Crashworthiness analysis of multi-cell square tubes under axial loads

In this paper, a theoretical expression for the mean crushing force Favg and the analysis of specific energy absorption (SEA) ratios of five different multi-cell square tubes were derived by applying the Simplified Super Folding Element (SSFE) theory. Then, the response surface models of the tubes were established separately based on the polynomial response surface method (PRSM). The models describe the response surfaces of SEA, peak crushing force Fmax and mean crushing force Favg under the variation of the side-length l1 of the exterior tube, the side-length l2 of the interior tube, and section form of the structure. Crashworthiness rules for tubes with different geometrical configurations including l1, l2 and different cross-sections were analysed. The numerical results matched the theoretical predictions. l2 exerted a slight influence. Compared to l1 and l2, the sectional form exerted a greater influence on the crushing force and energy absorption.