Composite Structures最新文献

Structure failure and strength evaluation of honeycomb-based sandwich composites under variable hydro-thermal-mechanical load 蜂窝状夹层复合材料在变水热机械载荷下的结构破坏及强度评价

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-30 DOI: 10.1016/j.compstruct.2024.118763

Y.J. Cui , Q. Zhou , Z.H. Xu , B.L. Wang , X.Q. Fang , K.F. Wang , B. Wang

The high-strength and lightweight sandwich structures have broad application prospect in aerospace, wind turbine generator, traffic and civil engineering. The sandwich structures usually service with severe environment and complicated mechanical load, structure failure and strength prediction are crucial issues. Under time-varying and optional position hydro-thermal–mechanical loading, this paper systematically analyzes strength failure, buckling and delamination of a sandwich beam with carbon fiber-reinforced polymer face sheet and aluminum honeycomb core. Effects of elastic boundary conditions, hydrothermal stress, configuration of honeycomb cell and thickness of face sheet on failure pattern and critical failure loading are evaluated. The theoretical deformation model is verified by performing a bending experiment of cantilever beam. For the honeycomb core with small re-entrant angle and shot horizontal cell wall, the sandwich cantilever beam occurs strength failure of face sheet and delamination is happened in simply supported beam. With increase of re-entrant angle and cell wall length, buckling of horizontal cell wall becomes the primary failure pattern of sandwich beam. With thickness increase of face sheet, the failure pattern switches from face sheet’s strength failure to delamination. The critical load for delamination decreases to a volley value and then increases with thickness of face sheet.

高强度轻质夹层结构在航空航天、风力发电、交通、土木等领域具有广阔的应用前景。夹层结构通常在恶劣的环境和复杂的机械载荷下工作，结构破坏和强度预测是关键问题。本文系统分析了时变可选位置水热机械载荷下碳纤维增强聚合物面板-铝蜂窝芯夹层梁的强度破坏、屈曲和分层问题。分析了弹性边界条件、热液应力、蜂窝单元形态和工作面厚度对破坏模式和临界破坏载荷的影响。通过悬臂梁的弯曲实验验证了理论变形模型。当蜂窝芯回入角较小且蜂窝壁水平破碎时，夹层悬臂梁出现面板强度破坏，简支梁出现分层。随着再入角和壁长的增加，水平壁屈曲成为夹层梁的主要破坏形式。随着工作面厚度的增加，工作面破坏模式由强度破坏向分层破坏转变。随着面板厚度的增加，分层临界载荷逐渐减小到一个截击值，然后逐渐增大。

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引用次数: 0

A comparative study on drilling characteristics of unidirectional thermosetting CF/epoxy and thermoplastic CF/PEEK composites 单向热固性CF/环氧树脂与热塑性CF/PEEK复合材料钻削特性的比较研究

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-29 DOI: 10.1016/j.compstruct.2024.118764

Zhijian Meng, Shunuan Liu, Shiming Liang, Tao Wang, Bin Luo, Kaifu Zhang

Thermoplastic carbon fiber reinforced polyetheretherketone (CF/PEEK) composites are increasingly utilized as substitutes for thermosetting carbon fiber reinforced epoxy (CF/epoxy) composites in high-end equipment, due to their superior mechanical performance and sustainable manufacturability. For both composite components, drilling is an indispensable operation in the manufacturing process. To distinguish the drilling characteristics of the two composites, comparative experiments on drilling unidirectional CF/epoxy and CF/PEEK under different parameters were conducted in this paper. Several aspects, including chip formation, drilling temperature, thrust force, hole damage, and dimensional accuracy, were examined. Particularly, the impact of fiber cutting angle on exit and hole wall damage was considered. Results demonstrate that due to the higher ductility and toughness of PEEK, CF/PEEK produces continuous chips, higher drilling temperatures, higher thrust forces, and smaller damage areas than that of CF/epoxy. However, CF/PEEK has more serious hole wall subsurface damage and poorer dimensional accuracy since PEEK is sensitive to temperature. Consequently, unlike CF/epoxy, increasing spindle speeds at the low feed cannot improve the hole quality of CF/PEEK. Moreover, the hole damage distribution of both composites is strongly associated with the fiber cutting angle. This study provides guidance for high-performance machining of CF/PEEK.

