thaïs de Mendonça Jorge. 2022. Fake News Explosion in Portugal and Brazil the Pandemic and Journalists’ Testimonies on Disinformation. Journalism and Media 3: 52–65

Abstract
Orchestrated manipulations spread lies and can create an environment of uncertainty in society, leading to concerns from politicians, scholars, educators, and journalists, among others. In this paper we explore what the emergence of fake news (understood as false news) represents for journalists, trying to answer the following question: Does false news pose a threat to the credibility of good journalism, causing a disruption of the traditional work? To answer it, we interviewed a sample of journalists from various media organizations in Portugal and Brazil. Among the main findings, journalists are aware that fake news is a problem to be faced, as the blame for the dissemination of false news erroneously lies with the profession. They are conscious that something must be done and agree that the best way to fight against fake news is to invest in media literacy. Most of the journalists of our sample think they must be also more cautious to check sources for veracity and for political motivations. The results show that there is a resolve to reinforce the role of journalism in society.
Abstract
Orchestrated manipulations spread lies and can create an environment of uncertainty in society, leading to concerns from politicians, scholars, educators, and journalists, [...]
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Epistemology of mobile journalism. A review
J. Canavilhas

Profesional de La Información (2021).

Abstract
The fast and global way which has characterized the presence of mobile phones in society has sparked the interest of several sectors of activity, including journalism. From the early stages of production to distribution, and then through the characteristics of content and consumption patterns, numerous changes have been introduced by these mobile devices in an activity that has been undergoing one of the most uncertain moments in its long history. This uncertainty has stemmed from the decrease in income which was caused by the emergence of new competitors, such as the online press and social networks. This bibliographic review aims at identifying the changes caused by smartphones in the production distribution and consumption of news, analyzing its effect on the epistemology of journalism. We attempt to ascertain if the increasing influence of mobile technologies in the journalistic activity has changed its nature, improving the production of knowledge. Upon closer reading of the bibliography, it can be concluded that the versatility of mobile devices has facilitated a set of new possibilities not only for journalists, namely more autonomy and a reduction in the time spent between the event and the publication, but also for consumers, who can do a mobile and personalized consumption on their screens. Due to its ability to continuously adapt to the rhythm of contemporary society, mobile journalism has become more universal and has been confirmed as a form of knowledge insofar as it responds more effectively to consumers’ expectations, in particular young people’s, who are moving away from journalism and thus prevent the generational renewal of readers, something which is fundamental for the media business model.
Abstract
The fast and global way which has characterized the presence of mobile phones in society has sparked the interest of several sectors of activity, including journalism. From [...]
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Artificial intelligence in journalism: Automatic translation and recommendation system in the project “A European Perspective
J. Canavilhas

Revista Latina de Comunicación (2022). Canavilhas, J. (2022). Inteligencia artificial aplicada al periodismo: traducción automática y recomendación de contenidos en el proyecto “A European Perspective” (UER). Revista Latina de Comunicación Social, 80, 1-13

Abstract
On July 1st, 2021, several European public broadcasters officially launched the project “A European Perspective”. It is an online news exchange service developed within the EBU European Broadcasting Union, which brought together ten public broadcast companies from nine countries. This project uses Artificial Intelligence for the translation and recommendation of content produced by the participants and that can be freely used on their websites. The main objectives of the project are the fight against misinformation and the affirmation of the European values in a social context in which social networks have been gaining more and more influence among public opinion. Methodology: This paper, a case study, explains how the project works and analyses the type of content shared in the first two months of operation on the website of RTP-Rádio Televisão Portuguesa.
Abstract
On July 1st, 2021, several European public broadcasters officially launched the project “A European Perspective”. It is an online news exchange service developed [...]
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Real-time monitoring of thermosetting composite manufacturing, repair and in-service behavior processes
N. González-Castro, T. Grandal, A. Pinto, J. Montenegro, R. Ruiz-Lombera, E. Rodríquez-Senín

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 35

Abstract
NERO project arises from the need to control and monitor the manufacturing, repair, and in-service life structures processes in composite materials, an area in full expansion that has been experiencing rapid growth in recent years. Composite materials are currently considered one of the strategic materials in the manufacturing processes of the future, due to the high functional impact and weight reduction they provide in a wide range of sectors. In this way, the monitoring systems that have been developed in the project will contribute to overcoming some of the main barriers to the introduction of these materials in the industrial environment, such as the high consumption of resources, low automation ratios, and high percentage of rejections, which will significantly lower production costs. Based on this background, NERO has developed an advanced monitoring system based on non-invasive embedded sensors, which allow to carry out more efficient and environmentally sustainable manufacturing and repair processes of composite material structures, and which, in turn, provide information on the structural behavior during their service life. The ad hoc monitoring system developed in NERO employs fiber optic sensors (FOS), based on FBG and Rayleigh scattering, and ion mobility (DC) sensors. The monitoring and control system developed was validated for the manufacturing and repair processes of composite in three different use cases and industrial sectors.
Abstract
NERO project arises from the need to control and monitor the manufacturing, repair, and in-service life structures processes in composite materials, an area in full expansion [...]
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Development of lightweight structural components based on low-cost processes for application in eco-efficient means of transport
P. Rodríquez, N. Pallares, A. Castro, A. Calvete, P. Cores, F. Jacobo, J. Sobral, Y. García, L. Mera

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 33

Abstract
The main objective of the LIGHTRANS project is the design and development of lightweight multi-material structures, through the development of optimized and low-cost manufacturing and joining processes. Which should allow its application in eco-efficient road transport vehicles. More specifically, within the framework of this project, the redesign of a bus superstructure as well as an electric three-wheeled vehicle will be developed. Within the LIGHTRANS project, due to the needs of the market, it is proposed to strategically combine materials of different nature in such a way that the resulting structures present a weight reduction but without affecting the properties of the final components. The multimaterial structurals developed within the framework of the project, for both study cases, are based on thermosetting and thermoplastic compounds, cellular polymers and steel. Throughout this article, the mechanical characterization of the materials used for the manufacture of the components of both study cases, the manufacture of all the proposed components, as well as the evaluation of each of them in the final structures through tests will be presented. field.
Abstract
The main objective of the LIGHTRANS project is the design and development of lightweight multi-material structures, through the development of optimized and low-cost manufacturing [...]
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Simulation and experimental testing of a bolted carbon-aluminium hybrid wingbox assembly under thermal loads
J. Garcia, A. Sasikumar, J. Llobet, J. Costa

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 31

Abstract
On the last decades, the aeronatical industry has increased the use of Carbon Fibre Reinforced Polymer matrix composites (CFRP), and at the same time, has kept the use of conventional metals. This has led to the presence of hybrid assemblies in the wingbox, fuselage, etc. Due to their high stiffness and strength, as well as the ease to dissasemble and repair, these assemblies are usually bolted. During its usage, an aircraft is subjected to large thermal jumps (the temperature difference between a landed aircraft and a flying one can reach 140 ºC). Because of the presence of hybrid bolted joints, the materials of the joint undergo different thermal expansion/contraction, which cause significant thermal stresses altering the mechanical behaviour of the joint. Framed in the aeronautical Clean Sky 2 project ‘INNOHYBOX’, this work studies the behaviour of hybrid bolted joints subjected to thermal loads, both numerically and experimentally, following a pyramidal approach. At the coupon level, a hybrid carbon-aluminium single-lap shear specimen with one bolt was used to comprehend and characterise its behaviour under thermal loads. At the substructural level, a subcomponent representative of a wingbox was tested under thermal conditions. Finally, a full wingbox was tested. Furthermore, a computationally efficient finite element model was developed to simulate the complex behaviour of these type of joints without comprimsing the computational cost. The numerical predictions correlate favourably against the experimental data.
Abstract
On the last decades, the aeronatical industry has increased the use of Carbon Fibre Reinforced Polymer matrix composites (CFRP), and at the same time, has kept the use of [...]
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Innovative tooling and manufacturing processes for pressure bulkheads of REG IADP Fuselage Demonstrator of Leonardo Aircrafts
M. Mendías, P. Tabarés-Fernández, G. Ingenito, G. Caputo, G. Ingenito

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 29

Abstract
The current work has been performed in the context of FUSINBUL, an European project framed within CleanSky2 research programme funded by the EU’s Horizon 2020 (Grant Agreement nº 831946). The scope of this project is to accomplish the full barrel demonstrator tests, needed to certify the new conception of fuselage created and manufactured in the Green Regional Aircraft context. Two advanced manufacturing processes for composites materials (prepreg cobonding process in autoclave and LRI infusion process out of autoclave) are developed and validated to achieve full scale innovative pressure bulkheads for Regional Aircraft Fuselage barrel on-ground demonstrators. The design of the tooling has taken into account the main needs of both manufacturing processes to carry out the bulkheads and the industrial requests. In addition to this, innovative tool technologies have been developed and applied, such as cast aluminium by lost foam casting, precise but robust indexing system split and seal system of tool too large to be fabricated one shot, then precisely assembled with no gap or step. For both manufacturing processes, the most advanced techniques of lay-up are used to reduce labor costs and increase the level of industrialization in serial production to achieve bulkheads with a diameter of 3.5m and the required standards in aeronautical industry.
Abstract
The current work has been performed in the context of FUSINBUL, an European project framed within CleanSky2 research programme funded by the EU’s Horizon 2020 (Grant [...]
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Recovery of glass fibre present in wind turbine blades through mechanical recycling
A. Pesquera, F. Verdugo

