Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-16DOI: 10.1016/j.compstruct.2026.120050
Xinying Zhu , Lulu Liu , Chenyang Shao , Jianwu Zhou , Gang Luo , Zhenhua Zhao , Wei Chen
{"title":"Intra-filament voids in FDM 3D-printed continuous carbon fiber composites: microstructure, quasi-static/dynamic mechanical properties, and damage mechanisms","authors":"Xinying Zhu , Lulu Liu , Chenyang Shao , Jianwu Zhou , Gang Luo , Zhenhua Zhao , Wei Chen","doi":"10.1016/j.compstruct.2026.120050","DOIUrl":"10.1016/j.compstruct.2026.120050","url":null,"abstract":"<div><div>Voids, characterized by intra-filament and inter-filament voids, are critical defects in fused deposition modeling (FDM) 3D-printed continuous fiber composites, significantly influencing their mechanical behavior and damage mechanisms. While previous studies have mainly focused on fiber printing damage and inter-filament voids, the impact of voids formed within the filaments during deposition has received limited attention, especially in relation to dynamic mechanical properties vital for structural impact resistance. This research gap hampers accurate assessments of FDM structural components with both intra- and inter-filament voids. To address this, the present study innovatively investigates the impact of intra-filament voids by comparing two types of continuous carbon fiber (CCF) filaments— as-received and printed— in terms of microstructural characteristics, quasi-static and dynamic mechanical properties, and damage mechanisms. Through quasi-static tests, the effects of intra-filament voids and fiber damage caused by the printing process are preliminary decoupled. Dynamic tests further reveal that intra-filament voids positively influence the dynamic mechanical properties of the composites. In addition, the quantitative analysis of microstructure and mechanical performance provides essential data for developing microscopic and constitutive models that incorporate void defects, advancing the design and assessment of FDM composites.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120050"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035134","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-12DOI: 10.1016/j.compstruct.2025.119941
Ahmed Lahbazi, Adrien Baldit, Jean-François Ganghoffer
{"title":"Hyperelastic anisotropic effective strain gradient models based on large strains homogenization and applications to architected materials","authors":"Ahmed Lahbazi, Adrien Baldit, Jean-François Ganghoffer","doi":"10.1016/j.compstruct.2025.119941","DOIUrl":"10.1016/j.compstruct.2025.119941","url":null,"abstract":"<div><div>Higher gradient nonlinear models capturing size effects are elaborated for soft composites and architected media. A two-scale homogenization method is established to identify the nonlinear response of the underlying periodic microstructure, in the framework of strain gradient mechanics. The response of the base material is supposed to obey isotropic nonlinear elasticity. The anisotropy of the microstructure is captured by structural tensors reflecting its material symmetry group. A set of kinematic invariants of the macroscopic energy density is derived as the components of the Cauchy–Green first and second gradient tensors in the basis of the principal directions of anisotropy, proving to be invariant under the action of the material symmetry group, and accounting for rotations, reflections and permutations of the principal directions of anisotropy. The developed hyperelastic formulation is validated thanks to both full-field FE simulations and comparison with measurements done over pantographic structures exhibiting pronounced strain gradient effects. We exemplify the proposed homogenization method with different 2D microstructures and demonstrate the predictive capacity of the identified anisotropic hyperelastic model.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 119941"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035138","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2025-12-23DOI: 10.1016/j.compstruct.2025.120006
Maximilian Jux, Thorsten Mahrholz, Peter Wierach