热塑性碳纤维增强聚醚醚酮（CF/PEEK）复合材料由于其优异的机械性能和可持续性，在高端设备中越来越多地被用作热固性碳纤维增强环氧（CF/环氧）复合材料的替代品。对于这两种复合部件，钻孔是制造过程中不可或缺的操作。为了区分两种复合材料的钻孔特性，本文对不同参数下的CF/环氧树脂和CF/PEEK单向钻孔进行了对比实验。考察了切屑形成、钻井温度、推力、孔损伤和尺寸精度等几个方面。特别考虑了纤维切割角度对出口和孔壁损伤的影响。结果表明，与CF/环氧树脂相比，由于PEEK具有更高的延展性和韧性，CF/PEEK可以产生连续切屑、更高的钻削温度、更高的推力和更小的损伤区域。然而，由于PEEK对温度敏感，CF/PEEK的孔壁亚表面损伤更严重，尺寸精度更差。因此，与CF/环氧树脂不同，在低进给时增加主轴转速不能改善CF/PEEK的孔质量。此外，两种复合材料的孔损伤分布与纤维切割角度密切相关。该研究为CF/PEEK的高性能加工提供了指导。

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引用次数: 0

Exploring deformability in 3D tufted composite reinforcements: Understanding bending behaviors in forming applications 探索三维簇状复合材料增强材料的可变形性：理解成形应用中的弯曲行为

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-29 DOI: 10.1016/j.compstruct.2024.118753

Hao Shen , Jue Zhao , Shenglei Xiao , Peng Wang

In simulations, the bending stiffness of fibrous reinforcements plays a crucial role in accurately predicting the morphology of wrinkle defects during the forming process. Three-dimensional (3D) tufted reinforcements exhibit distinct bending behaviors compared to traditional two-dimensional (2D) reinforcements due to the presence of tufting yarns in the thickness direction. This study employs cantilever bending tests to measure the bending stiffness of tufted reinforcements, examining the effects of various parameters, including tufting points, tufting distribution, number of layers, and tufting loop length, on their bending behavior. The experimental results show that through-thickness tufting yarns significantly enhance the bending stiffness of multilayered reinforcements, but have little impact on single-layer reinforcements. The improvement in bending stiffness is nonlinearly related to the number of tufting points, fabric layers, and tufting loop length, while tufting distribution has no effect. The underlying mechanisms of these tufting parameters are analyzed, and an analytical model is developed to explain the influence of tufting loop length.

在模拟中，纤维增强材料的抗弯刚度对准确预测成形过程中起皱缺陷的形态起着至关重要的作用。与传统的二维增强材料相比，三维（3D）簇绒增强材料由于在厚度方向上存在簇绒纱线而表现出明显的弯曲行为。本研究采用悬臂弯曲试验来测量簇状钢筋的弯曲刚度，考察各种参数对其弯曲行为的影响，包括簇状点、簇状分布、层数和簇状环长度。实验结果表明，透厚簇绒纱显著提高了多层增强筋的抗弯刚度，但对单层增强筋的抗弯刚度影响不大。抗弯刚度的提高与簇绒点数、织物层数和簇绒环长度呈非线性关系，而簇绒分布对抗弯刚度的提高没有影响。分析了这些簇绒参数的基本机理，并建立了一个解析模型来解释簇绒环长度的影响。

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引用次数: 0

Lamb wave S0/A0 mode conversion for imaging the internal structure of composite panel 用于复合材料板内部结构成像的Lamb波S0/A0模式转换

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-28 DOI: 10.1016/j.compstruct.2024.118748

