Documents published in 2024 : Scipedia

In-Situ Strain Measurement of Concrete Micro-Piles under Loading using Distributed Fiber Optic Sensing Systems
M. Terceros, A. Méndez, W. Paniagua, F. Carrion

Latam-SHM 2023.
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Experimental Investigation of Post-Tensioned Anchored Trunnion Rods of Navigation Structures
W. Zatar, H. Nghiem

Latam-SHM 2023.
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Asset Predictive Maintenance in Hydroelectric Power Station based on Convolutional Autoencoder and Novelty Detection Techniques
A. Ruales-Torres, B. Mancipe-Barrero, M. Jaramillo-Romero, Ó. Cardona-Morales

Latam-SHM 2023.
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Detection of Lossy Bolts in a Jacket-Type Wind Turbine Support Using a Vibration-Only Response Mechanism Based on Accelerometer Data
R. Prieto-Galarza, C. Tutivén, Y. Vidal

Latam-SHM 2023.
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Advancing Wind Turbine Reliability: Machine Learning-Based Early Detection of Rotor Imbalance for Proactive Maintenance Strategies
I. González, C. Tutivén, Y. Vidal

Latam-SHM 2023.
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Advancing Wind Turbine Safety: Vibration-Based Early Detection of Blade Ice Accumulation Using Extended Isolation Forest
A. Gómez, C. Tutivén, Y. Vidal

Latam-SHM 2023.
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Wind Turbine Gearbox Condition Monitoring Using Vibration Data and Mel-Frequency Cepstral Coefficients
C. Velandia-Cardenas, Y. Vidal, F. Pozo

Latam-SHM 2023.
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Nonlinear Tracking of Dynamic Properties in a Structure from Service condition to collapse
F. Consuegra, C. Marulanda

Latam-SHM 2023.
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Identification of Local Defect Resonances using global and local mode separation procedure
A. Klepka, M. Krzemiński, L. Pieczonka

Latam-SHM 2023.
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A variable-size iFEM for real time shape sensing of a large honeycomb antenna panel – LATAM-SHM 2023
T. Dong, S. Yuan, T. Huang

Latam-SHM 2023.
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Structural Damage Identification based on the Curvature Matrix of the Accelerance
J. Herrera

Latam-SHM 2023.
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Implementation of Seismic Eco-Isolators in a vehicular bridge
J. Martínez, A. Álvarez, F. Guerrero, A. Ortiz, J. Marulanda

Latam-SHM 2023.
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Modal Filtration without calculation of the modal model
Z. Dworakowski, K. Mendrok

Latam-SHM 2023.
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Implementation of Bayesian Model Updating in Five-Story Building
O. Hurtado, A. Ortiz, D. Gomez, P. Thomson

Latam-SHM 2023.
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Comparative assessment of data normalization methods for modal-based SHM
S. Gómez, A. Occhiuzzi, C. Rainieri

Latam-SHM 2023.
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Automated Modal Identification of Operational Wind Turbines Blades
F. Bravo, R. Astroza, M. Orchard

Latam-SHM 2023.
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Lamb Wave Analysis and Damage Detection in a Skin-stringer Composite Joint
L. Šedková, O. Vích, J. Šedek

Latam-SHM 2023.
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Numerical and experimental study for the identification of defects in wind turbine blades by infrared thermography
B. Topilko, Z. Salloum, B. Méthot, H. Loaiza-Correa, A. Restrepo, X. Madalgue

Latam-SHM 2023.
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Pattern recognition and damage detection in the "Energética 2030" wind turbine fiber glass tower through machine learning
S. Rodriguez, J. Sierra-Pérez, C. Blandón, M. Paz-Duque

Latam-SHM 2023.
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EmoGame: Unraveling Emotional Correlations in Teen Video Gamers for Health Monitoring Insights - Biomedical Analysis of the Emotional Impact of Fortnite and Minecraft
S. Clemente, P. Spoletini, M. Valero, A. Sim, A. Randolph

Latam-SHM 2023.
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Vibration Based Harvester for Wind Turbines
C. Castellano-Aldave, A. Plaza, X. Iriarte, A. Carlosena

Latam-SHM 2023.
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New generation of generic synchronized wireless sensors for shm
A. Bouché, V. Cam, L. Lemarchand

Latam-SHM 2023.
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Fault detection in industrial pumps based on recurrent autoencoder neural networks
V. Meruane, T. Hansen, I. Huerta, E. Roa, L. Quinteros, J. Marín

Latam-SHM 2023.
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Robust adaptive fault tolerant control for nonlinear systems with actuator failure and mismatched disturbance
X. Tao, J. Jiang

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 8

Abstract
In this paper, a class of nonlinear system with mismatched disturbance and actuator failure is investigated. A disturbance observer is proposed to estimate the disturbance first and the error of the estimation converges to zero exponentially. By introducing an integral sliding mode surface, the disturbance observer based integral sliding mode fault tolerant control scheme is proposed to attenuate the disturbance and to guarantee the stability of the system. Specially, the control law is designed for decoupling the partial disturbance and attenuating the disturbance that cannot be decoupled. Finally, two examples are given to illustrate the effectiveness of the proposed method. Index Terms—Actuator fault, Fault tolerant control (FTC), Disturbance observer, Adaptive Integral Sliding mode control, Nonlinear system.
Abstract
In this paper, a class of nonlinear system with mismatched disturbance and actuator failure is investigated. A disturbance observer is proposed to estimate the disturbance [...]
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The Implications of Selective Serotonin Reuptake Inhibitors Towards Adolescent Depression
H. Jacqmotte

J. of Dawn. R. (2024). Vol. 6, 2

Abstract
The current scientific understanding of adolescent depression is incomplete, requiring further research and attention. This review of Selective Serotonin Reuptake Inhibitors (SSRIs) in the context of adolescent depression seeks to inform adolescents about the mechanisms in which SSRIs affect the body, common side effects associated with this class of antidepressants, and the efficacy rates of SSRIs in their population group. This review also underscores the gaps in research regarding both adolescent depression and adolescent antidepressant usage. When considering the use of prescription drugs, especially ones that have large implications towards neurological function, it is essential to understand all facets of the medication. This review provides adolescents and their families with direct information that will inform their thinking about SSRI use. This review considers academic and popular sources in collating evidence for the impact and efficacy of SSRIs on adolescents. Through careful analysis of the consequences and benefits associated with SSRI usage, this review provides a comprehensive scientific overview of SSRIs. To inform adolescents and their families, this review will first offer a mechanistic overview of the SSRI drug class, next evaluate evidence for the neurological effects of SSRIs on the adolescent brain, and then highlight clinical testing of two specific SSRIs, Fluoxetine and Escitalopram. Both the implications of SSRIs on adolescent brain development and their possible short-term and long-term negative side effects are considered in this review. Most importantly, this review draws attention to the multitude of unknowns surrounding SSRI usage in adolescents and urges researchers to continue evaluating the implications of early antidepressant usage. With an adolescent centered viewpoint and a focus on extensivity, this report provides adolescents and their families with the resources to make personalized decisions about SSRI exposure.
Abstract
The current scientific understanding of adolescent depression is incomplete, requiring further research and attention. This review of Selective Serotonin Reuptake Inhibitors [...]
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Automated Detection of Surface Defects on Razor Blades through Video Analysis
L. Chen

Collection of Engineering (2024). 1

Abstract
In the manufacturing process of razor blades, the presence of surface defects directly impacts their quality and lifespan. Manual detection of these defects is not only inefficient but also susceptible to external interference. To achieve real-time and stable detection of blade defects, a method based on video analysis was proposed in this paper. Raw surface images of the blades were captured using a computer vision system, and binarization was performed using Otsu's algorithm. Subsequently, contours were identified and preliminarily analyzed using the CCL algorithm to obtain Regions of Interest (ROI). The ROI was then sorted, and subtle defects were filtered out through morphological analysis. A mask was obtained by comparing the ROI with a background model constructed based on frame averaging. Through mask analysis, defect types were determined, achieving efficient detection of surface defects on razor blades. Experimental results demonstrated that the proposed method enabled real-time detection of multiple defect types simultaneously.
Abstract
In the manufacturing process of razor blades, the presence of surface defects directly impacts their quality and lifespan. Manual detection of these defects is not only inefficient [...]
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Two iterative methods for sizing pipe diameters in gas distribution networks with loops
D. Brkić

Computation (2024). Brkić D. Two Iterative Methods for Sizing Pipe Diameters in Gas Distribution Networks with Loops. Computation. 2024; 12(2):25.

Abstract
Closed-loop pipe systems allow the possibility of the flow of gas from both directions across each route, ensuring supply continuity in the event of a failure at one point, but their main shortcoming is in the necessity to model them using iterative methods. Two iterative methods of determining the optimal pipe diameter in a gas distribution network with closed loops are described in this paper, offering the advantage of maintaining the gas velocity within specified technical limits, even during peak demand. They are based on the following: (1) a modified Hardy Cross method with the correction of the diameter in each iteration and (2) the node-loop method, which provides a new diameter directly in each iteration. The calculation of the optimal pipe diameter in such gas distribution networks relies on ensuring mass continuity at nodes, following the first Kirchhoff law, and concluding when the pressure drops in all the closed paths are algebraically balanced, adhering to the second Kirchhoff law for energy equilibrium. The presented optimisation is based on principles developed by Hardy Cross in the 1930s for the moment distribution analysis of statically indeterminate structures. The results are for steady-state conditions and for the highest possible estimated demand of gas, while the distributed gas is treated as a noncompressible fluid due to the relatively small drop in pressure in a typical network of pipes. There is no unique solution; instead, an infinite number of potential outcomes exist, alongside infinite combinations of pipe diameters for a given fixed flow pattern that can satisfy the first and second Kirchhoff laws in the given topology of the particular network at hand.
Abstract
Closed-loop pipe systems allow the possibility of the flow of gas from both directions across each route, ensuring supply continuity in the event of a failure at one point, [...]
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Research on early fault detection method for a new distribution system based on automatic arc power
L. Wang, X. Chen, Y. Zhao, J. Yang, H. Zou

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (2), 15

Abstract
'''The integration of a large amount of renewable energy sources into the new distribution system has significantly altered its fault characteristics, resulting in variable operation modes and limited short-circuit currents. Hence, early arc faults can serve as indicators of impending system short-circuits, and prevent the difficulty of tripping the new distribution system by effectively detecting them in advance. A quantitative analytical model for the early fault current and temperature is developed, and a theoretical analysis reveals the challenges of achieving reliable detection based solely on either current or temperature. A novel early fault detection method that combines current and temperature is proposed, which further utilizes arc power as a complex feature to identify early faults. The proposed feature integrates the promptness of the electrical signal (zero-sequence current) and the high sensitivity and reliability of the thermal signal (temperature), and exhibits higher reliability than the existing method. The validity of the proposed method is verified by PSCAD simulation, field data and laboratory simulated fault tests. '''Key words''': Early arc faults; Fault detection method; New distribution system; Arc model; Compound eigenquantity criterion.
Abstract
'''The integration of a large amount of renewable energy sources into the new distribution system has significantly altered its fault characteristics, resulting [...]
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Jugular Vein Compression Collars for Mitigating Traumatic Brain Injuries in High-Impact Activities: A Narrative Review
F. Syed, S. Khan, M. Toma

