【作者】 林小哲；

【导师】 王耘； 宋小文； 胡树根；

【作者基本信息】 浙江大学 ， 车辆工程， 2008， 硕士

【摘要】 随着汽车保有量的不断增加和车速的提高,汽车安全问题日益突出,成为汽车研究的主题之一。而交通事故统计资料表明转向机构是正面碰撞时造成驾驶员伤害的主要部件。本文分析了汽车碰撞安全的相关措施,重点研究了吸能防伤转向机构在汽车碰撞安全中的作用及其工作原理和结构型式。在此基础上,本文通过对世界上著名的发明问题解决理论——TRIZ进行系统研究,将其应用于吸能防伤转向机构的设计,一方面针对传统的机械式转向机构提出新型的吸能防伤方案;另一方面,通过分析国内某企业生产的电动助力转向机构(EPS)在吸能防伤方面的存在问题,利用TRIZ理论中的发明原理对其进行改进设计。同时,为了验证改进的EPS转向机构相比于原来设计方案的在吸能防伤方面的优势,本文在非线性有限元理论的基础上,按照GB11557-1998《防止汽车转向机构对驾驶员伤害的规定》的要求,利用著名的显式动力学分析软件ANSYS/LS-DYNA分别对原EPS转向机构和改进的EPS转向机构与人体模块进行碰撞仿真。为保证仿真的可靠性,首先,本文对用于碰撞仿真的人体模块模型进行了验证校核,使其满足GB11557中关于碰撞试验中人体模块的质量、变形刚度等的要求。第二,仔细研究了汽车碰撞仿真中在单元类型、材料模型选取以及网格划分、运算控制等方面的处理原则。第三,对于原EPS结构与改进结构中相同的结构本文采用一致的模型和网格处理方法,以保证仿真结果的可比较性,同时,两者采用一样的边界条件和初始条件,以及相同的分析参数。最后,本文对原EPS转向机构和改进的EPS转向机构的碰撞结果进行比较分析;并对碰撞仿真在转向机构设计中可能发挥的作用提出了自己的看法。更多还原

【Abstract】 As the constantly increase of automobile quantity and car speed, automobile safety is so urgent to be put on agenda, and is becoming one of major research topics. Statical material of traffic accidents indicates that steering assembly is the primary component resulting in driver’s injury in frontal impact.This paper presents the safety precautions of automobile crash briefly and focuses on the function, the principles and particular structures of energy-absorbingsteering assembly. Then, the famous problem solving theory──TRIZ is introducedgenerally and is applied on the design of energy-absorbing steering assembly: First, new conception of energy absorbing is proposed for traditional steering system. Second, the shortage of initial EPS assembly in frontal impact protection is put forward and the invention principles of TRIZ are used to make some improvement on it.Meanwhile, in order to compare the performance between the reformative EPS steering assembly and the initial one in energy-absorbing and impact-protection, impact simulation is done in this paper. The simulation is done according to the GB11557-1998 "The stipulation protecting drivers from being injured by motor vehicle steering mechanism" and based on the non-linear finite element analysis theory. The famous explicit dynamic analysis software ANSYS/LS-DYNA is used as the simulation environment.Some work is done to insure the precision of the simulation:Firstly, the humanbody model which is used in impact simulation is verified before simulation to make sure that its physical character, such as quality and distortion stiffness, meets the requests of GB11557.Secondly, great effort is made on the study of element selection, material model selection, model meshing and calculation control.Thirdly, identical modeling and meshing methods are applied in the simulation of the two above steering assemblies, so that the simulation results are comparable. Additionally, the simulation parameters, the boundary and initialization condition is identical, too.In the end of this paper, the results of the impact simulation of the two steering assembly are presented comparatively. Thereby, an analysis report is made.On the basis of the whole work of this paper, some viewpoints are made as a conclusion and an idea on how to bring impact simulation into the steering assembly design is proposed.更多还原