Núm. 1 - Sostenibilidad y reciclaje - Fabricación

• 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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• 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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• 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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• LIFE CYCLE ASSESSMENT OF LATTICE JOIST PRECAST SLABS WITH TIRE RUBBER RESIDUE ADDITION

  D. Sampaio, A. Sanches, J. AKASAKI

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 160

  
  

  Abstract

  The methodology that integrates the three sustainability pillars, from a life cycle perspective, is called Life Cycle Sustainability Assessment (LCSA). LCSA provides the highest level of assessment among the existing tools, as it allows a holistic understanding of the sustainability of products and processes, which translates into better support for decision-makers. In this work, LCSA was carried out considering the combined application of the Life Cycle Assessment (LCA), Life Cycle Costing (LCC) and Social Life Cycle Assessment (SLCA), to evaluate and compare the environmental, social and economic impacts of lattice joist precast slabs based on three scenarios: (I) conventional concrete, (II) slabs produced from concrete with the addition of tire rubber residue, (III) slabs produced from concrete with the addition of tire rubber residue and rice hulk ash (RHA). The SimaPro software and the Ecoinvent database were used to conduct the analyses, in addition to prices from local construction materials suppliers and official public data on Brazilian society. The Life Cycle Impact Assessment methods used were ReCiPe 2016 Midpoint Hierarquist v.1.01, in the environmental pillar; material acquisition, transportation and energy costs in the economic pillar; Reference Scale Approach focused on the category Workers in the social pillar. It was possible to conclude that Scenario I was the most adequate alternative, even though it did not have alternative materials in its composition. The replacement of tire rubber waste by sand in Scenarios II and III proved to be disadvantageous from the point of view of sustainability, even with the slight improvement by also replacing part of the cement with RHA in Scenario III. 

  Abstract
  The methodology that integrates the three sustainability pillars, from a life cycle perspective, is called Life Cycle Sustainability Assessment [...]

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• SELF-HEALING STRATEGIES IN RUBBER COMPOSITES

  S. Utrera-Barrios, J. Araujo-Morera, R. Manzanares, R. Verdejo, M. López-Manchado, M. Hernandez Santana

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 107

  
  

  Abstract

  Inspired by some of the mechanisms that occur in nature, self-healing materials are characterized by the ability to recover, partially or totally, their initial properties after suffering damage. These materials constitute an efficient alternative for extending the lifecycle of products, as well as for reducing the amount of waste generated. At the same time, they reduce maintenance and repair costs. In this work, examples of recent developments in the field of elastomeric composite materials are presented, studying different matrices, natural rubber (NR), epoxidized natural rubber (ENR), styrene-butadiene rubber (SBR) and nitrile rubber (NBR), and using diverse repair strategies, hydrogen bonds, disulfide exchange reactions, Diels-Alder chemistry and ionic interactions. The effect of adding carbon-derived reinforcing fillers (graphene oxide) and sustainable alternative fillers (ground tire rubber) is also analyzed. It is studied how the presence and type of filler influences the healing capacity of elastomeric matrices, reaching repair efficiencies of up to ~80%, without detriment to their mechanical performance.

  Abstract
  Inspired by some of the mechanisms that occur in nature, self-healing materials are characterized by the ability to recover, partially or totally, their initial properties [...]

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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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• 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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• 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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• Optimization of mechanical properties by the impregnation velocity control in infusion processes

  J. Almazán*, E. López, F. Díaz

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 1 - Sostenibilidad y reciclaje - Fabricación), 167

  
  

  Abstract

  Reducing defects in manufacturing processes is one of the greatest challenges in the composites industry. This reduction mean an increment in the mechanical properties, repeatability and optimized structural weight. It is known the relationship between the impregnation velocity and the amount of defects, especially air entrapment in liquid impregnation processes. Its consequences are highlighted in the resin infusion process, where the flow velocity is not constant throughout the process. Such heterogeneity leads to non-homogeneous mechanical properties in the material. This work is base on the development of a methodology to control the impregnation process. It has demonstrated a substantial improvement in the mechanical properties when the flow velocity is controlled and kept around the optimum value.The methodology aims to identify the optimum impregnation velocity value through experimentation, and then, this value is applied during during the whole infusion process. For this purpose, an artificial vision system has been used, which allows keeping the flow velocity constant and near to the optimum value which optimize the mechanical properties. Its experimental application in both conventional and stitched laminates has shown an increase in the tensile and impact mechanical properties. At the same time, level of control of the infusion process has been enhanced.