T. Wandowski, M. Radzienski, P. Kudela

Stiffened structures are utilised in various industries and their structural assessment is of paramount importance. In this paper, a novel, automated algorithm for internal structure imaging based on S₀/A₀ mode conversion effect is proposed. Moreover, a contrast indicator for the quantitative characterisation of structure imaging results was introduced. The research is exclusively experimental and focuses on fibre-reinforced, stiffened aerospace composite panel. Both non-contact (air-coupled transducer-ACT) and contact (piezoelectric transducer-PZT) methods of elastic wave generation were investigated. Low-frequency (40 kHz) wave generation was applied to ACT and PZT, while high-frequency excitations (100 kHz and 180 kHz) were analysed for the PZT. The results obtained for both excitation methods were compared. Full wavefield signals of elastic wave propagation were registered with a scanning laser Doppler vibrometer. The S₀/A₀ mode conversion observed on the specimens stiffeners led to the development of a new algorithm based on time–space guided wave signal filtering, which enables the imaging of the internal structure of the stiffened panel. The efficacy of the developed algorithm was proved to be higher than conventional weighted RMS (WRMS) and wave irregularity mapping (WIM) algorithms. The proposed method allows for the generation of easily interpretable maps illustrating discontinuities in the examined structure. The contrast indicator is two times higher for the proposed MCWA than for WRMS and WIM for wave frequency 100 kHz and three times higher for frequency 180 kHz.

加劲结构在各行各业都有应用，其结构评估是至关重要的。本文提出了一种基于S0/A0模式转换效应的内部结构自动成像算法。此外，还介绍了一种用于结构成像结果定量表征的对比指标。这项研究完全是实验性的，主要集中在纤维增强、加强的航空复合材料板上。研究了非接触式（空气耦合换能器- act）和接触式（压电换能器- pzt）弹性波产生方法。对ACT和PZT进行低频（40 kHz）波产生，对PZT进行高频（100 kHz和180 kHz）激励分析。比较了两种激励方法的结果。用扫描式激光多普勒测振仪记录了弹性波传播的全波场信号。在加筋试件上观察到的S0/A0模式转换导致了一种基于时空导波信号滤波的新算法的发展，该算法能够对加筋板的内部结构进行成像。结果表明，该算法比传统的加权RMS （WRMS）和波浪不规则性映射（WIM）算法具有更高的效率。所提出的方法允许生成易于解释的地图，说明在所检查的结构中的不连续性。在波频率为100千赫时，拟议的MCWA的对比度指标比WRMS和WIM高两倍，在频率为180千赫时高三倍。

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引用次数: 0

Three-point bending behaviors of sandwich beams with data-driven 3D auxetic lattice core based on deep learning 基于深度学习的数据驱动三维辅助格芯夹层梁三点弯曲行为

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-28 DOI: 10.1016/j.compstruct.2024.118751

Xi Fang, Hui-Shen Shen, Hai Wang

In this paper, flexural behavior of a novel sandwich beam featuring a 3D auxetic lattice core developed using an inverse design method powered by deep learning under three-point bending is investigated. Specifically, the bending behavior and effective Poisson’s ratio (EPR) of such beams under large deflection is demonstrated. With inverse design method based on conditional generative deep learning model, finite element analysis (FEA) results indicate that the sandwich beams with data-driven auxetic core have superior bending behavior compared to those obtained through forward topology optimization in previous studies. In order to validate the mechanical performances of data-driven 3D auxetic lattice structures and further explore the influence of incline angle on the EPR, experimental tests under uniform pressure are carried out with metal specimens fabricated through selective laser melting manufacturing process. Comprehensive FE simulations, incorporating analytical model and temperature-dependent material properties explore the effect of various factors on the bending behavior and EPR as the beam undergoes large deflection. Results demonstrate that functionally graded configurations, length-to-thickness ratio, facesheet-to-core thickness ratio, truss radii, and thermal environmental conditions will significantly affect the flexural behavior and EPR of the data-driven sandwich beam.

