Crushing behavior of hybrid hexagonal/octagonal cellular composite system: All made of carbon fiber reinforced epoxy

•Hexagonal/octagonal tubes were manufactured in a hybrid form for energy absorption.•Carbon fiber reinforced epoxy was used for the structure.•New parameters were defined for better assessment of the crashworthiness.•Specimens filled with foam were compared to the unfilled ones.•Different cellular arrangements were investigated.

Cellular carbon fiber-reinforced plastic (CFRP) composites, either unfilled or filled with foam, may be of interest for energy absorption application due to their improved crashworthiness. In the current paper, new combinations of octagonal and hexagonal cellular CFRP composites are introduced as energy absorption devices. Different arrangements of cells are tested. In addition, the effect of filling the structure with foam is studied. The well-known crashworthiness parameters are being used to compare the different configurations. In addition, 2 new parameters (crush load stability and springback coefficient) are introduced to assess both the difference between the peak and the average crushing load and the stability during the post crushing stage as well as the capability of the structure to retain its original height after crushing. The results show that the configurations with closed cells are advantageous in terms of the peak and the average crushing load and the energy absorption, whereas the open cells are of great interest when comparing the stability of the crushing load in the post-crushing stage.