Bending collapse of treble rectangular thin-walled tubes and its application in conceptual design for automobile crashworthiness

The aluminium profiles of treble rectangular thin-walled tubes (TRTWT) manufactured by extrusion processes are extensively applied in energy absorption structures of automobile due to the high crashworthiness and stiffness-to-mass ratio. Therefore, this paper investigates the bending collapse characteristics of the TRTWT and its application in conceptual design for automobile crashworthiness. Firstly, the bending collapse behaviours of the TRTWT are obtained through experimental method. Then, the analytical expressions for the bending collapse characteristics are derived in detail by using the global energy equilibrium theory, which are validated by comparing with experimental and numerical results. Furthermore, the bending collapse characteristics are applied in the simplified model to conduct crashworthiness analysis and optimization for the conceptual design of the automobile with the TRTWT, which can enhance the crashworthiness and greatly shorten design cycle. Finally, application examples for the front-end and side-wall structures of automobile demonstrate that the simplified model with the analytical bending collapse characteristics can be used as a substitute of detailed model for accelerating crashworthiness design of the automobile with the TRTWT.