This article presents an approach to accurately predict the Length of Cohesive Zone (LCZ) and model delamination under mixed-mode loading. A novel expression for estimating the cohesive zone length for the structure subjected to mixed mode delamination is proposed. The proposed expression of LCZ is validated for various structural configurations like mixed-mode delamination specimen, ply-drop, and L-bend. Besides, the effect of maximum interfacial strength and element size is also investigated. A modified embedded cohesive zone model based on cohesive surface modeling is suggested to predict intralaminar and interlaminar failures in ply-drop and L-bend structures. The cohesive surfaces are inserted in 90º plies to account for the matrix cracking and along the adjacent 0º plies to model interlaminar delamination. The delamination accompanied by matrix cracking, resulting in crack kinking and migration, is predicted. The predicted numerical results are in very good agreement with the experimental results available in the literature. A fine discretization of the mesh is necessary along the cohesive zone length for the precise estimation of various energy dissipation mechanisms. Thus, the present methodology aids in the mesh design by calculating LCZ and accurately predicting the structure's failure response under mixed-mode delamination.

本文提出了一种在混合模式加载下准确预测粘性区 (LCZ) 长度和模型分层的方法。提出了一种估计混合模式分层结构的内聚区长度的新表达式。LCZ 的拟议表达已针对各种结构配置进行了验证，例如混合模式分层试样、铺层下降和 L 弯曲。此外，还研究了最大界面强度和单元尺寸的影响。建议使用基于粘性表面建模的改进的嵌入粘性区域模型来预测层落和 L 弯曲结构中的层内和层间失效。粘性表面插入 90º 层以解释基体开裂，并沿相邻的 0º 层插入以模拟层间分层。预计伴随基体开裂的分层会导致裂纹扭结和迁移。预测的数值结果与文献中可用的实验结果非常吻合。为了精确估计各种能量耗散机制，需要沿着内聚区长度对网格进行精细的离散化。因此，本方法通过计算 LCZ 和准确预测混合模式分层下结构的失效响应来帮助网格设计。为了精确估计各种能量耗散机制，需要沿着内聚区长度对网格进行精细的离散化。因此，本方法通过计算 LCZ 和准确预测混合模式分层下结构的失效响应来帮助网格设计。为了精确估计各种能量耗散机制，需要沿着内聚区长度对网格进行精细的离散化。因此，本方法通过计算 LCZ 和准确预测混合模式分层下结构的失效响应来帮助网格设计。