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 25

Abstract
Wind energy remains the second most important source of power generation in Europe in 2019. This energy capacity is generated by wind turbines which have a lifespan of 20-25 years. The amount of blades produced by dismantling of wind farms will increase over time, which is going to be a major environmental problem because currently the out of use blades are going to landfill. For example, in 2025 it is expected that 500,000 tons of blade waste will be generated in Europe, which represents 324,738 tons of glass fibre. The objective of this study has been to design, build and optimize an innovative mechanical recycling prototype with a capacity of 100 kg/h to enhance the glass fibre that make up the wind turbine blades, favoring the recovery of this waste in order to reduce its presence in landfills and giving them a second life cycle for an application with high added value. To demonstrate the usefulness of these glass fibers, they have been incorporated into asphalt agglomerate, building a 1500 meter road demonstration section, which has been monitored for a year to study the improvement of its mechanical properties, the most important being an increase in the useful life of the pavement, an increase in its resistance, and an improvement in its acoustic qualities. Through all these objectives, the life cycle of this waste will be closed, providing great added value to both the waste and the resulting new product.
Abstract
Wind energy remains the second most important source of power generation in Europe in 2019. This energy capacity is generated by wind turbines which have a lifespan of 20-25 [...]
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MAYA – MAnufacturing of the lining panel using hYbrid technologies; Additive manufacturing, injection moulding and thermoforming
N. Blanco, J. Lobet, A. Tena, D. Piedrafita, C. Sarrado

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 23

Abstract
MAYA aims at developing innovative manufacturing routes integrating standard thermoplastic processes (such as injection moulding) and additive manufacturing to produce fuselage composite lining panels. These panels basically consist on sandwich structures with sheets reinforced with fibre-glass hold to the aircraft frame by a set of brackets. The high productivity rate of thermoplastic injection moulding associated to the design freedom of 3D printing will lead to an enhancement of the manufacturing process of the panel-bracket assembly resulting in lighter and less expensive panels with improved overall performance. The work carried out by the research group AMADE focuses on the experimental analysis for interface characterisation, material selection and validation of designs. The first stage of the experimental campaign includes the initial characterisation of the interface bonding of dissimilar materials with different thicknesses obtained by direct 3D printing on the composite skin or by using adhesives under mode I, static and fatigue, and mode II, static, to obtain the best material candidates and design properties. The second part of the work is based on the experimental analysis of the union between the composite skin and small-scale brackets under pull-out and shear-out conditions. Lastly, the final designs of the brackets, both for injection moulding and additive manufacturing, and the corresponding interface bonding with the sandwich panels are validated in large-scale tests under static and fatigue conditions simulating the in-use forces applied to the panels. In this work, the characterisation of the interface bonding of dissimilar materials is presented.
Abstract
MAYA aims at developing innovative manufacturing routes integrating standard thermoplastic processes (such as injection moulding) and additive manufacturing to produce fuselage [...]
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Reinventing industry with advance myco-fibers
E. Franco, F. Vilaplana, M. Zaragoza, E. Santana

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 21

Abstract
The increasing need to protect the planet, promoting sustainable development that does not compromise resources, has promoted the investigation of new materials that come from renewable sources, are respectful with the environment and at the end of their life cycle are biodegradable or recyclable, promoting the circular economy avoiding the generation of waste. The fungi produce the mycelium that appears as an emerging biomaterial that can be used in many industrial fields, as a source of novel compounds through biofabrication. In this work, different prototypes have been developed using mycelium material for the manufacture of composites using transfer and thermocompression molding technology.
Abstract
The increasing need to protect the planet, promoting sustainable development that does not compromise resources, has promoted the investigation of new materials that come [...]
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Development of self-healing rubber biocomposites: a sustainable approach - bioHEAL
S. Utrera-Barrios, J. Araujo-Morera, O. Ricciardi, R. Verdejo, M. López-Manchado, M. Hernandez Santana

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 19

Abstract
The bioHEAL project is part of the i-LINK+ Programme from the Spanish National Research Council (CSIC) that aims to stimulate the collaboration between CSIC research groups and international research groups of the highest relevance by means of its own resources with a common research topic and complementary strengths. All this within the scope of the 17 Sustainable Development Goals of the United Nations (UN-SDG). The purpose of i-LINK+ is the creation and consolidation of consortia of international excellence to compete in future calls for research and innovation (R&D) projects in the international arena, as well as the internationalization of International Thematic Platforms (PTI), a mixed (public-private) R&D instrument that brings together research teams, administrations and companies that join forces to solve specific problems. The objective of bioHEAL is to develop ad-hoc self-healing rubber biocomposites reinforced with natural fillers (bio-based and renewable). bioHEAL will count with the participation of the Institute of Polymer Science and Technology (ICTP-CSIC, Spain), which lead the project, Gdnask University of Technology (GUT, Poland), Chalmers University of Technology (CUT, Sweden), Vrije University of Brussel (VUB, Belgium) and the Unversity of Wisconsin-Madison (UWM, United States of America). With this collaboration we will contribute to UN-SDG12 through the promotion of strategies for sustainable consumption and efficient use of resources, such as reducing waste generation thanks to the implementation of a key property for the future of smart materials: self-healing.
Abstract
The bioHEAL project is part of the i-LINK+ Programme from the Spanish National Research Council (CSIC) that aims to stimulate the collaboration between CSIC research groups [...]
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Development of prepregs from sustainable materials for automotive applications
R. Garcia-Etxabe, S. Neira, P. Ares-Elejoste, K. Gondra, J. Ferrer-Dalmau, C. Mingazzini

Materiales Compuestos (2022). Vol. 06 - AEMAC en PROYECTOS EUROPEOS (2022), (Núm. 1 - Monográfico Proyectos Europeos), 17

Abstract
The tasks and conclusions presented in this article have been developed in the C2CC - "Cradle to Cradle Composites" project implemented in the framework of the EIT-Raw Materials program. This project proposes the replacement of metallic components in automobiles by using composites made from raw materials with lower environmental impact: (i) basalt fibers of mineral origin, (ii) furanic resin systems of natural origin and (iii) bio-based epoxy resin systems recyclable through the use of cleavable hardeners. In this article, the raw material characterisation tasks and the prepreg manufacturing process are discussed, using two manufacturing processes and their corresponding equipment. The tasks of obtaining thermoplastic matrices from the cleavable epoxy systems will also be documented, showing the demonstration prototypes developed in the project, both from the thermoset composites and from the recovered thermoplastic composites resulting from the recycling process.
Abstract
The tasks and conclusions presented in this article have been developed in the C2CC - "Cradle to Cradle Composites" project implemented in the framework of the EIT-Raw [...]
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Thermoforming of thermoset composites manufactured by pultrusion
I. Aranberri, A. Salaberria, G. Hoyos, A. Rekondo, H. Grandea, M. Landab, X. Pavónc, D. Ramosc

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 1

Abstract
In this work the development of a profile manufactured by pultrusion and thereafter curved by thermoforming is presented. The pultrusion profile is based on a new thermostable epoxy resin with dynamic bonds capable of being reprocessed, repaired and recycled thanks to the incorporation of reversible links within its reticulated structure (3R Technology). Being a resin that contains dynamic bonds, the cured composite shows unexpected properties for thermosetting materials. In a first phase, a new resin/hardener formulation processable by pultrusion with a viscosity, adhesion to the fibre and speed of curing similar to a conventional formulation have been developed and in a second phase, taking into account the properties of the new composite material, the parameters of the thermoforming process (pressure, temperature or speed of thermoforming) have been analysed and optimized. Thanks to the combination of pultrusion and thermoforming processes, longitudinal 3R composite profiles acquire a new curved geometry defined by the design of a mould. In this way, the thermoforming of the straight profiles will allow manufacturing curved parts from profiles of thermostable composites with high mechanical performance manufactured by pultrusion in medium-high rates, typical of the automotive sector. Additionally, it will be shown that the profiles manufactured using these composites can be recycled, reducing the amount of waste generated and offering these materials a second useful life.
Abstract
In this work the development of a profile manufactured by pultrusion and thereafter curved by thermoforming is presented. The pultrusion profile is based on a new thermostable [...]
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Optimization and characterization of the T_RTM process for polyamide 6
I. Harismendy, A. Calle, S. García-Arrieta, . C.Elizetxea

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 2

Abstract
One of the advantages of the T_RTM process of polyamide 6 is that the low viscosity of the molten monomer, ɛ-caprolactam (CL), allows to infiltrate it through the fiber, in a process very similar to the RTM of the thermoset materials. In this process the APA6 polymerizes and crystallizes during the molding process, being these two factors the ones that will provide the final properties to the material. Therefore, the knowledge, modeling and simulation of the effect of the process variables on these two phenomena would allow to optimize time/properties ratio in order to develop a strong and competitive manufacturing process. In the RTM 4.0 project, the effect of the different process variables on the crystallization and polymerization of APA6 has been studied through of different characterization and monitoring techniques. This work presents the results of the study of the influence of the type of reinforcement of the polymerization of the material. The results obtained indicate that repetitive and homogeneous polymerization degrees are achieved regardless of the type of reinforcement used.
Abstract
One of the advantages of the T_RTM process of polyamide 6 is that the low viscosity of the molten monomer, ɛ-caprolactam (CL), allows to infiltrate it through [...]
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Analysis of the manufacturing process of a car bonnet using Compression Resin Transfer Moulding (CRTM)
L. Aretxabaleta, C. Rytka, L. Walker, J. Maldonado, M. Baskaran, J. Aurrekoetxea

