Stiffness degradation and progressive failure of composite laminates are complex processes involving evolution and multi-mode interactions among fiber fractures, intra-ply matrix cracks and inter-ply delaminations. This paper presents a novel finite element model capable of explicitly treating such discrete failures in laminates of random layup. Matching of nodes is guaranteed at potential crack bifurcations to ensure correct displacement jumps near crack tips and explicit load transfer among cracks. The model is entirely geometry-based (no mesh prerequisite) with distinct segments assembled together using surface-based tie constraints, and thus requires no element partitioning or enrichment. Several numerical examples are included to demonstrate the model's ability to generate results that are in qualitative and quantitative agreement with experimental observations on both damage evolution and tensile strength of specimens. The present model is believed unique in realizing simultaneous and accurate coupling of all three types of failures in laminates having arbitrary ply angles and layup.

中文翻译：

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一种自动生成的基于几何的离散有限元模型，用于具有任意堆叠顺序的复合层压板的损伤演化

复合材料层压板的刚度退化和渐进式失效是复杂的过程，涉及纤维断裂、层内基体裂纹和层间分层之间的演变和多模式相互作用。本文提出了一种新颖的有限元模型，能够明确处理随机叠层层压板中的此类离散故障。在潜在的裂纹分叉处保证节点的匹配，以确保裂纹尖端附近的正确位移跳跃和裂纹之间的显式载荷传递。该模型完全基于几何（无网格先决条件），不同的段使用基于表面的连接约束组装在一起，因此不需要元素分区或丰富。包括几个数值例子来演示模型' 能够产生与试样损伤演变和拉伸强度的实验观察结果一致的定性和定量结果。在实现具有任意层板角度和铺层的层压板中所有三种类型的故障的同时和准确耦合方面，本模型被认为是独一无二的。