Crushing Analysis and Lightweight Design of Tapered Tailor Welded Hybrid Material Tubes under Oblique Impact

The increasing demand for lightweight design of the whole vehicle has raised critical weight reduction targets for crash components such as front rails without deteriorating their crash performances. To this end the last few years have witnessed a huge growth in vehicle body structures featuring hybrid materials including steel and aluminum alloys. In this work, a type of tapered tailor-welded tube (TTWT) made of steel and aluminum alloy hybrid materials was proposed to maximize the specific energy absorption (SEA) and to minimize the peak crushing force (PCF) in an oblique crash scenario. The hybrid tube was found to be more robust than the single material tubes under oblique impacts using validated finite element (FE) models. Compared with the aluminum alloy tube and the steel tube, the hybrid tube can increase the SEA by 46.3% and 86.7%, respectively, under an impact angle of 30°. Parameter analyses were performed to reveal the influence of four geometrical variables on the crashworthiness of the TTWTs. In addition, the radial basis function (RBF) metamodels were built for the SEA and PCF of the TTWTs, while the non-dominated sorting genetic algorithm (NSGA-II) was used to achieve the optimal solutions of the tube under oblique impact loads. The results show that the optimal solutions are different under different load angles and the solutions considering multiple load angles show more robust crashworthiness performance against oblique impacts. The proposed tapered hybrid tube has a potential application on vehicle bodies with improved crash performances under oblique loads.