J. of Dawn. R. (2024). Vol. 6, 1

Abstract
The "Q-Collar" is a device designed to mitigate head injuries, particularly in scenarios such as contact sports and military operations where trauma to the head is a significant risk. It operates by exerting an external compressive force on the jugular veins, which effectively increases blood volume within the brain to counteract the "slosh" effect—that is, the movement of the brain within the skull during sudden impacts. The research documented in this literature review investigates the Q-Collar's efficacy by examining various clinical studies, as well as animal models, to understand its role and proven effects on reducing head trauma. This review includes 21 studies that were identified through a literature search using keywords related to "Jugular Vein Compression Collar" in the PUBMED database. The discussion highlights the physiological mechanism behind the Q-Collar's function: by compressing the jugular veins, it reduces the compliance of the cranial cavity, thereby stabilizing the brain and decreasing the risk of traumatic brain injury. The review finds evidence of the Q-Collar's effect in increasing intracranial and intraocular pressures, which suggests a mechanical countermeasure to the destabilizing effects of brain movement after an impact. Moreover, the findings include significant data from studies on high school athletes and special forces personnel, showing that Q-Collar users exhibited fewer microstructural brain alterations, better maintenance of cognitive functions, and fewer changes in white matter integrity than their non-collared counterparts. Preclinical small animal studies similarly present a reduction in inflammatory biomarkers associated with brain injury, indicating the collar's potential in protecting against histopathological changes. Research on the Q-Collar's use following blast exposure in military training shows additional benefits in memory function protection and auditory processing, as well as reduced auditory injury and tympanic membrane rupture, augmenting the case for the collar's protective effects. Finally, the review also touches on a potential application for patients with orthostatic hypotension, given the collar's influence on carotid baroreceptor-induced sympathetic activity. Hence, while the body of evidence under review supports the notion that the Q-Collar may be a valuable adjunct to helmets in the prevention of traumatic brain injuries, the review calls for further, longer-term studies to fully understand the extent of its benefits and potential limitations. The collective findings so far point towards a positive impact of the Q-Collar in scenarios of head trauma, with the device contributing to protective anatomical and functional changes within the brain. However, the nature of these studies—predominantly short-term and focusing on immediate or season-long effects—highlights the need for future research that extends beyond these temporal boundaries.
Abstract
The "Q-Collar" is a device designed to mitigate head injuries, particularly in scenarios such as contact sports and military operations where trauma to the head [...]
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Serbian Energy Sector in a Gap Between East and West
D. Brkić

Serbian energy sector in a gap between east and west (2024). 1. Brkić, D. (2024). Serbian energy sector in a gap between east and west. Energy Exploration & Exploitation, Vol. 42, No. 1, 330-340., https://doi.org/10.1177/01445987231215445, eISSN 2048-4054 (online version) - ISSN 0144-5987 (printed version)

Abstract
Serbia’s energy sector is heavily reliant on Russian inﬂuence. On the other hand, Serbia’s status as a candidate country for joining the European Union (EU) membership requires active working toward diversifying energy sources of supply. In the past decade, Serbia has secured a reduced price for natural gas through a bilateral agreement with Russia, addressing the shortfall in its domestic production. The former agreement priced Russian gas at US$270 per thousand cubic meters and expired in 2021. The new deal links gas prices to crude oil and ranges between US $310 and US$408, maintaining its competitive position as one of Europe’s lowest import prices. Furthermore, alongside the new gas pipeline for Russian gas exports, the EU is funding the construction of a new interconnector, both with entry points from Bulgaria. Serbia also faces signiﬁcant dependence on crude oil, and this reliance is compounded by the inability to import it from Russia any longer. Opposite, Serbia is usually self-sufﬁcient in electricity production which still remains under state ownership. The domestic exploration and processing of oil and gas, as well as the sole underground gas storage facility in Serbia, have partial ownership by Russian Gazprom while the transportation of gas is under the full control of the Serbian government. This Communication about the energy situation in the Republic of Serbia put particular emphasis on the evolving political dynamics in the global energy market with a speciﬁc focus on the Russia– Ukraine war. The topic is also linked to the contentious status of the southern Serbian autonomous province, recognized as an independent state by the majority of Western nations but not by Serbia. It is feared that Serbia’s energy dependence on Russia could have signiﬁcant ramiﬁcations for its EU candidacy.
Abstract
Serbia’s energy sector is heavily reliant on Russian inﬂuence. On the other hand, Serbia’s status as a candidate country for joining the European Union (EU) [...]
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A novel Digital Twin-based Structural Health Monitoring solution for offshore wind turbine platforms
J. García-Espinosa, B. Servan Camas, A. Pastor, D. Di Capua

Julio García-Espinosa's Presentations at Congresses and Seminars (2024). 1

Abstract
This work introduces an innovative Structural Health Monitoring (SHM) solution for offshore wind platforms, featuring an advanced Digital Twin (DT) built on a fully-coupled aero-servo-hydro-elastic model. Our approach utilizes a detailed Finite Element model of the structure, meeting the requirements of the main assessment/certification standards. The application of the unique Enriched Modal Matrix Reduction technique leads substantially reduces CPU time, enabling near real-time calculations without compromising accuracy compared to the original FE model. The SHM system is completed with an optimized sensors setup to monitor the most relevant deformation modes. Additionally, it enables precise fine-tuning of the DT model using machine learning, resulting in an accurate Hybrid Analysis Model. Our modular and flexible DT-based SHM solution can be customized for any offshore wind platform concept, covering substructure, towers, mooring, and umbilicals. The solution is demonstrated through sea trials on Enerocean’s W2Power prototype.
Abstract
This work introduces an innovative Structural Health Monitoring (SHM) solution for offshore wind platforms, featuring an advanced Digital Twin (DT) built on a fully-coupled [...]
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Ranking of Electronic Business Processes with TOPSIS Technique
M. Rezaei, M. Kalian, M. Hosseini

International Journal of Business Information Systems (IJBIS) collection (2024). 1

Abstract
E-business is similar to e-commerce, but goes beyond simply buying and selling products and services online. E-business includes a wider range of business processes, such as supply chain management, electronic order processing and customer relationship management. Therefore, e-business processes can help companies operate more efficiently and effectively. The purpose of this research is to rank the main and key options in electronic business using the TOPSIS algorithm. The results showed that the most important among the indicators is related to the idea and creativity to find a new and effective customer in the market and the large and significant network of suppliers, and the indicators of continuous innovation and productivity and the ability to track orders in comparison with the indicators They are less important.
Abstract
E-business is similar to e-commerce, but goes beyond simply buying and selling products and services online. E-business includes a wider range of business processes, such [...]
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Ranking of Electronic Business Processes with TOPSIS Technique
H. Hussein Al Mahdi

(Select a year).

Abstract
E-business is similar to e-commerce, but goes beyond simply buying and selling products and services online. E-business includes a wider range of business processes, such as supply chain management, electronic order processing and customer relationship management. Therefore, e-business processes can help companies operate more efficiently and effectively. The purpose of this research is to rank the main and key options in electronic business using the TOPSIS algorithm. The results showed that the most important among the indicators is related to the idea and creativity to find a new and effective customer in the market and the large and significant network of suppliers, and the indicators of continuous innovation and productivity and the ability to track orders in comparison with the indicators They are less important.
Abstract
E-business is similar to e-commerce, but goes beyond simply buying and selling products and services online. E-business includes a wider range of business processes, such [...]
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Analytical solution for one-dimensional consolidation of structured soft soils with continuous drainage boundary
J. Feng, X. Ma, X. Liu, L. Wang, Z. Wu, G. Mei

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 5

Abstract
A closed form analytical solution is proposed to analyze the one-dimensional consolidation behavior of structured saturated clay soils under continuous drainage boundary. Firstly, the soil structural properties and arbitrary loading conditions are taken into account in the established mathematical model. Using the finite sine Fourier transform and characteristic function methods, analytical calculation is conducted, and the solution effectiveness is evaluated against the degradation of solutions and the results of finite difference analysis. Finally, the influences of interface parameter, properties of soil structure and structural yield stress on consolidation behaviors are discussed. Results show that the larger the interface parameter is, the easier the soil structure enters the failure stage, and the smaller the consolidation degree is. Furthermore, the time for initiating the failure stage does not change, when the interface parameter and structural yield stress keep unchanged; in the meanwhile, the greater the consolidation coefficient is, the greater the consolidation degree of foundation becomes when the soil structure begins to fail, and the earlier the soil enters the complete failure stage. When the interface parameter is determined, the ratio of structural yield stress to load can accelerate the soil consolidation rate, but all consolidation curves coincide for the same ratio.
Abstract
A closed form analytical solution is proposed to analyze the one-dimensional consolidation behavior of structured saturated clay soils under continuous drainage boundary. [...]
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Determination of local stiffness for the joint of tunnel lining in the simulation
Z. Xiao, J. Wang, J. Wang, H. Zhou

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (2), 12

Abstract
In the numerical simulation of shield tunnel, the treatment of joints will greatly affect the accuracy of numerical analysis. Because the stiffness of the joint is lower than the stiffness of segments, the local weakening method is adopted in this paper , which can simulate the stiffness heterogeneity in the transverse and longitudinal directions of the tunnel lining. In the method, lower local stiffness is used for the joint which is the connection between segments and rings of lining, while the stiffness of segments keeps to be unchanged. The local stiffness of the joint, which is represented by the elastic modulus of the joint in the simulation, is the key point. To verify the validity of the method, multiple full-scale experiment [11-14] objects are analyzed and the simulation results are compared to the experiment data. Then the empirical formula of elastic modulus of the weakening joint is proposed by analyzing the three-ring lining in a full-scale experiment under different assemblages. Further, the empirical formula of elastic modulus for the joint is expanded to the large-diameter tunnel and super-large-diameter tunnel. It provides a good reference for the determination of elastic modulus of the joint in the simulation of shield tunnel.
Abstract
In the numerical simulation of shield tunnel, the treatment of joints will greatly affect the accuracy of numerical analysis. Because the stiffness of the joint is lower than [...]
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What are the growth benefits of watering cherry tomatoes with acidic teas?
E. Davidoff, T. Rawshan, D. Kemmett