  Abstract
  Reducing defects in manufacturing processes is one of the greatest challenges in the composites industry. This reduction mean an increment in the mechanical properties, repeatability [...]

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Núm. 2 - Aplicaciones Industriales - Caracterización

• 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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• Damage detection in a fiber reinforced polymers based tower of a floating offshore wind and tidal power platform using structural dynamic parameters

  P. Sierra, X. Martinez, R. Chacon, F. Otero, F. Turon

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 170

  
  

  Abstract

  The development of offshore renewable energy structures is growing at a fast pace, and their maintenance will become critical in further years. Because steel corrosion on offshore structures is one of their highest maintenance cost, researchers are working to replace steel by Fibre Reinforced Polymers (FRP), due to their immunity to corrosion. This is done in the EU H2020 funded project FIBREGY, which also seeks improving maintenance costs by incorporating Structural Health Monitoring (SHM) strategies. A critical issue in SHM is the damage detection process, which is addressed in this paper. This study aims to characterize the dynamic behaviour of an offshore windmill FRP tower, and its evolution due the presence of structural damage. This analysis will be carried out using a Finite Element Model (FEM) of the structure, and the Serial-Parallel mixing theory to characterize the material performance. A sensitivity analysis of the changes in the dynamic response of the tower (frequencies and modal shapes) produced by structural damage is carried out. This analysis will provide the optimum design variables and objective functions required by a damage detection algorithm. The algorithm is optimization based, since it converts the damage detection problem into a mathematical one, and finds the best design variables to minimize the objective function. The algorithm is also model based, as it uses the structural model to obtain the objective function for the proposed design variables. Finally, this work presents the analysis of a potential damage scenario, in order to evaluate if the damage is effectively detected.

  Abstract
  The development of offshore renewable energy structures is growing at a fast pace, and their maintenance will become critical in further years. Because steel corrosion on [...]

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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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• Fast and efficient manufacture of carbon fiber aeronautical preforms by using direct resistive heating

  A. Iriarte Legarreta, M. Segura, R. Mezzacasa, B. Canflaca

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 172

  
  

  Abstract

  The manufacture of preforms for composite structures is predominantly carried out in large hot drape forming facilities. However, these conventional heating sources are very inefficient since a large part of the heat provided is transferred to the molds in which the preforming process is carried out. This implies long heating and cooling times. In the current context in which it is essential to reduce the carbon footprint of each component, the reduction in the energy needed and in the cycle times to obtain competitive processes is fundamental. In this context, Tecnalia has developed an advanced preforming cell for the manufacture of dry fibre preforms for RTM or infusion components by applying direct resistive heating. The application of a current directly on the material to be processed has the advantage of avoiding the heating and cooling of molds and obtaining results in a much faster and more efficient way than with the methods traditionally used until now. The application of heating only to the preform guarantees the obtaining of much shorter cycle times, and a reduction in energy consumption of up to 90%. This results in a reduction in the cost of the process associated with lower energy consumption and shorter cycle time. The resistive preforming offers results of a quality of the preforms similar to that of conventional hot drape forming technology, being also a repetitive process, which has been validated by impregnating preforms tested under flight conditions.

  Abstract
  The manufacture of preforms for composite structures is predominantly carried out in large hot drape forming facilities. However, these conventional heating sources are very [...]