本文采用基于深度学习的反设计方法，研究了一种具有三维形变格芯的新型夹层梁在三点弯曲下的弯曲行为。具体来说，研究了这种梁在大挠度下的弯曲性能和有效泊松比。采用基于条件生成深度学习模型的反设计方法对夹层梁进行有限元分析，结果表明，采用数据驱动辅助芯的夹层梁的弯曲性能优于以往采用正向拓扑优化的夹层梁。为了验证数据驱动的三维形变晶格结构的力学性能，进一步探讨倾角对EPR的影响，采用选择性激光熔化法制备金属试样进行了均匀压力下的实验测试。综合有限元模拟，结合分析模型和温度相关的材料性能，探讨了各种因素对梁在大挠度下的弯曲行为和EPR的影响。结果表明，功能梯度结构、长厚比、面板-芯厚比、桁架半径和热环境条件将显著影响数据驱动夹层梁的弯曲性能和EPR。

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引用次数: 0

Ultrasonic detection and evaluation of delamination defects in carbon fiber composites based on finite element simulation 基于有限元模拟的碳纤维复合材料分层缺陷超声检测与评价

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-28 DOI: 10.1016/j.compstruct.2024.118749

Ziang Jing , Gaoshen Cai , Xiang Yu , Bingxu Wang

Delamination defects are prone to occur during the production and use of carbon fiber composites, which seriously affect the mechanical properties of the material. The production cost of carbon fiber composites is high, and it is difficult to create defect samples. In light of this, a method for ultrasonic testing of delamination defects in carbon fiber composites based on finite element simulation was studied, and the test results were evaluated accordingly. First, a finite element model of the carbon fiber composite material was established using COMSOL software, and ultrasonic testing was employed to detect delamination defects of varying sizes and positions. Next, ultrasonic detection signals and sound field cloud images were obtained through simulation. Finally, quantitative positioning detection was conducted by fabricating laminated carbon fiber composite samples with embedded delamination defects. The results indicate that the finite element model accurately reflects the sound field propagation of ultrasonic waves. The simulated and experimental waveform signals show high consistency in both amplitude and time-domain positioning, with an error margin within 3%. The simulation model exhibits good reliability. This study provides a time-saving, labor-saving, and cost-effective approach for the detection and analysis of defects in carbon fiber composites.

碳纤维复合材料在生产和使用过程中容易出现分层缺陷，严重影响材料的力学性能。碳纤维复合材料的生产成本高，而且很难制造出缺陷样品。据此，研究了基于有限元模拟的碳纤维复合材料分层缺陷超声检测方法，并对检测结果进行了评价。首先，利用COMSOL软件建立碳纤维复合材料的有限元模型，采用超声检测方法检测不同尺寸和位置的分层缺陷。然后，通过仿真得到超声探测信号和声场云图。最后，通过制造嵌入脱层缺陷的碳纤维复合材料层压样品进行定量定位检测。结果表明，有限元模型能较准确地反映超声波的声场传播。仿真和实验波形信号在幅度和时域定位上具有较高的一致性，误差范围在3%以内。仿真模型具有良好的可靠性。本研究为碳纤维复合材料缺陷的检测和分析提供了一种省时、省力、经济的方法。

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引用次数: 0

A multi-scale uncertainty analysis method based on the Hermite–Chebyshev polynomials for dynamic responses of FRP composite structures with hybrid uncertainties 混合不确定性FRP复合材料结构动力响应的Hermite-Chebyshev多项式多尺度不确定性分析方法

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-26 DOI: 10.1016/j.compstruct.2024.118713

Sheng-Yu Qian , Xiao-Yi Zhou , Neng-Wei Wang

Multi-scale hybrid uncertainties in material properties of FRP composites stemming from their manufacturing processes present significant challenges for dynamic analysis and reliability assessment. This paper proposes a multi-scale uncertainty surrogate model based on Hermite–Chebyshev polynomials. The relationship between micro- and macro-scale material properties is established using the Mori–Tanaka method. To demonstrate the efficacy of the proposed method, case studies are conducted on both a FRP wide-flange I-beam structure and a FRP truss bridge. Results indicate that this method accurately determines the probability density functions and cumulative distribution functions of natural frequencies and mode shapes. Notably, the method efficiently computes the upper and lower bounds of dynamic failure probability of FRP truss bridge with high numerical efficiency.

