基于优化准则和材料映射法的汽车耐撞性设计

Vehicle Crashworthiness Design Based on Optimization Criteria and Material Mapping Method

汽车正面碰撞安全性能是汽车耐撞性设计的重点,其中碰撞能量吸收和碰撞载荷传递是两大关键问题。以某款运动型多用途汽车(SUV)为研究对象,以提高汽车正面碰撞安全性能为设计目标,开展汽车耐撞性设计,提出前纵梁选材优化方案。把车体减速度和乘员舱侵入量作为正面碰撞工况下的汽车耐撞性关键评价指标,提出能量吸收和载荷传递模型,得到汽车耐撞性整体和局部优化准则。提出基于刚度等效原理的材料映射法,定量预测设计结构在材料发生改变后等效刚度的变化程度。将优化准则与材料映射法相结合,对汽车前纵梁结构的选材进行优化,试验验证表明车体减速度峰值减小了10.5g、发动机后移量减小了10.5 mm,门框变形量减小了1.5 mm,方向盘后移量减小了5.5 mm,方向盘上移量减小了1.4 mm。新的前纵梁选材方案使汽车耐撞性得到了显著提高,基于优化准则和材料映射法的汽车耐撞性设计可以实现预期的汽车正面碰撞安全性能。

The safety performance of the vehicle frontal crash is the focus of the vehicle crashworthiness design,in which the crash energy absorption and the crash load transfer are two key issues.Taking a sport utility vehicle(SUV)as the research object,the vehicle crashworthiness design was carried out with the design goal of improving the safety performance of the vehicle frontal crash,and the optimization scheme of material selection on the frontal longitudinal beam was put forward.Taking the deceleration of vehicle body and the intrusion of passenger compartment as the key evaluation indicators of the vehicle crashworthiness under frontal crash,an energy absorption and load transfer model were proposed,and the overall and local optimization criteria of the vehicle crashworthiness were obtained.A material mapping method based on the stiffness equivalence principle was proposed to quantitatively predict the change extent of the equivalent stiffness of designed structures after material changes.Combining the optimization criteria with the material mapping method,the material selection of the vehicle frontal longitudinal beam structure was optimized.The experimental results show that the peak deceleration of the vehicle body is reduced by 10.5g,the backward movement of the engine is reduced by 10.5 mm,the deformation of the door frame is reduced by 1.5 mm,the backward movement of the steering wheel is reduced by 5.5 mm,and the upward movement of the steering wheel is reduced by 1.4 mm.The new scheme of material selection on the frontal longitudinal beam has significantly improved the vehicle crashworthiness,and the vehicle crashworthiness design based on the optimization criteria and the material mapping method can realize the expected frontal safety performance of the vehicle crashworthiness design.