FLHS Science Research (2024). FLHS

Abstract
Cherry tomatoes have a short growth cycle consisting of three phases: growth, flowering, and fruiting. In this study, cherry tomatoes were watered using water and three different teas with varying acidities—chamomile tea, green tea, and black tea. Previous studies typically focused on tomato growth in controlled environments with consistent pH levels. They often aimed to maintain the appropriate pH in soil for plants that thrive in acidic or basic soils, rather than neutral ones. However, this experiment aimed to explore the use of tea to alter soil pH for more effective tomato growth. While there exist numerous studies on acidic teas, this research consolidated their effects into a single study. The experiment involved 40 pots organized into groups of 10, each receiving one of the three teas or water. Soil was filled in these pots, and 7 germinated seeds were planted in each pot, followed by daily watering with 20 mL of the designated liquid. Throughout the study, soil pH levels remained stable across the different groups tested, suggesting that the primary factor influencing variations in leaf yield and plant height was gallic acid. However, the findings regarding plant height and leaf production were statistically not significant. Future work will involve analyzing different teas with diverse properties to expand understanding in this area.
Abstract
Cherry tomatoes have a short growth cycle consisting of three phases: growth, flowering, and fruiting. In this study, cherry tomatoes were watered using water and three different [...]
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ANALYSIS OF THE IMPACT OF RESOURCE DEPENDENCE ON THE DEPTH AND STRUCTURE OF THE FINANCIAL SECTOR
A. Bozhechkova, U. Dzhunkeev, P. Trunin, I. Yakovleva

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2023). 1

Abstract
Under the conditions of the inflation targeting regime, monetary policy decisions have an impact on the economy through the financial sector. Given the significant dependence of the Russian economy on the export of oil, it is actual to study the specifics of the financial sector of resource economies and identify bottlenecks that reduce the effectiveness of the monetary policy of the Bank of Russia In this study, using the example of 109 countries for the period 1980-2019, we assessed the degree of influence of resource dependence on the depth and structure of the financial sector. It is revealed that for a group of developing countries, the hypothesis of the "resource curse" of the financial sector is not rejected. This means that in conditions of resource dependence, the depth of the banking sector is decreasing, and the financial sector is more focused on stock markets. In the second part of the study, we investigated the degree of influence of financial sector development indicators on the effectiveness of monetary policy of commodity exporting countries which are also inflation targeters. The results of estimates obtained by the system generalized method of moments indicate that for resource economies, stock market development indicators play an important role in reducing inflation, whereas for non-resource economies, the influence of banking sector parameters prevails. In addition, in the period after the global financial crisis, as a result of increased volatility of world commodity prices there is an increasing role of financial stability indicators in ensuring the effectiveness of monetary policy in a group of developing resource countries. In the future, the study can be supplemented by taking into account, within the framework of econometric models, the sanctions episodes that affect the development of the financial sector in the oil-exporting countries.
Abstract
Under the conditions of the inflation targeting regime, monetary policy decisions have an impact on the economy through the financial sector. Given the significant dependence [...]
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Innovative superregions: best practices, formation mechanisms and prospects for creation in Russia
V. Akimova, A. Voloshinskaya, N. Moskvitina, V. Komarov

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2023). 2

Abstract
Relevance of the research: at the present time, a new round of competitive technological race, spurred on by the United States and China, is clearly visible. Even today, the budget for research and development in China and the United States is 20 times higher than the budget for R&D in Russia, which creates the risk of losing national technological sovereignty. The answer to this challenge could be the creation of super-regions territories of scientific and technological breakthrough, in which intelligence, research and innovation infrastructure are concentrated, where there are world-class campuses with high quality conditions, and effective interaction between business, science and education is organized. The aim of the study is to analyze the best world practices for creating technological super-regions in order to form an effective national innovation system and to develop conceptual proposals for creating technological super-regions in Russia. Research methods and methodology: comparative analysis, system analysis, quantitative and qualitative analysis, historical and economic analysis. Scientific novelty: the work contains a comprehensive analysis of the factors and mechanisms of formation of 10 global super-regions of the world with different spatial formats and genesis, which include: Silicon Valley (USA), urban innovation ecosystems of Boston (USA) and Cambridge (UK), Raleigh Research Triangle Durham Chapel Hill (Research Triangle Park, USA), Sophia Antipolis (France), Silicon Allee (Germany), Tsukuba (Japan), Bangalore-Karnataka (India), Shenzhen (China) and Guangzhou (China). An author's model of a super-region has been developed, as well as criteria for choosing locations for creating superregions. Results: based on the analysis of foreign practices, it was revealed that among the mechanisms for the formation of super-regions, a hybrid model prevails: government intervention is combined with the initiative of business and academic circles. The authors have developed a model of an innovative super-region, where in the center there are two equivalent factors the 'place' factor (everything that is created in a given location by a person) and the 'climate' factor (nature and climate that cannot be changed), as well as a set of selection criteria for potential locations. On the basis of the developed model, recommendations are proposed for choosing territories for creating innovation centers in Russia: in the short term, these include Greater Sochi (Adler, Krasnaya Polyana), New Moscow; in the medium term the southern coast of Crimea, Primorsky Krai and the Kaliningrad region.
Abstract
Relevance of the research: at the present time, a new round of competitive technological race, spurred on by the United States and China, is clearly visible. Even today, the [...]
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DISTRIBUTIONAL ANALYSIS OF THE TAX BURDEN ON INDIVIDUALS IN THE RUSSIAN FEDERATION
I. Sokolov, S. Belev, A. Deryugin, E. Leonov, K. Vekerle

RUSSIAN PRESIDENTIAL ACADEMY OF NATIONAL ECONOMY AND PUBLIC ADMINISTRATION (2023). 3

Abstract
The relevance: during the period 2000–2020 in the Russian Federation, there were serious changes in terms of taxation. An assessment of the tax burden on individuals is important in order to answer the question to which degree tax reforms are in line with the initially stated goals, primarily from the fairness criteria point of view. The consequences of these changes for both the budgetary system and the Russian population are still poorly understood, in particular, how changes in social contributions, VAT, and the introduction of various tax incentives and/or spending contributed to reducing income inequality. Such studies are needed both in terms of determining the extent to which various incentives are distorted by tax policy measures, and in terms of assessing the effectiveness of these measures. The object: taxation systems and features of tax administration in world practice and the Russian Federation. The subject of the study is distribution of the tax burden on taxpayers in the Russian Federation. The aim of the study is to assess the distribution of the tax burden by groups of taxpayers and types of taxes in the Russian Federation. When forming the work, such methods as the hypothetical-deductive method, grouping and comparison methods, analysis of international and Russian experience, econometric and statistical analysis, case methods were used. The study used data from the Tax Code of the Russian Federation, Rosstat and the Russian Monitoring of the Economic Situation and Health of the Population of the Higher School of Economics. The scientific novelty of the study lies in the assessment of the distribution of tax burdens of personal income tax, social contributions and VAT by individuals and households, as well as in assessing the degree of regressivity/progressivity of taxation using regression analysis. The result of the work was a report containing: 1. International experience in determining and assessing the tax burden. 2. Generalization of empirical and theoretical approaches to assessing the distribution of the tax burden. 3. Russian experience in terms of the main changes that determine the tax burden on taxpayers. 4. The results of the assessment of the tax burden by categories of taxpayers and various types of taxes. The results allowed us to conclude that when analyzing the tax burden of personal income tax and social contributions on the basis of RLMS data, the distribution of the share of tax payments in the payroll by net labor income is almost identical to the distribution by the total disposable income of an individual. It is important to note, however, that in both cases the share drops sharply when people employed in the informal sector are included in the analysis. For the officially employed, on average for the period under review, the share of tax payments in the payroll ranged from 26.9% to 30%, and for the full sample from 21.3% to 26.3%. When analyzing the distribution of the VAT tax burden, a weaker degree of regressivity was found compared to taxes on labor income. In the future, the authors plan to continue the study of the distribution of the tax burden on individuals in Russia and in the world.
Abstract
The relevance: during the period 2000–2020 in the Russian Federation, there were serious changes in terms of taxation. An assessment of the tax burden on individuals [...]
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How Does the Sound of Stream Water Affect the Growth of Cucumis sativus Plants Under Drought?
M. Melika, S. Huang, T. Boumakis, J. Zhu, L. Wang

J. of Dawn. R. (2024). Vol. 6, 3

Abstract
This experiment investigated how the sound of stream water affects the growth of ''Cucumis sativus'' plants under drought stress. Plants can recognize vibrations (sounds). Additionally, plants limit their growth when they receive suboptimal amounts of water to preserve resources. The purpose of this study was to determine how the sound of stream water affects plants under drought stress, in order to determine if it will affect their growth. Four groups of 10 plants were germinated, with 3 experimental groups treated with the sound of stream water for different amounts of time (0.5, 2, or 3 hrs; control group had 0 hr). Once plants were germinated, drought stress began in all groups, but each group’s respective amount of treatment stayed the same (0, 0.5, 2, 3 hrs). During all stages of the experiment, the plants were watered during the period of sound treatment to develop a correlation. At the end of the experiment, it was found that growth significantly increased corresponding to increasing treatment time. Group 4 (3 hr) had the largest increase in growth compared to control, while group 2 (0.5 hr) had the least improvement over control. Subsequently, the sound of stream water treatment beneficially impacts plant growth, directly correlated to exposure.
Abstract
This experiment investigated how the sound of stream water affects the growth of ''Cucumis sativus'' plants under drought stress. Plants can recognize vibrations [...]
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Design and optimization of Halbach magnetic gear
P. Wang, J. Yang, Y. Ge

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 6

Abstract
This article proposes a new structure to enhance the torque and torque density of permanent magnet gears. The outer magnet is designed with a dual-layer permanent magnet configuration, where the first layer adopts a Halbach array, and the other layer utilizes a conventional radial magnetization structure. With the optimization objectives defined as maximum torque and torque density, and guided by parameter sensitivity, optimization analysis was conducted using response surface method and multi-objective genetic algorithm. The optimized parameters were determined, and finite element simulations were performed to validate the optimization results. The result indicate a 22.22% increase in torque and a 27.42% increase in torque density compared to the previous the traditional magnet gear. The performance of the proposed new structure of magnetic gear has shown significant improvement.
Abstract
This article proposes a new structure to enhance the torque and torque density of permanent magnet gears. The outer magnet is designed with a dual-layer permanent magnet configuration, [...]
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Application of virtual element methods for numerical simulation of inelastic response
P. Wriggers, B. Hudobivnik, M. Cihan, F. Aldekheel, C. Böhm

complas2023.

Abstract
The Virtual Element Method (VEM) is a novel technology for the approximate solution of partial differential equations that shares the variational background of the finite element method. VEM has the flexibility to deal with general polygonal/polyhedral meshes, including “hanging vertices” and non-convex element shape, while retaining the conformity of the method. This allows different applications in the area of inelastic materials which include homogenization of materials with polycrystalline microstructure, thermo-mechanical responses at finite strains and impact problems. In this presentation we will discuss different aspects of the formulation of low order three-dimensional virtual elements for the class of problems mentioned above
Abstract
The Virtual Element Method (VEM) is a novel technology for the approximate solution of partial differential equations that shares the variational background of the finite [...]
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Enhancing Material Point Method for Disaster Simulation
K. Terada, R. Nomura, S. Moriguchi

complas2023.

