This paper presents an explicit finite element methodology for predicting fatigue delamination in composite laminates using twin cohesive models and a combined static & fatigue cohesive formulation; one model is loaded under the peak-load envelope, whilst the other model is loaded under the trough-load envelope. The twin models contain pairs of twin cohesive interface elements that predict delamination growth by exchanging data at every time increment. The cohesive formulation evaluates fracture mechanics parameters, e.g. the local minimum to maximum fracture energy ratio via local information associated with the twin cohesive elements, without the need to know the global loading information, e.g. the global R ratio. The method allows predicting the mechanical condition of a laminate at both the peak and trough loads. This method is validated by multiple test cases with varying mode mixities and R ratios, showing a high computation efficiency.

本文提出了一种显式的有限元方法，该方法使用双粘性模型以及静态和疲劳粘性组合公式预测复合材料层压板的疲劳分层。一个模型加载在峰值负载包络线下，而另一种模型加载在波谷负载包络线下。孪生模型包含成对的孪生内聚界面元素，这些元素通过在每个时间增量交换数据来预测分层增长。粘性配方可通过与双粘性元素相关的局部信息来评估断裂力学参数，例如局部最小与最大断裂能之比，而无需了解整体载荷信息，例如整体R比率。该方法允许在峰值和谷底载荷下预测层压板的机械状态。该方法已通过具有不同模式混合比和R比的多个测试用例进行了验证，从而显示出很高的计算效率。