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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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• 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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• Experimental validation of a novel anti-buckling device for compression after impact tests

  F. Simón Fuentes, M. Jiménez, P. Luna, K. Muñoz, R. Ocaña, L. Vicente, J. Toral, R. Olmo

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 175

  
  

  Abstract

  Compression After Impact (CAI) test is normally used for the assessment of damage tolerance of composite laminates. The applicable specification for the execution of these tests is AITM 1-0010. However, for thicknessess under 4mm were buckling occurs, the applicable specification is the AITM 1-0077, which introduces the use of anti-buckling tooling covering the entire surface of the specimens. The tooling, which is used in the aeronautical industry  for the testing of thin specimens presents two problems which are the difficulty of assembly and of obtaining realiable results, and the visibility of the specimen during the test. This work comprises the design, manufacturing and validation of a novel anti-buckling device for compression after impact thin specimens. For that purpose, a study of the specification toolings along with a review of the already developed anti-buckling tooling literature has been carried. As part of the validation process three series of impacted specimens of 3mm thickness. This activity is developed as part of the project CERES, which is framed under Clean Sky 2, and has the main objective of validating the manufactured anti-buckling tooling. This tooling has been developed as an innovative solution for its application in compression after impact thin specimens. 

  Abstract
  Compression After Impact (CAI) test is normally used for the assessment of damage tolerance of composite laminates. The applicable specification for the execution of these [...]

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• Pseudo-ductility under tensile and compressive loading in ±45º laminates

  M. Serna Moreno, S. Horta Muñoz

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 176

  
  

  Abstract

  This work focuses on analyzing the uniaxial response of carbon fiber reinforced polymer matrix laminates with the configurations [±45]2S under tension and [±45]4S under compression. These present non-linear stress-strain evolutions that allow them to withstand large deformations before losing their load-carrying capacity. Both responses are characterized by a first linear stage, followed by a plateau in which the strain grows without increasing the stress level, and finally by a re-stiffening phase. But there are quantitative differences that lead to different failure patterns, which are explained with the help of the state of stress in the plane of maximum shear stress. For a better understanding of the process, tensile load-unload-reload tests are performed to verify if the energy recovered in each cycle could be related to the loss of the apparent stiffness. During the first two stages of the mechanical response, the laminate suffers a progressive damage with a reduction in stiffness related to the dissipated energy, but this pattern is not repeated in the last stage of strain hardening. Based on the experience of other authors, it is assumed that the re-stiffening stage follows a different pattern due to possible microstructural changes in the matrix during the plateau. These are promoted by a narrowing process under tensile loads and a local widening of the test zone under compression. The dimensional changes perpendicular to the load direction are observed thanks to the strain fields obtained by Digital Image Correlation.

  Abstract
  This work focuses on analyzing the uniaxial response of carbon fiber reinforced polymer matrix laminates with the configurations [±45]2S under tension and [±45]4S [...]

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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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• Two-plane bending test applied to unidirectional composite laminates

  U. Garitaonaindia, N. Carbajal, M. Isasa, F. Mujika

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 178

  
  

  Abstract

  This paper analyses the two-plane bending test to characterise the behaviour of unidirectional composite laminates. This test consists of a flat plate supported at four points to which a point force is applied at the centre. Currently, this configuration is not mathematically solved for orthotropic materials. Initially, the displacements and bending moments produced in plates of isotropic material have been analysed by means of numerical simulation and analytical approach. The results obtained have been corroborated with other works published in the scientific literature. Subsequently, the numerical models and the analytical development have been applied to plates formed with orthotropic material, in the configuration of the two-plane bending test. For this purpose, rectangular plates with different aspect ratio have been analysed in order to obtain different stress ratios along the fibre and perpendicular to it. Finally, the results obtained both by numerical simulation and by the analytical approach have been compared with experimental tests carried out on unidirectional composite specimens made of epoxy matrix and carbon fibre.

  Abstract
  This paper analyses the two-plane bending test to characterise the behaviour of unidirectional composite laminates. This test consists of a flat plate supported at four points [...]

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• Study of the influece of flame retardant additives on ultra-violet curing thermosetting composites

  N. Eulate, F. Vallejo, G. Goenaga, M. Urrutxua, J. Ballestero, P. Ares, A. Allue, J. Gómez

  Materiales Compuestos (2022). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 2 - Aplicaciones Industriales - Caracterización), 179

  
  

  Abstract

  Fibre-reinforced polymer composites are materials capable of reducing weight while maintaining optimised properties in multiple applications. However, the use of composite materials is not suitable for all sectors, where the need for improved fire properties is highlighted. In the present study, a thermosetting matrix composed of UV-curable acrylic monomers and UV-transparent aluminium trihydrate (ATH) flame retardant fillers have been added to UV-transparent polyester resin for the manufacture of flame retardant composites. An in-depth study of the most suitable types of ATH-based flame retardant additives and possible synergistic combinations to improve the fire performance of the UV-curable composite has been carried out. Not only has the type of flame retardant been studied, but also the most suitable additive percentage to comply with railway sector regulations. The compatibility between the fillers and the matrix has been analysed by means of dielectric analysis, as well as the properties of the matrix and final composites against fire and mechanical properties.