Abstract
Several recently developed enhancements to material point methods (MPMs) are presented to increase the reliability and predictability of disaster simulations. The details of the enhanced techniques are as diverse as those listed below.
Abstract
Several recently developed enhancements to material point methods (MPMs) are presented to increase the reliability and predictability of disaster simulations. The details [...]
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Advances In Particle Finite Element Method For The Simulation Of Phase Change Problems And Fluid-Structure Interactions
J. Ponthot, E. Fernandez, S. Fevrier, M. Lacroix, B. Bobach, L. Papeleux, R. Boman

complas2023.

Abstract
Particle Finite Element Method (PFEM) is a still rather young method that tries to combine the advantages of classical methods such as FEM and more recent methods known as particle methods (SPH…) The method is quite versatile and can be applied to both solid and fluids material behavior. It is a Lagrangian method that combines computations over one time step using FEM with a fast remeshing algorithm trying to avoid mesh distortions consequent to very large deformations such as the ones encountered for fluid flow with free surfaces. New developments will be presented here, such as the use of a level set function, instead of the traditional alpha-shape algorithm to determine the new boundaries of a body after remeshing, as well as the implementation of phase-change algorithm, including vaporization. The lecture will cover several applications including the simulation of the fluid behavior in a melt pool during LPBF (laser Powder Bed Fusion) where the initial powder is melted by the laser, and then solidifies again when the laser goes away. During this process, due to the high power density of the laser, some part of the material is not only melted but also vaporized. Other applications of the PFEM will illustrate fluidstructure interactions simulations including contact between different solid parts and plastic deformation of some components of the system.
Abstract
Particle Finite Element Method (PFEM) is a still rather young method that tries to combine the advantages of classical methods such as FEM and more recent methods known as [...]
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Interaction of particulate fluids and structures. Modelling and computational challenges
E. Oñate

complas2023.
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Towards Multiscale Computational Design of Shock-absorbing Metamaterials: (II) From the low-scale to the upper-scale
X. oliver, A. Nuñez, J. Cante, A. Huespe

complas2023.

Abstract
To explore the computational design of shock-absorbing metamaterials, this work is a continuation of the one that was presented in COMPLAS 2021 " Towards the Multiscale Computational Design of Shock-absorbing Metamaterials: (I) From the Upper-Scale to the Low-Scale" (see [1]). Once explored there the mechanisms for mechanical dissipation that arise from propagating shocks on the high scale via “theoretical" nonconvex hyperelastic materials, the concept of multiscale metamaterial design is retrieved by defining a mesoscale constituted by a beams lattice, which buckles due to the interaction with the macro-scale (Hill-Mandel energetic equivalence principle), thus giving rise to a homogenized constitutive behavior exhibiting, on the macro-scale, the nonconvexity requested to exhibit “extrinsic” dissipation features. The goal now is exploring the computational challenges associated to this computational modeling i.e. 1) The homogenization of a representative volume element (RVE), made of 1D buckling beams at the mesoscale, into a 2D constitutive model at the macro-scale, 2) the controversial issue of the dependence of resulting homogenized macro-scale behavior on the RVE size, 3) the efficiency in generating mechanical dissipation at the upper scale, this qualifying the proposed setting as amenable for shock absorbing metamaterial design purposes. Representative examples show the degree of achievement of solutions to the aforementioned challenges.
Abstract
To explore the computational design of shock-absorbing metamaterials, this work is a continuation of the one that was presented in COMPLAS 2021 " Towards the Multiscale [...]
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Interactions of dislocations and twins with grain boundaries: unraveling the mechanisms of plastic deformation in polycrystals
J. Llorca

complas2023.

Abstract
Grain boundaries play a critical role in the plastic deformation of metallic materials. They may hinder slip transfer, leading to the formation of dislocation pile-ups and to size effects (HallPetch) or allow slip transfer, allowing the localization of deformation in suitably oriented grains clusters. They can also absorb and/or emit dislocations, nucleate twins, induce fracture, etc. As a result, interaction of dislocations and twins with grain boundaries as well as the role of grain boundaries in the nucleation of twins has received a lot of attention from the scientific community. However, most of experimental results are limited to surface observations in which the 3D nature of grains boundaries is not accounted for while atomistic simulations are mostly focused on coincidence lattice site boundaries that are different from the disordered grain boundaries of polycrystals. Thus, reliable criteria to quantify the role of grain boundaries in polycrystal deformation are still lacking. In this talk, large experimental data sets of the interaction of dislocations with grain boundaries were obtained using state-of-the-art characterization techniques to assess the influence of grain boundary orientation in 3D on the possibility of slip transfer/blocking in Ti and Mg. Similarly, in situ mechanical tests within the scanning electron microscope were carried to study the nucleation of tensile twins in Mg near grain boundaries. This information was analyzed using statistical methods and machine learning tools to determine the critical microstructural parameters that dominate slip transfer/blocking and twin nucleation. This information was then implemented in crystal plasticity finite element models to predict the mechanical behavior of polycrystals.
Abstract
Grain boundaries play a critical role in the plastic deformation of metallic materials. They may hinder slip transfer, leading to the formation of dislocation pile-ups and [...]
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Convolution Hierarchical Deep Learning Neural Network (C-HiDeNN)-AI: From Topological Optimization to Additive Manufactured Materials
W. Liu

complas2023.
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Automated model discovery – A new paradigm in computational mechanics?
E. Kuhl

complas2023.
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Fracture with Phase-Field Models: Discretization, Acceleration, Application
S. Kollmannsberger, L. Hug, L. Herrmann, A. Daneshyar, P. Kopp, O. Oztoprak, K. Thuro, Y. Schapira, L. Radke, A. Düster, E. Rank

complas2023.

Abstract
This presentation will provide an overview and an evaluation of modern discretizational techniques of phase-field methods for fracture. To this end, this talk will open with a motivating example of a geometrically very complex 3D fracture of a core rock sample (see Figure 1). It is well known that such computations are challenging. This is mainly because: • the phase-field regularization of the sharp crack is based on a length-scale parameter that requires very fine computational meshes, • domains of interest may possess very complex topologies described e.g. by CTscans, which in turn leads to very large systems of equations. • phase-field models for fracture result in an unsymmetric coupled problem of at least two fields whose staggered solution typically suffers from slow convergence. This talk will present a set of recently developed numerical tools to address these challenges. First, a type of local refinement is introduced, which is particularly well suited for transient situations and for which very efficient open-source implementations now exist. This discretization is then combined with the Finite Cell Method, which delivers the possibility to compute phase-field fracture models on complex domains in a straightforward manner. At this point, an extension of the phase-field method for the modelling of rock will be introduced
Abstract
This presentation will provide an overview and an evaluation of modern discretizational techniques of phase-field methods for fracture. To this end, this talk will open with [...]
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Phase-field Fracture: Toward a General Purpose Technology
T. Hughes

complas2023.
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High-resolution computational plasticity at the micron scale
M. Geers, J. Wijnen, L. Liu, T. Vermeij, V. Rezazadeh, R. Peerlings, J. Hoefnagels, V. Kouznetsova, F. Maresca

complas2023.

Abstract
The persistent demand for green, strong and ductile advanced high strength steels, with a reduced climate footprint, calls for novel and improved multi-phase microstructures. The development of these new steels requires an in-depth understanding of the governing plasticity mechanisms at the micron scale. In order to address this challenge, novel numerical-experimental methods are called for that account for the discreteness, statistics and the intrinsic role of interfaces. This lecture sheds light on recent and innovative developments unravelling metal plasticity at the micron scale
Abstract
The persistent demand for green, strong and ductile advanced high strength steels, with a reduced climate footprint, calls for novel and improved multi-phase microstructures. [...]
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Physics-based and data-driven hybrid modelling of materials and their processing
F. Chinesta, E. Cueto

complas2023.

Abstract
Physics aware digital twins of materials, processes, components and systems enable emulating real assets while ensuring fidelity and efficiency. They embrace physics-based and data-driven functionalities, both enriching mutually. Both should proceed in almost real-time, and the last being able to proceed in the scarce data limit. When applied to materials and processes, model order reduction technologies enable the construction of the so-called surrogate model, whereas data-driven modelling, based in advanced machine learning and artificial intelligence technologies, must be informed by the physics to encompass rapidity and accuracy, in the low data limit. This hybrid approach allows improving accuracy of existing models, as well as constructing models when the existing ones remains too poor or uncertain. Moreover, this setting allows to speed-up predictions, enabling real-time control, decision-making as well as the exploration of the whole design space, crucial in the design of materials and components
Abstract
Physics aware digital twins of materials, processes, components and systems enable emulating real assets while ensuring fidelity and efficiency. They embrace physics-based [...]
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Phase field for compaction band formation: capture of grain crushing and permeability evolution in heterogeneous media
S. Ip, R. Borja

complas2023.

Abstract
Compaction bands form when the pore spaces between the solid grains of a rock mass collapse into a narrow zone. This deformation style has attracted much attention in the theoretical and numerical modeling community since the porosity reduction associated with pore collapse reduces the overall permeability of the rock, thus enhancing its potential to serve as a fluid flow barrier. Recent publications [1, 2] demonstrate the capability of the phase-field modeling approach for capturing the formation and propagation of compaction bands in porous rocks. In this talk, the phase-field approach is utilized to show how grain crushing and fluid flow impact the formation and propagation of compaction bands. In the context of the finite element method, a three-field variational formulation in terms of solid displacement, fluid pressure, and the phase-field variable is employed for this purpose. Using material parameters calibrated from real rocks, we show how the volume constraint imposed by fluid flow could impact the stress-strain responses of the rock as well as the ensuing geometric style of the compaction band.
Abstract
Compaction bands form when the pore spaces between the solid grains of a rock mass collapse into a narrow zone. This deformation style has attracted much attention in the [...]
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Additive Manufacturing: some dreams, some nightmares
F. Auricchio

complas2023.