{"title":"Influence of boehmite nanoparticles on moisture absorption and temperature effects in GFRP used for wind turbine blades","authors":"Maximilian Jux, Thorsten Mahrholz, Peter Wierach","doi":"10.1016/j.compstruct.2025.120006","DOIUrl":"10.1016/j.compstruct.2025.120006","url":null,"abstract":"<div><div>While boehmite nanoparticle integration enhances GFRP mechanical performance under standard conditions, their behavior under environmental stressors is less understood. This study investigates the effect of moisture absorption and temperature on nanoparticle-reinforced GFRP. A wind power-proven epoxy resin was modified with 5 and 10 wt% taurine-modified boehmite nanoparticles using a three-roll mill. Appropriate processing parameters are identified using viscosity and DSC measurements. Nanomodified GFRP composites are prepared via Vacuum Assisted Resin Infusion (VARI). Furthermore, the influence of moisture and temperature on GFRP properties, considering particle content and layer thickness, was investigated. Therefore, samples are stored under hot-wet conditions (50 °C; 70 % RH) until water saturation. Tensile properties of saturated and dry samples are then evaluated at test temperatures between − 20 °C and + 60 °C. Rheological tests have shown that the viscosity increases more quickly with rising temperature and increasing particle content. At the same time, the initial viscosity drops and the pot life extends by increasing the temperature, particularly for the particle-reinforced resins. DSC measurements confirm that the investigated particle modification only has a small impact on the epoxy system’s cross-linking, while the addition of water leads to reduced cross-linking. Furthermore, the storage of GFRP samples under hot-wet conditions showed that particle modification leads to reduced moisture absorption, which, however, increases again with increasing particle content. Different mechanisms, particularly based on polarity and tortuosity effects, are discussed. The tensile tests reveal that storage under hot-wet conditions results in a decrease in secant modulus (up to 58 %), ultimate tensile strength (up to 53 %) and strain to failure (up to 62 %). This effect is more pronounced in materials with particle modification.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120006"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923695","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-02DOI: 10.1016/j.compstruct.2025.120028
Wonjong Jeong , Joowon Suh , Suk Hoon Kang , Taejeong An , Avinash Chavan , Sang Hoon Kim , Heung Nam Han , Ho Jin Ryu
{"title":"Laser-driven in-situ synthesis of boride-reinforced Inconel 718 for overcoming high temperature deformation instabilities","authors":"Wonjong Jeong , Joowon Suh , Suk Hoon Kang , Taejeong An , Avinash Chavan , Sang Hoon Kim , Heung Nam Han , Ho Jin Ryu","doi":"10.1016/j.compstruct.2025.120028","DOIUrl":"10.1016/j.compstruct.2025.120028","url":null,"abstract":"<div><div>Additive manufacturing (AM) of Inconel 718 suffers from severe high-temperature ductility loss and dynamic strain aging (DSA) attributed to solute–dislocation interactions and microstructural heterogeneities. This study introduces a laser-driven in-situ boride-formation strategy using laser powder-directed energy deposition (LPDED) with SMART-processed powders containing up to 3 wt% TiB<sub>2</sub>. During deposition, TiB<sub>2</sub> decomposes and reacts with Cr, Mo, and Nb to form thermally stable (Cr,Mo,Nb)<sub>3</sub>B<sub>2</sub> borides, while increasing Al<sub>2</sub>O<sub>3</sub> particle density and refining the microstructure. These in-situ phases reduce thermal conductivity, promote Zener pinning during heat treatment, and modify γ′/γ″ precipitation by enriching the matrix in Ti and depleting Nb. Mechanical testing demonstrates that TiB<sub>2</sub> addition enhances both strength and strain-hardening at room and high temperatures. At 650 °C, the 1 wt% TiB<sub>2</sub> composite achieved a yield strength of 1013 MPa with 12.6 % elongation, exceeding the AMS requirement. While the unreinforced alloy exhibited pronounced DSA-induced serrations, TiB<sub>2</sub>-reinforced samples exhibited smooth flow behavior. DSA suppression arises from the sequestration of Nb, Cr, and Mo into stable M<sub>3</sub>B<sub>2</sub> borides, eliminating solute-dislocation pinning, while the borides provide barriers. Overall, in-situ boride formation effectively addresses deformation instabilities in AM Inconel 718, enabling simultaneous improvements in high-temperature strength, ductility, and thermal stability.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120028"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923684","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-12DOI: 10.1016/j.compstruct.2026.120047
Yang Li, Zhi-Jian Wang, Yu-Hang Ke, Jian Zang, Ye-Wei Zhang
