基于能量分析的乘员约束系统优化研究

发布时间：2018-09-05 20:39

【摘要】：汽车技术迅猛发展的同时,交通事故也在不断增多。安全气囊、安全带等乘员约束系统作为车内主要的保护装置,对降低乘员的伤亡率作用显著。因此,乘员约束系统在汽车安全领域的研究中尤为重要。目前,乘员约束系统正在向多样化、智能化方向发展。因其是一个多参数输入、多响应值输出的系统,所以在众多参数中寻找到重要参数并且实现其性能的快速优化,将对缩短研发周期和降低成本起到重要作用。针对该问题,本文立足于一个全新的乘员约束系统研究角度,从正碰过程中的能量转移与分配出发,提出基于能量分析的乘员约束系统优化方法。主要内容分为以下几个部分:(1)介绍了汽车安全领域的主要研究内容和研究方法,从国内外学者对乘员约束系统的发展、优化以及能量相关的研究中,总结研究思路并结合理论分析,确定本文的研究内容与技术路线。(2)基于实车碰撞试验,利用MADYMO7.5软件建立车辆正面碰撞仿真模型并验证其有效性。通过灵敏度分析从乘员约束系统众多参数中确定出五个重要参数,采用正交试验的方法,获得不同参数组合下的乘员约束系统与其对应的乘员综合损伤值WIC。(3)结合能量理论和相关研究方法,将假人划分为头部、胸部、髋部和腿部四大部分。通过对车辆正碰过程中各部分能量的逐一分析,明确假人能量的传递途径与乘员约束系统的能量吸收情况。(4)利用MATLAB对正交试验的数据进行拟合分析,从关系图表和拟合公式中先定性后定量地确定乘员综合损伤值WIC与约束系统吸能分布之间的关系。结果表明,WIC值与安全肩带、安全腰带以及汽车座椅吸能峰值成负相关;与护膝板及地板的吸能峰值成正相关。(5)选取安全带、汽车座椅等,与乘员综合损伤值WIC存在明显相关关系的乘员约束子系统,对其进行参数分析,逐一构建约束子系统参数与其吸能峰值的关系式。并结合WIC值与各个约束子系统吸能峰值的关系,确定最优的乘员约束系统参数组合。由此通过能量方法完成本文约束系统的快速优化,获得如下最优结果:安全肩带和安全腰带的织物延伸率取13%,预紧器的点火时间取16.7ms,安全带的限力值取5400N,护膝板与垂直方向的倾角取24.5o,护膝板刚度取初始值的93%。此外,当地板摩擦系数适当减小,座椅坐垫倾角调至与水平方向成9.5°夹角时,能够使得安全肩带、安全腰带、汽车座椅的吸能峰值都达到最大值,汽车护膝板和地板的吸能峰值达到最小值。得出在最优参数组合下WIC值为0.4023,比原始值降低了7.35%,完成了乘员约束系统性能优化。
[Abstract]:With the rapid development of automobile technology, traffic accidents are also increasing. As the main protective device, airbag, seat belt and other occupant restraint system can reduce the casualty rate of the occupant. Therefore, the passenger restraint system is particularly important in the field of automobile safety. At present, the passenger restraint system is developing towards diversification and intelligence. Because it is a multi-parameter input and multi-response output system, it will play an important role in shortening the research and development cycle and reducing the cost. In order to solve this problem, based on a new research point of view of occupant constraint system, this paper proposes an optimization method for crew constraint system based on energy analysis from the point of view of energy transfer and distribution in the positive collision process. The main contents are as follows: (1) the main research contents and methods in the field of automobile safety are introduced. The research ideas and theoretical analysis are summarized to determine the research content and technical route of this paper. (2) based on the real vehicle crash test, the vehicle frontal impact simulation model is established by using MADYMO7.5 software and its validity is verified. Through sensitivity analysis, five important parameters were determined from many parameters of the occupant constraint system, and the orthogonal test method was used. According to the energy theory and the energy theory, the occupant restraint system with different parameters is divided into four parts: head, chest, hip and leg. Through the analysis of the energy of each part of the vehicle forward impact process, the energy transfer path of the dummy and the energy absorption of the occupant restraint system are clarified. (4) the orthogonal test data are fitted and analyzed by using MATLAB. The relationship between the comprehensive damage value (WIC) of the occupants and the energy absorption distribution of the constrained system is determined qualitatively and then quantitatively from the relational diagrams and fitting formulas. The results showed that the WIC value was negatively correlated with the peak of energy absorption of safety shoulder straps, safety belts and car seats, and positively correlated with the peak of energy absorption of knee pads and floors. (5) selecting seat belts, car seats, etc. The parameters of the occupant constraint subsystem which has obvious correlation with the comprehensive damage value of the occupants WIC are analyzed and the relationship between the parameters of the constraint subsystem and the peak energy absorption value is constructed one by one. Combined with the relationship between the WIC value and the peak energy absorption of each constraint subsystem, the optimal parameter combination of the occupant constrained system is determined. Therefore, the fast optimization of the constrained system in this paper is accomplished by the energy method. The optimum results are as follows: the elongation of the fabric with safety straps and belts is 13, the ignition time of the preload is 16.7ms, the limiting force of the safety belts is 5400Ns, the inclination angle between the kneading plate and the vertical direction is 24.5o, and the stiffness of the kneepad is 93o of the initial value. In addition, when the friction coefficient of the floor is reduced properly and the seat cushion inclination angle is adjusted to 9.5 掳with the horizontal direction, the maximum energy absorption value of the safety shoulder strap, safety belt and car seat can be reached. The peak energy absorption of the kneepad and floor reaches the minimum value. Under the optimal parameter combination, the WIC value is 0.4023, which is 7.35% lower than the original value, and the performance optimization of the occupant constrained system is completed.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U491.61

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