EXPERIMENTAL AND NUMERICAL CHARACTERIZATION OF HIGH-VELOCITY IMPACT DAMAGE IN CFRP LAMINATES

This study experimentally and numerically characterizes the high-velocity impact damage in CFRP laminates to clarify the damage extension mechanisms. To this end, we focus on impact damage near perforation. High-velocity impact tests were conducted for two types of cross-ply laminates. At a relatively low velocity less than 200 m/s, a crater with fiber breaks, oblique matrix cracks, and delamination were observed just beneath the impact point. Delamination had a fan shape, which was similar to that observed in low-velocity impact tests. Catastrophic ply-failure zone, which included extensive fiber breaks, matrix cracking, matrix crushing, and delamination, appeared in the middle of the laminate at an impact velocity over 300 m/s. The extension of high-velocity impact damage in composite laminate was then predicted by smoothed particle hydrodynamics (SPH). A crater was formed by matrix failure and fiber breaks generated in the top 0 degrees ply near the impact point. Ply interfaces were then delaminated, and a matrix cracking and crushing zone appeared in the middle plies. This damage pattern, including the delamination shape, agreed with the observation. Delamination mainly extended at a ply-interface along the matrix crack in the lower ply regardless of the stacking sequence. Based on the experiments and the analyses, the mechanisms of high-velocity impact damage in CFRP laminates will be discussed.