Optimal design of a crashworthy octagonal thin-walled sandwich tube under oblique loading

摘要

Thin-walled structures are major energy-absorbing components on the vehicle for crashworthiness. Most of the past and current research works on such structures are focused on their behaviour under single and simple loading conditions such as axial impact, and their deformation mode/failure under combined and complex loading conditions are much less studied. In this paper, we used numerical models to analyze the structural response and energy-absorbing performance of a novel octagonal thin-walled sandwich tube under oblique impact at various impact angles. The effect of key geometric parameters (internal reinforced plate thickness t(1) and external wall thickness t(2)) on the overall structural behaviour (i.e. specific energy absorption and peak crush force) was discussed in detail. Based on the numerical model, a multi-objective optimisation was further performed to enhance its performance. The results indicate that the optimal design would be different based on various impact angles, and the effect of key geometric parameters are also the functions of impact angle. Specifically, the optimal t(1) at the impact angles of 0 degrees, 10 degrees, 20 degrees and 30 degrees are 1.92, 1.93, 2.00 and 0.84 mm, respectively, while optimal t(2) are identical, and equal to 2.40 mm at each angle. These findings would provide a valuable guideline for the design of thin-walled energy absorbers under multiple oblique loading.