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 13

Abstract
Compression resin transfer moulding (CRTM) can help to reduce costs and increase the productivity of composite parts in the automotive industry. This process is suited for fast production of high quality parts, but a number of parameters must be precisely characterised and well controlled during the process. This work describes the CRTM manufacturing process of a real sports car bonnet. Resin and carbon fibre reinforcement have been characterised (viscosity, permeability), and this information has been used to perform numerical simulations to optimise the process parameters in order to reduce the cycle time. The heating cycle has also been optimised and the possible implementation of an induction heating system has been analysed. Once the process parameters have been defined, the mould has been manufactured and bonnet prototypes have been manufactured. This work has been carried out within the framework of the project ADVANCRTM.
Abstract
Compression resin transfer moulding (CRTM) can help to reduce costs and increase the productivity of composite parts in the automotive industry. This process is suited for [...]
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A microlevel capillary study in composite materials by X-ray tomography
J. Castro, F. Sket, C. González

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 12

Abstract
One of the main problems associated with the manufacture of composite materials by liquid moulding (injection, infusion, etc.) is the generation of porosity. The optimization of the properties of the composites passes through a better understanding of the mechanisms of pore formation and transport. This pore formation is associated with a non-homogeneity of resin flow during the manufacturing process as a consequence of the double-scale porosity present in textile preforms. In the channels between bundles of fibers, the resin flows controlled by the pressure gradient and its viscosity. However, within the fiber bundles, the resin flows as a result of the capillary pressure. As a consequence, if the viscous and capillary forces are not balanced, non-homogeneous local flow occurs and the formation of pores, either between the fiber bundles, or internally to the bundles is produced.In this work a systematic study of the spontaneous wetting process of an E glass fiber bundle through wicking tests, using several fluids with different properties, viscosity, surface tension and contact angle is presented. The visualization of the front position of the resin flow at microscopic scale, as well as the formation of the menisci between fibers has been performed using X-ray tomography techniques using synchrotron radiation. The reconstructed volumes have made it possible to obtain detailed quantitative information on the geometry of the menisci which occur as a consequence of the surface tension operating at such scale. These characterization techniques constitute a fundamental tool for the optimization of the processing of composite materials buy liquid moulding.
Abstract
One of the main problems associated with the manufacture of composite materials by liquid moulding (injection, infusion, etc.) is the generation of porosity. The optimization [...]
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Optimization of liquid resin infusion process (LRI) using finite element simulation software
C. Churiaque, J. Sánchez-Amaya, J. Botana, R. Páez, L. Utrera

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 11

Abstract
Infusion processes as LRI (Liquid Resin Infusion) can lead to a significant cost reduction but are not yet so widespread in aeronautical applications. Some of its advantages are: no need of autoclave, lower costs of materials, and the possibility of fabricating integrated structures that reduce the number of joints. However this process still presents some drawbacks such as the need to apply the "Test-Error" method or availability of extensive experience in the design of structures. The risk and cost associated with the infusion process is high, so the industry tends to use more conservative designs or adopt other less competitive alternative technologies and materials. For this reason, a simulation tool is essential to optimize the LRI process. In this work, the optimization and validation of a demonstrator of a wing box of an aircraft has been carried out using the PAM-COMPOSITES simulation software. Firstly, a geometric study and discretization of model has been carried out, secondly, the parameters that govern the process have been defined, and finally an analysis and validation of results have been carried out by means of a experimental infusion of the demonstrator. The obtained results have allowed us to control manufacturing times, improve injection and vacuum ports, and predict dry zones and front flow velocity. Simulations have allowed us to optimise the LRI process of the demonstrator, thus giving continuity to other studies on the viability of the infusion processes in primary structures in the aeronautical sector.
Abstract
Infusion processes as LRI (Liquid Resin Infusion) can lead to a significant cost reduction but are not yet so widespread in aeronautical applications. Some of its advantages [...]
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Additive manufacturing of 3D reinforced structures: effects of process parameters on mechanical properties
. M.A.Caminero, ,. J.M.Chacón, E. García-Plaza, . P.J.Núñez, I. García-Moreno, G. Rodríguez

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 10

Abstract
Three dimensional (3D) printing or Rapid Prototyping (RP) provides an innovative additive manufacturing method for prototypes and functional components. Fused deposition modeling (FDM) is a fast growing rapid prototyping technology for fabricating thermoplastic parts due to its ability to build functional parts having complex geometrical shapes in reasonable time periods with the advantages of low cost, minimal wastage, and no tooling or touch labour. The quality of a built part (surface finish, dimensional accuracy or mechanical properties) depends on several process variables. Assessing the influence of these process parameters on mechanical properties is vital for understanding the performance of 3D printed materials, and to determine the needs for further research. The aim of this study is to characterize and assess of different process parameters on the mechanical performance of PLA and ABS samples manufactured with low cost 3D printing. Tensile and three-point bending tests series were carried out to determine the mechanical response of the printed specimens with different process parameters. Finally, the practicality of the results was assessed by testing an evaluation structure as a case example.
Abstract
Three dimensional (3D) printing or Rapid Prototyping (RP) provides an innovative additive manufacturing method for prototypes and functional components. Fused deposition modeling [...]
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Manufacturing tests of the lower skin of a wing in dry fiber by laying in FP and subsequent forming and infusion
P. Tabarés, B. Fantina

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 9

Abstract
In recent years many of the developments in the field of composite materials have focused on processes of dry carbon fiber, and efforts have been directed to achieve with these materials the same levels of industrialization as with pre-impregnated materials, since it is a technology of low cost and with a high productivity. The objective of this project has been to develop dry carbon fiber manufacturing methods to obtain an automated, robust and efficient process for reaching manufacture the lower skin of a wing with stringers and integrated spars by automatic laying in Fiber Placement, posterior Hot forming and finally a process of resin infusion by "Vacuum Assisted Process". To achieve this objective, the Fiber Placement machine has been set up to optimize the laying parameters for the processing of the material to be used (½” Hexcel Hi-Tape fiber). On the other hand, several tests of hot forming of this laminates have been carried out by means of the previous process, modifying process variables, tooling details and forming bag configuration, in order to obtain the preforms of stringers and spars. Finally, the integration of spars, stringers and skin was performed by a resin infusion process using the VAP technique "Vacuum Assisted Process".
Abstract
In recent years many of the developments in the field of composite materials have focused on processes of dry carbon fiber, and efforts have been directed to achieve with [...]
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Flexible, efficient and automated fast manufacturing of high performance composite parts
. R.Mezzacasa, . M.Segura, . X.Irastorza, . I.Harismendy, . H.Sehrschon

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 8

Abstract
Fibre-reinforced polymer composite materials are leading candidates as component materials to improve the efficiency and sustainability of many transport modes. Advantages of high performance composites are numerous including lighter weight and reduced assembly costs due to high level of integration potential. This translates into greater weight savings resulting in improved performance, greater payloads, fuel savings and emissions reductions. However, the current manufacturing processes used in aeronautic and automotive still represent high capital investments for SMEs and this represents a major barrier for their deployment in sectors like automotive and others. In this context, during the LOWFLIP project, Tecnalia, Fill and other partners have recently developed a low cost manufacturing process dedicated to structural composite parts for sectors like automotive and others, with the following features: • New fully automated process chain with pick and place multigripper solution providing high production capacity and high quality/ structural performance, with low level of investment, accessible for SMEs. • Fast preforming, heating and curing with snap cure prepregs and very significant reduction of energy consumption during the process due to innovative toolings The automated cell developed is ready for implementation in the main sectors using composites.
Abstract
Fibre-reinforced polymer composite materials are leading candidates as component materials to improve the efficiency and sustainability of many transport modes. Advantages [...]
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Development and automation of a new composites manufacturing process based on UV curing prepregs
A. Aramburu, F. Vallejo

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 7

Abstract
With the aim of improving composites manufacturing process costs and properties, in order to compete with others materials, a new process of impregnation, compaction and curing of fibre glass reinforcing composites, has been developed. This new process based on UV curing prepregs could be an alternative to the traditional manufacturing process, including infusion process and autoclave curing. These new process consists of two stages. First, the automated manufacturing of the UV curing prepregs. Second, the compaction of the composite by means of application of pressure and UV radiation giving rise to the finished part. In this work, the UV prepregs manufacturing process will be analysed, and the effect of the control parameters of the all process, composed by impregnation, resin content adjustment and precuring, will be analysed. The durability of different manufactured UV prepregs and the mechanical behaviour of the resulted composite will be also studied. Finally, the prototypes necessary to the automation of the two stages of the process will be described.
Abstract
With the aim of improving composites manufacturing process costs and properties, in order to compete with others materials, a new process of impregnation, compaction and curing [...]
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Study of curing of composite by DEA and DSC in the automotive industry
G. Oteo, S. Knappe

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 6

Abstract
Fiber reinforced plastics are the current protagonist in the automotive industry, their mechanical properties and their lightweight make them unique in reducing the impact of the weight on fuel consumption. The curing of thermosetting resins as the polymer matrix for an FRP is one of the main issues facing this sector. Through applications examples, it is demonstrated how the behavior of curing of thermosetting resins can be studied by the techniques of dielectric analysis (DEA) and differential scanning calorimetry (DSC). In-situ cure monitoring is possible by DEA.
Abstract
Fiber reinforced plastics are the current protagonist in the automotive industry, their mechanical properties and their lightweight make them unique in reducing the impact [...]
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Dry carbon fiber applications in aerospace sector and automation options
A. Gandarias, H. Gutierrez, J. Nuñez