  Abstract
  Fibre-reinforced polymer composites are materials capable of reducing weight while maintaining optimised properties in multiple applications. However, the use of composite [...]

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Núm. 3 - Materiales y Estructuras - Modelos Numéricos

• VITRIMER RESIN DEVELOPMENT FOR AERONAUTICAL APPLICATION

  T. Blanco, E. Puerto*, N. Markaide*, A. Luzuriaga, A. Salaberria

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 1

  
  

  Abstract

  Due to the environmental challenges the aeronautical industry is facing, the development of recyclable aeronautical chemistries have recently raised huge interest. Within this context, different alternatives are being considered with the aim of obtaining new resins with current thermoset resin chemical and mechanical performance, while showing reprocessing, repairability and recyclability capabilities, like thermoplastics. New vitrimer resins, based on dynamic covalent chemistry, become a very attractive alternative to combine the main advantages of aeronautical thermosets (processing conditions / temperature, means, properties…) and thermoplastics (recycling, welding…). Therefore, they can be the solution to overcome the current limitations of thermoset epoxy resin, which is widely used in composite airframe. This project, framed within the national funding PTA (Plan Tecnológico Aeronáutico), was focused on the preliminary development of aeronautical vitrimer resin for composite airframe. It was proposed as continuation of the EU Horizon 2020 consortium AIRPOXY led by CIDETEC, where a first generation of aeronautical RTM vitrimer was developed and characterised, while a second generation vitrimer development was only started. This chemistry is based on the use of dynamic aromatic disulfides as hardener. In the first 2021 project phase, following key activities were performed: Definition of targets or reference values for aeronautical infusion resin Second generation of infusion vitrimer: development completion and characterization Flat CFRP laminates with second generation vitrimer: production and thermoforming trials. Next steps of the project in 2022 and 2023, will be focused on developing, evaluating and demonstrating an aeronautical prepreg based on vitrimer resin with higher Tg in line with current aeronautical resin values.

  Abstract
  Due to the environmental challenges the aeronautical industry is facing, the development of recyclable aeronautical chemistries have recently raised huge interest. Within [...]

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• TOWARDS COPOLYMERISATION OF STEREOSPECIFIC PROPYLENE NANOCOMPOSITES WITH POLAR COMONOMERS BY IN SITU POLYMERISATION. OPTIMISING MECHANICAL PROPERTIES

  K. Nuñez-Carrero, M. Asensio, J. Guerrero, M. Herrero, J. Pastor

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 2

  
  

  Abstract

  The use of different stereospecific metallocene catalysts: isotactic (iPP, C2-symmetry) and syndiotactic (sPP, Cs-symmetry) has been investigated in order to improve the mechanical properties of polypropylene/nanoclay nanocomposites obtained by in-situ polymerisation. Stereoregular nanocomposites have been synthetized in the presence of polar comonomers (1-undecenol (R-OH) and acid-undecenoic (R-COOH) for improving the matrix-nanoclay chemical compatibility. An important study of variables: amount of nanoparticles used as co-catalyst support, type of catalyst, type and amount of comonomer have been studied in a full factorial design of experiments in order to identify the main factors that achieve a balance between the stiffness and toughness of the polypropylene nanocomposites. Important results were found from ANOVA (analysis of variance): the nanoclay has a greater influence on the syndiotactic configuration and, the amount of polar comonomer is the main factor in maximising mechanical properties, irrespective of stereospecificity of the polypropylene nanocomposites.  

  Abstract
  The use of different stereospecific metallocene catalysts: isotactic (iPP, C2-symmetry) and syndiotactic (sPP, Cs-symmetry) has been investigated in order to improve the mechanical [...]

