A Numerical Study of Multiple Oblique Impacts on Carbon Fiber‐Reinforced Polymer Laminates Based on Discrete Crack Model

ABSTRACT Since impact damaged laminates may experience re‐impacts before maintenance, it is of great necessity to understand the accumulation of damage under such a circumstance. Although existing studies indicate that normal impacts generally cause more severe damage than oblique impacts with the same impact energy, the directional nature of damage may lead to a larger scope of damage coupling in the case of multiple impacts. In this study, multiple oblique impacts on carbon fiber‐reinforced polymer (CFRP) laminates are studied numerically with a discrete crack model based on cohesive elements in order to capture the interaction between matrix cracking and delamination. Meanwhile, a simplified plasticity model is introduced to describe the nonlinear response of the material. It is found that for oblique re‐impact following normal impact, delamination in the interface closest to the impact surface increases with the inclination of impact, while other interlaminar delamination damages decrease. In comparison to identical‐angle oblique re‐impact, reversed‐angle oblique re‐impact generates more interlaminar delamination in almost every interface, especially when the inclination angle of impact is small. However, when the inclination angle is large enough, delamination of the interface near the back surface of impact becomes smaller when the direction of re‐impaction is reversed.