{"title":"Vibration characteristics of composite support structures with complex cutouts based on image recognition technique","authors":"Yang Li, Zhi-Jian Wang, Yu-Hang Ke, Jian Zang, Ye-Wei Zhang","doi":"10.1016/j.compstruct.2026.120047","DOIUrl":"10.1016/j.compstruct.2026.120047","url":null,"abstract":"<div><div>Driven by the demand for lightweight design in aerospace composite structures, this study proposes an image recognition technique (IRT) to analyze the vibration behavior of aircraft composite support structures (ACSS) containing irregularly shaped cutouts. The image recognition technology accurately extracts the shape, dimensions and quantity of cutout from photographs of the support structure. Moreover, compared to traditional methods, IRT does not require specific formulas or equations to solve for the cutouts. By combining IRT with the Rayleigh-Ritz method, a dynamic model for aircraft composite support structures with complex cutouts is established. Numerical results analysis and modal validation through finite element analysis and modal experiments confirmed the model’s accuracy. Furthermore, the study investigates the effects of varying notch shapes, quantities, and sizes on the vibration characteristics of composite combined structures. This technology provides a rapid, non-contact tool for designing and optimizing perforated composite components in aerospace applications.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120047"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146035142","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-14DOI: 10.1016/j.compstruct.2026.120072
Elshan Ahani , Jian Yang , Ali Ahani
{"title":"Structural glass health monitoring: A comparative evaluation of flaw detection approaches","authors":"Elshan Ahani , Jian Yang , Ali Ahani","doi":"10.1016/j.compstruct.2026.120072","DOIUrl":"10.1016/j.compstruct.2026.120072","url":null,"abstract":"<div><div>Laminated glass (LG) has become a core construction material, yet its brittle behavior and configuration dependent mechanics complicate reliable assessment under dynamic loading. The need for early damage detection is critical, as even small stiffness losses or microcracks can rapidly undermine façade safety. This study establishes a regulation compliant SHM framework by integrating a finite element (FE) and Python engine with 1944 impact simulations across nine LG configurations, incorporating polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and SentryGlas Plus (SGP) interlayers for ply thicknesses of 4, 6, and 8 mm. Modal, spectral, time frequency, and statistical indicators are extracted from pre impact and post impact responses. The results show that only a select subset of features, principally eigenfrequencies, frequency response function (FRF) descriptors, and targeted transmissibility function (TF) metrics, retains stable discriminative power, with damaged cases presenting frequency reductions exceeding 8–12 % in higher modes. Small missile impacts generate strain peaks nearly twice those of large missile events, producing far clearer diagnostic signatures. These findings provide a physically grounded basis for SHM driven failure detection, digital twin integration, and intelligent monitoring strategies for next generation glass façades.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120072"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974438","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-07DOI: 10.1016/j.compstruct.2025.120034
Yanqin Zeng , Lihua Xu , Fanghong Wu , Le Huang , Min Yu , Yin Chi
{"title":"Eccentric compression behavior of GFRP tube-confined UHPC-filled steel-encased stub columns","authors":"Yanqin Zeng , Lihua Xu , Fanghong Wu , Le Huang , Min Yu , Yin Chi","doi":"10.1016/j.compstruct.2025.120034","DOIUrl":"10.1016/j.compstruct.2025.120034","url":null,"abstract":"<div><div>The GFRP tube-confined UHPC-filled steel-encased column (FUSRC), renowned for its ultrahigh load-carrying capacity and superior corrosion resistance, emerges as a highly promising structural candidate for future marine engineering applications. This study presented an experimental investigation on 20 FUSRC stub specimens subjected to eccentric compression for varying GFRP winding angles and tube thicknesses. Pressure-sensing films and a macro-mesoscale finite element model were employed to elucidate the working mechanism of the specimen throughout the loading process. Experimental results showed that FUSRC stub specimens exhibited two distinct failure patterns: compression-controlled and tension-controlled failure patterns, which can be influenced by the GFRP winding angles and thickness. Specimens with a fiber winding angle <span><math><mrow><mi>θ</mi><mo>≥</mo></mrow></math></span> 70° predominantly exhibited compression-controlled failure with the same load eccentricity. The pressure-sensing films and simulations reveal that the confinement provided by the GFRP tube mainly exists in the compressive region of UHPC, decreasing by 56 % as the load eccentricity <span><math><msub><mi>e</mi><mn>0</mn></msub></math></span> increased from 20 mm to 60 mm, resulting in a maximum reduction of 67 % in load-carrying capacity. Moreover, the reinforcing effect of the GFRP tubes combined with the bridging action of steel fibers effectively inhibited the propagation of existing tensile cracks, thereby improving the ductility of FUSRC and inducing a multi-cracking failure pattern. The results confirm that FUSRC specimens satisfy the plane-section assumption, and the yield of the profile steel’s flange on the tension side is recommended as an indicator for predicting the load-carrying capacity of FUSRC exhibiting a tension-controlled failure pattern. This research can inform the practical application of FUSRC, leading to more efficient, resilient, and sustainable structural solutions in marine and harsh environments.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120034"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974436","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-09DOI: 10.1016/j.compstruct.2026.120056
Komal Chawla , Ahmed Arabi Hassen , Nikhil Garg , Deepak Kumar Pokkalla , Tyler Smith , Brittany Rodriguez , Desheng Yao , Rayne Zheng , Ellen Lee , Iskander Farooq , Matthew Rebandt , Asim Khan , Seokpum Kim
{"title":"Performance assessment of 3D printed multi-material energy absorber for automotive bumper: pedestrian lower extremity protection","authors":"Komal Chawla , Ahmed Arabi Hassen , Nikhil Garg , Deepak Kumar Pokkalla , Tyler Smith , Brittany Rodriguez , Desheng Yao , Rayne Zheng , Ellen Lee , Iskander Farooq , Matthew Rebandt , Asim Khan , Seokpum Kim","doi":"10.1016/j.compstruct.2026.120056","DOIUrl":"10.1016/j.compstruct.2026.120056","url":null,"abstract":"<div><div>Designing an energy absorber for automotive bumpers involves balancing low-speed and high-speed impacts to ensure safety, reduce repair costs, and meet regulatory standards. This study explores a novel design using multi-material 3D printing and structural optimization to fabricate a lightweight and cost-efficient energy absorber. The design effectively dissipates energy in low-speed collisions and minimizes force transmission in high-speed pedestrain impacts, helping to meet both safety and performance requirements. The energy absorber design combines 20% carbon fiber-reinforced acrylonitrile butadiene styrene (CF-ABS) and thermoplastic polyurethane (TPU) for optimal stiffness and flexibility. It uses 3D-printed lattice structures optimized through finite element simulations to help meet both low-speed and high-speed impact requirements. Full-scale energy absorbers were 3D-printed using optimized CF-ABS/TPU blends and tested under high-speed impact using the Flexible Pedestrian Legform Impactor (Flex-PLI). For fair comparison, a baseline bumper with a traditional triangular lattice structure, also 3D-printed from the same CF-ABS/TPU materials, was similarly tested. Interestingly, both the optimized and baseline 3D-printed energy absorbers showed nearly identical performance, successfully meeting injury limits. Their performances were also benchmarked against an injection-molded energy absorber. While both 3D-printed and injection-molded designs met injury limits, the 3D-printed absorber exhibited a higher tibia bending moment, indicating an opportunity for further optimization. A Techno-Economic Analysis compared the costs of producing energy absorbers using traditional manufacturing and 3D printing. The analysis highlighted that 3D printing offers cost benefits for low to medium production volumes, with the total cost per energy absorber at ∼ $74, compared to traditional methods that become economical beyond 2000 units.