【作者】 唐超群；

【导师】 杨济匡；

【作者基本信息】 湖南大学 ， 车辆工程， 2010， 硕士

【摘要】 追尾碰撞作为主要交通事故形态之一,其发生率仅次于正面碰撞和侧面碰撞。而在全国高速公路事故中,追尾碰撞事故所占比例一直位居首位。由于追尾碰撞容易导致乘员发生包括颈部损伤在内的各种损伤,且在碰撞过程中和碰撞后极易发生燃油泄漏从而造成的火灾,造成重大伤亡事故和财产损失。因此,如何降低追尾碰撞中燃油泄漏风险和乘员损伤成了车辆安全领域一个亟待解决的问题。针对轿车追尾碰撞中燃油系统的稳定性和车身后部结构耐撞性研究,本文首先建立并验证了某款轿车的整车有限元模型,按照北美联邦机动车安全法规新FMVSS 301要求,建立追尾碰撞仿真模型并对其有效性进行验证。采用正交试验设计方法和综合平衡法,以油箱的最大有效塑性应变值为主要评价指标,后纵梁和后保险杠的总吸能量和油箱周围主要结构的变形为辅助评价指标,对后纵梁及后保险杠的厚度和材料参数进行优化。针对追尾碰撞中乘员损伤防护的问题,本文重点研究了座椅参数对驾驶员损伤的影响。应用MADYMO软件,建立并验证了一个追尾碰撞多刚体仿真模型,利用该模型进行仿真试验,研究座椅的参数,如头枕与头部的位置(包括水平距离和竖直距离)、靠背倾角、座垫倾角和靠背刚度等对驾驶员损伤的影响。本论文仿真分析研究工作可得到如下主要结果和结论：整车有限元追尾碰撞模型的分析结果表明,通过对后保险杠和后纵梁厚度和材料的优化,油箱的最大有效塑性应变值降低了50.07%。有效地降低了燃油泄漏的风险性,增强了轿车追尾碰撞的耐撞性,为今后开展轿车高速追尾碰撞结构安全性研究提供了可借鉴的方法。多刚体动力学座椅-假人模型仿真分析结果显示,在高速追尾碰撞中,头枕与头部的竖直距离在一定高度范围内,计算得到的驾驶员的损伤参数值没有显著的变化。当头枕与头部的竖直距离达到一定高度后,会显著增加驾驶员的头部和颈部损伤几率。过大或过小的座垫倾角会增加颈部损伤的风险。更多还原

【Abstract】 Passenger car rear-end crash is one of the major categories of the urban road traffic accidents, the incidence is ranking after the front and side impact categories. This type of accidents ranked first of all accidents on national freeways. The neck injury is one of the typical injuries occurred frequently in rear-end impact. Moreover, the fires resulting from fuel spillage are likely to happen in this type of accidents, which can lead to additional property losses and casualties. So how to prevent fuel spillage risk and injuries from rear impacts becomes an increasing problem in the filed of vehicle safety.In order to study on vehicle crashworthiness and the integrity of fuel systems of vehicle in rear-end impact, a finite element model of car was adapted. Then, according to the new FMVSS 301 requirement, an FE model of passenger car was built and validated with available experiment data to make an analysis of the rear impact. Furthermore, the rear bumper and rail structure were optimized by using orthogonal experimental design (OED) and comprehensive equilibrium methods. The effects of 4 parameters of thickness and type of material of rear rail and rear bumper on integrity of fuel system of the car were considered as main design parameters. The main objective of optimization was the maximum effective strain of fuel tank. The secondary objectives were the energy-absorbing capability of rear rail and rear bumper and the deformation of tank structure around.In order to study on the risk of passenger injuries in rear-end impacts, a multi-body model of rear-end impact were developed and validated. The model was used to investigate the influence of driver seat on driver injuries in terms of design parameters, such as distance between head and head-restrain, obliquity of seat back, seat cushion, and stiffness of seat back.According to simulation results, the following conclusions were made.The simulation results of rear impact analysis model showed that the maximum effective strain of fuel tank was reduced by 50.7% after optimization of the design parameters of rear bumper and rear rail. The approach of mathematical models combined with optimization procedures is very useful in the design of car body structure, considering the improvement of passenger car crashworthiness.Simulation results of multi-body model showed that when the vertical distance between head and headrest within a certain range, there was no marked change on driver injury parameters, once the distance beyond the boundary, the risk of head and neck injuries of driver increased distinctly. Either raising or lower of obliquity of cushion will increase the risk of neck injuries.更多还原