Multi-objective crashworthiness optimisation of tapered star-shaped tubes under oblique impact

摘要

Thin-walled structures play an important role as an energy absorber in all kinds of crash accidents due to their excellent energy absorption characteristics and lightweight. This paper aims to investigate the crashworthiness of thin-walled tapered tubes with star-shaped cross section under oblique impact. Firstly, the finite element model is validated through compressive tests. Then, the tapered star-shaped tube is impacted under five different loading angles and the impact responses are studied through parameters such as the peak force (F-max) and specific energy absorption (SEA). Finally, based on the response law of tapered tubes under oblique impact, spline curve is put forward as a new type of linking path, which connects the top and bottom of tapered tubes instead of the traditional straight line. A multi-objective optimisation about the shape of spline curve for the tapered star-shaped tubes is carried out by using the non-dominated sorting genetic algorithm-II to reduce the F-max and increase the SEA under oblique impact. The SEA of the optimal spline curve tapered star-shaped tube is improved by 9.87% compared with the normal tapered tube, while F-max is reduced slightly. The results show that tapered tubes with concave spline curve have better crashworthiness and the research provides a new idea for improving crashworthiness of thin-walled tubes.