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• Novel Manufacturing Approaches For Car Body Shell Applications Based On Sandwich Structures

  L. Carral, L. Mera, A. Gutierrez, P. Rodriguez, X. Pérez, M. Pletting, S. Renner

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 3

  
  

  Abstract

  The transport sector has exerted and continue to be the driving force for the development of new materials and lightweigth solutions. The present study focuses on the work developed in a recently completed European project (CARBODIN https://carbodin.eu/) where one of the main objectives is to develop innovative and affordable solutions for advanced car body shells. Composite materials appear to be one of the most promising candidates to attain these ambitious targets. However, to overcome the cost barrier as well as meet additional railway requirements, new strategies such as process integration and novel manufacturing routes are needed, which will offer a cost-effective industrial solution. The case study corresponds to a C-Groove insert used as an anchoring point to hang passenger seats off the car body side walls, to fix Interior Panels or luggage racks. To improve this design, a trendsetting design was developed to integrate composite C-Grooves to Composite sidewalls. This work will display the details of such design as well as the optimal manufacturing strategy to achieve it. An out of autoclave (OoA) manufacturing process was assisted through different monitoring technologies such as resin arrival sensors and thermography to ensure high quality components. Additionally, a multi-material approach based on 3D printed technologies has been tackled. A thorough analysis of the joint has been performed and different integration approaches have been explored by designing co-cured and co-bonded manufacturing stages. Finally, several demonstrators have been made and tested to define the most promising integration approach and scaling up yet again to a larger demonstrator.

  Abstract
  The transport sector has exerted and continue to be the driving force for the development of new materials and lightweigth solutions. The present study focuses on the work [...]

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• AEROPLAS – Desarrollo de componentes para la industria aeronáutica mediante tecnologías de bajo coste

  . , S. Pintos

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 4

  
  

  Abstract

  El futuro del sector aeronáutico está orientado a fabricar estructuras y componentes más ligeros y rentables, empleando materiales y tecnologías más ecológicos que permitan reducir costes, peso y consumo de combustible con ciclos de fabricación más cortos, a la vez que se aumenta la eficiencia energética en la fabricación. En este contexto surge el proyecto AEROPLAS, con el objetivo de contribuir al proceso de fabricación avanzada de composites termoplásticos utilizando tecnologías de bajo coste para la industria aeronáutica. En el presente estudio se abarca la sustitución de piezas aeronáuticas fabricadas actualmente en composite termoestable por composite termoplástico, en dos componentes reales: panel de cubierta y puerta de acceso del carenado ventral del A350, empleando dos materiales de distinta calidad: un semipreg de LM-PAEK/CF (TenCate Cetex® TC1225) y un prepreg de PC/CF (ePreg245CHT/PC40). Mediante diseño y cálculo, se han obtenido los apilados y espesores de pieza necesarios para cubrir los requerimientos estructurales de ambos componentes, a partir de los datos obtenidos de la caracterización de los materiales de partida. Se han estudiado y comparado dos procesos de fabricación para la obtención de las nuevas piezas, seleccionando el termoformado y la estampación como los más prometedores. Por último, se ha llevado a cabo la caracterización de las piezas obtenidas mediante ensayos no destructivos (inspección visual, verificación por ultrasonidos, inspección dimensional mediante laser tracker) y destructivos (tracción en sentido plano [AITM1-0066], resistencia al aplastamiento [AITM1-0009], resistencia a tracción del laminado [AITM1-0007], resistencia a tracción de unión atornillada [AITM1-0067]).

  Abstract
  El futuro del sector aeronáutico está orientado a fabricar estructuras y componentes más ligeros y rentables, empleando materiales y tecnologías [...]

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• Micromechanical modeling of the non-linear behaviour of angle-ply laminates under different plane-stress states

  S. Horta Muñoz, M. Serna Moreno, D. Garoz, R. Sevenois, W. Paepegem

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 5

  
  

  Abstract

  The non-linear behaviour ocurring in symmetrical angle-ply laminates formed by unidirectional layers of carbon fiber reinforced polymeric matrix (CFRP), known as pseudo-ductility, has been previously studied numerically and experimentally under different uniaxial, biaxial and bending loads. This phenomenon is associated with different mechanisms which affect the mechanical behaviour of the material: large permanent strains, fiber reorientation and matrix cracking. The present study is based on a microscale approach through simulations based on the Finite Element Method (FEM), with the aim of predicting the homogenized response of these laminates subjected to multiaxial in-plane. The micromechanical model is based on a Representative Volume Element (RVE) where Periodic Boundary Conditions (PBC) are applied, together with a non-linear material model of the matrix and a cohesive interface between fibre and matrix. In addition, the implementation of the model is updated to be able to reproduce any plane stress state in a [±45]S laminate, without the need to add other meso- or macroscale models.

