A new bi-tubular conical–circular structure for improving crushing behavior under axial and oblique impacts

Abstract

In this study single and double wall structures for crashworthiness are investigated to introduce a novel system with better energy absorption and crushing characteristics under both axial and oblique loading. The new developed double wall structure is constructed from inner conical and outer circular tubes, incorporated with and without foam filler. Foam filled bi-tubular structure subject to direct axial and oblique impact loadings are simulated using nonlinear finite element analysis software package LS-DYNA. Numerical simulations obtained via non-linear explicit dynamic FEM are firstly validated using theoretical and experimental solutions. Next, effectiveness of the new developed bi-tubular structure has been shown by comparing with similar common thin-walled structures. Different types of structures namely bi-tubular empty and foam filled new design, empty and filled frusta as well as empty and foam filled circular tubes were considered in order to make a more insightful of capabilities of the proposed structure. A parametric study including the effect of geometrical and material properties of the structure on the crashworthiness has been carried out. Results show the possibility of amending the peak crushing load along with keeping other energy absorption characteristics unchanged or even improved. Also an improvement in absorbed energy under oblique loading by using the new developed structure is observed.