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 5

Abstract
Considering the latest introduction of the dry multiaxial fabrics into Aeronautical applications/programs (wing skins, Vertical Tail Plane [VTP] skins, winglets, bulkheads, cargo doors, etc.), together with the lack of automation for the preform creation and its deposition onto the corresponding molds, this paper will cover different potential solutions for the manufacturing of skins and stiffeners. In all cases, looking to the automated dry multiaxial fabric preform creation, lay-up and forming.
Abstract
Considering the latest introduction of the dry multiaxial fabrics into Aeronautical applications/programs (wing skins, Vertical Tail Plane [VTP] skins, winglets, bulkheads, [...]
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PLATFORM: Study of the integration of materials manufactured with CNTs in current processes of manufacture by infusion in aeronautics
L. Sánchez, B. López, I. Gaztelumendi, R. Seddon, M. Chapartegui, ,. P.Latko

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 4

Abstract
The need to improve non-intrinsic properties of composite materials is a fact that leads to studies such as the one carried out in this project, where the possibility of integrating new materials development into common materials is analyzed to provide them with an improved properties: mechanical or electric. The main objective of the project is to analyze the possibility of introducing the new materials into the current manufacturing processes, improving the properties of the raw material (dry carbon fiber fabric infused with monocomponent epoxy resin), under aeronautical requirements. Two material developments are made with carbon nanotubes in two different formats: buckypapers and thermoplastic doped veils. The implementation of each materials has been studied in current infusion processes, more concretely manufacturing processes by RTM (Resin Transfer Molding). The studied possibilities are: buckypapers incorporated in dry preforms, for their subsequent infusion and doped veils embedded in dry preforms, for their subsequent infusion. The obtained results at this moment (2nd year of the project) are satisfactory, although it´s necessary to optimize the materials to improve the automation of the manufacturing process and achieve a greater improvement of properties.
Abstract
The need to improve non-intrinsic properties of composite materials is a fact that leads to studies such as the one carried out in this project, where the [...]
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Accurate Vacuum Assisted Resin Infusion simulation through a fluid-solid coupled modeling
A. Dereims, L. Dufort, A. Juan

Materiales Compuestos (2022). Vol. 03 - Comunicaciones Matcomp17 (2019), (Núm. 3 - Procesos de Fabricación II y Materiales Avanzados), 3

Abstract
The need for an increase of production rate in aerospace industry implies a growing interest in composite manufacturing process simulation with a strong requirement on predictive accuracy. In this context, ESI enhanced its PAM-COMPOSITES software introducing fluid-solid coupled approach in PAM-RTM module in order to simulate more accurately Vacuum Assisted Resin Infusion (VARI) process. VARI consists in impregnating a dry preform laid on a rigid mold and placed under a distribution medium and a vacuum bag. During the impregnation resin flows preferentially into the distribution medium and then in the preform which may undergo deformations due to the flexibility of the vacuum bag. Usual 2.5D approaches, using shell elements with thickness depending on resin pressure, cannot account for resin flow through the thickness due to permeability and fiber fraction gradients implied by the material used and/or solid mechanics effects (such as compression in curvatures). ESI new approach, resulting from several years of collaboration with academics, consists in a 3D finite element modeling. It is based on the coupling of resin flow, governed by Darcy’s law, with the preform behavior, considered as porous medium undergoing deformations, through Terzaghi’s principle. Thus it results in more predictive filling time and properties (thicknesses, fiber volume contents, geometry) of the final product.
Abstract
The need for an increase of production rate in aerospace industry implies a growing interest in composite manufacturing process simulation with a strong requirement on predictive [...]
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Adaptive breakwaters with inflatable elements for coastal protection. Preliminary numerical estimation of their performance
P. Ryzhakov, F. Hermosilla, P. Ubach, E. Oñate

Ocean Engineering (2022). Volume 251, 110818

Abstract
Excessive erosion of sand beaches defines a serious problem worldwide and is particularly pronounced in the Mediterranean region. One of the typical measures for alleviating this erosion consists in building rigid breakwaters in the vicinity of the coast for diminishing sand transport. This solution, however, is often accompanied by undesirable alteration of the coastline. In this work we address the viability of using conceptually new structures with inflatable elements striving to improve the control over the sediment transport. The aim of the inflatable element is to adapt the breakwater configuration to the sea state. A preliminary design is proposed and tested in a number of storm scenarios using an in-house finite element/level set model. Influence of various breakwater design parameters upon its functionality is studied. Transmission coefficients and maximum pressures exerted upon the breakwater are estimated. Numerical study performed shows that for the considered range of storm scenarios the proposed design is characterized by transmission coefficients below 0.5. It is also shown that the use of inflatable elements facilitates adaptation of the breakwater functionality to a given sea state.
Abstract
Excessive erosion of sand beaches defines a serious problem worldwide and is particularly pronounced in the Mediterranean region. One of the typical measures for alleviating [...]
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Numerical simulation of particle impact drilling (PID) systems: a one-way coupled approach
G. Casas, I. de-Pouplana, R. Gandikota, E. Oñate

Computational Particle Mechanics (2022). pp. 1-23

Abstract
A numerical technique based on a CFD-DEM method is presented for the analysis of particle impact drilling (PID) systems. The method is built from a preexisting finite element Navier–Stokes solver for the fluid phase and a discrete element method module for the steel particles which this drilling technology utilizes to enhance the penetration rate. We provide a detailed description of the most relevant implementation issues, including our choice of the hydrodynamic forces appropriate for power-law fluids. We also discuss several critical aspects related to the validity of the simplifying assumptions that will be helpful to simulation engineers. We apply our simple, one-way coupled approach on designs provided by an industrial partner to illustrate its potential as an analysis tool for this promising drilling technology. The goal of this work is, on the one hand, to provide evidence for the usefulness of the numerical approach as a design tool for PID systems, as well as a detailed discussion of the different aspects to be assessed for an effective simulation campaign. On the other hand, a series of modeling aspects that require further work are identified. The focus of the simulation campaign presented is on the particles and fluid flow characteristics within the drill bit.
Abstract
A numerical technique based on a CFD-DEM method is presented for the analysis of particle impact drilling (PID) systems. The method is built from a preexisting finite element [...]
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A FIC-FEM procedure for the shallow water equations over partially wet domains
M. Maso, I. de-Pouplana, E. Oñate

Computer Methods in Applied Mechanics and Engineering (2022). Volume 389, 114362

Abstract
We present a stable finite element formulation for the shallow water equations using the finite increment calculus (FIC) procedure. This research is focused on the stability properties of the FIC technique and uses linear triangles for the spatial discretization with an equal order of interpolation for all the variables. The extension to higher order polynomial interpolation functions and different geometries is straightforward. The present FIC-FEM procedure is also able to introduce artificial viscosity for an adequate shock capturing. An implicit time integration has been used. Special attention has been payed to the dry domain in order to solve the moving boundaries with a fixed mesh Eulerian approach. Three academic examples are included in order to test the capabilities of the FIC-FEM procedure: the global stabilization, the shock capturing technique and the dry-wet interface. An experimental benchmark tests the overall accuracy of the present formulation.
Abstract
We present a stable finite element formulation for the shallow water equations using the finite increment calculus (FIC) procedure. This research is focused on the stability [...]
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Combination of the finite element method and particle-based methods for predicting the failure of reinforced concrete structures under extreme water forces
E. Oñate, A. Cornejo Velázquez, F. Zarate, K. Kashiyama, A. Franci

Engineering Structures (2022). Vol. 251, Part B, 113510

Abstract
We present a combination of the Finite Element Method (FEM), the Particle Finite Element Method (PFEM), and the Discrete Element Method (DEM) for modeling and analyzing the failure of reinforced concrete structures under impulsive wave forces originating from free-surface flows in critical water hazards. The free-surface water flow is modeled with the PFEM, while the structural behavior and the fractures induced by the water forces in the structure are modeled with a coupled FEM–DEM technique. The concrete material behavior is simulated with a standard isotropic damage model. The reinforcing bars are modeled by a rule of mixtures procedure, for simplicity. The possibilities of the new integrated PDFEM approach for predicting the evolution of free-surface tsunami-type waves and their devastating effect on constructions are validated with experiments on the failure of reinforced concrete plates under large impacting waves, performed in a laboratory facility in Japan.
Abstract
We present a combination of the Finite Element Method (FEM), the Particle Finite Element Method (PFEM), and the Discrete Element Method (DEM) for modeling and analyzing the [...]
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Virtual reality stories for construction training scenarios: the case of social distancing at the construction site
F. Rivera, J. Mora-Serrano, E. Oñate

WIT Transactions on The Built Environment (2022). Vol. 205, pp. 37-47

Abstract
The architecture, engineering, construction and operation industry has high accident rates, and its workers are susceptible to certain risks due to the variability of their worksites, the tasks they perform and the equipment they use. Of particular interest is the coexistence of workers and heavy machinery in the same space, which is one of the main causes of high accident rates. Increasing digitisation also incorporates the use of new systems (e.g. UAVs, autonomous vehicles, robotic devices), which must function while preserving worker safety. As such, worker training is also essential in these contexts. Research indicates that occupational risk prevention training in construction is not satisfactory. Traditional methods based on lectures (where the student does not take an active role) and traditional test-type assessments do not result in significant learning and fail to create a culture of prevention among workers. In the context of the COVID-19 pandemic, the construction industry has had to incorporate new prevention measures to continue projects while protecting workers’ health and safety. Virtual reality has demonstrated advantages in adapting to different contexts, allowing for the agile development of training experiences with immersive characteristics and more significant learning than traditional methods. This research shows the application and agile development of a training experience for social distancing at construction sites to prevent COVID-19 transmission, based on virtual reality and building information modelling and using serious games as a teaching strategy.
Abstract
The architecture, engineering, construction and operation industry has high accident rates, and its workers are susceptible to certain risks due to the variability of their [...]
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Factors influencing Safety on Construction Projects (fSCPs): Types and categories
F. Rivera, J. Mora, E. Oñate

