{"title":"Crack initiation, propagation and strain mapping during composite bending using digital image correlation and theoretical calculations","authors":"Karolina Głowacka , Tadeusz Smolnicki","doi":"10.1016/j.compstruct.2025.119680","DOIUrl":"10.1016/j.compstruct.2025.119680","url":null,"abstract":"<div><div>The study focuses on analyzing strains and stresses in bent specimens of various dimensions. Depending on the maximum normal to shear stress ratio during bending, two failure modes can occur: translaminar and interlaminar. A higher value of this ratio increases the likelihood of translaminar failure. The research demonstrates that the critical value for polypropylene reinforced with unidirectional continuous glass fibers is 24. In this case, specimens exhibited both translaminar and interlaminar failure modes. The study also examined the specimens’ appearance at different stages of the bending test, as well as their microstructure after failure. Digital image correlation (DIC) was employed, enabling the determination of strain values for individual specimens and the comparison of theoretical values with those obtained experimentally via DIC. It was found that while the linear strain along the fibers and the shear strain were consistent, the actual strain across the specimen’s height was significantly higher than the theoretically calculated value. This discrepancy is likely due to the occurrence of additional stresses within the specimen, particularly associated with Hertzian contact phenomena, which caused localized compression and further influenced the strain distribution.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119680"},"PeriodicalIF":7.1,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinye Luo , Juanjuan Zhang , Pengcheng Li , Xiaodong Xia , Han Du , George J. Weng
{"title":"Nonlinear mechanical behavior and multi-field coupling characteristics in polymer-based multiferroic composites under combined tension and bending","authors":"Jinye Luo , Juanjuan Zhang , Pengcheng Li , Xiaodong Xia , Han Du , George J. Weng","doi":"10.1016/j.compstruct.2025.119653","DOIUrl":"10.1016/j.compstruct.2025.119653","url":null,"abstract":"<div><div>Polymer-based multiferroic composites simultaneously exhibit ferroelasticity, ferroelectricity, and ferromagnetism, supporting applications in flexible electronics, biomimetics, and biomedicine. Their macroscopic properties are influenced by averaging, synergy, antagonism, and product interactions. This study investigates these behaviors by incorporating nonlinear hysteresis, interface polarization, and leakage effects, integrating a crystal phase transformation model with two-step homogenization theory. A theoretical framework is developed to analyze nonlinear mechanical responses and magnetoelectric (ME) effects under combined tension and bending, based on Kirchhoff thin plate theory and tension-bending control equations. Analytical expressions are derived for natural frequencies, vibration modes, displacements, and ME coefficients. Results reveal that increasing ferromagnetic particle content enhances ferromagnetism but causes dielectric relaxation, percolation, and leakage, reducing piezoelectricity. Moderate content promotes <em>β</em>-phase formation, enhancing piezoelectric performance. The composite shows multiple natural frequencies, with resonance at specific ones. The ME properties exhibit hysteresis, significantly amplified under combined deformation. Theoretical predictions of magnetization, polarization, piezoelectric coefficient, leakage current, and ME coefficient closely match experimental results, validating the model’s accuracy and applicability. To address leakage at high particle fractions, two strategies are proposed. Under optimal conditions, the ME coefficient improves by 2.4 times, establishing a solid basis for the design and optimization of polymer-based multiferroic composites.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119653"},"PeriodicalIF":7.1,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Abdelmageed , Ibrahim H. ZainElabdeen , Kamran A. Khan , Wael Zaki , Wesley Cantwell
{"title":"Systematic numerical design of a supported FCC plate lattice with structural reinforcement and gradation for energy absorption","authors":"Mohamed Abdelmageed , Ibrahim H. ZainElabdeen , Kamran A. Khan , Wael Zaki , Wesley Cantwell","doi":"10.1016/j.compstruct.2025.119677","DOIUrl":"10.1016/j.compstruct.2025.119677","url":null,"abstract":"<div><div>In structural engineering and protective applications, efficient energy-absorbing materials are essential. Additively manufactured plate lattices are promising due to their high stiffness-to-density ratio. This study presents a numerical analysis of three basic plate lattices, simple cubic (SC), body-centered cubic (BCC), and face-centered cubic (FCC), under large-strain quasi-static compression. The effects of unit cell count, relative density, and axial grading on energy absorption and stability are investigated. Hybrid structures