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120056"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974445","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":"Improvement of figure-of-merit in nanostructured vanadium-zinc-oxide composites thin film for high-sensitivity underwater piezoelectric micromachined transducers","authors":"Wei Gao , Jianing Zhang , Chuqiao Wang , Yongyao Chen","doi":"10.1016/j.compstruct.2025.120008","DOIUrl":"10.1016/j.compstruct.2025.120008","url":null,"abstract":"<div><div>Piezoelectric micromachined ultrasonic transducers (PMUTs), leveraging micro-electro-mechanical-systems technology and piezoelectric effects, have emerged as a promising solution for underwater acoustic applications. Piezoelectric material performance has been a decisive element for unlocking PMUTs potential. Key properties including piezoelectric coefficient (<em>e<sub>31, f</sub></em>, <em>d<sub>33, f</sub></em>), dielectric permittivity (<em>ε<sub>33, f</sub></em>) and loss, directly govern PMUTs functionality. In this work, a nanostructured vanadium-zinc-oxide (VZO) piezoelectric composite film is prepared, characterized and implemented to achieve high-performance PMUTs for underwater detection. The VZO-PMUT is designed and fabricated using micromachined process. The influences of key fabrication parameters including sputtering power, pressure, argon-oxygen ratio, and annealing temperatures on the films are detailed studied. Through observing the surface morphologies, measuring the crystal structure, and identifying chemical element states etc., the mechanisms of the enhanced piezoelectric and dielectric behavior are analyzed. A record figure of merit (FOM, <em>e<sup>2</sup><sub>31, f</sub> /ε<sub>0</sub>ε<sub>33, f</sub></em>) of 1090 GPa is achieved with significant advances of <em>e<sub>31, f</sub></em> (−12.5 C/m<sup>2</sup>) and <em>ε<sub>33, f</sub></em> (16.2). Demonstrations in a water tank for VZO-PMUTs reveal with a transmitting response of 154.5 dB re. 1 <!--> <!-->V/µPa @ 127 <!--> <!-->kHz and receive sensitivity of −158 dB<!--> <!-->re.<!--> <!-->1<!--> <!-->µPa/V @ 123 <!--> <!-->kHz. Moreover, VZO-PMUTs achieve precisely range-finding of underwater obstacles, indicating great potentials in underwater acoustic application.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120008"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923696","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}
Composite StructuresPub Date : 2026-04-01Epub Date: 2026-01-04DOI: 10.1016/j.compstruct.2025.120025
Mehmet Zor
{"title":"A generalized equivalent volume theory and model including Poisson interactions for layered composite structures","authors":"Mehmet Zor","doi":"10.1016/j.compstruct.2025.120025","DOIUrl":"10.1016/j.compstruct.2025.120025","url":null,"abstract":"<div><div>This study proposes a new equivalent volume model that incorporates Poisson effects to represent the planar elastic behavior of n-layered composite structures. Although each layer may exhibit orthotropic or monoclinic behavior in its own local coordinate system, the equivalent volume shows a monoclinic mechanical response in the global x-y plane. The theory assumes perfect bonding between layers, leading to equal directional strains across the structure under tensile or compressive loading in the layer plane. It is formulated to generalize the model for all n-layered structures by considering each layer with different thickness and locally orthotropic properties.</div><div>The unique aspect distinguishing the theory from other methods is the incorporation of Poisson interactions between layers into the calculations and the ability to express equivalent volume properties through closed-form equations. Specially defined Poisson interaction coefficients are introduced, allowing the mechanical interaction potential of each layer with others to be integrated into the model. As a result, directional elastic properties such as <span><math><mrow><msub><mi>E</mi><mi>x</mi></msub></mrow></math></span><em>,</em> <span><math><mrow><msub><mi>E</mi><mi>y</mi></msub></mrow></math></span><em>,</em> <span><math><mrow><msub><mi>v</mi><mrow><mi>xy</mi></mrow></msub></mrow></math></span> and <span><math><mrow><msub><mi>v</mi><mrow><mi>yx</mi></mrow></msub></mrow></math></span> are derived analytically, while the shear modulus <span><math><mrow><msub><mi>G</mi><mrow><mi>xy</mi></mrow></msub></mrow></math></span> is calculated by volumetric averaging under the assumption of common shear deformation in all layers.</div><div>The model is applicable to both symmetric and non-symmetric n-layered structures and has been evaluated against classical methods such as Voigt, Reuss, CLT and other methods for laminates composed of orthotropic layers. Comparisons show that changes in fiber orientation or layer properties lead to distinct differences between the model and classical methods.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"381 ","pages":"Article 120025"},"PeriodicalIF":7.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145923697","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}