拉伸状态下碳纤维复合材料T型接头的断裂行为

Fracture behavior of carbon fiber T-joints under tensile load

建立了碳纤维复合材料T型接头数值模型，模拟了其在拉伸载荷下的损伤产生、扩展及失效过程，并对碳纤维复合材料T型接头试件进行了静态拉伸试验。结果表明，接头的初始损伤载荷为9.8~12.0 kN，损伤发生后接头的载荷值发生突降（降低约27%~38%），此时接头仍具有一定承载能力；试件完全脱胶载荷较初始损伤载荷略有降低（载荷范围为8.0~8.6 kN）。数值计算和试验结果吻合，结果均显示填料区是碳纤维复合材料T型接头最薄弱的部位，易发生破坏；填料区破坏后裂纹迅速向填料区周围的胶层扩展，导致胶层的剥离，这是导致碳纤维复合材料T型接头失效的最主要原因。

The numerical mode of carbon fiber T-joints was built by finite element analysis software, and its cohesive mode technique. The damage formation, extension and failing process of T-joints under tensile load were investigated. Then the static tension test was carried out on the carbon fiber T-joints. The test results demonstrate that the initial damage load was between 9.8 kN and 12.0 kN, and after the damage appeared, the bearing value on the T-joints descends sharply （approximately by 27%-38%）. The ultimate damage load is between 8.0 kN and 8.6 kN, which is slightly lower than the initial one, because the filling area was destroyed. Both of the numerical and test results confirm that the filling area is the weakest part of the T-joints where the damage first appears. The crack then rapidly spreads to the glue film around the filling area. It was the peeling off of the glue film that accounts mostly for the failure of T-joints.