Composite Structures最新文献

{"title":"Enhanced parameterization for variable stiffness laminated composite panels: Buckling optimization based on a semi-analytical model","authors":"Gabriela de Freitas Gandorphi,&nbsp;Mauricio Vicente Donadon,&nbsp;Rafael Thiago Luiz Ferreira","doi":"10.1016/j.compstruct.2026.120654","DOIUrl":"10.1016/j.compstruct.2026.120654","url":null,"abstract":"<div><div>Due to tailored stiffness distribution and enhanced performance, variable stiffness composites (VSC) have been a recent research focus. Variable angle tow (VAT) panels have improved buckling from curvilinear fiber paths within laminae. However, manufacturing still presents challenges. Overlaps and gaps are common in automated fiber placement (AFP); continuous tow shearing (CTS) may present irregular thicknesses. This work presents an alternative fiber tow path parameterization named the QP (quasi-parallel), inspired by fused filament fabrication (FFF), which generates offset curves from a reference path, minimizing overlaps and gaps, while maintaining constant thickness. Buckling performance is investigated for VAT and QP parameterizations, comparing optimal VSC to constant stiffness composites (CSC). Linear buckling of cylindrical panels is evaluated with a semi-analytical framework based on Sanders’ shell formulation and Rayleigh–Ritz solution, including compression-shear combinations, enabling efficient optimization. Numerous case studies are investigated, considering variations in loading, aspect ratio and panel curvature. Graphical search and simulated annealing (SA) optimization are employed to identify optimal designs. Both QP and VAT parameterizations show buckling improvement over CSC. The QP method delivers up to 40% increases for a square compressed plate. Advantages and limitations, such as the need for tow curvature constraint, are discussed for insights on VSC design.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120654"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fatigue behavior of assembled carbon/epoxy–titanium hybrid stacks with drilling-induced hole defects","authors":"Philippe Blais,&nbsp;Lotfi Toubal,&nbsp;Redouane Zitoune","doi":"10.1016/j.compstruct.2026.120660","DOIUrl":"10.1016/j.compstruct.2026.120660","url":null,"abstract":"<div><div>Fatigue performance of multi-material composite–titanium stacks is a critical issue in aerospace structures, where drilling-induced defects can strongly influence damage initiation and lifetime. In such assemblies, the entire stack is often drilled in a single operation, leading to suboptimal machining conditions for at least one material. This study investigates the influence of drilling-induced hole characteristics on the fatigue behavior of carbon/epoxy–titanium hybrid stacks. Abrasive waterjet and conventional drilling processes are compared through open-hole and assembled fatigue tests. Fatigue crack propagation in open-hole specimens and stiffness evolution in assembled joints are modelled to identify damage initiation thresholds. Post-drilling hole characteristics are quantitatively measured and correlated with the model parameters. In the open-hole configuration, fatigue failure is governed by titanium cracking, with crack initiation occurring earlier for conventionally drilled holes, primarily correlated with titanium surface roughness. In assembled fatigue tests, damage initiation and lifetime are instead controlled by hole conicity, with abrasive waterjet drilling leading to earlier damage initiation and reduced fatigue life. These results highlight the critical role of drilling-induced geometric and surface defects on fatigue damage mechanisms in hybrid composite–titanium joints and provide guidelines for process optimization to improve fatigue performance.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120660"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intermediate crack-induced debonding of CFRP-to-concrete joints with transversely compressed mechanical anchorages","authors":"Hugo C. Biscaia,&nbsp;Alba Codina,&nbsp;Mehdi Aghabagloo,&nbsp;Cristina Barris","doi":"10.1016/j.compstruct.2026.120657","DOIUrl":"10.1016/j.compstruct.2026.120657","url":null,"abstract":"<div><div>Flexural strengthening of reinforced concrete (RC) beams with externally bonded (EB) carbon fibre-reinforced polymers (CFRP) is frequently limited by intermediate crack debonding (ICD). Although some analytical and numerical studies have investigated ICD in conventional CFRP-to-concrete joints, the behaviour of hybrid bonded joints with transversely compressed mechanical anchorages remains poorly understood, particularly regarding the influence of the anchorage location. This study introduces a new Finite Difference Method (FDM) formulation that simulates the end debonding (ED) and ICD in mechanically anchored CFRP-to-concrete joints. Unlike existing bond-slip formulations, the proposed exponential relationship is based on an odd and continuous function, enabling stable modelling of opposite slip signs developed between adjacent cracks under variable load ratios. The model also allows the analysis of different anchorage locations along the bonded interface, which has barely been addressed in previous ICD studies available in the literature. Sixty numerical cases combining different crack spacings, load ratios, and anchorage configurations were analysed and validated against Finite Element Method (FEM) simulations. The results demonstrate that the proposed approach accurately reproduces the load-slip response and provides an efficient tool for assessing ICD mechanisms in hybrid CFRP-strengthened RC beams.