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低速冲击损伤对复合材料胶接结构的力学性能存在威胁。对在搭接区域3个不同位置承受低速冲击的斜搭接接头进行冲击后拉伸试验,并分别建立胶接接头冲击及冲击后拉伸有限元模型。试验结果表明:冲击位置在搭接区尖端背侧,造成的凹坑深度最大,冲击后拉伸强度最低;冲击位置在搭接区中部,凹坑深度最小,冲击后拉伸强度最大;冲击位置在搭接区尖端侧,凹坑深度及冲击后拉伸强度居中。有限元分析结果表明胶层损伤和复合材料纤维损伤的大范围扩展是导致结构失效的主要原因。
Low velocity impact damage poses a threat to the mechanical properties of the composite cementitious structures. The oblique lap joints subjected to low-speed impact at three different positions in the lap area were subjected to the impact test after impact, and the finite element models of impact and post-impact tensile were established respectively. The test results show that the impact position is at the tip dorsal side of the overlap zone, which results in the largest depression depth and the lowest tensile strength after impact; the impact location is in the middle of the overlap zone with the smallest depression depth and the largest tensile strength after impact; At the tip side of the overlap zone, the depth of the pit and the tensile strength after impact are centered. Finite element analysis results show that the major cause of structural failure is the large-scale expansion of the plastic layer damage and composite fiber damage.