Abstract Adhesive joints with composite adherends have been widely applied in the automotive and aerospace industry. The demands on high performance adhesive joints highlight the importance of understanding their respective fracture mechanisms. In this paper, single-lap joints (SLJs) bonded with a brittle and a tough adhesive were manufactured and tested, respectively. Experimentally, the fracture mechanisms of the joints were investigated based on failure load, detailed fracture surface observation and images captured by high-speed camera. The results showed that SLJs bonded with the brittle adhesive failed cohesively in the adhesive, while SLJs bonded with the tough adhesive failed by interlaminar delamination in the CFRP. The sandpaper treatment on adherend can cause a intralaminar delamination failure mode of SLJs even if the adherend is stronger than the adhesive. Numerically, finite element models with cohesive zones were built to determine the damage of materials and to validate the fracture mechanisms. The parameters estimated in literature were experimentally tested and varified by a parameter study. Convergent failure load were obtained by a mesh size study for models with and without end-tabs. Both models showed good consistency with the experimental failure load and failure mode.

中文翻译：

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准静态张力下复合材料胶粘单搭接接头的断裂机理

摘要 复合被粘物粘接接头已广泛应用于汽车和航空航天工业。对高性能粘合接头的需求凸显了了解其各自断裂机制的重要性。在本文中，分别制造和测试了用脆性和坚韧粘合剂粘合的单搭接接头 (SLJ)。在实验上，基于破坏载荷、详细的断裂面观察和高速相机拍摄的图像研究了接头的断裂机制。结果表明，与脆性粘合剂粘合的SLJs在粘合剂中无法内聚，而与坚韧粘合剂粘合的SLJs由于CFRP中的层间分层而失效。即使被粘物比粘合剂强，对被粘物的砂纸处理也会导致 SLJ 的层内分层失效模式。在数值上，建立了具有内聚区的有限元模型来确定材料的损坏并验证断裂机制。文献中估计的参数通过参数研究进行了实验测试和改变。收敛失效载荷是通过网格尺寸研究获得的，对于带和不带端片的模型。两种模型都与实验失效载荷和失效模式表现出良好的一致性。收敛失效载荷是通过网格尺寸研究获得的，对于带和不带端片的模型。两种模型都与实验失效载荷和失效模式表现出良好的一致性。收敛失效载荷是通过网格尺寸研究获得的，对于带和不带端片的模型。两种模型都与实验失效载荷和失效模式表现出良好的一致性。