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120657"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress-oriented path planning for 3D printing of continuous carbon fiber composites under combined tensile-compressive stress states","authors":"Zhijie Li,&nbsp;Ben Deng,&nbsp;Fangyu Peng,&nbsp;Aodi Yan,&nbsp;Jiale Yi,&nbsp;Jinguo Shen,&nbsp;Xiangyang Du","doi":"10.1016/j.compstruct.2026.120711","DOIUrl":"10.1016/j.compstruct.2026.120711","url":null,"abstract":"<div><div>Continuous carbon fiber composites exhibit high strength, modulus in the fiber direction and significant anisotropy. In 3D printing, planning fiber paths along the stress direction enhances the axial reinforcement effect, improving the overall mechanical properties of the printed part. However, for parts under three-dimensional spatial loads, traditional planar slicing methods limit the consistency between stress direction and fiber orientation. At the same time, the internal stress state of parts becomes more complex, with both tensile and compressive stresses possibly coexisting in the same area. This paper presents a stress-oriented curved slicing and path planning methodology for parts under combined tensile-compressive stress states. It also researches variable stiffness for adaptive control over trajectory density and stress magnitude. Mechanical tests were conducted to validate the proposed method. The results demonstrated that the stress-oriented path outperforms the conventional planar slicing configurations with cross-path, with improvements ranging from a minimum of 26.9% in maximum load and 51.5% in compressive stiffness (compared to the XZ slicing method) to a maximum of 213% and 339%, respectively (compared to the YZ slicing method). Furthermore, the variable stiffness technique enhanced the maximum load and compressive stiffness by 8.85% and 20.83%, respectively. The proposed method can leverage the improving effect of fibers along the axial direction of the part, enhancing the mechanical properties.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120711"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645948","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":"Mechanical behaviors of bioinspired helicoidal laminates with cracks: an extended isogeometric analysis approach","authors":"Yaoxin Huang,&nbsp;Yu Zhang,&nbsp;Erasmo Carrera","doi":"10.1016/j.compstruct.2026.120679","DOIUrl":"10.1016/j.compstruct.2026.120679","url":null,"abstract":"<div><div>Bioinspired helicoidal composite structures possess exceptional damage tolerance; yet they remain susceptible to fractures under high-intensity operational stresses. Consequently, evaluating the mechanical performance of such structures in the presence of defects is essential for reliable engineering implementation. This study presents a numerical investigation into the free vibration and bending behaviors of bioinspired helicoidal laminated composite plates containing center and edge cracks. An Extended Isogeometric Analysis (XIGA) framework is employed to model the plate kinematics, utilizing Non-Uniform Rational B-Splines (NURBS) basis functions in conjunction with First-Order Shear Deformation Theory (FSDT) to accurately capture discontinuity fields without mesh refinement difficulties. Six distinct bioinspired architectures (Helicoidal Recursive, Helicoidal Exponential, Helicoidal Semi-circular, Linear Helicoidal, Fibonacci Helicoidal and Quasi-isotropic) are analyzed and benchmarked against conventional quasi-isotropic laminates. The investigation systematically evaluates the influence of crack length, layer count, layup configuration, slenderness ratio, modulus ratio, and boundary conditions on the structural response. Numerical results indicate that the Helicoidal Recursive and Linear Helicoidal configurations generally exhibit smoother changes in natural frequency and central deflection as crack length increases. In contrast, the Helicoidal Semi-circular configurations, especially HS2 (Type two of Helicoidal Semi-circular) in several cases, show stronger sensitivity to crack growth. The Fibonacci Helicoidal configuration exhibits comparatively stable behavior when the crack position changes from center to edge under simply supported boundary conditions. These findings demonstrate the efficacy of the XIGA approach for analyzing complex bioinspired laminates and offer useful insights for optimizing defect-tolerant composite designs.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120679"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645857","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":"Ballistic penetration resistance of soft targets with ultra-high molecular weight polyethylene 4UD structure","authors":"Qiangang Shuai,&nbsp;Ping Liu,&nbsp;Yanfeng Niu,&nbsp;Fubao Zhang,&nbsp;Shuangqing Qian,&nbsp;Jiang Wu,&nbsp;Tianyi Gu,&nbsp;Hao Zou,&nbsp;Yanfeng Cao,&nbsp;Susu Liu","doi":"10.1016/j.compstruct.2026.120673","DOIUrl":"10.1016/j.compstruct.2026.120673","url":null,"abstract":"<div><div>To quantify the energy dissipation behavior of ultra-high molecular weight polyethylene (UHMWPE) 4UD structures against projectile penetration, ballistic experiments and numerical simulations were conducted to analyze the penetration process of 7.62 mm lead-core projectiles into 4UD structures. A Markov random