Abstract
Laser-based Powder Bed Fusion of Metals (PBF-LB/M) is an additive manufacturing technology suitable for producing metal components with complex geometries and remarkable mechanical properties and performances. However, a widespread adoption of this technology in many industrial context is yet hindered due to the high stochasticity of the process. In fact, the complex process-structure-property relationships occurring in PBF-LB/M are today not yet fully understood. Therefore, suitable physical and numerical models need to be developed to shed light on these complex phenomena to boost a broader adoption of AM technologies in industrial applications. It is well known for example that the elastic behavior of lattice structures is dramatically underestimated when computed on the as-designed geometry. Furthermore, due to the inherent variability of PBF-LB/M process parameters, several sources of uncertainty hinder a full understanding of the complex process-structure-property relationships. In the presentation we will highlights some of the interesting applications open by the power of AM but also some limitations due the problems highlighted above.
Abstract
Laser-based Powder Bed Fusion of Metals (PBF-LB/M) is an additive manufacturing technology suitable for producing metal components with complex geometries and remarkable mechanical [...]
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Application of high-dimensional multi-objective differential evolutionary algorithm based on global ordering to heat supply pipe network resistance identification
E. Zhou, Y. Yang, J. Yu, Z. Liu, W. Xu, M. Xiang

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (2), 14

Abstract
The distribution of resistance coefficients of heat supply pipe networks is the key data guiding the hydraulic balance adjustment of heat networks. Since the heat supply pipe network is composed of many pipe segments and the resistance coefficient of each pipe segment is different during heat supply operation, the identification of the resistance coefficient of the heat supply pipe network is an optimization problem with multiple objective functions. In this paper, a high-dimensional multi-objective differential evolutionary algorithm based on global sorting is developed as a method to identify the resistance coefficients of the heat network and the multi-objective algorithm is applied to the resistance identification of the heat network, and the computational process of resistance identification is improved. The fuzzy mathematical method is applied to the process of resistance identification, and a set of optimal solution sets are generated through the identification of each pipe segment and the optimal solutions are selected from the optimal solution sets based on the fuzzy degree of subordination to solve the problem of determining the optimal solutions. The problem of determining the optimal solution is solved. The results show that compared with the single-objective algorithm, the high-dimensional multi-objective differential evolutionary algorithm based on global sorting produces a uniform and concentrated optimal solution set, and the optimal solution accuracy is higher.
Abstract
The distribution of resistance coefficients of heat supply pipe networks is the key data guiding the hydraulic balance adjustment of heat networks. Since the heat supply pipe [...]
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Reliable iterative techniques for solving the KS equation arising in fluid flow
M. Alotaibi, D. Rizk, A. Al−Hanaya, A. Hagag

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 7

Abstract
In this study, we examine the Kuramoto-Sivashinsky equation, which is a nonlinear model that describes several physical and chemical events arising in fluid flow. The approximate analytical solution for the fractional KS (FKS) problem is calculated using the Temimi-Ansari method (TAM) and the natural decomposition method (NDM). The projected procedure (NDM) combines the adomian decomposition method with the natural transform. Each technique can deal with nonlinear terms without making any assumptions. The methodologies under consideration provide english\omega _{n}-curves that display the convergence window of the power series solution that approaches the exact solution. We explore two distinct examples to confirm the efficiency and applicability of the proposed strategies. The acquired outcomes are compared numerically with the q-homotopy analysis transform method (q-HATM). The numerical investigation is carried out to validate the precision and dependability of the approaches under consideration. Additionally, the nature of the outcomes gained has been displayed in a different order. The obtained results show that the proposed techniques are highly efficient and simple to use to analyze the behavior of other nonlinear models.
Abstract
In this study, we examine the Kuramoto-Sivashinsky equation, which is a nonlinear model that describes several physical and chemical events arising in fluid flow. The approximate [...]
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Sensitivity analysis of stability of anti-dip rock slope under fluctuating water level in the Three Gorges Reservoir Area
W. Jiang, W. Yi, G. Han, G. Chen, G. Sun

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 3

Abstract
The fluctuation of water levels in large reservoirs has long been recognized as a critical external factor that affects the stability of bank slopes. However, there have been limited studies investigating the influence of reservoir water level (RWL) fluctuation on anti-dip layered rock slopes. In this study, we constructed a conceptual model by selecting the sandstone in the Three Gorges Reservoir Area (TRGA) as the strata and considering variations in strata thickness, strata dip angle, permeability coefficient, RWL fluctuation rate, and slope height. Through seepage-stress field coupled analysis, we obtained the seepage field and groundwater lines, and determined the factor of safety (FoS) using the improved cantilever beam limit equilibrium method. We then investigated the variations of the groundwater line and FoS throughout the entire process of RWL rising and drawdown. Our results indicate that the changes in groundwater levels in the slope clearly lag behind RWL fluctuations, with stability improving during the rising stage but deteriorating during the drawdown stage. Range analysis, using the maximum curvature (MaxCurve) of the groundwater level line as the reference, reveals that the permeability coefficient has the most significant impact on the lagging effect, followed by the fluctuation rate, thickness, and dip angle. Similarly, when considering the amplitude of variation in FoS during the entire process of RWL rising and drawdown as the reference, range analysis shows that the permeability coefficient has the greatest impact on stability variation, followed by the fluctuation rate, thickness, dip angle, and slope height.
Abstract
The fluctuation of water levels in large reservoirs has long been recognized as a critical external factor that affects the stability of bank slopes. However, there have been [...]
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Research on the identification of modulus parameters for rigid pavement panel foundations
H. Cao, H. Zhao, X. Yan

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (2), 13

Abstract
Based on the Pasternak two-parameter foundation model, this study establishes a dynamic model for analyzing the deflection of slabs under moving loads. The variational method and reciprocal equal work theorem are employed to obtain the deflection solution, while the Matlab program is utilized with practical examples to calculate the foundation response modulus considering transfer shear force, bending moment, and their combined effects. By fitting measured dynamic deflections with theoretical predictions using the least square method, the response modulus K of the foundation is determined, demonstrating that our proposed model effectively captures the realistic behavior of rigid pavements.
Abstract
Based on the Pasternak two-parameter foundation model, this study establishes a dynamic model for analyzing the deflection of slabs under moving loads. The variational method [...]
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Research of an EPB shield pressure and depth prediction model based on deep neural network and its control device
J. Shao, J. Ling, R. Zhang, X. Cheng, H. Zhang

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 1

Abstract
Based on the construction data of Fuzhou Metro Line 4 in Fujian Province, China, this paper proposes a soil pressure prediction model that combines Long Short-Term Memory (LSTM) and Particle Swarm Optimization (PSO). The values of Mean Absolute Error, Mean Squared Error, and Coefficient of Determination are 0.007MPa, 0.007%, and 0.93, respectively, indicating an improvement in accuracy.Wang-Mendel algorithm is used to establish fuzzy rules. The Mean Absolute Error and Mean Squared Error of the rotating speed of the screw machine are 0.065rpm and 1.528%, and the Coefficient of Determination is 0.82. The calculation accuracy of this algorithm is high.A set of knob intelligent control device is developed.The Mean Absolute Error and Mean Squared Error of 0.015rpm and 0.392%, respectively, and the Coefficient of Determination of 0.95, indicating a small execution error of the device. This paper provides a new and effective method for the control of EPB shield pressure.
Abstract
Based on the construction data of Fuzhou Metro Line 4 in Fujian Province, China, this paper proposes a soil pressure prediction model that combines Long Short-Term Memory [...]
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Research on seismic performance of corrugated web rigid structures
H. Cao, G. Wang, H. Liu

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 9

Abstract
Corrugated web H-beam refers to a steel beam with a wavy shape along its length, which is extensively utilized in various parts of building structures such as beams, columns, and walls. It serves the purpose of connection and support, while the corrugated or folded design enhances the shear resistance and out-of-plane stiffness of the web to some extent. However, despite their advantages including high strength, stiffness, and lightweight construction, relevant regulations stipulate that these members can only be used in lower-intensity applications or higher-intensity scenarios if specific conditions are met. One crucial condition is that the ratio between the design value of axial force subjected to seismic action and the product of the member's flange section area and steel's tensile strength should not exceed 0.4. In this study, we aim to further investigate the seismic characteristics and applicable intensity of corrugated steel structures under earthquakes through large-scale finite element ABAQUS simulations. We will observe dynamic characteristics and failure modes of corrugated rigid frame structures using elastic-plastic time-history analysis methods as well as examine plastic deformation features of steel beam members under low cyclic loads via hysteretic analysis methods. The findings demonstrate that when properly designed with reasonable beam spans, corrugated web rigid frame structures can still be employed in high-intensity areas above 7 degrees even when subjected to an axial compression ratio up to 0.5.
Abstract
Corrugated web H-beam refers to a steel beam with a wavy shape along its length, which is extensively utilized in various parts of building structures [...]
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Microstructure effect analysis of carbon black-filled rubber composites
L. Huang, X. Tao, T. Wei, Z. Li

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 2

Abstract
The unidirectional tensile stress-strain curves of four kinds of carbon black-filled rubbers with different volume contents were obtained by mechanical experiments, and the fine morphology maps of the carbon black-filled rubber composites were obtained by electron microscope experiments. Based on the hyperelastic constitutive model of rubber, an ellipsoidal carbon black particles randomly distributed finite element model was established using DIGIMAT and ABAQUS, and uniaxial tensile simulation was carried out on the established two-dimensional model. The effects of the volume fraction, distribution angle and number of agglomerates of carbon black particles on the stress-strain relationship curve and stress distribution of the composites were analyzed. The results show that: with the increasing volume fraction of carbon black particles, the stiffness value of the composite material becomes larger; when the particle direction is 0° to the load direction, the strength of the material is improved and the stress concentration phenomenon is less; with the increasing number of carbon black agglomerates, the strength of the composite material decreases and the stress concentration phenomenon is obvious in agglomerated area. '''Key words''': Rubber composites; carbon black; RVE; finite element
Abstract
The unidirectional tensile stress-strain curves of four kinds of carbon black-filled rubbers with different volume contents were obtained by mechanical experiments, and the [...]
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Humor detection using deep learning in 10 years: A survey
C. Ren, Z. Guo, P. Zhang, Y. Gao

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 4

Abstract
Humor is an important part of personal communication. How to create a computational model to recognize humor is still a very challenging task in natural language processing and linguistics. In this survey, we applied some rules to leave 29 articles spanning 10 years (2012 to 2023). The main elements covered by this survey include: recent state-of-the-art detection methods using deep learning from years 2012-2023, (2) summarizing features for humor detection from a linguistic perspective, (3) humor detection datasets, evaluation metrics, data domains and languages, (4) some tricks used in humor detection (e.g. Attention mechanism, multimodal), (5) recognizing open problems and highlight the feasible opportunities for future research directions. To the best of our knowledge, this is the first systematic survey for humor detection using deep learning. The survey can be used to assist novice and prominent researchers to understand the concept of humor, popular method and future research direction and so on.
Abstract
Humor is an important part of personal communication. How to create a computational model to recognize humor is still a very challenging task in natural language processing [...]
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Prediction of EV charging behavior using BOA-based deep residual attention network
J. Appadurai, D. G, R. Yugha, R. Sarkar, A. Thirumalraj, B. kavin, D. Seng

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (2), 16

Abstract
In smart city applications, electric vehicles (EVs) are rapidly gaining popularity due to their ability to help cut down on carbon emissions. Numerous environmental conditions, including terrain, traffic, driving style, temperature, and so on, affect the amount of energy an EV needs to operate. However, the burden on power grid infrastructure from widespread EV deployment is one of the biggest obstacles. Smart scheduling algorithms can be used to handle the rising public charging demand. Scheduling algorithms can be improved using data-driven tools and procedures to study EV charging behaviour. Predictions of behaviour, including temperature, departure time, and energy requirements, have been the focus of research on past charging data. Weather, traffic, and surrounding events are all factors that have been mostly ignored but which could improve representations and predictions. The DRA-Net, or Deep Residual Attention Network, was developed by the researchers and is used to recognize EV charging patterns. To minimize data loss, the Res-Attention component utilized tighter connections and smaller convolutional kernels (3 x 3). In addition, an Artificial Butterfly Optimisation Algorithm (BOA) model is used to fine-tune the DRA-Net's hyper-parameters. We highlight the significance of traffic and weather info for charging behaviour predictions, and the study's experimental forecasts show a considerable improvement over prior work on the same dataset. The future of electric vehicle (EV) research has been mapped out thanks to in-depth study, and as a result, EVs will soon significantly impact the auto industry.
Abstract
In smart city applications, electric vehicles (EVs) are rapidly gaining popularity due to their ability to help cut down on carbon emissions. Numerous environmental conditions, [...]
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Analysis of deformation of levee caused by large diameter shield tunneling in river crossing tunnel
L. Zhongxiang, S. Lingchao, R. Abdullah, M. Shahrin, C. Yintao, S. Xin, F. Wenju, A. Islam, Z. Hengxu

