Collapse Behavior and Energy Absorption in Elliptical Tubes with Functionally Graded Corrugations

Abstract

Thin walled structures are an integral part of the energy absorbing structures. Corrugations along the length of thin walled structures produce controlled deformation during crash. In the present study, LS-DYNA nonlinear code has been used to study the effect of corrugations on the energy absorption characteristics of the elliptical tubes. The tubes are modelled using shell elements and mesh density has been obtained by convergence. The corrugations are graded varying their wavelength and amplitude linearly and parabolic. The study also elucidates the effect of aspect ratio and angle of impact (0, 5, 10) on the crashworthiness of the tube by evaluating the specific energy absorption (SEA), crush force efficiency (CFE) and peak force. The simulation results have shown improvements in the response of the tube. There is a 72% reduction in peak force reaction in simple corrugated tube over simple elliptical tube. In oblique impact, a more common phenomenon, the corrugated tubes have higher energy absorption and less force fluctuations at higher angles over the normal tube which fails in bending at very low angles. Overall, introduction of corrugations has resulted in improved efficiency of a thin walled elliptical tube in impact loading.