A comprehensive failure model for crashworthiness simulation of aluminium extrusions

TLDR

Accurate crashworthiness simulation requires correct representation of plastic deformation and failure of individual component parts. This paper proposes a comprehensive failure prediction approach based on macroscopic strains and stresses. The method incorporates necking, ductile and shear fracture criteria that account for non‑linear strain paths and is applied to EN AW‑7108 T6 aluminium extrusions. The approach accurately predicts failure, as shown by agreement between numerical results and three‑point bending and axial compression tests on double‑chamber extrusion components.

Abstract

Abstract A correct representation of the plastic deformation and failure of individual component parts is essential to obtaining accurate crashworthiness simulation results. The aim of this paper is to present a comprehensive approach for predicting failure in a component based on macroscopic strains and stresses. This approach requires the use of a number of different failure mechanism representations, such as necking (due to local instabilities), as well as ductile and shear fracture. All failure criteria have been developed in a way to include the influence of non-linear strain paths. The effectiveness of this approach in predicting failure is then discussed by comparing numerical results with test data by three point bending and axial compression tests of double chamber extrusion components. All studies presented in this paper were carried out on extrusions made from aluminium alloy EN AW-7108 T6.