FEM analysis of external inversion and energy absorbing characteristics of inverted tubes

The inverted tube can be used as an energy absorber in transport vehicles like aircraft and automobiles. The aim of this paper is to contribute to an extension of the actual knowledge of the deformation process and mechanical parameters by means of finite element simulation. Experiments were performed on 3A21 alumimium alloy tubes and 1Cr18Ni9Ti stainless steel tubes, mainly utilized for supporting and validating the results of finite element simulation. An experimental setup to investigate the energy absorbing capacity of inverted tube was designed. The investigation indicates: (1) the value of die radius or half-tapered-angle makes an important influence on the stability of external inversion and quality of the inverted tube; (2) the deforming load of inverted tubes under quasi-static load is very stable with a good energy absorbing capacity; (3) the finite element simulation results agree with the experimental ones.