In order to solve the conflict between the peak collision force and the total absorbed energy of vehicle' s front rail during collision, a new type of steel-aluminum hybrid structure is presented, in which aluminum alloy and advanced high-strength steel (AHSS) are respectively used for the front and the back parts. Then, by taking the material type and the sheet thickness as the variables, a mathematical model for the multi-objective optimization in terms of lightweight and crashworthiness is established, and the feasibility and applicability of such three approxi-mate methods as the polynomial, the Kriging and the radial basis function (RBF) in solving the combinational opti-mization problem are investigated. The results show that RBF is more suitable for the combinational optimization concerning material type and sheet thickness, and that the use of steel-aluminum hybrid materials remarkably im-proves the crashworthiness and lightweight of front rails.%为了解决汽车前纵梁碰撞时峰值碰撞力和吸能量之间的矛盾,通过对前纵梁前端使用铝合金、后端使用高强度钢板,提出了一种钢铝混合前纵梁结构.以纵梁两端所用材料类型及厚度为组合变量,建立了该结构轻量化和耐撞性多目标优化问题的数学模型,并对多项式、Kriging和径向基函数(RBF)3种常用近似模型解决该特定问题的适用性进行了研究.结果表明,RBF更适合作为近似模型解决材料类型和板厚的组合优化问题,且优化后的前纵梁结构能在改善耐撞性的同时,显著提高轻量化水平.
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