field K-means++ model incorporating physical damage constraints was employed to characterize the damage morphology of the soft-target 4UD structures, and the anti-penetration performance of 4UD targets with different layer counts (areal densities) was investigated. The results indicate that the inter-layer damage of 4UD soft targets exhibits a significant layer-count threshold effect, and the damage extent of a single layer at the same layer position is highly correlated with the total number of layers. The ballistic limit velocity of the 20-layer 4UD target reaches 531.2 m/s; beyond target perforation, the energy dissipation efficiency decreases, and further increase in layer count leads to saturation of protective gain. The findings provide theoretical basis and data support for lightweight layup design of UHMWPE soft protective structures.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120673"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645946","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":"An integrated experimental and numerical study on X52 dented pipelines repair using composite sleeve reinforcement","authors":"Ali Azzam,&nbsp;Emad El Din El-kashif,&nbsp;Mostafa Shazly","doi":"10.1016/j.compstruct.2026.120667","DOIUrl":"10.1016/j.compstruct.2026.120667","url":null,"abstract":"<div><div>The primary focus of this study is to enhance the capability of pipeline integrity management in addressing dent defects using reliable repair techniques, experimental validation, and predictive finite element analysis (FEA). Burst testing of dent-defective API 5 L X52 carbon steel pipes repaired with fiberglass composite sleeves demonstrated that this method effectively restored the structural integrity and improved the service life. A highly accurate FEA model was developed and validated against experimental data, achieving an exceptional correlation with errors consistently below 1%, supporting its predictive capability for the dented and repaired pipeline configurations investigated in this study. Analysis of variance (ANOVA) of the experimental results quantified the practical significance of each parameter, identifying dent depth as the dominant factor in terms of Sum of Squares-based contribution (39.2%), followed by dent diameter (22%), and composite repair (12.86%). Although the dent diameter showed slightly higher statistical sensitivity based on the F-values, this reflects the distinction between effect magnitude and statistical significance. Owing to the limited sample size and lack of replication, the statistical analysis was intended to highlight relative trends rather than establish definitive significance. The results demonstrate that although undented pipes are superior, composite repair significantly minimizes the devastating drop in burst pressure associated with increased dent depth, thereby mitigating the detrimental impact of dents. This study demonstrates that fiberglass composite repairs provide a promising repair solution for improving the structural integrity of dented pipelines within the investigated conditions.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120667"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645949","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":"Temperature-dependent stiffness of a composite wind turbine blade: experimental investigation at material and structural scales","authors":"Przemysław Kalitowski,&nbsp;Arkadiusz Jenta,&nbsp;Agnieszka Tomaszewska,&nbsp;Marcin Krajewski,&nbsp;Michał Wójcik,&nbsp;Beata Zima","doi":"10.1016/j.compstruct.2026.120682","DOIUrl":"10.1016/j.compstruct.2026.120682","url":null,"abstract":"<div><div>Operation of wind turbines in cold climates involves substantial temperature variations that may affect the mechanical behaviour of composite blades and thereby interfere with structural health monitoring and digital twin applications if not properly accounted for. This study investigates the influence of sub-zero temperature on both material-level properties and global structural stiffness of a composite wind turbine blade. Material characterization was performed using tensile tests on specimens extracted directly from a 12.6 m research blade and tested at four temperature levels between +20 °C and −20 °C. Young’s modulus and Poisson’s ratio were identified to quantify temperature-dependent elastic behaviour. In parallel, static tests were conducted on the full blade inside a large-scale climate chamber under controlled thermal conditions. Quasi-static flap-wise loading was applied incrementally, while the response was measured using strain gauges, displacement sensors, load measurements, and internal temperature monitoring. The coupon-level results revealed substantial specimen-to-specimen scatter, which limited the statistical clarity of the identified temperature trends, although an overall increase in stiffness with decreasing temperature was observed. In contrast, the blade-level tests showed a clear, repeatable, and nearly linear increase in effective stiffness as temperature decreased. The mean structural stiffness change over the investigated temperature range was 2.7%, with good repeatability across measurement channels. Comparison of the two scales highlights that coupon-level trends cannot be directly translated into structural behaviour without accounting for blade architecture and load transfer mechanisms. The findings demonstrate that temperature-induced stiffness variations should be explicitly considered in the interpretation of monitoring data and in the development of reliable digital twins for wind turbines operating in cold climates.