A micro-scale simulation scheme is developed in this study to evaluate in-situ damage and strength properties of CFRP laminates with various ply thicknesses. To capture both the initiation and propagation of transverse cracks, the microscopic random fiber configuration and the constraint effect from neighboring plies should be carefully considered. This study considers the representative volume element (RVE), consisting of the ‘inhomogeneous’ ply in which the solid elements individually modeled the fiber and matrix, and the ‘homogenized’ plies, homogeneously modeled by the shell elements. Matrix damage and debonding between fiber and matrix were modeled in the inhomogeneous ply to reproduce transverse crack propagation. Furthermore, in the RVE simulation, the key degree of freedom method was incorporated to evaluate the in-situ properties of each ply effectively. The validity of the proposed tool was examined by comparing the predicted cracking behavior with the results of unidirectional tensile tests on cross-ply laminates having different 90º ply thicknesses. The effects of ply thickness on the in-situ damage and strength properties of cross-ply laminates were numerically investigated, and the continuum damage mechanics model for thin-ply laminate was proposed based on the numerical results.

中文翻译：

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通过微尺度有限元分析评估薄层 CFRP 层压板的原位损伤和强度特性

本研究开发了一种微尺度模拟方案，以评估具有不同层厚度的 CFRP 层压板的原位损伤和强度特性。为了捕捉横向裂纹的萌生和扩展，应仔细考虑微观随机纤维配置和相邻层的约束效应。本研究考虑了代表性体积单元 (RVE)，其中实体单元分别模拟纤维和基体的“非均质”层和由壳单元均质模拟的“均质”层。纤维和基体之间的基体损伤和脱粘在非均匀层中模拟，以再现横向裂纹扩展。此外，在 RVE 模拟中，结合关键自由度方法来有效评估每层的原位特性。通过将预测的开裂行为与具有不同 90º 层厚度的交叉层层压板的单向拉伸试验结果进行比较，检验了所提出工具的有效性。数值研究了层板厚度对交叉层板原位损伤和强度特性的影响，并在此基础上提出了薄层层板的连续损伤力学模型。