Rev. int. métodos numér. cálc. diseño ing. (2024). Vol. 40, (1), 10

Abstract
This study utilizes ABAQUS finite element software to analyze embankment deformation during shield tunneling. Results reveal that shield tunneling effects are manageable.The left tunnel line successfully tunnels beneath the embankment, causing a maximum settlement of 8.7 mm, meeting regulations. The ground surface exhibits a "V"-shaped lateral settlement trough, approximately five times the tunnel centerline width. Conversely, the right tunnel line induces a more extensive impact, with a 12.2 mm maximum settlement.Different lateral settlement patterns emerge in soil at varying depths. The left tunnel creates a "V" shape, with slightly increasing settlement above the tunnel axis as depth increases, accompanied by narrower troughs. The right tunnel line results in a pronounced "W" shape, especially at the grouting layer depth.Horizontal displacement forms an "S" shape, with maximum displacement at positions ±i from the tunnel axis. The right tunnel line induces greater maximum horizontal displacement than the left.In summary, this numerical analysis provides insights into embankment deformation during shield tunneling, aiding in assessing the impact and guiding safe tunneling beneath embankments.
Abstract
This study utilizes ABAQUS finite element software to analyze embankment deformation during shield tunneling. Results reveal that shield tunneling effects are manageable.The [...]
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Experimental study of the use of ultra-thin plies in quasi-isotropic laminates under cyclic tension after impact
C. Sandino, S. Sánchez Carmona, E. Correa Montoto, F. Paris

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 8

Abstract
In this work, the authors propose an experimental study on the possible improvement of the mechanical behaviour produced by ultra-thin plies in laminates subjected to cyclic loading after impact. More specifically, this work introduces the use of these plies in carbon fibre quasi-isotropic laminates, with the aim of studying the evolution of impact damage under tensile cyclic loads. To this aim, the behaviour of quasi-isotropic laminates consisting of conventional thickness plies is compared with laminates with 90° ultra-thin plies, keeping the same stacking sequence. When considering the same loading level, the damage evolution shows a lower progress and a later failure for the laminates containing ultra-thin plies.
Abstract
In this work, the authors propose an experimental study on the possible improvement of the mechanical behaviour produced by ultra-thin plies in laminates subjected to cyclic [...]
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Study of delamination behavior in adhesive joints with epoxy-based adhesive under Mode II
P. Vigón, A. Argüelles, I. Viña, M. Lozano, J. Viña

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 12

Abstract
This study experimentally analyses the phenomenon of delamination under static and fatigue loading in mode II using the standardized End-Notched Flexure (ENF) test. Adhesive joints made of two epoxy matrix laminates reinforced with unidirectional carbon fiber are studied, bonded with an epoxy adhesive, and subjected to environmental degradation in a saline environment for exposure periods of 1, 2, 4, and 12 weeks. By conducting initial static tests on the joints, we identified crucial values for the rate at which energy is released under mode II conditions. These values served as a benchmark to establish the approach for dynamic fatigue testing. Our objective was to generate characteristic curves that illustrate how these adhesive joints behave when fatigue delamination begins, while also assessing the impact of varying exposure periods on their performance. To enhance result interpretation, we employed a probabilistic model rooted in the Weibull distribution to analyse the experimental data. The results show that adhesive joints experience a decrease in their delamination resistance when exposed to a saline environment.
Abstract
This study experimentally analyses the phenomenon of delamination under static and fatigue loading in mode II using the standardized End-Notched Flexure (ENF) test. Adhesive [...]
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Use of digital image correlation to quantify the different fracture modes in the Longitudinal Half Fixed Beam (LHFB) test
M. Lozano, A. López, A. Argüelles, J. Viña, P. Vigón

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 6

Abstract
One of the failures with significant practical repercussions in structural elements made of laminated composite materials is the formation and growth of interlaminar cracks (delamination) under static and dynamic loading. Although the cracks can be subjected to three different modes of stress, the material toughness in mode III is higher than in the other two, so delamination mainly occurs in modes I or II. This is true when there is more than one fracture mode acting in the element. However, by using a testing methodology that allows testing in pure or nearly pure mode III, such as the Longitudinal Half Fixed Beam (LHFB) method, it is possible to characterize the material against this mode. Therefore, the degree of purity of mode III, compared to the residual modes I and II, will be an important indicator of the adequacy of the testing methodology. In this research work, the degree of purity of mode III in LHFB-type tests has been determined by using a digital image correlation (DIC) system. This technique allowed for the analysis of displacements in the X, Y, and Z directions in specimens with initial crack lengths of 1, 5, 10, 15, 20, 25, and 30 mm, using AS4/8552 and AS4/3501-6 materials. Considering the displacements measured with DIC during the different tests, it has been possible to determine the level of combination of modes I, II, and III achieved during the tests.
Abstract
One of the failures with significant practical repercussions in structural elements made of laminated composite materials is the formation and growth of interlaminar cracks [...]
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Elastomeric composite materials reinforced with natural fibers and with self-healing capacity
S. Utrera-Barrios, O. Lopes, M. Hernandez Santana

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 17

Abstract
Elastomeric composite materials are widely used in multiple applications, especially in the automotive industry; however, they have the drawback of being difficult to recycle, generating a significant environmental impact. For this reason, in recent years there has been an increase in research for the development of self-healing and biodegradable materials that minimize this impact by extending their lifetime. In this context, the aim of this work is to design a new generation of self-healing elastomeric composite materials using additives of natural origin. For this, epoxidized natural rubber (ENR) and cellulose propionate (CP) were used as matrix, reinforced with cellulose fibers. Self-healing was achieved by combining the flow of the thermoplastic (CP) phase (extrinsic mechanism) and the formation of hydrogen bonds between the ENR and the CP (intrinsic mechanism). A promising repair efficiency of 95% was obtained, as well as an increase in tensile strength in the presence of cellulose fibers, without affecting the healing capacity of the material. Therefore, this work overcomes the well-known dichotomy between mechanical performance and self-healing and constitutes a new contribution in the field of self-healing elastomeric composites using bio-based additives.
Abstract
Elastomeric composite materials are widely used in multiple applications, especially in the automotive industry; however, they have the drawback of being difficult to recycle, [...]
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Study of the influence of stacking sequence in the failure of cross-ply laminates manufactured with ultra-thin plies
M. Velasco*, E. Correa, S. Sánchez-Carmona, F. Paris

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 11

Abstract
Numerous studies on the use of laminates manufactured with ultra-thin composite laminates have shown the existence of a significant delay in the appearance of damage, a phenomenon known as the Scale Effect. To study the effect that layer thickness may have on the damage mechanisms that appear at higher values of the load, this work analyses whether the use of ultra-thin laminates exhibits a better behaviour in the instants prior to failure and laminate rupture. For this purpose, different laminates have been manufactured with ultrathin thickness material formed by the same number of laminae oriented at 0 and 90 degrees, but with different stacking sequences, distributing the laminae such that the thicknesses of the resulting layers are different. The laminates have been subjected to uniaxial tension up to values close to the ultimate load in order to observe and compare the different damage morphologies that appear in the 90 and 0 degrees layers, using optical microscopy techniques for the observation of the damage. On the other hand, the loads for which the failure of the selected laminates happens have also been compared. The results obtained from this study show different behaviour of the laminates depending on the thickness of their 0 and 90 degrees layers in the moments prior to failure and at the instant when failure occurs.
Abstract
Numerous studies on the use of laminates manufactured with ultra-thin composite laminates have shown the existence of a significant delay in the appearance of damage, a phenomenon [...]
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New life for aeronautical dry carbon fiber
A. Calero, T. Blanco Varela, J. Sistach

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 18

Abstract
Our latest generation aircraft are more efficient by design, lighter and emit on average 25% less CO2 than previous generation aircrafts. Lightweight materials like composites have contributed significantly to reach the current emissions levels, like the A350 with more than 50% of structural weight made of composites. However, composites drive also the environmental footprint of the aircraft life-cycle without considering the operational phase, involving currently important drawbacks in terms of energy consumption and waste recycling. The transition towards a composite circular economy needs to be anticipated due to the aviation sector de-carbonization challenge as well as the regulation evolution. This transition will be leveraged by several elements, being the composite recycling one of the most important, due to the need to transform the composite waste from production and end of life into new added value materials. For this, the development of efficient composite recycling technologies to not only recover energy during incineration but also high value recycled carbon fibers and semi-products are needed. This project was focused on the recycling of dry carbon fiber scrap, which can proceed from part production by infusion technologies (e.g. RTM) or from pyrolysis of end of life composite part. The approach was to obtain a non-woven mat from the dry fiber scrap, following a mechanical process, which was, then, fully characterized to identify potential applications in aeronautical field. Different approaches of hybridization of the recycled non-woven fabric with virgin fabric were also evaluated.
Abstract
Our latest generation aircraft are more efficient by design, lighter and emit on average 25% less CO2 than previous generation aircrafts. Lightweight materials like composites [...]
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Behaviour of fibre/matrix interface cracks under biaxial stress state caused by edge effect in carbon/epoxy laminates
S. Sánchez Carmona, C. Sandino, E. Correa Montoto, A. Barroso, F. Paris

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 10

Abstract
A recent study about the ''edge effect'' phenomenon in cross-ply laminates made of ultra-thin plies composites has shown the presence of a relevant stress component through the laminate thickness. This fact implies that there is a biaxial stress state in the 90° ply block, which is present both before and after the cyclic loading tests. 4 cross-ply laminates were analysed, only varying the 90° ply block thickness. In each case, the biaxial stress state was obtained, selecting the most detrimental one to analyse the Energy Release Rate (G) with respect to the fibre/matrix interface crack growth. This analysis is performed using a BEM model from a previous study of the authors. An exhaustive microscopic revision is performed both before (only sanded and polished after curing process) and after cyclic testing, corroborating the occurrence of different crack growth of the present longitudinal fibre/matrix interface debonds. In conclusion, the single fibre numerical model using BEM and the experimental microscopic observations shed light on the micromechanical behaviour of the interface cracks which are subjected to a biaxial stress state.
Abstract
A recent study about the ''edge effect'' phenomenon in cross-ply laminates made of ultra-thin plies composites has shown the presence of a relevant stress [...]
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Characterisation of the mode I interlaminar fracture toughness in multidirectional interfaces in a 3D-printed composite
J. Santos, N. Blanco, J. Guerrero