Int. J. Environ. Res. Public Health (2021). Vol. 18(20), 10884

Abstract
Due to the fact of activity, environment and work dynamics, the construction industry is characterised by high accident rates. Different initiatives have emerged to reduce these figures, which focus on using new methodologies and technologies for safety management. Therefore, it is essential to know the key factors and their influence on safety in construction projects (fSCPs) to focus efforts on these elements. Through a systematic literature review, based on PRISMA methodology, this article identifies, describes and categorises 100 factors that affect construction safety. It thus contributes by providing a comprehensive general framework, unifying previous studies focused on specific geographic areas or case studies with factors not considered or insufficiently disaggregated, along with an absence of classifications focused on understanding where and how factors affect the different dimensions of construction projects. The 100 factors identified are described and categorised according to the dimensions and aspects of the project in which these have an impact, along with identifying whether they are shaping or immediate factors or originating influences for the generation of accidents. These factors, their description and classification are a key contribution to improving the systematic creation of safety and generating training and awareness materials to fully develop a safety culture in organisations.
Abstract
Due to the fact of activity, environment and work dynamics, the construction industry is characterised by high accident rates. Different initiatives have emerged to reduce [...]
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The P-DNS method applied to the numerical simulation of turbulent multiphase flows
J. Giménez, S. Idelsohn, E. Oñate

Mecánica Computacional (2021). Vol. 38 (30), 1177-1177

Abstract
The Pseudo-Direct Numerical Simulation (P-DNS) method is a numerical approach to solve multiscale fluid dynamics phenomena overcoming the computational burden associated with direct numerical resolution of the governing equations. In P-DNS, both the coarse scale and the fine scale are solved numerically. The most expensive part of the computations, the solutions of the fine scale, are parametrized to be performed offline and store their results in dimensionless databases. This latter allows us to construct synthetic models to emulate the fine scale behavior when coarse scale solutions are computed. In this work, a multiphase representative volume element (RVE) is designed for the specific case of a dispersed flow of heavy particles in air. Making use of high performance computing facilities, a set of numerical experiments for a wide range of volume fractions, particle distribution sizes, and inertial forces introduced as shear loads are carried out. Quantitative results of the statistically stationary turbulent state are obtained. This brings insights into the turbulence modulation phenomenon, i.e. the change of the kinetic energy of the carrier flow due to the presence of the particles. The database of RVE results is stored in an artificial neural network to facilitate its use in general flow solvers via a fast interpolation technique. Global case studies of particulate flows are analyzed, highlighting the differences and similarities found using the fine-scale model developed vis-a-vis a standard turbulence modeling.
Abstract
The Pseudo-Direct Numerical Simulation (P-DNS) method is a numerical approach to solve multiscale fluid dynamics phenomena overcoming the computational burden [...]
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Simulation of the burning and dripping cables in fire using the particle finite element method
J. Marti, B. Schartel, E. Oñate

Journal of Fire Sciences (2022). Vol. 40(1), pp. 3-25

Abstract
The behavior of the cable jacket in fire characterized by the tendency to melt and drip constitutes a major source of fire hazard. The reason is that the melted material may convey the flame from one point to another, expanding fire and contributing to the fire load. In this article, the capability of a new computational strategy based on the particle finite element method for simulating a bench-scale cables burning test is analyzed. The use bench-scale test has been previously used to simulate the full-scale test described in EN 50399. As the air effect is neglected, a simple combustion model is included. The samples selected are two cables consisting of a copper core and differently flame retarded thermoplastic polyurethane sheets. The key modeling parameters were determined from different literature sources as well as experimentally. During the experiment, the specimen was burned under the test set-up condition recording the process and measuring the temperature evolution by means of three thermocouples. Next, the test was reproduced numerically and compared with a real fire test. The numerical results show that the particle finite element method can accurately predict the evolution of the temperature and the melting of the jacket.
Abstract
The behavior of the cable jacket in fire characterized by the tendency to melt and drip constitutes a major source of fire hazard. The reason is that the melted material may [...]
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New Strategies for Initialization and Training of Radial Basis Function Neural Networks
D. Franco, M. Steiner

Time Series Forecasting (2017). D. G. B. Franco and M. T. A. Steiner, "New Strategies for Initialization and Training of Radial Basis Function Neural Networks," in IEEE Latin America Transactions, vol. 15, no. 6, pp. 1182-1188, June 2017, doi: 10.1109/TLA.2017.7932707.

Abstract
In this paper we proposed two new strategies for initialization and training of Radial Basis Function (RBF) Neural Network. The first approach takes into consideration the "error" between the input vector p of the network and the x-axis, which are the centers of radial functions. The second approach takes into account the "error" between the input vector p and the network output. In order to check the performances of these strategies, we used Brazilian financial market data for the RBF networks training, specifically the adjusted prices of the 10 greater weighted shares in the Bovespa index at the time of data collection - from April 8th , 2009 to October 31th , 2014. The first approach presented a 52% of improvement in the mean squared error (MSE) compared to the standard RBF network, while the improvement for the second approach was 38%. The strategies proved to be consistent for the time series tested, in addition to having a low computational cost. It is proposed that these strategies be improved by testing them with the Levenberg-Marquardt algorithm.
Abstract
In this paper we proposed two new strategies for initialization and training of Radial Basis Function (RBF) Neural Network. The first approach takes into consideration the [...]
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Classification Algorithms in Financial Application: Credit Risk Analysis on Legal Entities
F. Assef, M. Steiner, P. Steiner Neto, D. Franco

IEEE Latin America Transactions (2019). F. Assef, M. T. Steiner, P. J. Steiner Neto and D. G. d. B. Franco, "Classification Algorithms in Financial Application: Credit Risk Analysis on Legal Entities," in IEEE Latin America Transactions, vol. 17, no. 10, pp. 1733-1740, October 2019, doi: 10.1109/TLA.2019.8986452.

Abstract
This research aims at analyzing bank credit of legal entity (in non-default, default and temporarily default), for the purpose of assisting the decision made by the analyst of this area. For that, we used Artificial Neural Networks (ANNs), more specifically, the Multilayer Perceptron (MLP) and the Radial Basis Functions (RBF) and, also, the statistical model of Logistic Regression (LR). For the implementation of the ANNs and LR, the softwares MATLAB and SPSS were used, respectively. For the simulations developed 5.432 data with 15 attributes were collected by the experts of the institution bank (called “XYZ”). The results show that the default clients are easily identifiable, but for the nondelinquent clients and for the temporarily defaulters, the techniques had greater difficulty in the discrimination, suggesting that they are no so discriminants. The main contributions of this work are: the analysis of three classes of clients (non-default, default and temporarily default), rather than just two (non-default and default) as is usually done; the coding of variables (attributes) of the company XYZ aiming to maximize the accuracy of the techniques and the use of the one-against all method, little used by the researchers of this research area. This work presents new insights towards research over Credit Risk Assessment showing other possibilities of client classification and codification, allowing different types of studies to take place.
Abstract
This research aims at analyzing bank credit of legal entity (in non-default, default and temporarily default), for the purpose of assisting the decision made by the analyst [...]
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Classification of Abandoned Areas for Solar Energy Projects Using Artificial Intelligence and Quantum Mechanics
D. Franco, M. Steiner

Journal of Geographic Information System (2021). Franco, D. and Steiner, M. (2021) Classification of Abandoned Areas for Solar Energy Projects Using Artificial Intelligence and Quantum Mechanics. Journal of Geographic Information System, 13, 318-339. doi: 10.4236/jgis.2021.133018.

Abstract
The increasing demand for energy has intensified recently, requiring alternative sources to fossil fuels, which have become economically and environmentally unfeasible. On the other hand, the increasing land occupation in recent centuries is a growing problem, demanding greater efficiency, particularly in the reuse of abandoned areas, which has become an alternative. An interesting alternative would be installing energy facilities like solar, wind, biomass, and geothermal, in these areas. The objective of this paper is to develop a classification methodology, based on Artificial Intelligence (AI) and Quantum Theory (QT), to automatically carry out the classification of abandoned areas suitable for the settlement of these power plants. Artificial Neural Networks (ANNs) improved by the hybrid algorithm Quantum-behaved Particle Swarm Optimization (QPSO) together with the Levenberg-Marquardt Algorithm (LMA) were used for the classification task. In terms of Mean Squared Error (MSE), the QPSO-LMA approach achieved a decrease of 19.6% in relation to the classical LMA training with random initial weights. Moreover, the model’s accuracy showed an increase of 7.3% for the QPSO-LMA over the LMA. To validate this new approach, it was also tested on six different datasets available in the UCI Machine Learning Repository and seven classical techniques established in the literature. For the problem of installing photovoltaic plants in abandoned areas, the knowledge acquired with the solar dataset can be extrapolated to other regions.
Abstract
The increasing demand for energy has intensified recently, requiring alternative sources to fossil fuels, which have become economically and environmentally unfeasible. On [...]
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Application of the ARIMA Model to Predict Under-Reporting of New Cases of Hansen’s Disease during the COVID-19 Pandemic in a Municipality of the Amazon Region
V. Cunha, G. Botelho, A. Oliveira, L. Monteiro, D. Franco, R. Silva