FRP复合材料性能的多尺度混合不确定性来源于其制造工艺，这对动态分析和可靠性评估提出了重大挑战。提出了一种基于Hermite-Chebyshev多项式的多尺度不确定性替代模型。采用Mori-Tanaka方法建立了材料微观和宏观性能之间的关系。为了证明该方法的有效性，对玻璃钢宽翼缘工字梁结构和玻璃钢桁架桥进行了实例研究。结果表明，该方法准确地确定了固有频率和振型的概率密度函数和累积分布函数。值得注意的是，该方法能够高效地计算FRP桁架桥梁动力破坏概率的上下界，具有较高的数值效率。

引用次数: 0

Characterization of Direct Ink Writing carbon fiber composite structures with serial sectioning and DREAM.3D 直接墨水书写碳纤维复合材料结构的连续切片和DREAM.3D表征

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-26 DOI: 10.1016/j.compstruct.2024.118730

Kenneth M. Clarke , Michael Groeber , John Wertz , Andrew Abbott , Roneisha Haney , Michael Chapman

Direct Ink Writing (DIW) combines the flexibility of 3D printing with increased material applications such as thermoset carbon fiber composites, ceramic composites, and metals. The usefulness of direct ink writing, like many additive manufacturing (AM) processes, remains limited for reasons ranging from quality control to lack of process parameter optimization. This study looks to introduce a methodology for characterizing direct ink written carbon fiber composites to facilitate exploration into the relationships between process parameters and material structure. The presented study utilized nine 3D specimens of direct ink writing carbon fiber composites printed with varying process parameters – speed differential, layer height, step-over distance, and nozzle diameter – as the data set. The data was collected with an automatic serial sectioning system, LEROY, from the Air Force Research Laboratory. The collected data was processed in DREAM.3D and analyzed with statistical comparisons of 2D orientation distributions of the fibers, 2D size distributions of the voids, and 2D shape distributions of the voids.

直接墨水书写（DIW）结合了3D打印的灵活性和增加的材料应用，如热固性碳纤维复合材料，陶瓷复合材料和金属。与许多增材制造（AM）工艺一样，由于质量控制和缺乏工艺参数优化等原因，直接墨水书写的实用性仍然有限。本研究旨在介绍一种表征直接墨水书写碳纤维复合材料的方法，以促进探索工艺参数与材料结构之间的关系。本研究使用了9个直接墨水书写碳纤维复合材料的3D样品，这些样品具有不同的工艺参数——速度差、层高、台阶距离和喷嘴直径——作为数据集。数据是由空军研究实验室的自动串行切片系统LEROY收集的。将收集到的数据在DREAM.3D中进行处理，统计比较纤维的二维方向分布、空隙的二维尺寸分布和空隙的二维形状分布。

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引用次数: 0

Numerical prediction of impact damage in thick fabric composite laminates 厚织物复合材料层压板冲击损伤的数值预测

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-26 DOI: 10.1016/j.compstruct.2024.118726

Niels van Hoorn , Sergio Turteltaub , Christos Kassapoglou , Wouter van den Brink

A simulation methodology for assessing the damage in thick fabric Carbon Fibre Reinforced Polymer (CFRP) composite laminates under low- and high-velocity impacts is presented. It encompasses steps for calibration, verification, and validation of the elastic and fracture material properties as well as determination of model parameters for the numerical simulations. Damage is modelled using a discrete fracture approach with cohesive interface elements that capture individual cracks occurring in and between plies. For computational efficiency, the method is implemented in a two-dimensional (2D) axi-symmetric model. Results from double-cantilever beam, end-notched flexure, and quasi-static indentation experiments align well with numerical simulations and serve to calibrate and verify the implementation of the discrete fracture approach. The methodology is extended to dynamic impact analysis to predict damage mechanisms, force–displacement histories, and is validated using test results. This methodology combines meaningful insight in the failure mechanisms with a manageable computational effort, achieving a factor 50 improvement compared to a benchmark. A parametric analysis summarised in failure maps relates damage mechanisms to impact energy, mass, and laminate thickness. The proposed methodology strikes a balance between computational efficiency and accuracy, making it a valuable tool for optimum design and certification of thick CFRP composite laminates under impact.

