【作者】 葛如海；

【导师】 苏清祖；

【作者基本信息】 江苏大学 ， 车辆工程， 2007， 博士

【摘要】 汽车碰撞安全性是当前国内研究的热门课题。汽车碰撞安全性研究的核心是研究如何使乘员和车外人员在碰撞中减少伤害和死亡。本文依据某轿车建立了乘员约束系统仿真分析模型,提出了新型的乘员约束理论,并据此开展了深入的研究。本文主要研究的内容有以下几个方面:1、分析了当前国内外汽车乘员约束系统中安全带、安全气囊、安全座椅的发展动态,并根据汽车交通事故统计数据,得出当前汽车乘员约束系统在保护乘员的同时也存在乘员造成伤害的风险,有必要开发汽车智能乘员约束系统的结论。2、分析了当前汽车智能乘员约束系统的发展动态,分析了当前汽车乘员约束系统（含智能乘员约束系统）存在的问题:①安全带约束不尽合理;②安全气囊的展开会对人体产生伤害;③汽车座椅未能在汽车正面碰撞中对乘员提供有效的保护。3、本文提出新的汽车乘员约束系统理论及开发汽车正面碰撞座椅坐垫调节机构的设想,即在汽车正面碰撞前或碰撞中调节座椅坐垫使其增大与地板的夹角,对乘员能够承受较大载荷的髋部和腿部提供约束,以提高乘员约束系统的效率。并在此约束系统理论的指导下申请了《机动车碰撞安全座椅》发明专利。4、在分析了台车碰撞试验系统中现有的吸能装置基础上,对台车试验中钢筋阻尼吸能器的波形复现原理进行了理论分析,研制开发出了钢筋阻尼吸能器,并根据单根钢筋阻尼力随台车位移变化特性曲线,提出了试验中的钢筋排布方案。试验结果表明该方案能够较好地再现实车碰撞试验波形。5、采用MADYMO软件建立了包括汽车地板、防火墙、仪表板、加速踏板、搁脚板、风挡与车顶系统、A柱及内饰以及座椅等车体模型,建立了包括仪表板固定横梁、转向柱托架、倾角调整机构、压溃转向柱、转向盘等部件的转向系统模型,建立了包括气囊网格模型、气囊的折叠、安装等安全气囊模型,建立了包括安全带卷收器（含安全带预张紧和限力器）、高度调节器、固定的锚点带扣等安全带模型;选用MADYMO分析软件中自带的HvbridⅢ男性第50百分位椭球假人进行定位;将以上模型按实车工况定位,定义各部件的特性、载荷等,定义各部件之间的接触,从而构建了完整的汽车碰撞分析乘员约束系统模型。该模型碰撞分析结果与实车碰撞试验结果基本吻合。6、运用所建立的碰撞仿真分析模型进行不同座椅坐垫倾角仿真分析,结果表明在汽车碰撞时座椅坐垫倾角由10°增大到25°,能够使头部损伤下降21.4%,胸部损伤下降16.6%,而髋部损伤仅仅增加8.2%,腿部损伤依然较低。这说明,采用座椅坐垫倾角调节机构能够更好地对乘员提供碰撞保护。7、选择安全带的刚度、安全带预紧器预紧量、限力器限力水平、气体发生器特性质量流率、气囊排气孔面积、气囊织物涂层的泄气率、坐垫的刚度这七个设计参数,采用ModeFRONTIER软件进行参数灵敏度分析,确定了乘员伤害指标的主要影响因数。8、根据参数灵敏度分析结果,选用前六个项设计参数作为优化设计变量,选用胸部组合损伤概率P^combine作为优化目标,采用头部损伤指标、胸部累积3ms损伤值与设计变量的响应面分析方法确定优化后的设计参数。使优化后相对于优化前乘员的头部和胸部的损伤指标有了显著地下降,而其他损伤值变化不大。头部损伤指标下降特别明显,达43.4%,使乘员的头、胸部受AIS4级以上的损伤概率由4.0%降为3.2%,大大提高了碰撞时乘员的安全性。最后,探讨了座椅坐垫倾角调节机构还需研究的问题。更多还原

【Abstract】 Now it is a hot research project on vehicle crash safety in China. The major objective is how to decrease the injuries and deaths of passengers and pedestrians in collisions. A MADYMO simulation model was established to analyze the passenger restraint systems. A new theory about passenger restraint systems has been put forward and further research is in progress.The sum total of study on the subject is contained as follows:1、The present development situation of belts, airbags and safety seat at home and abroad, and the statistic data of accidents were analyzed. The conclusion that the passenger restraint system can protect the passengers and there is potential danger was drawn. So we need to develop the intelligent passenger restraint system accordingly.2、The development trend of the current intelligent passenger restraint system was researched. There are the following problems: 1) unreasonable belt restraint system; 2) the injuries to the body from the deployment of airbags; 3) short of effective protection to the passengers in frontal impact from safety seat.3、The seat cushion with the adjustable mechanism which increases the angle between the seat cushion and floor in collisions is developed. As a result, the pelvis and leg was restrained to sustain higher load and increase restraint system efficiency.4、The recent energy absorbing system used in sled test system was analyzed. Based on the analysis, the pulse regained theory of steel rods damping absorber in sled tests was researched, developed the steel rods damping absorber. According to single steel rod damping force-sled displacement curve, the program about putting steel rods was set up in the experiment. The result showed that this program is able to represent the pulse of collision in a good way.5、The vehicle cabin model was built up in MADYMO. The cabin is made up of floor, firewall, dashboard, accelerator pedal, toe board, windshield, roof, A-pillar, trim, seat, steering system containing cross member, steering column bracket, inclination adjustor, energy absorbed steering column, steering wheel etc. The restraint system is made up of the folded airbag system, belt retractor, pretensioner, load limiter, height adjustor, fixed anchor point, buckle etc. The 50tile Hybrid-III male dummy is sitting in seat according to test dummy posture. The properties of components, load and contact were defined. The simulation results were validated according to the test results.6、The influence of different cushion angle on dummy injuries by the simulation model was analyzed. The results indicated that the head injury index decreased by 21.4%, the chest injury index decreased 16.6%, the pelvis injury index increased only 8.2% and the leg injury index kept low during increasing from 10 to 25 degree in collision. It indicated that the inclination adjustor of seat cushion can supply much better protection to occupants.7、The stiffness of seat belt, the pay-in of pretensioner, the level of load limiter, the mass flow rate of airbag gas generator, the area of airbag vent hole, the permeability coefficient of airbag fabric coating, the stiffness of cushion were selected as the design variables. Then the parameters sensitivity analysis was finished by ModeFRONTIER. The main factors which influence injury criterion of occupants were confirmed.8、The former six parameters were chosen as the design variable of the optimization, the probability of combination injury was chosen as the aim of optimization. Response surface method of head injury criterion, thorax cumulative 3ms injury criterion to the design variables was used to optimize. The head and chest injury criterion is remarkably reduced after the optimization. The other injury criterions don’t have obvious change. The head injury criterion is reduced by 43.4%, the probability above AIS4 level of the head and chest combination injury is reduced from 4.0% to 3.2%, it improved the effect of occupant protecting significantly.Finally, we discuss the problems about the cushion inclination adjustor.更多还原