International Journal of Environmental Research and Public Health (2022). da Cunha, V.P.; Botelho, G.M.; de Oliveira, A.H.M.; Monteiro, L.D.; de Barros Franco, D.G.; da Costa Silva, R. Application of the ARIMA Model to Predict Under-Reporting of New Cases of Hansen’s Disease during the COVID-19 Pandemic in a Municipality of the Amazon Region. Int. J. Environ. Res. Public Health 2022, 19, 415. https://doi.org/10.3390/ijerph19010415

Abstract
This work aimed to apply the ARIMA model to predict the under-reporting of new Hansen’s disease cases during the COVID-19 pandemic in Palmas, Tocantins, Brazil. This is an ecological time series study of Hansen’s disease indicators in the city of Palmas between 2001 and 2020 using the autoregressive integrated moving averages method. Data from the Notifiable Injuries Information System and population estimates from the Brazilian Institute of Geography and Statistics were collected. A total of 7035 new reported cases of Hansen’s disease were analyzed. The ARIMA model (4,0,3) presented the lowest values for the two tested information criteria and was the one that best fit the data, as AIC = 431.30 and BIC = 462.28, using a statistical significance level of 0.05 and showing the differences between the predicted values and those recorded in the notifications, indicating a large number of under-reporting of Hansen’s disease new cases during the period from April to December 2020. The ARIMA model reported that 177% of new cases of Hansen’s disease were not reported in Palmas during the period of the COVID-19 pandemic in 2020. This study shows the need for the municipal control program to undertake immediate actions in terms of actively searching for cases and reducing their hidden prevalence.
Abstract
This work aimed to apply the ARIMA model to predict the under-reporting of new Hansen’s disease cases during the COVID-19 pandemic in Palmas, Tocantins, Brazil. This [...]
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Machine learning techniques applied to the coronavirus pandemic: a systematic and bibliometric analysis from January 2020 to June 2021
M. Steiner, D. Franco, P. Steiner Neto

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (3), 31

Abstract
During the pandemic caused by the Coronavirus (Covid-19), Machine Learning (ML) techniques can be used, among other alternatives, to detect the virus in its early stages, which would aid a fast recovery and help to ease the pressure on healthcare systems. In this study, we present a Systematic Literature Review (SLR) and a Bibliometric Analysis of ML technique applications in the Covid-19 pandemic, from January 2020 to June 2021, identifying possible unexplored gaps. In the SLR, the 117 most cited papers published during the period were analyzed and divided into four categories: 22 articles that analyzed the problem of the disease using ML techniques in an X-Ray (XR) analysis and Computed Tomography (CT) of the lungs of infected patients; 13 articles that studied the problem by addressing social network tools using ML techniques; 44 articles directly used ML techniques in forecasting problems; and 38 articles that applied ML techniques for general issues regarding the disease. The gap identified in the literature had to do with the use of ML techniques when analyzing the relationship between the human genotype and susceptibility to Covid-19 or the severity of the infection, a subject that has begun to be explored in the scientific community.
Abstract
During the pandemic caused by the Coronavirus (Covid-19), Machine Learning (ML) techniques can be used, among other alternatives, to detect the virus in its early stages, [...]
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D3.3 Report of ensemble based parallelism for turbulent flows and release of solvers
R. Tosi, R. Codina, J. Principe, R. Rossi, C. Soriano

Open Access Repository of the ExaQUte project: Deliverables (2022). 6

Abstract
In this work we focus on reducing the wall clock time required to compute statistical estimators of highly chaotic incompressible flows on high performance computing systems. Our approach consists of replacing a single long-term simulation by an ensemble of multiple independent realizations, which are run in parallel with different initial conditions. A failure probability convergence criteria must be satisfied by the statistical estimator of interest to assess convergence. Its error analysis leads to the identification of two error contributions: the initialization bias and the statistical error. We propose an approach to systematically detect the burn-in time in order to minimize the initialization bias, accompanied by strategies to reduce simulation cost. The framework is validated on two very high Reynolds number obstacle problems of wind engineering interest in a high performance computing environment.
Abstract
In this work we focus on reducing the wall clock time required to compute statistical estimators of highly chaotic incompressible flows on high performance computing systems. [...]
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D4.5 Framework development and release
J. Ejarque, R. Tosi, M. Nuñez, S. Böhm, R. Badia, C. Soriano, R. Rossi

Open Access Repository of the ExaQUte project: Deliverables (2022). 5

Abstract
This deliverable presents the nal release of the ExaQUte framework as result of task 4.6 of the project focused on the framework development and optimization. The rst part of the document presents an overview of the dierent parts of the ExaQUte framework providing the links to the repositories where the code of the dierent components can be found as well as the installation and usage guidelines. These repositories will include the nal version of the ExaQUte API and its implementation for the runtimes provided in the project (PyCOMPSs/COMPSs and Quake). The second part of the document presents a performance analysis of the framework by performing strong and weak scaling experiments. In this case, we have focused on the analysis of the new features introduced during the last part of the project to support and optimize the execution of MPI solvers inside the framework. The support for OpenMP was already reported in Deliverable D4.3 [21]. The results of the experiments demonstrate that the proposed framework allow to reach very good scalability for the analysed Monte Carlo problems.
Abstract
This deliverable presents the nal release of the ExaQUte framework as result of task 4.6 of the project focused on the framework development and optimization. The rst part [...]
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D6.5 Report on stochastic optimisation for wind engineering
F. Nobile, Q. Ayoul-Guilmard, S. Ganesh, M. Nuñez, A. Kodakkal, C. Soriano, R. Rossi

Open Access Repository of the ExaQUte project: Deliverables (2022). 4

Abstract
This report presents the latest methods of optimisation under uncertainties investigated in the ExaQUte project, and their applications to problems related to civil and wind engineering. The measure of risk throughout the report is the conditional value at risk. First, the reference method is presented: the derivation of sensitivities of the risk measure; their accurate computation; and lastly, a practical optimisation algorithm with adaptive statistical estimation. Second, this method is directly applied to a nonlinear relaxation oscillator (FitzHugh–Nagumo model) with numerical experiments to demonstrate its performance. Third, the optimisation method is adapted to the shape optimisation of an airfoil and illustrated by a large-scale experiment on a computing cluster. Finally, the benchmark of the shape optimisation of a tall building under a turbulent flow is presented, followed by an adaptation of the optimisation method. All numerical experiments showcase the open-source software stack of the ExaQUte project for large-scale computing in a distributed environment.
Abstract
This report presents the latest methods of optimisation under uncertainties investigated in the ExaQUte project, and their applications to problems related to civil and wind [...]
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D5.5 Report on the application of multi-level Monte Carlo to wind engineering
Q. Ayoul-Guilmard, F. Nobile, S. Ganesh, M. Nuñez, R. Tosi, C. Soriano, R. Rossi

Open Access Repository of the ExaQUte project: Deliverables (2022). 3

Abstract
We study the use of multi-level Monte Carlo methods for wind engineering. This report brings together methodological research on uncertainty quantification and work on target applications of the ExaQUte project in wind and civil engineering. First, a multi-level Monte Carlo for the estimation of the conditional value at risk and an adaptive algorithm are presented. Their reliability and performance are shown on the time-average of a non-linear oscillator and on the lift coefficient of an airfoil, with both preset and adaptively refined meshes. Then, we propose an adaptive multi-fidelity Monte Carlo algorithm for turbulent fluid flows where multilevel Monte Carlo methods were found to be inefficient. Its efficiency is studied and demonstrated on the benchmark problem of quantifying the uncertainty on the drag force of a tall building under random turbulent wind conditions. All numerical experiments showcase the open-source software stack of the ExaQUte project for large-scale computing in a distributed environment.
Abstract
We study the use of multi-level Monte Carlo methods for wind engineering. This report brings together methodological research on uncertainty quantification and work on target [...]
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D7.4 Final report on Stochastic Optimization results
S. Bidier, U. Khristenko, A. Kodakkal, C. Soriano, R. Rossi

Open Access Repository of the ExaQUte project: Deliverables (2022). 2

Abstract
This deliverable report focuses on the final stochastic optimization results obtained within the EXAscale Quantification of Uncertainties for Technology and Science Simulation (ExaQUte) project. Details on a novel wind inlet generator that is able to incorporate local wind-field data through a deep-learned rapid distortion model and generates the turbulent wind data during run-time is presented in section 2. Section 3 presents the results of the overall stochastic optimization procedure applied to a twisted tapered tower with multiple design parameters within an uncertain synthetic wind field. Thereby, the significance of the developed methods and the obtained results are discussed and their integration in industrial wind-engineering workflows is outlined in section 4.
Abstract
This deliverable report focuses on the final stochastic optimization results obtained within the EXAscale Quantification of Uncertainties for Technology and Science Simulation [...]
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D8.4 Report on dissemination activities
C. Soriano, R. Rossi

Open Access Repository of the ExaQUte project: Deliverables (2022). 1

Abstract
In Deliverable D8.1 (M18) we presented a first version of the Dissemination Plan for the ExaQUte project. The present document, prepared during the 2nd (and last) review period of the project, represents the updated version of the Dissemination Plan of ExaQUte, and therefore builds on the aforementioned deliverable. This document, thus, focuses on the new activities that have been undertaken from M18 to M42 regarding the dissemination activities. It should be mentioned that the pandemic situation that started in Mach 2020 (actually, in Spain we were sent to confine to our houses the day after the celebration of the First Review meeting of this project) has had an impact in our life, and in our project, particularly in the dissemination actions. The lockdown made impossible most of the activities related to dissemination (travels, conferences, consortium meetings…). But we reinvented our work and found different ways to do things and fulfil pour obligations. Still, in this deliverable, you will find indeed a difference between the type of action that we carried on up to M18 and our activities after M18.
Abstract
In Deliverable D8.1 (M18) we presented a first version of the Dissemination Plan for the ExaQUte project. The present document, prepared during the 2nd (and last) review period [...]
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A Structural Design Comparison Between Two Reinforced Concrete Regular 6-Level Buildings using Soil-Structure Interaction in Linear Range
N. López

A Structural Design Comparison Between Two Reinforced Concrete Regular 6-Level Buildings using Soil-Structure Interaction in Linear Range (2021).

