Compression characteristics, energy absorption, and feasibility evaluation of egg-box panels made of long fibre prepreg sheets

In this study, the feasibility of using long-fibre-reinforced composites for preparing energy-absorbing structures with a complex geometry was verified by comparing the mechanical performance of two types of egg-box panels, fabricated using plain weave fabric composites (WSN3k, SK Chemical, Korea) and a long-fibre prepreg sheet (LFPS, SK Chemical, Korea). Two types of egg-box panels (large and small models) with different dimensions were prepared to determine the influence of the panel size on the collapsing behaviour and energy absorption rate of the panels. The failure modes at each deformation stage were identified through a multiply interrupted compression test. Furthermore, a high-density polyurethane foam was filled in the cavity of the egg-box panels to suppress premature buckling during crushing. The nominal stress–strain relationships of both types of egg-box panels were obtained through a compression test. Thus, the maximum compressive strength, plateau stress, and energy absorption rate of both types of egg-box panels were experimentally determined and compared. Accordingly, a method to apply LFPS in the fabrication of energy-absorbing structures with a complex geometry was suggested.