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120682"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148651587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free vibration analysis of orthotropic L-shaped stepped plates based on the symplectic superposition method","authors":"Zhenzhen Tong,&nbsp;Jiacheng Han,&nbsp;Zhuoqi Yuan,&nbsp;Bingxin Liu,&nbsp;Wei Wang,&nbsp;Zhen Zhao","doi":"10.1016/j.compstruct.2026.120676","DOIUrl":"10.1016/j.compstruct.2026.120676","url":null,"abstract":"<div><div>Orthogonally anisotropic L-shaped stepped plate is a thin plate that exhibits different mechanical properties along orthogonal directions. This characteristic makes it widely applicable in the engineering field. Currently, the primary methods for solving the free vibration problem of such plates are numerical methods and the finite element method (FEM). However, in practical applications, analytical solutions can yield results with higher accuracy. Therefore, this paper focuses on orthogonally anisotropic L-shaped stepped plate and employs the symplectic superposition method to solve the free vibration problem of such plates. First, starting from the free vibration equations for thin plates, the orthogonally anisotropic thin plate is incorporated into the Hamilton system, and the original problem is decomposed into three subproblems. Then, the free vibration problem of the thin plate with boundary conditions is superimposed to obtain a basic solution set. Based on this, the three subproblems of the orthotropic L-shaped stepped plate are superimposed to determine the free vibration frequencies and modes. Next, the analytical solutions for frequencies and mode shapes are derived through ensuring the equivalence between the initial problem and the combination of sub-problems. Finally, the finite element method is used to validate and present a comprehensive analysis of the natural frequencies and mode shapes obtained from this method. This method possesses the benefits of rapid convergence and accurate precision, rendering it well suited for the analytic modeling of a broader range of plate-related problems.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120676"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645855","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":"Stability and vibration analysis of GOri metamaterial sandwich cylindrical panel supported by elastic foundation","authors":"E.Mohammad-Rezaei Bidgoli,&nbsp;O. Civalek","doi":"10.1016/j.compstruct.2026.120671","DOIUrl":"10.1016/j.compstruct.2026.120671","url":null,"abstract":"<div><div>In the current work, the aerodynamic behavior and free vibration characteristics of a circular cylindrical sandwich panel are investigated. The panel features a core reinforced with graphene origami (GOri) particles, while the face sheets are reinforced with carbon nanotube (CNT) inclusions. The structure lies on a Pasternak elastic foundation and is subjected to thermal loading as well as a three–dimensional electric field, with all material properties considered temperature–dependent. In addition, the face sheets exhibit piezoelectric properties. The panel is exposed to a supersonic airflow, representing the aerodynamic loading condition assumed in this study. To model the distribution of GOri particles through the core thickness, four distinct patterns are adopted. Likewise, three forms of CNT alignment throughout the face sheets’ thickness are utilized to accurately simulate the piezoelectric layers. Using the higher–order sinusoidal shear deformation theory (HSSDT) in conjunction with Hamilton’s principle, a unified formulation is developed to capture the coupled aerodynamic, thermal, and electromechanical behavior of the GOri–core/CNT–reinforced cylindrical sandwich panel. Under simply supported boundary conditions, the formulated equations are solved through the Galerkin method to examine both aeroelastic and free vibration behaviors of the structure. The accuracy of the results and the reliability of the developed code are verified by comparing them with previously published studies. The effects of several key parameters including ambient temperature, various distributions of GOri and CNT particles, geometric characteristics of the cylindrical panel, the folding degree of GOri–reinforced structures, and the applied electric voltage are thoroughly examined. The obtained results reveal that increasing temperature causes a simultaneous reduction in both the nondimensional critical aerodynamic pressure and the nondimensional natural frequencies. For the considered temperature variations of ΔT = 0, 50, and 80  K, the corresponding nondimensional critical aerodynamic pressures are 4.34, 3.98, and 3.45, respectively. The results provide new insights into how nano–reinforcement architecture and thermal environments interact to influence aeroelastic stability boundaries and vibration characteristics of multifunctional sandwich structures, which is particularly relevant for next–generation aerospace panels operating under coupled thermo–aerodynamic conditions.</div></div>","PeriodicalId":281,"journal":{"name":"Composite Structures","volume":"394 ","pages":"Article 120671"},"PeriodicalIF":7.8,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148645858","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}