A cohesive zone model for delamination propagation in laminated composites under static and fatigue loading has been derived and validated with experimental data under different mode conditions. This study presents a new approach to quantify fatigue delamination degradation based on damage mechanics to evaluate the rate of fatigue damage ( ∂ D / ∂ N ). The static damage evaluation and fatigue damage degradation are derived from damage surface concept. Both static and fatigue damage linked each other to establish fatigue crack growth formula in the laminated composites. A user-defined subroutine, UMAT, has been employed to develop and implement a damage model in ABAQUS. Two different specimens; a double cantilever beam and a single lap joint were used to investigate the effectiveness of the new method. The simulation results revealed that the developed model had good agreement with experimental data available in literature.

中文翻译：

---

疲劳载荷作用下层压复合材料的渐进破坏机制

已经推导出了在静态和疲劳载荷下用于层压复合材料分层传播的内聚区模型，并使用不同模式条件下的实验数据进行了验证。本研究提出了一种基于损伤力学量化疲劳分层退化的新方法，以评估疲劳损伤率 (∂ D / ∂ N )。静态损伤评估和疲劳损伤退化来源于损伤面概念。静态和疲劳损伤相互关联，以建立层状复合材料中的疲劳裂纹扩展公式。用户定义的子程序 UMAT 已被用于在 ABAQUS 中开发和实现损伤模型。两个不同的标本；双悬臂梁和单搭接接头用于研究新方法的有效性。