Experimental investigation on damage mechanisms and buckling behaviors of thin composite laminates in compression after impact

This paper presented an experimental investigation on the damage mechanisms and buckling behaviors of thin composite laminates under low-velocity impact and compression-after-impact (CAI) loading conditions. Barely visible impact damage was introduced into the laminates through drop-weight impact tests. The CAI tests were performed with a non-standard device in order to suppress the global buckling of plates. Three different stacking sequences were compared in this paper. A stage loading method in conjunction with ultrasonic C-scan was adopted to observe the process of delamination propagation and located the position of initial propagation. The 3D digital image correlation technique was employed to monitor the evolution of the out-of-plane displacement of the specimens. The effects of stacking sequences on delamination morphology, the compression damage propagation mode of thin laminates and the influence factors on local buckling were then discussed.