【作者】 王秀丽；

【导师】 王辉；

【作者基本信息】 哈尔滨工程大学 ， 车辆工程， 2010， 硕士

【摘要】 近几年,随着道路交通事故的增多,行人保护逐渐成为汽车被动安全领域的重点研究对象。在汽车碰撞事故中,腿部是人体最容易受伤的部位之一其损伤主要是由保险杠撞击造成的,因此保险杠的研究工作对提高汽车的行人保护性能具有重要的意义。本文采用计算机仿真的方法对汽车保险杠的小腿保护性能进行了研究。首先,从生物力学的角度,分析了交通事故中行人腿部各关键部位的损伤机理。根据EEVC行人保护法规,建立了小腿冲击器的有限元模型,通过静态弯曲试验、静态剪切试验和动态冲击试验的验证,冲击器模型的各项力学性能均达到了法规的要求。其次,在小腿冲击器有限元模型的基础上,建立了可代替汽车前部结构的简易模型。通过正交试验分析了保险杠高度、宽度、前伸量及发动机罩前缘高度等对行人的膝关节最大弯曲角度、最大剪切位移和胫骨最大加速度的影响趋势和差异性,为保险杠的设计工作提供了依据。最后,以某款车的保险杠为研究对象,针对保险杠的行人保护性能存在的问题,提出了改进措施,研究了蒙皮材料的力学参数、吸能块的结构和材料对行人小腿损伤的影响,并在原始模型的基础上增设了副保险杠,减小了碰撞过程中膝关节的弯曲变形。同时对保险杠原始模型进行综合改进,并通过仿真计算,验证了改进方案的合理性和可行性,改善了保险杠的吸能特性,减小了行人小腿的损伤。更多还原

【Abstract】 In the recent years, with the rapid increase of traffic accidents, pedestrian protection had gradually become the focus of Automotive Passive Safety. In the traffic accident, the lower leg of pedestrian was easily suffered from injuries, and the injuries were mainly caused by the strike of front bumper, so the research of the bumper was very important for improving the pedestrian protection capability.The lower leg protection capability of vehicle bumper was researched by computer simulation. Firstly, what causing the injuries of the pedestrian leg in the traffic accident was analyzed from the degree of Biomechanics. According to the criteria of EEVC pedestrian protection, the finite element model of the lower legform was established, the model was tested by computer simulation of the static bending test, static shearing test and dynamic impacting test, and the Bio-mechanical behaviors of model had satisfied the criteria.Secondly, based on the finite element model of the lower legform, simple model replacing automotive front structure was established. It was analyzed by Orthogonal Experiment that maximum knee bending and shearing deformation, and tibial peak acceleration were how to influenced by the height, width, protrusion amount of bumper, the height of bonnet leading edge, etc. Moreover, the trends and differences of the influence were obtained, they would provide reference for the vehicle design.Finally, the bumper of a car was as the researched object in this paper, for the pedestrian protection performance of the bumper, some improvement measures were proposed. It was researched that the injuries of pedestrian lower leg were how to influenced by the material mechanical parameters of vehicle skin, the structure and material of energy-absorbing block. In order to adjust the state of lower leg motion in the collision accident, a new auxiliary bumper was added to the system. Meanwhile, the original bumper was improved comprehensively, and the rationality and feasibility of improvement measures were confirmed by computer simulation, then, the energy-absorbing performance of the bumper was improved, the injuries of pedestrian lower leg were reduced greatly.更多还原