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 9

Abstract
Debonding between plies, or delamination, is a critical failure mechanism for laminated composite materials and has been analysed in several scientific investigation. Usually in real applications delamination initiates and propagates between interface layers with different reinforcement orientation. However, most of the experimental works are carried out using unidirectional specimens for determining the interlaminar fracture toughness because in laboratory conditions it is difficult to propagate the crack between multidirectional interface layers without other failure mechanisms that invalidate the test. Among these failure mechanisms, crack plane migration and crack branching at several planes are the most common. In this communication it will be detailed and analyzed the experimental characterization of the interlaminar fracture toughness in multidirectional interfaces of 3D-printed composite materials is detailed, including the manufacturing process of the Double Cantilever Beam (DCB) specimens that warranty crack propagation under pure mode I loading and without plane migration. Finally, a quantitative comparison is carried out between multidirectional interlaminar fracture toughness and the unidirectional one and a fractography analysis is reported.
Abstract
Debonding between plies, or delamination, is a critical failure mechanism for laminated composite materials and has been analysed in several scientific investigation. Usually [...]
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Thermoplastic weld fatigue behaviour analysis using structural health monitoring sensors data
M. Mazzeschi, K. Nuñez-Carrero, M. Fernandez, E. Cañibano, J. Merino

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 13

Abstract
Thermoplastic composite joints show many advantages in comparison to conventional fasteners. However, thermoplastic welding of primary aircraft structures is still a certification issue. Long and extensive fatigue and test campaign is required for a depth understanding of damage progression. In fact, scarce historical data are currently available and the joint fatigue performances are extremely sensitive to numerous welding process parameters. In this context, Structural Health Monitoring (SHM) technologies consists of a built-in sensors network providing real-time condition and the damage state of a structure. SHM brings several benefits. First of all, SHM ensures safety in-flight through continuously assessing damages and alerting if strength reduction approaches acceptable limits. The data obtained are useful for future structure retrofitting and new developments. Moreover, SHM has the potential to support and speed up the certification of thermoplastic composite joint. SHM data give added value to each individual fatigue test contributing to a greater understanding of damage progression and making fatigue campaign shorter and more efficient. In the present work, both quasi-static as well as fatigue tests were conducted to evaluate performances of thermoplastic induction welded joints. Strain gauges and purpose-designed electromagnetic-based SHM sensor were integrated into the specimens in order to collect useful data during tests in three main cases: lap-joint specimens manufactured (i), (ii) with two different set of process parameters and (iii) with an artificially generated lack of weld at the joint interface. The approach proposed and data collected by the sensors has provided valuable information for understanding damage propagation in this kind of joint.
Abstract
Thermoplastic composite joints show many advantages in comparison to conventional fasteners. However, thermoplastic welding of primary aircraft structures is still a certification [...]
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Thermochemical recycling of epoxy matrix composite materials with Diels-Alder bonds
I. Lorero, C. Bravo, M. Campo, A. Jiménez, S. Prolongo, I. Lorero

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 19

Abstract
The high cross-linking degree of thermosetting resins, which gives them remarkable mechanical properties, also implies an irreversible structure that impedes proper recycling at the end of life. This problem influences both thermosetting matrices and composite materials, since the crosslink irreversibility of the matrix hinders the recovery of the fibers. One way to solve this problem is the development of new thermosetting resins that incorporate Diels-Alder thermo-reversible bonds. The introduction of Diels-Alder bonds allows thermosets to have a polymeric network capable of disengaging at temperatures above 90 °C, acquiring certain fluidity and recyclability. However, its composition and curing cycle must be carefully adjusted to avoid undesired chemical reactions and to maintain certain mechanical properties, since the addition of Diels-Alder bonds in high contents usually results in a notable embrittlement of resin. In the present work, the manufacture of an epoxy matrix composite material with 60% Diels-Alder bonds reinforced with carbon fiber is developed, which shows mechanical properties similar to those of a conventional epoxy resin laminate. After that, the recovery of the fiber is addressed thermochemically by dissolving the matrix in dimethyl sulfoxide at 150 °C, achieving the reuse of the fiber to manufacture new composite materials with mechanical properties comparable to the original.
Abstract
The high cross-linking degree of thermosetting resins, which gives them remarkable mechanical properties, also implies an irreversible structure that impedes proper recycling [...]
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Analysis of the pure shear stress-strain state obtained by biaxial tension-compression test
S. Horta Muñoz, M. Serna Moreno

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 1

Abstract
Characterization of shear properties in unidirectional fibre composite materials can be a complex process due to the difficulty in obtaining uniform and pure shear stress-strain states at the moment of failure. This limits the range of application of the most commonly used standardized methods, as they focus on small deformations. Therefore, this work proposes an alternative solution: the tension-compression test applied to cruciform specimens with ±45° symmetric laminates for the characterization of lamina in-plane shear properties. By using a test method that provides uniform and pure shear stress-strain states, the accuracy of the results can be improved, and the range of application of the method can be expanded. The analysis is based on experimental tests, supported by simulations performed using the finite element method. Special attention is paid to verifying the achieved shear state, and the obtained response is compared with standardized tests that generate non-pure shear stress-strain states on the principal material directions. Additionally, Digital Image Correlation is used during the test to verify the appearance of nonlinear response in different regions of the cruciform specimen, which allows ensuring the validity of the test.
Abstract
Characterization of shear properties in unidirectional fibre composite materials can be a complex process due to the difficulty in obtaining uniform and pure shear stress-strain [...]
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Validation of a laboratory-scale technology for complete recycling of wind turbine blades
A. Lopez-Urionabarrenechea, A. Serras-Malillos, E. Perez-Perez, B. Perez-Martinez, E. Acha, B. Caballero, A. Lopez-Urionabarrenechea

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 22

Abstract
This paper presents the experimental validation of a thermal treatment technology to recover added-value substances from the plastic matrix of end-of-life wind turbine blades, when these are subjected to a pyrolysis process to recover the glass fibres. The experiments have been carried out in a laboratory installation consisting of two reactors in series, in which pyrolysis and thermal treatment of pyrolysis gases and vapours take place, respectively. The application of this treatment enables a 25 wt.% reduction in the production of pyrolysis liquids, increasing the production of gases in an equivalent way and without compromising the pyrolysis conditions to be used to recover the glass fibres. The two-phase liquids are converted into single-phase aqueous ones, while the hydrogen concentration in the gases increases from 4 % to almost 50 % in volume. This high concentration of hydrogen in the gases allows them to be used as a source of hydrogen for various applications. Consequently, the technology demonstrates that the plastic matrix of wind turbine blades can be valorised in a pyrolysis based recycling process.
Abstract
This paper presents the experimental validation of a thermal treatment technology to recover added-value substances from the plastic matrix of end-of-life wind turbine blades, [...]
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Solvolysis of carbon fibre reinforced composites under mild conditions
L. Fulgencio, A. Asueta, S. Arnaiz, J. Leivar, I. Amundarain, R. Miguel, A. Iruskieta, L. Fulgencio

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 20

Abstract
Carbon fibre reinforced composites (CFRP) are key in different industrial sectors as they combine lightness and robustness. This circumstance and the growing need to take advantage of the resources of any product, has triggered a strong demand to establish sustainable technological solutions that allow the effective use of composite materials: resins (matrix) and fibres (reinforcement). Limited to mechanical recycling, recycling alternatives for CFRP with thermosetting resins have focused on thermochemical treatments, usually pyrolysis to recover the fibres, degrading the matrix. In addition to thermal routes, solvent treatments under supercritical conditions have also been studied. However, these processes exclude resin recovery and involve a partial loss of mechanical properties of the fibres due to the heat treatment (450-550 °C). As an alternative, a solvolysis using mild conditions is proposed to treat CFRPs with amine-hardened epoxy resins, so that the fibres are recovered with all their properties and the organic matrix is materially valorised. This process is applied to reference materials of known composition and validated with real residues with good results in terms of degree of resin decomposition. The recovered fibres show almost resin-free surface and seem to have mechanical properties comparable to those of virgin fibres.
Abstract
Carbon fibre reinforced composites (CFRP) are key in different industrial sectors as they combine lightness and robustness. This circumstance and the growing need to take [...]
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New analytical models for non-symmetric Double Cantilever Beam and End-Notched Flexure tests
F. Mujika, A. Arrese, J. Gracia, A. Boyano

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 5

Abstract
The fundamentals of new analytical models based on energy and coenergy of deformation are explained to analytically address asymmetric interlaminar fracture tests. After reviewing some concepts of laminated beam theory, the energy release rate as a function of coenergy is determined from a global point of view, including in an unprecedented way the contribution of hygrothermal stresses. On the other hand, after the determination of the J integral in the cohesive zone, the conditions required for the asymmetric fracture tests to occur in pure mode in linear elastic fracture are explained, based on the forces and displacements of the crack tip. Furthermore, knowing these forces and displacements, it is possible to determine the energy release rate that corresponds to each fracture mode.
Abstract
The fundamentals of new analytical models based on energy and coenergy of deformation are explained to analytically address asymmetric interlaminar fracture tests. After reviewing [...]
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Analytical approach for two-plane bending applied to unidirectional composite plates
U. Garitaonaindia, N. Carbajal, M. Isasa, F. Mujika

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 2

Abstract
In this work, a new analytical procedure is developed to obtain the displacement field of a unidirectional composite plate subjected to bending in two planes. The analysed configuration consists of a plane plate supported at four points to which a point force is applied at the centre. The calculation procedure is based on the strain energy. The effects created by bending moments, torsional moments and shear forces in the plate have been considered. The results obtained analytically have been validated by comparing them with existing literature and with numerical simulations performed with the finite element software ABAQUS. High correlations have been obtained for the values corresponding to the vertical displacements in different alignments of points belonging to the plate, however, the same has not occurred with the distribution of moments.
Abstract
In this work, a new analytical procedure is developed to obtain the displacement field of a unidirectional composite plate subjected to bending in two planes. The analysed [...]
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Characterization of induction welded thermoplastic composites
J. Sogorb, N. Sarin, C. Worrall, J. Wächter, S. Gonzalez, R. Buelga, F. Lasagni

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 4

Abstract
Rib-AM project aims to contribute to the development of novel in-situ manufacturing technologies applied to large size components of primary structure of aircrafts. Framed in Clean Sky 2, the activities within Rib-AM are set out to develop a leading-edge (LE) concept based on reinforced thermoplastic materials avoiding mechanical joints between the skin and the ribs. Induction Welding (IW) process has been selected for the integration of the ribs into the leading-edge structure. The development of an appropriate IW process methodology, including the introduction of magnetic flux concentrators and new coil designs, are key to assure the quality and structural integrity of the produced joints. In this research, the mechanical strength of induction welded thermoplastic composites have been evaluated at sample level. Characterization specimens have been obtained by welding: (i) short carbon fiber reinforced polyether ether ketone (SCFR/PEEK), with 10 % carbon content, processed by additive manufacturing – fused deposition modeling; and (ii) multidirectional carbon fiber reinforced polyether ether ketone (CFR/PEEK) laminates processed by oven consolidation. The mechanical characterization of the strength has been carried out by means of the block shear test method. In addition, light optical microscopy has been performed to analyse the SCFR/PEEK - CFR/PEEK interface. Infrared thermography (IRT) has been considered for the non-destructive characterization of the welded joints to evaluate the feasibility of being applied as an inspection method for induction welded structures. IRT results have been validated by X-ray computed tomography.
Abstract
Rib-AM project aims to contribute to the development of novel in-situ manufacturing technologies applied to large size components of primary structure of aircrafts. Framed [...]
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Life cycle assessment of new Talgo lightweight prototypes
. M.Cerdeira*, E. Guerra, F. García, J. Fernández, . V.Meroño

