Honeycomb core sandwich panels (hereinafter, HSP for brevity) exhibit excellent energy absorption under overall compressive loads. However, they are prone to local deformation under localized compressive loads, which may lead to structural failure. In this study, woven CFRP was used for the face sheets, and stiffness distribution was introduced by varying the number of laminate plies in different regions to enhance impact mitigation. Drop weight impact tests were conducted to obtain load-displacement curves, and the energy absorption capacity was evaluated based on the deformation up to either the peak load or the onset of local damage. As a result, it was confirmed that placing a circular high-stiffness region directly under the impact point improved energy absorption performance compared to a uniformly stiff panel. On the other hand, when a ring-shaped high-stiffness region was used, stress concentration occurred at the stiffness boundaries, which reduced the impact mitigation performance. These findings indicate that appropriate stiffness distribution in CFRP face sheets can significantly influence the energy absorption characteristics of HSP.
Sato et al. (Wed,) studied this question.