combining two or three lattice types are also studied across various component ratios. Based on the findings, a new design combining FCC with vertical supports is proposed. Numerical results are validated through experiments on FCC, BCC, and the binary-hybrid FCC + BCC lattices, showing good agreement in force response and deformation patterns. The SC structure achieves the highest specific energy absorption (SEA) but suffers from poor stability due to vertical walls, while the FCC offers the best stability. Integrating 70 % SC into FCC or BCC enhances SEA but reduces structural stability. The proposed hybrid structure outperforms all others, achieving 30 % higher SEA than FCC alone while maintaining stable deformation. Axial grading further boosts SEA by 11.6 %. This work demonstrates a pathway to optimizing both energy absorption and mechanical stability in lattice-based materials.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119677"},"PeriodicalIF":7.1,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multilevel homogenization framework for equivalent elastic properties of TSV heterostructures: integrating theoretical modeling and micromechanical FEM","authors":"Jian Liu , Xiaojing Zheng , Qingya Li","doi":"10.1016/j.compstruct.2025.119669","DOIUrl":"10.1016/j.compstruct.2025.119669","url":null,"abstract":"<div><div>This study presents a hetero-structured interposer incorporating complete Through-Silicon Vias (TSVs) with functional barriers and insulating layers. A multiscale homogenization framework is developed to characterize the mechanical behavior of TSV architectures, explicitly considering constitutive relationships among constituent materials to capture intrinsic heterogeneities affecting macroscale interposer performance. The proposed methodology combines elastic mechanics theory with micromechanical finite element analysis to calculate equivalent elastic constants and thermal expansion coefficients of TSV assemblies through a representative volume element model. Numerical validation demonstrates maximum discrepancies of 13.16% between theoretical predictions and finite element simulations when scaling TSV copper core diameters from 0.1 mm to 0.6 mm. Parametric analysis reveals significant orthotropic effects: modeling silicon as isotropic induces substantial errors (42.94%) in equivalent properties compared to orthotropic treatment, emphasizing the critical need to account for crystalline orientation in TSV mechanical analysis. The homogenization framework successfully predicts the bending deformation and free vibration responses of TSV-embedded interposers under clamped boundary conditions. Comparative assessments show excellent agreement between theoretical and numerical results, with displacement errors below 8% and natural frequency deviations within 5%, confirming the model’s accuracy in capturing global structural behavior. This methodology establishes a validated computational framework for TSV reliability assessment in 3D integrated circuits, achieving less than 15% prediction errors that meet industrial accuracy requirements. The demonstrated capability to resolve interfacial stress interactions while maintaining computational efficiency positions this approach as a critical tool for advanced packaging optimization.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119669"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multi-physics property evaluation and actuation response of first-order fractal-inspired photostrictive composites: a finite element analysis","authors":"Manish Kumar Sharma , Diwakar Singh , Reeta Chauhan , Rajeev Kumar , Vishal Singh Chauhan","doi":"10.1016/j.compstruct.2025.119671","DOIUrl":"10.1016/j.compstruct.2025.119671","url":null,"abstract":"<div><div>A photostrictive actuator helps the smart structure to be actuated wirelessly. Researchers are attempting to enhance its actuation response. This research article explores first-order fractal-inspired photostrictive 3–3 composites to enhance the actuation response of photostrictive actuators. The proposed structure has been considered and designed for enhanced multifunctional actuation. This configuration consists of piezoelectric PMN-35PT reinforcements and photovoltaic PTB7-Th as a matrix, enabling opto-electro-mechanical coupling. All effective material properties were evaluated using a representative volume element (RVE) approach for fiber aspect ratios (L/D = 2, 2.5, 3). Actuation performance was analyzed under 60 mW/cm<sup>2</sup> light irradiation using the finite element method. Maximum deflections for the cantilever beam decreased from −3.77 × 10<sup>−3</sup> m (L/D = 2) to −1.45 × 10<sup>−3</sup> m (L/D = 3), the simply supported beam 4.71 × 10<sup>−4</sup> m (L/D = 2) to 1.81 × 10<sup>−4</sup> m (L/D = 3), and clamped square plate shows 1.6 × 10<sup>−4</sup> m (L/D = 2) demonstrating the tunability of actuation response. To the best of our knowledge, this is the first demonstration of a photostrictive actuator based on a first-order fractal-inspired composites, modelled via fully-coupled multiphysics finite-element framework. This study highlights the potential of fractal-inspired photostrictive composites for applications in aerospace, robotics, and MEMS, where adaptive material performance is crucial.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119671"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145105812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mengdie Liang , Xin Wang , Xinyan Yuan , João R. Correia , Zhishen Wu