Abstract
Structural engineers commonly design superstructures as fixed at the base and transmit the reactions to the infrastructure in order to design the foundation system and estimate the displacement of the soil while disregarding the change in seismic response that this induces. In this article, the foundation system was transformed into equivalent springs, and the seismic response in the linear range was compared and quantified, obtaining results such as increased periods, increased amounts of steel reinforcement in beams (between 7% and 25%) and columns (between 29% and 39%), an increase in the number of stirrups per linear meter (between 3% and 11% in columns and between 5% and 45% in beams) and drifts (between 1% and 14%), and a decrease in basal shear (up to 20%), which directly affects the design of the structure. This study concludes that the inclusion of the soil-structure interaction is necessary for structural design in the linear range.
Abstract
Structural engineers commonly design superstructures as fixed at the base and transmit the reactions to the infrastructure in order to design the foundation system and estimate [...]
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RAINWATER STORAGE IN URBAN ENVIRONMENTS USING GREEN ROOFS
A. GREEN, N. López

RAINWATER STORAGE IN URBAN ENVIRONMENTS USING GREEN ROOFS (2021).

Abstract
This article discusses the use of green roofs as rainfall water storage in its soil matrix. The methodology is analytical based on mathematical models, where runoff produced in an urban area is compared with current conditions of ordinary roofs with ceramic or bituminous materials as the original scenario, against another where green roofs are used. The study area is located in the Palavecino municipality of Lara state in Venezuela, in the flood zone of Quebrada Tabure. In this research, a quantitative comparison of the direct runoff hydrographs of the proposed scenarios was used, obtaining as a main result the reduction of runoff between 60 % and 80 % according to the period of return. An interesting point of this research was the incorporation of the routing of hydrographs on the roofs, reducing even more the peak flow over 90 %, and delaying the peak time of the generated hydrographs between 10 and 12 minutes while the total duration of the hydrographs increase more than three times.
Abstract
This article discusses the use of green roofs as rainfall water storage in its soil matrix. The methodology is analytical based on mathematical models, where runoff produced [...]
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An 8-Nodes 3D Hexahedral Finite Element and an 1D 2-Nodes Structural Element for Timoshenko Beams, Both Based on Hermitian Intepolation, in Linear Range
. Article, N. López

An 8-Nodes 3D Hexahedral Finite Element and an 1D 2-Nodes Structural Element for Timoshenko Beams, Both Based on Hermitian Intepolation, in Linear Range (2022).

Abstract
The following article presents the elaboration and results obtained from a 3D finite element, of the 8-node hexahedron type with 6 degrees of freedom (DOF) per node (48 DOF per element) based on third degree Hermitian polynomials, and of a 2-node structural element, with 6 DOF per node (12 DOF per element), based on third degree Hermitian polynomials and the theory of Timoshenko for beams. This article has two purposes; the first one is the formulation of a finite element capable of capturing bending effects, and the second one is to verify whether it is possible to obtain the deformation of the beam’s cross section of a structural member of the beam type, based on the deformations of its axis. The results obtained showed that the 8-node hexahedron FE was able to reproduce satisfactory results by simulating some cases of beams with different contour and load conditions, obtaining errors between 1% and 4% compared to the ANSYS software, educational version. Regarding the structural element of the beam type, it reproduced results that were not as precise as the FE Hexa 8, presenting errors of between 6% and 7% with regard to the axis but with error rounding between 10% and 20%.
Abstract
The following article presents the elaboration and results obtained from a 3D finite element, of the 8-node hexahedron type with 6 degrees of freedom (DOF) per node (48 DOF [...]
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Bibliography - Overview of the digital economy
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Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 11
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Case Study Development
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Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 10
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Conclusion - Overview of the digital economy
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 9
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Digital innovations transforming value chains to value networks
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 8
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Improving hydrological safety by rehabilitating the stilling basin of a gravity dam using numerical modelling
F. Salazar, J. San Mauro

XII Jornadas Españolas de Presas, Las Palmas de Gran Canaria (Spain), October 2021

Abstract
La presa de Sant Ponç entró en funcionamiento en 1954. Es de gravedad de planta recta, con 59,5 m de altura sobre cimientos. Su aliviadero consta de un vertedero recto de tres vanos de 17 m cada uno regulados por compuertas. La estructura de disipación es singular e incluye un tramo de solera no hormigonado que ha sufrido erosiones. Aunque no comprometen la seguridad de la presa, se ha diseñado una solución para la mejora de su funcionamiento, que se ha basado fundamentalmente en los resultados de modelos numéricos. Los avances en las prestaciones de estas herramientas permiten analizar con detalle el comportamiento hidráulico de las alternativas planteadas en diversas situaciones de vertido, así como el de los desagües intermedios y de fondo.
Abstract
La presa de Sant Ponç entró en funcionamiento en 1954. Es de gravedad de planta recta, con 59,5 m de altura sobre cimientos. Su aliviadero consta de un vertedero [...]
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The impact of digital innovations on business models
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 7
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Difference between sustainable and disruptive innovations
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 6
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Analysis of La Baells Dam monitoring data with machine learning techniques
F. Salazar, A. Conde, N. Silva

SPANCOLD. XII Jornadas Españolas de Presas. Las Palmas de Gran Canaria

Abstract
La Baells arch dam has a height above the foundations of 102 m. It entered service in 1976 and since then it had correct performance, which has been controlled with a very complete monitoring system and conventional interpretation techniques. This communication presents the results of a pilot study in which machine learning techniques have been applied to analyze their monitoring data. These techniques offer greater flexibility than conventional procedures for generating dam response prediction models, as well as for identifying relationships between devices of a different nature. This allows a better understanding of the behavior of the structure and greater safety control.
Abstract
La Baells arch dam has a height above the foundations of 102 m. It entered service in 1976 and since then it had correct performance, which has been controlled with a very [...]
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Preliminary Aircraft Design Optimization Using Genetic Algorithms
I. Chaudhry, A. Ahmed

(2014). Journal of Scientific and Industrial Research

Abstract
Aircraft design is a highly nonlinear problem and inherently multidisciplinary activity that involves a large number of design variables and different models and tools for various aspects of design. A spreadsheet based genetic algorithm (GA) approach is presented to optimize the preliminary design of an aircraft. A domain independent general purpose genetic algorithm is proposed to implement the optimization routine. Breguet range equation is used as the objective function for the design evaluation. A total of sixteen design variables are considered in the optimization process. It has also been demonstrated that the proposed approach can be adapted to any objective function without changing the optimization routine. The model is applicable to commercial airliner as well as a multirole jet fighter. The proposed model has been validated against known configurations of various aircraft.
Abstract
Aircraft design is a highly nonlinear problem and inherently multidisciplinary activity that involves a large number of design variables and different models and [...]
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Case Based Reasoning Support for Adaptive Finite Element Analysis - Mesh Selection for an Integrated System
A. Research, . May, I. Chaudhry

(2014). Applied Physics Research

Abstract
An Adaptive Finite Element Analysis Integrated System supported through application of Case Based Reasoning (CBR) methodology is being proposed in this paper. The approach is fruitful for selection of an initial mesh from a library of solutions to initiate analysis process, as already tested optimal mesh will have lesser refinement iterations. The optimal mesh distribution, represented by object-oriented method, can be easily adapted to the topology of new problem in same domain. An integrated and universal structural analysis system models human reasoning by forming solutions through the retrieval and adaptation of successful strategies used in the past. Basic insight of two distinct subjects along with resolution of involved issues and integration strategy for development of an intelligent system is elaborated here. The research explains an algorithm for case retrieval and mesh generation procedures based on the principles of mapping method.
Abstract
An Adaptive Finite Element Analysis Integrated System supported through application of Case Based Reasoning (CBR) methodology is being proposed in this paper. The approach [...]
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Object Oriented Case Representation for CBR Application in Structural Analysis
A. Khan, I. Chaudhry

Applied Artificial Intelligence (2015). Applied Artificial Intelligence

Abstract
Knowledge representation is an essential element of a problem-solving technique through computational work. This article describes the knowledge representation scheme formulated to represent a problem in the structural analysis domain for solution through case-based reasoning (CBR). The numerical knowledge is extracted from a real-life problem that can be used as an input in a case-based reasoner. The geometric topology, loading, and mesh distribution for structure from a solved problem is represented in the form of numerical values for easy adaptation by the new problem. The representation scheme is a step forward in development of a system to be utilized for the time-consuming structural analysis requiring heavy computational power, such as an aircraft wing and fuselage components. The success of the representation strategy is a proof that CBR can work as a powerful problem-solving tool in this domain.
Abstract
Knowledge representation is an essential element of a problem-solving technique through computational work. This article describes the knowledge representation scheme [...]
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Proposal to compute hydrodynamic pressures and sloshing heights in ground-supported rectangular tanks subjected to earthquakes
J. De-la-Colina, C. González-Pérez

