Preliminary Study on Evaluation System of Capability of Composites to Withstand Impact

This paper summarizes the authors' experimental study on the characterization system of composite behavior to withstand impact. The content includes: (1)The dent depth is the best parameter describing the impact damage state. (2) There exists the knee point phenomenon for damage resistance behavior (i. e. the relationship between impact energy or contact force and dent depth) and damage tolerance behavior (i. e. the relationship between dent depth and compressive failure strain or stress) of composite laminates. (3) The physical meaning of the knee point phenomenon is that the failure mechanisms change of damaged composites to fiber breakage in the first front plies from matrix crack and delamination. Some suggestions on the characterization system of composite behavior to withstand impact were proposed.