Energy absorption of circular aluminium tubes with functionally graded thickness under axial impact loading

Abstract

The main objective of this study is to investigate the effects of thickness-gradient patterns on energy absorption characteristics of aluminium-based circular tubes under axial impact loading. Functionally graded thickness (FGT) enables to obtain variable stiffness throughout the length of a structure; thus, it provides more efficient control of the crashworthiness parameters when compared with traditionally designed uniform thickness (UT) counterparts. In order to investigate the crash behaviour of FGT tubes, different thickness-gradient patterns are introduced to the axial direction of the tubes and then impact with a fixed rigid wall is simulated by using the nonlinear explicit finite element (FE) method. To show the efficiency of FGT tubes, crashworthiness performance of the FGT tubes are compared with their UT counterparts at the same weight. The effects of thickness range and aspect ratio of the tubes on their crash behaviours are also investigated. The simulation results show that the FGT tubes have superior crashworthiness performance than that of their UT counterparts and the crashworthiness parameters of the FGT tubes can be controlled and improved with the appropriate selection of geometric parameters of the tubes.

Keywords:

• crashworthiness
• functionally graded thickness
• circular tubes
• finite element method