Theoretical development and numerical investigation on energy absorption behavior of tapered multi-cell tubes

In this study, the crashworthiness behavior of the tapered multi-cell tubes is theoretically and numerically investigated. The side wall tapering and the cross section dividing into the cells are used in order to improve the energy absorption of the thin walled structure. In order to estimate the non-constant mean crush load of the tapered multi-cell tubes, incorporating the theoretical relations on the energy absorption of the simple multi-cell and tapered single-cell tubes, in conjunction with numerical results, would lead to the development of the analytical formula. The analytical formula is based on the mean crush load calculation of the equivalent segmented simple multi-cell tubes. In order to prepare a realistic finite element model, the elastic-plastic-damage material assumption is introduced into the numerical simulation. The numerical predictions of the mean crush load are consisted with experimental data in literature. The results reveal that the increase of the taper angle, the wall thickness and the number of cells in the cross section would enrich the crashworthiness capacity of the structure. The results indicate that the crashworthiness improvement rate of the structure with number of cells in the cross section is decreased in such a way that the variation of the energy absorption efficiency in the thin walled structure with the 8 x 8, 9 x 9 and 10 x 10 cells in the cross section would be negligible. The transition wall thickness in which the crashworthiness of the tapered multi-cell structure transits from thin to thick walled behavior are determined. (C) 2016 Elsevier Ltd. All rights reserved.