The wide adoption of composite structures in the aerospace industry requires reliable numerical methods to account for the effects of various damage mechanisms, including delamination. Cohesive elements are a versatile and physically representative way of modelling delamination. However, using their standard form which conforms to solid substrate elements, multiple elements are required in the narrow cohesive zone, thereby requiring an excessively fine mesh and hindering the applicability in practical scenarios. The present work focuses on the implementation and testing of triangular thin plate substrate elements and compatible cohesive elements, which satisfy C1-continuity in the domain. The improved regularity meets the continuity requirement coming from the Kirchhoff Plate Theory and the triangular shape allows for conformity to complex geometries. The overall model is validated for mode I delamination, the case with the smallest cohesive zone. Very accurate predictions of the limit load and crack propagation phase are achieved, using elements as large as 11 times the cohesive zone.

翻译：复合材料结构在航空航天工业中的广泛应用需要可靠的数值方法来考虑各种损伤机理的影响，包括分层。内聚单元是一种通用且具有物理代表性的分层建模方法。然而，当使用与实体基底单元相容的标准形式时，需要在狭窄的内聚区内布置多个单元，由此导致网格过于细化，限制了其在实际场景中的适用性。本研究聚焦于三角形薄板基底单元及兼容性内聚单元的实施与测试，这些单元在域内满足C1连续性。增强的正则性满足了基尔霍夫板理论提出的连续性要求，而三角形形状则便于适应复杂几何构型。针对具有最小内聚区的I型分层工况，对所建模型进行了验证。采用尺寸可达内聚区11倍的单元，即可实现对极限载荷和裂纹扩展阶段的高精度预测。