Rev. int. métodos numér. cálc. diseño ing. (2022). Vol. 38, (3), 29

Abstract
A proposal to estimate both the hydrodynamic pressures and the maximum wave height of liquids contained in rectangular tanks subjected to earthquake ground motions is presented. The computation procedure, based on the Rayleigh-Ritz method, assumes the fluid as a continuum and it does not use concentrated masses or springs. The solution is achieved by equating the seismic input energy of the system with the total kinetic energy of the fluid assuming liquid velocity fields. The resulting design formulas are simple and they are intended to simplify the seismic design of tanks. Numerical results lead to both the liquid maximum sloshing height and hydrodynamic pressure distributions that are similar to those obtained with other simplified methods and those estimated with the finite element method. Preliminary estimations of shear forces and bending moments for a numerical example resulted 13% and 6% larger (respectively) than the corresponding values obtained with the finite element method.
Abstract
A proposal to estimate both the hydrodynamic pressures and the maximum wave height of liquids contained in rectangular tanks subjected to earthquake ground motions is presented. [...]
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Steady-State Analysis of Electrical Networks in Pandapower Software: Computational Performances of Newton–Raphson, Newton–Raphson with Iwamoto Multiplier, and Gauss– Seidel Methods
J. Vysocký, L. Foltyn, D. Brkić, R. Praksová, P. Praks

Sustainability (2022). Vysocký, J.; Foltyn, L.; Brkić, D.; Praksová, R.; Praks, P. Steady-State Analysis of Electrical Networks in Pandapower Software: Computational Performances of Newton–Raphson, Newton–Raphson with Iwamoto Multiplier, and Gauss–Seidel Methods. Sustainability 2022, 14, 2002. https://doi.org/10.3390/su14042002

Abstract
At the core of every system for the efficient control of the network steady-state operation is the AC-power-flow problem solver. For local distribution networks to continue to operate effectively, it is necessary to use the most powerful and numerically stable AC-power-flow problem solvers within the software that controls the power flows in these networks. This communication presents the results of analyses of the computational performance and stability of three methods for solving the AC-power-flow problem. Specifically, this communication compares the robustness and speed of execution of the Gauss–Seidel (G–S), Newton–Raphson (N–R), and Newton–Raphson method with Iwamoto multipliers (N–R–I), which were tested in open-source pandapower software using a meshed electrical network model of various topologies. The test results show that the pandapower implementations of the N–R method and the N–R–I method are significantly more robust and faster than the G–S method, regardless of the network topology. In addition, a generalized Python interface between the pandapower and the SciPy package was implemented and tested, and results show that the hybrid Powell, Levenberg–Marquardt, and Krylov methods, a quasilinearization algorithm, and the continuous Newton method can sometimes achieve better results than the classical N–R method.
Abstract
At the core of every system for the efficient control of the network steady-state operation is the AC-power-flow problem solver. For local distribution networks to continue [...]
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Approximate flow friction factor: Estimation of the accuracy using Sobol’s Quasi-Random sampling
P. Praks, D. Brkić

Axioms (2022). Praks, P.; Brkić, D. Approximate Flow Friction Factor: Estimation of the Accuracy Using Sobol’s Quasi-Random Sampling. Axioms 2022, 11, 36. https://doi.org/10.3390/axioms11020036

Abstract
The unknown friction factor from the implicit Colebrook equation cannot be expressed explicitly in an analytical way, and therefore to simplify the calculation, many explicit approximations can be used instead. The accuracy of such approximations should be evaluated only throughout the domain of interest in engineering practice where the number of test points can be chosen in many different ways, using uniform, quasi-uniform, random, and quasi-random patterns. To avoid picking points with undetected errors, a sufficient minimal number of such points should be chosen, and they should be distributed using proper patterns. A properly chosen pattern can minimize the required number of testing points that are sufficient to detect maximums of the error. The ability of the Sobol quasi-random vs. random distribution of testing points to capture the maximal relative error using a sufficiently small number of samples is evaluated. Sobol testing points that are quasi-randomly distributed can cover the domain of interest more evenly, avoiding large gaps. Sobol sequences are quasi-random and are always the same, which allows the exact repetition of scientific results.
Abstract
The unknown friction factor from the implicit Colebrook equation cannot be expressed explicitly in an analytical way, and therefore to simplify the calculation, many explicit [...]
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An introduction to Digital Economy, Part 1
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 5
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Introduction to digital economy
S.

Entrepreneurship for Digital Economy (2022). Vol. Chapter 1 – Overview of the digital economy, 4
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Identical parallel-machine scheduling and worker assignment problem using genetic algorithms to minimize makespan
I. Chaudhry, S. Mahmood

Lecture Notes in Electrical Engineering (2011).

Abstract
dentical parallel machine scheduling problem for minimizing the makespan is a very important production scheduling problem which has been proven to be NP-hard. The problem further compounds with additional constraints. Genetic algorithms (GA) have shown great advantages in solving the combinatorial optimization problem in view of its characteristic that has high efficiency and that is fit for practical application. In this chapter we present a spreadsheet based GA approach for minimizing the makespan for scheduling of a set of tasks for identical parallel machines and worker assignment to machines. The results obtained from the proposed approach are compared with two sets of benchmark problems consisting of 100 problems each. It has been demonstrated that the performance of proposed approach is superior to the results that have been obtained earlier. The proposed approach produces optimal solution for almost 95% of the problems demonstrating the effectiveness of the proposed approach. An empirical analysis of GA parameters has also been carried out to see the effect on the performance of the proposed algorithm.
Abstract
dentical parallel machine scheduling problem for minimizing the makespan is a very important production scheduling problem which has been proven to be NP-hard. The problem [...]
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A research survey: review of flexible job shop scheduling techniques
I. Chaudhry, A. Khan

International Transactions in Operational Research (2016).

Abstract
In the last 25 years, extensive research has been carried out addressing the flexible job shop scheduling (JSS) problem. A variety of techniques ranging from exact methods to hybrid techniques have been used in this research. The paper aims at presenting the development of flexible JSS and a consolidated survey of various techniques that have been employed since 1990 for problem resolution. The paper comprises evaluation of publications and research methods used in various research papers. Finally, conclusions are drawn based on performed survey results. A total of 404 distinct publications were found addressing the FJSSP. Some of the research papers presented more than one technique/algorithm to solve the problem that is categorized into 410 different applications. Selected time period of these research papers is between 1990 and February 2014. Articles were searched mainly on major databases such as SpringerLink, Science Direct, IEEE Xplore, Scopus, EBSCO, etc. and other web sources. All databases were searched for “flexible job shop” and “scheduling” in the title and
Abstract
In the last 25 years, extensive research has been carried out addressing the flexible job shop scheduling (JSS) problem. A variety of techniques ranging from exact methods [...]
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A layered genetic algorithm with iterative diversification for optimization of flexible job shop scheduling problems
I. Chaudhry

Advances in Production Engineering & Management (2020).
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Integrated process planning and scheduling using genetic algorithms
I. Chaudhry

Tehnički Vjesnik–Technical Gazette (2017).
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Minimisation of total tardiness for identical parallel machine scheduling using genetic algorithm
I. Chaudhry, I. ELBADAWI

Sadhana – Academy Proceedings in Engineering Sciences (2017).

Abstract
In recent years research on parallel machine scheduling has received an increased attention. This paper considers minimisation of total tardiness for scheduling of n jobs on a set of m parallel machines. A spread-sheet-based genetic algorithm (GA) approach is proposed for the problem. The proposed approach is a domain-independent general purpose approach, which has been effectively used to solve this class of problem. The performance of GA is compared with branch and bound and particle swarm optimisation approaches. Two set of problems having 20 and 25 jobs with number of parallel machines equal to 2, 4, 6, 8 and 10 are solved with the proposed approach. Each combination of number of jobs and machines consists of 125 benchmark problems; thus a total for 2250 problems are solved. The results obtained by the proposed approach are comparable with two earlier approaches. It is also demonstrated that a simple GA can be used to produce results that are comparable with problem-specific approach. The proposed approach can also be used to optimise any objective function without changing the basic GA routine.
Abstract
In recent years research on parallel machine scheduling has received an increased attention. This paper considers minimisation of total tardiness for scheduling of n jobs [...]
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Minimising total flowtime in a no-wait flow shop (NWFS) using genetic algorithms
I. Chaudhry

Ingeniería e Investigación (2018).

Abstract
This paper considers a no-wait flow shop scheduling (NWFS) problem, where the objective is to minimise the total flowtime. We propose a genetic algorithm (GA) that is implemented in a spreadsheet environment. The GA functions as an add-in in the spreadsheet. It is demonstrated that with proposed approach any criteria can be optimised without modifying the GA routine or spreadsheet model. Furthermore, the proposed method for solving this class of problem is general purpose, as it can be easily customised by adding or removing jobs and machines. Several benchmark problems already published in the literature are used to demonstrate the problem-solving capability of the proposed approach. Benchmark problems set ranges from small (7-jobs, 7 machines) to large (100-jobs, 10-machines). The performance of the GA is compared with different meta-heuristic techniques used in earlier literature. Experimental analysis demonstrate that solutions obtained in this research offer equal quality as compared to algorithms already developed for NWFS problems.
Abstract
This paper considers a no-wait flow shop scheduling (NWFS) problem, where the objective is to minimise the total flowtime. We propose a genetic algorithm (GA) that is implemented [...]
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