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 14

Abstract
The European rail network is largely electrified, and rail emits far less CO2 than equivalent travel by road or air. It accounts for only 0.4 % greenhouse gas emissions from EU transport, while all EU transport accounts for 25% of the EU’s total emissions. Additionally, rail is the only transport that between 1990 and 2017 has consistently reduced its emissions and energy consumption, while increasingly using renewable energy sources. Following this green line, this article presents the Life Cycle Assessment (LCA) study of new generation trains, mainly based on lightweighted primary structures made of composite material (about 30-50% weight loss compared to conventional ones). The composite materials are novelty in the railway sector. Their introduction brings a clear advantage from the point of view of train capacity or energy/infrastructure canon savings. However, it needs to be justified from the LCA point of view. Two different stages are developed in this article. An LCA of the new prototypes (production, assembly, transport and use phase). It is completed with an LCA of conventional structures. The second phase presents a comparison between the environmental impact produce using CFRP materials or metallic materials at the end of a useful life (EoL) of a carbody. The results indicates that, at EoL, the composite material would be more economically and environmentally attractive than the current materials.
Abstract
The European rail network is largely electrified, and rail emits far less CO2 than equivalent travel by road or air. It accounts for only 0.4 % greenhouse gas emissions from [...]
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Impact behavior of thermoplastic matrix composites reinforced with basalt fibers and manufactured by RTM
M. Baskaran, R. Hoto, J. García-Manrique, J. Aurrekoetxea

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 16

Abstract
Reducing the environmental impact of composite materials by using new matrices and fibres, as well as a manufacturing process that allows obtaining high-quality standards, is on the strategic agenda of academia and industry. Replacing thermosetting matrices with thermoplastics is a challenging vector for improvement, facilitating recycling. Regarding the fibres, natural fibres of mineral origin, such as basalt, reduce the ecological footprint in the raw material extraction phase. Characterising the impact behaviour of these new composites is necessary to identify potential applications. Otherwise, direct comparison with reference materials is essential since differences in the manufacturing process, fibre content, or test conditions make it impossible to put the new material in context. In this paper, we compared the impact properties of two thermoplastic-matrix (pCBT) composites manufactured using resin transfer moulding (RTM). On the one hand, as a reference material, the pCBT is reinforced with carbon fibres, and on the other hand, with basalt fibres. The results are better for the composite reinforced with basalt fibres, regardless of whether the properties are compared in absolute terms (×2.2), in weight reduction (×1.8) or in reduction of energy consumed during the primary production of the fibres (×4.4).
Abstract
Reducing the environmental impact of composite materials by using new matrices and fibres, as well as a manufacturing process that allows obtaining high-quality standards, [...]
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Bio-based recyclable crosslinked polyurethanes based on a thermally reversible Diels-Alder adduct
A. Restrepo Montoya, I. Larraza, K. Gonzalez, O. Echeverria Altuna, I. Harismendy, A. Saralegi, A. Eceiza

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 15

Abstract
Thermosets comprise a family of chemically cross-linked networks formed by irreversible chemical reactions, resulting in polymers with outstanding properties such as superior mechanical properties, high thermal stability and chemical resistance. However, their high stability precludes reprocessing or recycling, thus making it difficult to move towards a circular economy and sustainability. During the last years, research has focused on dynamic chemistry, in order to introduce reversible bonds along the polymer chain and synthesize reprocessable and/or recyclable thermosets. In this context, the Diels-Alder reaction is of special interest, as it can give thermoreversible reactions with a relatively low coupling and high decoupling temperature. Within this work, a trifunctional polyol containing the furan-maleimide Diels-Alder adduct has been developed to facilitate the recycling of cross-linked polyurethanes. The maleimide-furan adduct forms covalent bonds at low temperatures, but when heated these bonds break down, splitting the polymer chain into smaller chains and softening the polymer, allowing it to be reprocessed. Then, when the temperature drops, the bonds between the maleimide and the furan are reformed and the polymer regains its mechanical properties. Thereby, a thermoset polyurethane was synthesized reacting the triol containing Diels-Alder adduct with a polymeric isocyanate. The reprocessability and/or recyclability of the synthesized polyurethane was then evaluated by breaking it into small pieces and reprocessing them by pressing at high temperature, in order to obtain new sheets and evaluate their mechanical properties, being similar to the original ones.
Abstract
Thermosets comprise a family of chemically cross-linked networks formed by irreversible chemical reactions, resulting in polymers with outstanding properties such as superior [...]
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Analysis of multiple high-velocity impact phenomenon in composite laminate plates
M. Paredes-Gordillo, I. Iváñez, S. García-Castillo, C. Navarro

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 7

Abstract
High-velocity impact is one of the most common load states to which composite material structures can be subjected during their service life and can cause a sudden loss of properties favouring its catastrophic failure. Impact loads are usually caused by external elements such as debris, particles carried by the wind, hail, fragments derived from an explosion, etc. All these cases can be represented as high-velocity impacts; however, in general, these impacts are not usually reduced to the action of a single projectile on the structure but can be represented as multiple projectiles that impact simultaneously, or sequentially, on it. This is known as multiple impact phenomenon. In this work a numerical model is developed, using a commercial finite-element software, that allows to analyse the phenomenon of multiple impact in composite material laminates, focusing attention on the wave’s interaction between projectiles. The model is validated with experimental results from the scientific literature for a single high-velocity impact. The interaction among waves generated by the action of two projectiles impacting at the same velocity, and that are separated at a certain distance from each other (simultaneous high-velocity multiple impact), is studied in terms of out-of-plane displacement, and relative movement between projectiles.
Abstract
High-velocity impact is one of the most common load states to which composite material structures can be subjected during their service life and can cause a sudden loss of [...]
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Thermoset polyurethanes based on recycled and biobased constituents
E. Mendiburu-Valor, I. Larraza, O. Echeverria Altuna, I. Harismendy, A. Eceiza

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 21

Abstract
Poly(ethylene terephthalate) (PET) is one of the most consumed plastics in the world, so it is very common to find it in the sea or ocean. Thermomechanical recycling is normally used for urban and industrial PET waste, but it is not suitable for highly degraded marine litter. Chemical recycling of marine PET litter is presented as an alternative for the valorization of this highly degraded waste. The bis(2-hydroxyethyl) terephthalate (BHET) monomer obtained can be used in the synthesis of new polymers. This study explores the potential of using BHET for the synthesis of high modulus and high strength thermoset polyurethanes. In addition, a renewable reagent, such as a polyol derived from castor oil, has been used to synthesize a recycled and biobased polyurethane thermoset (BHET-BioPU). The resulting BHET-BioPU has been thermally, thermo-mechanically and mechanically characterized to evaluate its potential applications. In addition, the recyclability by glycolysis of the BHET-BioPU has been demonstrated, thus advancing towards a circular economy. The results of this study provide fundamental knowledge for the development of sustainable, environmentally friendly and high performance materials and recyclable as well, materials, and represent an important achievement in the global effort to reduce dependence of fossil resources and plastic pollution.
Abstract
Poly(ethylene terephthalate) (PET) is one of the most consumed plastics in the world, so it is very common to find it in the sea or ocean. Thermomechanical recycling is normally [...]
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New functionalities and recycling opportunities for dynamic epoxy-based composites
A. Rekondo*, I. Azcune, A. Huegun

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 4 - Sostenibilidad y Reciclaje), 23

Abstract
Reprocessable, repairable, and recyclable thermoset composites have the potential to improve the circularity of composites and ensure their sustainability. Disulfide-based epoxy matrices are under development to meet the specifications of key sectors (transport, wind energy, etc.). The manufacturing of reinforced composites by different techniques (infusion, prepregs, etc.) has been validated (TRL 4-5). The incorporation of new functionalities, such as fire resistance, and the validation of recycling are now on the table. Conventional chemical recycling separates the reinforcement from the composite for reuse, leaving aside the polymer matrix. The new functionalities incorporated require recovery and validation of the matrix. Dynamic resins allow milder conditions to be applied during recycling, and the challenge remains to find new applications that reuse these recycled products. On the other hand, the rational use of resources demands for new recycling routes that do not require separation of the components, apply few steps, be economically viable, and maintain the value of the reinforcement and the matrix. Vitrimers allow the thermoforming of composite parts through the application of heat and pressure. This process opens the way from reusing final parts with new shapes to generating short new fibre composites from mechanical pre-crushing. This communication will present the latest developments and objectives of several European projects funded under the HE framework (SURPASS, GA no. 101057901; MC4, GA no. 101057394) in which work on the maturity of the technologies is in progress.
Abstract
Reprocessable, repairable, and recyclable thermoset composites have the potential to improve the circularity of composites and ensure their sustainability. Disulfide-based [...]
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Energy absorption capacity of pre-homologated polyamides against fire for 3D-printing
U. Morales, A. Esnaola, I. Sukia, U. Olaziregi Cuevas, J. Aurrekoetxea

Materiales Compuestos (2024). Vol. 08 - COMUNICACIONES MATCOMP21 (2022) Y MATCOMP23 (2023), (Núm. 3 - Caracterización - Daño, Fractura y Fatiga), 3

Abstract
Recent advances in developing new concepts for railway structures demand new lightweight structure concepts not only to reduce their energy consumption but also to reduce the load transmitted to the rail track. Fibre-reinforced polymers (FRP) have gained attention in the railway industry due to their lightweight properties, specific strength and stiffness, and corrosion resistance. Most published studies on the design of lightweight structures, for body and rolling stock, focus on continuous fibre-reinforced thermoset polymers (cFRP). However, derailment risk and fire safety must never be compromised due to this weight-reduction process. Therefore, new structure designs must be impact resistant and the materials must comply with EN-45545-2. A wide variety of fire protection, self-extinguishing or flame retardant systems for composite components and structures are available in the literature. The influence of flame retardant loading on the impact properties of a continuous carbon fibre reinforced polyamide 6 manufactured by 3D printing of continuous carbon fibre prepregs (FFF) has been analysed in the present work. The impact characterisation of a sandwich panel with a bio-inspired cellular core was carried out in this study. From the results, it has been concluded that the pre-homologated materials (Onyx-FR and cCF/PA-FR) have a similar energy absorption capacity (EAS) to that of the reference reinforced polyamide 6 used in 3D printing processes - FFF.
Abstract
Recent advances in developing new concepts for railway structures demand new lightweight structure concepts not only to reduce their energy consumption but also to reduce [...]
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