基于6σ稳健设计的轿车侧碰车身B柱轻量化研究

LIGHTWEIGHT OF THE VEHICLE B PILLAR BASED ON SIX SIGMA ROBUST DESIGN UNDER SIDE IMPACT

考虑不确定性因素的稳健设计是提高轿车设计中结构可靠性与碰撞安全性的有效途径。传统的轿车车身优化设计,由于忽略加工、制造和环境等不确定性因素,导致设计目标如碰撞性能或者轻量化效果不稳健。研究了考虑不确定性因素干扰下的6σ稳健性设计,以某轿车侧面碰撞为实例,首先根据相关碰撞法规建立了准确的有限元模型并进行了验证,然后在建立了确定性优化模型以及代理模型后,采用序列二次规划算法求得了最优解并进行可靠性分析,最后采用6σ稳健性设计方法对原车身B柱进行了轻量化研究和改进并与确定性优化结果以及原车身B柱进行了对比分析。分析结果表明,优化后的轿车车身B柱碰撞工况下性能稳健性得到全面的提高,且质量相比于原车身B柱减小了3.2%。

Robust design is an effective way to improve the reliability of structure and crash safety by considering uncertainty in vehicle design. In the traditional optimization design of vehicle body,due to ignoring of uncertainty factors,such as processing,manufacturing and environment,leading to design goals such as collision performance or lightweight effect unstable. In this paper,by considering uncertainty factors,taking side impact of a car as an example,first of all,an accurate finite element model is established and verified according to relevant crash regulations,then,after building an approximate model and a deterministic optimization model,the optimal solution is obtained by sequential quadratic programming algorithm and the reliability analysis is used,finally the original vehicle B pillar is accomplished lightweight research and improvement by using six sigma robust design method. After robust optimization design,the results are carried out a comparative analysis with the original vehicle B pillar and also with the deterministic optimization results. The analysis results show that comprehensive improvements are obtained on the robustness of collision performance after robust optimization design of vehicle B pillar,meanwhile,the quality of vehicle B pillar have reduced 3. 2% compared to the original one.