{"title":"Behaviors and load distribution of sleeved bolted joints between pultruded FRP box profiles with multi-directional fiber layups","authors":"Mengdie Liang , Xin Wang , Xinyan Yuan , João R. Correia , Zhishen Wu","doi":"10.1016/j.compstruct.2025.119673","DOIUrl":"10.1016/j.compstruct.2025.119673","url":null,"abstract":"<div><div>Pultruded fiber-reinforced polymer (PFRP) composites have recently garnered significant attention for truss structures. However, the low connection efficiency and inherent brittleness of traditional PFRP profiles, with mostly unidirectional (UD) reinforcement, pose critical challenges that limit their structural applications. This study presents experimental and numerical investigations about the tensile performance of bolted sleeved joints between PFRP box profiles with multi-directional (MD) fiber layups, aiming to explore effective strategies for enhancing joint connection efficiency. The studied parameters included bolt layout, fiber layup, end distance and bolt spacing. Results indicate that the incorporation of MD fiber layups can improve the joint strength of the bolted sleeved joints by 90 %. Moreover, arranging the bolts to pass through all four walls of the box profile mitigated the uneven load distribution among bolts, thereby improving connection efficiency without requiring additional bolts or increased connection length compared to joints where bolts were arranged passing only through two walls. Increasing bolt spacing proved more effective in enhancing ultimate load than adjusting end distance. For engineering applications, it is recommended that bolt spacing exceeds five times the bolt diameter in order to guarantee pin-bearing failure.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119673"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Fine-scale model of concrete composite for long-term cycling transient loads incorporating nonlinear hardening and softening effects","authors":"Himanshu Rana , Adnan Ibrahimbegovic","doi":"10.1016/j.compstruct.2025.119649","DOIUrl":"10.1016/j.compstruct.2025.119649","url":null,"abstract":"<div><div>Concrete modeling under long-term cyclic transient loading has always been a challenging task due to the highly heterogeneous nature of the material. In this context, the present study proposes a fine-scale model of concrete by representing it as a two-phase material composed of aggregates and mortar. For this, the material domain is discretized into Voronoi cells connected by cohesive links using Delaunay triangulation, and an aggregate assignment algorithm is proposed to associate these links to either aggregates or mortar. Following this, the cohesive links representing mortar are modeled as 2D Timoshenko beam elements incorporating a distinct nonlinear kinematic hardening model along with isotropic softening model, separately in tension, compression, and shear. Softening in the material is introduced using the Embedded Discontinuity Finite Element Method (EDFEM) to model localized discontinuities. In contrast, the cohesive links associated with aggregates are modeled as elastic 2D Timoshenko beam elements. Lastly, compressive cyclic and three-point bending tests are performed on the concrete specimen, and the results are compared with experimental data reported in the literature, showing very good agreement with the experiments. Additionally, an active Bayesian Optimization (BO) procedure is performed to determine the optimal set of parameters for the three-point bending test by minimizing the Mean Squared Error (MSE) of energy between the present model and the experimental results.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119649"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of low strain rate on the strength of CFRP laminates after hygrothermal exposure in seawater","authors":"Haiwei Zhan , Jiayu Wu , Jian-Fei Chen","doi":"10.1016/j.compstruct.2025.119663","DOIUrl":"10.1016/j.compstruct.2025.119663","url":null,"abstract":"<div><div>This paper presents a study on the effect of strain rate on the strength of carbon fiber reinforced polymer (CFRP) laminates after hygrothermal exposure in seawater at 60 °C. A ten-month water absorption test was conducted on CFRP immersed in 60 °C seawater, and its non-Fickian moisture uptake behavior was accurately modeled using a Weibull relaxation model optimized by particle swarm optimization (PSO). Tensile tests were conducted on CFRP specimens subjected to varying seawater aging durations (0, 35, 70, and 105 days) at