基于侧碰耐撞性的B柱轻量化设计

B⁃pillar Lightweight Design for Side Impact Crashworthiness

研究了薄壁梁三点弯曲工况压溃力与材料强度和板厚的关系,并提出了一种B柱轻量化设计方法。对于B柱下端,侧撞时发生压溃折弯,可近似等效为三点弯曲工况,且用高延性高强钢代替普通的强度较低的高强钢,进行B柱下端的轻量化设计。至于B柱上端,因其侧撞时主要发生刚性转动,可等效为静力学问题,施加侧撞等效静载力,将B柱上端划分成N段,利用Optstruct软件对各段板厚进行优化。最后以某车型为例,将B柱上、下端优化方案导入整车侧撞模型中进行优化。结果表明优化后B柱关键部位的侵入速度和侵入量与原始设计几乎相当,证明该轻量化设计是有效的,优化实现了24%(1.9 kg)的轻量化效果,而其耐撞性不受影响。

The relationship between the crushing force and material strength and thickness of thin⁃walled beam under three⁃point bending condition is studied,and a lightweight design method for B⁃pillar is proposed.For the lower end of B⁃pillar,it crushes and bends in side crash,which can be approximately equivalent to three⁃point bending condition,the high⁃strength steel with high⁃ductility is used instead of the ordinary high⁃strength steel with lower strength,and its lightweight design is carried out.For the upper end of the B⁃pillar,the rigid rotation occurs in side crash,which can be equivalent to the statics problem.The equivalent static force of side crash is applied,the upper end of the B⁃pillar is divided into N segments,and the thickness of each segment is optimized by using Optstruct software.Finally,an optimization is conducted on a real vehicle by introducing the optimization schemes for upper and lower ends of B⁃pillar into the side crash model of the vehicle.The results show that after optimiza⁃tion,the intrusion speed and intrusion amount of the main parts of B⁃pillar are almost equal to those of the original design,demonstrating the effectiveness of the lightweight design.The optimization achieves a lightweighting effect of 24%(1.9 kg),with its crashworthiness unaffected.