基于儿童行人头部保护的发动机罩设计分析

Hood design analysis of child-pedestrian head protection

为了改善被研究车辆的儿童行人保护性能,建立了儿童头锤冲击汽车前部结构的有限元模型,并采用同类车型试验数据验证了模型的有效性.研究了同样结构下低碳钢和铝合金发动机罩的行人保护性能,并针对儿童行人头部保护设计了波浪式内板和夹层铝合金2种不同结构的发动机罩.为了增加发动机罩的吸能特性和降低头部损伤相关的加速度参数值,研究了发动机罩边缘和翼子板间的吸能结构.结果表明:设计的新型发动机罩使整个发动机罩的刚度分布更加均匀,能在儿童行人头部的碰撞区域有效地减小儿童行人头部损伤风险;这2种结构在具有原发动机罩模型相当的静态刚度的同时,提高了发动机罩的侧向弯曲和扭转刚度.

To improve safety performance of the investigated vehicle for child pedestrian protection, a fi- nite element model of child pedestrian head-form impact with hood was developed. The validity of the proposed model was evaluated based on the test data of a similar car in literature. A comparison of protec- tive performance between steel and aluminum hoods with the same initial structure was conducted for pe- destrian protection. Two types of alloy aluminium hoods with wavilness inner panel hood and sandwich structure hood were designed to protect pedestrian head. The energy absorber structure between hood- side-edges and wings was investigated to increase energy absorption and minimize the head impact acce- leration. The results show that a significant mitigation of the head injury risk is achieved by the proposed hood design during the child head-form impact with hood in the test zones of the investigated car. The two types of proposed hoods have a comparable bending static stiffness with that of original hood, and in- creased lateral bending and torsion stiffness can be achieved.