中文摘要：

当行人与车辆发生碰撞时,车身最前端的部件将直接与行人下肢腿部发生接触,其设计是满足行人下肢保护要求的关键。然而针对传统要求的基于刚性腿型行人保护车辆前结构设计方法,在应对柔性腿型行人保护要求已呈现明显的局限性。为了提高保险杠结构的柔性腿型保护功能,结合试验设计技术、组合近似建模技术、多目标优化算法和可靠性分析方法,以行人腿部的伤害值最低为优化目标,对车辆前端结构参数进行可靠性优化设计并对优化结果进行试验验证。研究结果表明：优化后的车辆前端结构与原设计相比,行人柔性腿型保护功能得到明显提高,为车辆前端结构的设计与开发提供有效的参考。

英文摘要：

When the pedestrian and vehicle collision occurs, the vehicle front-end structure which has direct contact with the pedestrian lower leg, it is designed to meet the critical requirements of pedestrian lower leg protection. However, there are obvious limitations in dealing with the vehicle front-end structure design to meet the flexible pedestrian legform impactor（Flex-PLI） pedestrian protection according to the requirements of transport research laboratory pedestrian legform impactor（TRL-PLI）. To improve the performance of TRL-PLI pedestrian protection, the research will adopt to combine with experimental design, the ensemble of metamodels, the multiobjective optimization algorithm and reliable analysis methods, with minimizing the injuries of lower leg as the objectives, and optimize vehicle front-end structure parameters. The optimization design result is validated by test. Compared with the original design, pedestrian leg protection performance is significantly improved, which provides a reference for the design and development of the vehicle front-end structure.