Tensile behaviors after impact of composite scarf joints

The damage introduced by low-velocity impact is a threat to adhesively bonded composite joints. The impact response and tensile behaviors after impact of composite scarf joints was investigated using experimental and finite element analysis techniques. 18 specimens were impacted in three different locations and tensile tests after impact were conducted. The test results demonstrated that when impacted on the back face of scarf tip, the average dent depth was largest and the average tensile strength after impact was lowest. When impacted in the middle of the bondline slope, the dent depth was smallest and the tensile strength after impact was highest. When impacted on the front face of scarf tip, the dent depth and the tensile strength after impact was mediate. Stress concentration was observed in the scarf tips and areas beside the impact location because of the influence of bending stress and bypass load. The finite element analysis results showed that the extensive expand of fiber damage and adhesive damage lead to catastrophic failure of the whole structure.