Theoretical development and numerical analysis on the energy absorption of tapered multi-cell automotive structures under oblique impacts

Abstract

In this paper, the crashworthiness characteristics of tapered structures with the uniform cells in cross-section subjected to oblique impacts are theoretically and numerically investigated. Benefiting from tapered structure simplifications into the corner, crisscross and T-shape parts in non-tapered structures, an engineering formula is proposed to estimate the mean crush load during structure deformations. In order to represent the behavior of the structures subjected to oblique impacts with regard to energy absorption, an oblique impact coefficient extracted from a comprehensive parametric study on the responses of the structures is considered in the formulation. In order to conduct the parametric study, a finite element model for the crumpling processes of different tapered and non-tapered structures with the uniform cells in the cross-section under axial and oblique impacts is prepared. The contributions of cell-number in the cross-section, taper angle, wall thickness, aspect ratio and impact angel on the peak crush load, mean crush load, specific energy absorption, crush force efficiency, transition thickness and transition impact angle in the crushing processes of the tapered structures with uniform cells in cross-section subjected to oblique impacts are presented and discussed. In particular case, the predicted structural energy absorption by the numerical model is compared with those experimental results that are available in the literature, indicating a good agreement.