Controlling energy absorption capacity of combined bitubular tubes under axial loading

The purpose of this study was to investigate the effect of geometry on the energy absorption of aluminum tubes with different cross-section and the effect of combined bitubular tubes to absorb more energy under axial crushing. In the experimental part, aluminum tubes with circular and square cross-section were prepared and then the quasi-static tests with static loading rate were performed and the load-deflection diagrams in each test were obtained. A numerical model is proposed based on finite element analysis to simulate the collapse process considering the non-linear responses due to material behavior, contact and large deformation. The comparison of numerical and experimental results showed that the present model provides an appropriate procedure to determine the collapse mechanism, crushing load and the amount of energy absorption. The validated finite element model was then used for the parametric studies, in order to determine the effect of the geometry factors such as combined substitution of bitubular tubes, multi-cell reinforced and fiat end-capped on the energy absorption. The primary outcome of the study is new research information which will facilitate the design of thin walled tubes as energy absorbers in crushing applications.