Abstract Transverse intralaminar cracks in layers with perpendicular orientation referred to the main loading direction have a significant affection on the apparent ultimate strength of the corresponding composite laminate. This effect stems from the fact that such transverse cracks generally promote the occurrence of other failure mechanisms leading to the specimen collapse in subsequent stages of the loading process. With the aim of conducting a careful investigation regarding the onset and progression of transverse intralaminar cracking events, in this investigation, a micro-mechanical analysis of cross-ply laminates is performed. Particularly, the cross-ply laminates belonging to the family [ 0 ° 2 / 90 ° n / 0 ° 2 ] are considered via the generation of high-fidelity micro-mechanical models, which reproduce the direct representation of internal fiber arrangements using the reference results addressed in Saito et al. 2012, Experimental evaluation of the damage growth restraining in 90° layer of thin-ply CFRP cross ply laminates, Adv. Comp Mat, 21:1,57-66. Differing from alternative approaches, current predictions are equipped with the combined used of two fracture-based modeling methods: (i) the variational phase field (PF) approach for triggering crack events into the matrix, and (ii) the bilinear cohesive zone model (CZM) for the simulation of fibre-matrix decohesion failures. Relying on this computational methodology, the focus of this work is to analyze the influence of the transverse ply thickness (n) on the onset and propagation of damage under tensile conditions, in conjunction with the transition from micro-cracking to meso-scale damage states. For this purpose, several models are generated into the FE package ABAQUS using user-defined capabilities replicating configurations of specimens included in previous experimental investigations, i.e. through the consideration of different transverse ply thickness (n=1, 2, 4). Present results show the potential of the proposed methodology to predict the transverse matrix cracking phenomena and the ability and reliability for capturing the delay of the crack with thinner plies, a phenomenon which is usually denominated as in-situ effect in the related literature.

中文翻译：

---

长纤维增强复合材料中的原位强度效应：使用断裂相场法的微观力学分析

摘要 以主加载方向为垂直方向的层间横向层内裂纹对相应复合材料层合板的表观极限强度有显着影响。这种影响源于这样一个事实，即这种横向裂纹通常会促进其他失效机制的发生，导致试样在加载过程的后续阶段坍塌。为了对横向层内开裂事件的发生和进展进行仔细调查，在本调查中，对交叉层层压板进行了微观力学分析。特别是，属于 [0°2/90°n/0°2] 族的交叉层层压板是通过生成高保真微机械模型来考虑的，使用 Saito 等人提出的参考结果再现内部纤维排列的直接表示。2012, 90° 薄层 CFRP 交叉层层压板损伤增长抑制的实验评估, Adv. 比较垫，21:1,57-66。与替代方法不同，当前的预测配备了两种基于裂缝的建模方法的组合使用：(i) 用于在基质中触发裂纹事件的变分相场 (PF) 方法，以及 (ii) 双线性内聚区模型（ CZM) 用于模拟纤维矩阵脱聚失效。依靠这种计算方法，这项工作的重点是分析横向层厚度 (n) 对拉伸条件下损伤开始和扩展的影响，结合从微裂纹到中尺度损伤状态的转变。为此，使用用户定义的功能复制先前实验研究中包含的样本配置，即通过考虑不同的横向层厚（n=1、2、4），在有限元软件包 ABAQUS 中生成了几个模型。目前的结果表明，所提出的方法具有预测横向基体开裂现象的潜力，以及用更薄的层捕捉裂纹延迟的能力和可靠性，这种现象在相关文献中通常被称为原位效应。使用用户定义的功能复制先前实验研究中包含的样本配置，即通过考虑不同的横向层厚度（n = 1, 2, 4），在有限元软件包 ABAQUS 中生成了几个模型。目前的结果表明，所提出的方法具有预测横向基体开裂现象的潜力，以及用更薄的层捕捉裂纹延迟的能力和可靠性，这种现象在相关文献中通常被称为原位效应。使用用户定义的功能复制先前实验研究中包含的样本配置，即通过考虑不同的横向层厚度（n = 1, 2, 4），在有限元软件包 ABAQUS 中生成了几个模型。目前的结果表明，所提出的方法具有预测横向基体开裂现象的潜力，以及用更薄的层捕捉裂纹延迟的能力和可靠性，这种现象在相关文献中通常被称为原位效应。