本文介绍了在低速和高速冲击下评估厚织物碳纤维增强聚合物（CFRP）复合材料层压板损坏情况的模拟方法。该方法包括弹性和断裂材料属性的校准、验证和确认步骤，以及数值模拟模型参数的确定。采用离散断裂方法对损伤进行建模，并使用内聚界面元素捕捉层内和层间出现的单个裂缝。为提高计算效率，该方法在二维（2D）轴对称模型中实施。双悬臂梁、端部缺口挠曲和准静态压痕实验的结果与数值模拟结果非常吻合，可用于校准和验证离散断裂方法的实施。该方法可扩展到动态冲击分析，以预测破坏机制、力-位移历史，并通过测试结果进行验证。该方法将对破坏机理的深刻理解与可控的计算量相结合，与基准相比提高了 50 倍。失效图中总结的参数分析将损坏机制与冲击能量、质量和层压板厚度联系起来。所提出的方法在计算效率和准确性之间取得了平衡，使其成为冲击下厚 CFRP 复合材料层压板优化设计和认证的重要工具。

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引用次数: 0

Geometrically nonlinear analysis of composite beams based on global–local superposition 基于全局-局部叠加的组合梁几何非线性分析

IF 6.3 2区材料科学 Q1 MATERIALS SCIENCE, COMPOSITES

Composite Structures

Pub Date : 2024-11-26 DOI: 10.1016/j.compstruct.2024.118732

Alfredo R. de Faria , Jürgen A. Baier-Saip , André S. de Lima

A composite beam finite element is designed to capture through-thickness effects, specifically normal stress and strain and transverse shear, in the context of geometrically nonlinear analyses. The starting point for the formulation is a similar element already proposed for linear analyzes based on a global–local superposition approach, where local functions are defined in each layer of the laminate, and global functions are defined along the thickness. The consistency of the kinematic hypotheses is guaranteed by imposing the continuity equations of displacements through the thickness, the force balance equations along the thickness, directly or indirectly, by imposing the continuity of transverse stresses, and by applying the boundary conditions on the lower and upper surfaces of the elements. In the context of nonlinear analyzes, the imposition of continuity of displacements is straightforward. However, the continuity of the transverse stresses needs to be carefully imposed, as the relevant stresses are the second order Piola-Kirchhoff stresses and the strains are the Green-Lagrange strains, consistent with the total Lagrangian approach used. The constitutive equations are written in incremental form and a detailed analysis is conducted to ensure that the stresses and strains involved are physically consistent across the different reference frames employed. In order to assess the accuracy of the numerical model implemented, a unique semi-analytical technique is developed to obtain the response of asymmetrical laminated beams under compression.

在几何非线性分析的背景下，组合梁有限元设计用于捕获贯穿厚度效应，特别是法向应力和应变以及横向剪切。该公式的出发点是基于全局-局部叠加方法的线性分析中已经提出的类似元素，其中在层压板的每一层中定义局部函数，并沿厚度定义全局函数。通过直接或间接地施加位移沿厚度的连续性方程、沿厚度的力平衡方程、施加横向应力的连续性以及在单元的上下表面上应用边界条件，保证了运动学假设的一致性。在非线性分析的背景下，位移连续性的施加是直接的。然而，横向应力的连续性需要小心地施加，因为相关应力是二阶Piola-Kirchhoff应力，应变是格林-拉格朗日应变，与所使用的全拉格朗日方法一致。本构方程以增量形式书写，并进行了详细的分析，以确保所涉及的应力和应变在不同的参考系中是物理一致的。为了评估所实现的数值模型的准确性，开发了一种独特的半解析技术来获得不对称层合梁在压缩下的响应。

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引用次数: 0