  Abstract
  The non-linear behaviour ocurring in symmetrical angle-ply laminates formed by unidirectional layers of carbon fiber reinforced polymeric matrix (CFRP), known as pseudo-ductility, [...]

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• Design of toroidal Pressure Vessels for Hydrogen Trains using FEM and Artificial intelligence Techniques

  A. CORZ, D. Patiño-Perez, M. Lopez

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 6

  
  

  Abstract

  One of the main objectives in the design of HSS (Hydrogen Storage Systems) containers for trains is to be able to store hydrogen as a compressed gas at a pressure of 70MPa and to consider the stresses and fatigue cycles due to loading and unloading (type IV tanks). ); In addition, failure analysis by means of finite elements for the generation of toroidal models will be included in the study. Given that another aspect of the design is to be able to rationalize the price of HSS tanks, by optimizing the geometry and thickness of CFRP (Carbon Fiber Reinforced Polymer), which generally represents 50% of the total price, and which It can be done through one of Ansys' own optimization methods that provides a reliable result at a high computational cost for each new container pattern that is modelled; Through the use of artificial intelligence techniques, a model will be created that has the capacity to learn from the characteristics of each new container model, but at a low computational cost and with a high level of reliability; the prediction methodology will be based on a regression and classification model through supervised learning and deep learning techniques through the use of artificial neural networks implemented on Keras, reliable results will be obtained that will speed up virtual tests in the design of a resistant container, light and with a high storage capacity.  

  Abstract
  One of the main objectives in the design of HSS (Hydrogen Storage Systems) containers for trains is to be able to store hydrogen as a compressed gas at a pressure of 70MPa [...]

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• Curing distortion simulation applied to thermoset CFRP components

  J. González Cantero, S. Van-der-Veen, P. Bourbon

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 7

  
  

  Abstract

  Manufacturing Process Simulation (MPS) is on the rise nowadays to predict manufacturing defects and deviations, especially during the design phases where it allows the engineers to take earlier decisions and helps to reduce the manufacturing trials to go for a Right at First Time philosophy. MPS, focusing on composite materials, lies on the physical and chemical behavior of the material during the different stages of manufacturing (e.g. forming, infusion, curing, etc.) to predict defects, distortion and residual-stresses in the final component. Airbus Group has developed simulation tools and defined procedures to obtain an accurate prediction of the shape of a thermoset CFRP component. These simulations are run by using a high-fidelity description of the material considering its chemical and physical behavior during the full curing cycle. Curing distortion shape is obtained by simulating the cure cycle on the properly meshed component. This procedure is shown on an industrial component, where the final deformation is validated with experimental measurements and it is linked with additional manufacturing process simulations. The experience gained shows that future research should focus on linking up simulations of successive manufacturing steps: start by simulating the lay-up process or the forming, then carry across predicted fields such as real local fiber angle and volume fraction into the curing distortion prediction and so on up to high-fidelity simulation of the assembly of the airframe.  A particular point of interest is the viscoelastic behavior in post-curing, as well as the analysis of the stress relaxation in ply overlaps during curing.

  Abstract
  Manufacturing Process Simulation (MPS) is on the rise nowadays to predict manufacturing defects and deviations, especially during the design phases where it allows the engineers [...]