different strain rates (from 10<sup>−7</sup> to 10<sup>−3</sup> s<sup>−1</sup>). The experimental results indicate that the strength of CFRP increases with an increase in strain rate, regardless of whether the material has undergone seawater aging. It decreases with aging time until reaching water absorption saturation across all test strain rates, but increases slightly after saturation. A two-way analysis of variance (ANOVA) was innovatively applied to assess the interaction effects of strain rate and aging time on CFRP strength. The results confirmed that both factors are statistically independent, offering a novel and quantitative perspective on the mechanical-environmental coupling effects. Finally, an empirical model is developed to represent the strengths of CFRP at different strain rates following hygrothermal exposure.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119663"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145155288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Design, modelling and experimental validation of a composite suspension system for solar EVs","authors":"Ana Pavlovic, Giangiacomo Minak","doi":"10.1016/j.compstruct.2025.119650","DOIUrl":"10.1016/j.compstruct.2025.119650","url":null,"abstract":"<div><div>This study presents the design, finite element modeling, and experimental validation of a novel rear suspension system for lightweight, solar-powered electric vehicles. The proposed system features stiffness-tunable components made entirely from carbon fiber-reinforced polymers (CFRPs), including a torsion bar and flexural springs engineered to maximize the strength-to-weight ratio while ensuring fail-safe operation. This work represents one of the first fully integrated efforts to design, simulate, and validate a complete CFRP-based suspension system tailored for solar vehicle applications, with specific attention to redundancy and reliability. A multilayer layup strategy is adopted to customize the mechanical response under vertical, lateral, and torsional loading. Finite Element (FE) analyses using layered shell elements are conducted to assess stress distributions and identify potential failure zones, employing the Tsai–Wu failure criterion. Experimental testing confirms the accuracy of the numerical predictions, with stiffness deviations below 10% under representative loading conditions. The results demonstrate the feasibility of using anisotropic CFRP laminates to achieve compact, efficient, and reliable suspension systems with stiffness-tuning capabilities. The proposed approach offers a validated design methodology suitable for long-distance solar vehicle competitions, where weight, safety, and operability under partial damage are critical.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119650"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145106446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Francesco D’Orazio, Federico Cottini, Fabio Spazzini, Valentina Furlan, Hermes Giberti
{"title":"A novel and flexible path planning algorithm for robotic filament winding of non-axisymmetric tubular structures","authors":"Francesco D’Orazio, Federico Cottini, Fabio Spazzini, Valentina Furlan, Hermes Giberti","doi":"10.1016/j.compstruct.2025.119647","DOIUrl":"10.1016/j.compstruct.2025.119647","url":null,"abstract":"<div><div>With the increasing automation and use of composite materials in manufacturing processes, one of the most interesting and attractive technologies is Filament Winding. While this technology is already widely used with the support of robotic systems for the production of large and typically axisymmetric components, the same cannot be said when looking at the market for smaller and more complex objects. The real lack in this area is the development of robust and flexible algorithms capable of planning a path on complex real objects whose main information is derived from STL files. In this work, a new discrete algorithm for path planning based on IPS and NIS is proposed. This algorithm exploits information derived from STL geometries and friction to actively control the winding angle and to plan the trajectory with more flexibility. Its non-iterative approach ensures less computational effort, and the generated trajectory simplifies the transport condition along the geodesic direction used in previous algorithms. The algorithm was first validated with an analytically defined geometry (with errors below 2%) and subsequently its application was extended to geometries of varying degrees of complexity, demonstrating its robustness and accuracy. A non-axisymmetric tubular structure was used as a case study. Tests performed for different winding angles (45°to 80°) demonstrated the feasibility of the process based on the new algorithm. The results obtained with errors generally below 5°testify to the stability and accuracy of the solution.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"373 ","pages":"Article 119647"},"PeriodicalIF":7.1,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}