基于元胞自动机的变厚度薄壁梁侧向耐撞性优化设计方法

薄壁结构是汽车等运载工具的重要防护装置,除了其轴向防撞能力外,侧向耐撞性能分析与提升方式也非常重要。研究基于薄壁结构厚度合理分布的侧向耐撞性能提升方式和建立基于元胞自动机的变厚度薄壁梁侧向耐撞性优化方法。以汽车B柱受力环境和性能要求为设计需求,首先利用所建立的方法给出了连续变厚度的薄壁梁厚度分布设计,其性能较常规的等厚度薄壁梁最大侵入位移大幅下降(下降82%),验证了变厚度设计的有效性;然后,考虑单向变厚度便于柔性轧制工艺制成TRB,给出了轴向连续变厚度薄壁梁的厚度分布设计,该设计较等厚度梁最大侵入位移下降73%;与连续变厚度梁相比,在侵入位移降低量略小的情况下,实现了可制造性。设计实例表明本文提出的连续变厚度设计能够有效提高侧向耐撞性能,所建立的方法能够获得合理的厚度分布设计,是有效的耐撞性优化设计方法。

A hybrid cellular automata based method of variable thickness thin-walled beam for crashworthiness optimization under lateral impact

Thin-Walled beams (TWB) are the most important kind of impact protection devices of automobiles and other vehicles.Research on the lateral crashworthiness and its improvement method,besides the axial crashworthiness,is very important.In this paper,a method to improve the lateral crashworthiness of variable thickness thin-walled beam(VTWB) through reasonably designing the thickness distribution was studied,and a hybrid cellular automata based method for designing the thickness distribution was proposed.Based on the performance requirements and structural characters of an automobile B-pillar,the thickness distribution is designed firstly for optimization of the lateral crashworthiness of a simply supported VTWB.The penetration displacement has an 82% decrease from that of the uniform thin-walled beam,which proved the effectiveness of the design.Then,considering the convenience to manufacture through flexible rolling technology,the VTWB with wall thickness varying along axial direction was given.The penetration displacement in this design has a 73% decrease from that in the uniform thin-walled beam.The reduction of the penetration displacement is slightly decreased compared with that of the VTWB with 3D thickness distribution,but the manufacturing is much more convenient.The design examples indicate that variable thickness design can effectively improve the lateral crashworthiness of the thin-walled beam.The proposed method can get a reasonable thickness distribution of VTWB,and thus it is an effective optimization design method for lateral crashworthiness.