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• Comparative study of the mechanical properties of carbon fiber composite materials for the development of aeronautical structural elements

  J. Sánchez Garrucho, M. Jiménez, N. Muñoz, P. Luna, K. Muñoz, M. Iglesias, L. Rubio, F. Martín

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 8

  
  

  Abstract

    Carbon fibre reinforced polymer composite material structures continue to be, despite the tremendous technological maturity achieved in recent decades, one of the most promising options to address the challenges of the aeronautical industry with respect to behaviour in the face of efforts such as improvements, regarding weight or costs. Ongoing demands to address major societal challenges, promote industrial leadership in Europe, and address aviation decarbonisation for the purpose of protecting the environment drive the demand for more optimal materials designed to improve these aspects. The previous tasks carried out to complete the test campaign will be described, showing its plan and design, details of preparation, assembly of the specimens and the execution of the tests. The philosophy proposed by Airbus (ADS) is presented with the consolidation of admissible design against alterations of the material that could realize its evolution or arise in the manufacturer's batches. Observing changes in the material, leading to the improvement of its mechanical and handling characteristics, a comparison has been made by Airbus with the one used previously for the determination of admissible design. It is intended to incorporate assessments of effects associated with the process of its industrialization. Once the results and analyzes are available, the normalized results of the conclusions would be presented. The activity carried out is included within the CERES project (Advanced Rear End Structural test program), belonging to the Clean Sky 2 Joint Undertaking European research aeronautical program.

  Abstract
    Carbon fibre reinforced polymer composite material structures continue to be, despite the tremendous technological maturity achieved in recent decades, one of the [...]

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• Development of more sustainable PUR formulations for structural applications

  O. Echeverria Altuna, O. Ollo, I. Harismendy, A. Eceiza

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 9

  
  

  Abstract

  The industry decarbonization has become in a fundamental challenge for the industries such as automotive or wind power. In this way, the structural components lightening is one of the principal issues for material manufacturers. For this objective, the composites are a competitive alternative, due to their unique relation between their strength and weight. Among the different structural composite part fabrication processes, liquid composite moulding (LCM) is one of the most interesting, due to its efficiency in terms of costs, time and energy consumption. In this sense, resins with fast cure and low viscosity are gaining attention, among them polyurethanes are of particular interest. This family of polymers is characterized by its great versatility, among them high-performance thermosetting polyurethanes (PUR). The advantages offered by PUR-based technology are great fatigue resistance, low viscosity and fast cure. However, the commonly used PUR’s for structural applications have some environmentally drawbacks, such as their components petrochemical origin and their low recyclability. For this reason, the aim of this work was the development of a more sustainable PUR formulation with the required mechanical properties for structural applications and suitable processability for LCM processes. Because of that, this work has focused on the analysis, synthesis and characterization of new PUR formulations and also the manufacturing process simulation and optimization.

  Abstract
  The industry decarbonization has become in a fundamental challenge for the industries such as automotive or wind power. In this way, the structural components lightening is [...]

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• AUTOMATIZATION IN NEW MANUFACTURING APPROACHES FOR BODY SHELL APPLICATIONS

  A. Gutierrez, L. Mera, L. Carral, I. Coto, F. Ansedes, M. Plettig, S. Renner

  Materiales Compuestos (2023). Vol. 07 - COMUNICACIONES MATCOMP21 (2022), (Núm. 3 - Materiales y Estructuras - Modelos Numéricos), 12

  
  

  Abstract

  The transport sector has exerted and continue to be the driving force for the development of new materials and lightweight solutions. The present study focuses on the work developed in a European project (CARBODIN https://carbodin.eu/) where one of the main objectives is to develop innovative and affordable solutions for advanced car body shells. Thus, contributing to the development of the next generation of passenger trains that will be lighter as well as more energy- and cost-efficient. Composite materials appear to be one of the most promising candidates to attain these ambitious targets. Therefore, new strategies to achieve greater automation are presented as novel manufacturing routes and offer a cost-effective industrial solution. This study has allowed the integration of unconventional technologies, such as AFP, within conventional production systems, such as VIP, which is the key to developing sustainable units, overcoming the common difficulties associated with processing and achieving the modularity of the manufacturing process and the reduction of the weight of the final rail structure. For this reason, a comparison of the manufacture of both monolithic composites and sandwich structures have been obtained through the VIP process, manufactured in an automated and manual way. Several automated approaches have been studied, with the choice of the robotized lay up of bindered dry fibers. An out of autoclave manufacturing was assisted through different monitoring technologies such as resin arrival sensors and thermography in order to ensure high quality components.

  Abstract
  The transport sector has exerted and continue to be the driving force for the development of new materials and lightweight solutions. The present study focuses on the work [...]

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