In this work, multi-scale finite element analyses based on three-dimensional (3D) hybrid macro/micro-scale computational models subjected to various loading conditions are carried out to examine the in-situ effect imposed by the neighboring plies on the failure initiation and propagation of cross-ply laminates. A detailed comparative study on crack suppression mechanisms due to the effect of embedded laminar thickness and adjacent ply orientation is presented. Furthermore, we compare the results of in-situ transverse failure strain and strength between the computational models and analytical predictions. Good agreements are generally observed, indicating the constructed computational models are highly accurate to quantify the in-situ effect. Subsequently, empirical formulas for calculating the in-situ strengths as a function of embedded ply thickness and different ply angle between embedded and adjacent plies are developed, during which several material parameters are obtained using a reverse fitting method. Finally, a new set of failure criteria for σ₂₂-τ₁₂, σ₂₂-τ₂₃, and σ₁₁-τ₁₂ accounting for the in-situ strengths are proposed to predict laminated composites failure under multi-axial stress states. This study demonstrates an effective and efficient computational technique towards the accurate prediction of the failure behaviors and strengths of cross-ply laminates by including the in-situ effects.

在这项工作中，基于三维（3D）混合宏观/微观尺度计算模型在各种载荷条件下进行多尺度有限元分析，以检查相邻层对失效萌生的现场影响和交叉层压板的传播。对由于嵌入层状厚度和相邻层方向的影响而产生的裂纹抑制机制进行了详细的比较研究。此外，我们还比较了计算模型和分析预测之间的原位横向失效应变和强度的结果。通常观察到良好的一致性，这表明构建的计算模型对于量化原位效应是高度准确的。随后，开发了计算原位强度作为嵌入层厚度以及嵌入层和相邻层之间的不同层角度的函数的经验公式，在此期间使用反向拟合方法获得了几个材料参数。最后，提出了一套新的考虑原位强度的σ ₂₂ - τ ₁₂ 、 σ ₂₂ - τ ₂₃和σ ₁₁ - τ ₁₂失效准则，以预测多轴应力状态下层合复合材料的失效。这项研究展示了一种有效且高效的计算技术，可以通过包括原位效应来准确预测交叉层合板的失效行为和强度。