汽车侧气囊仿真与优化

发布时间：2018-01-13 13:29

本文关键词：汽车侧气囊仿真与优化　出处：《宁波大学》2015年硕士论文　论文类型：学位论文

【摘要】：在汽车碰撞发生瞬间,传感器感受到碰撞产生的信号,安全带、安全气囊和其他一些安全设备全部开始工作来防止乘员受到伤害,这些设备和系统称之为被动安全系统。我国城市交通现状使得交叉路口的侧面碰撞事故发生概率较高,固有必要特别重视汽车侧面碰撞的乘员保护。由于车身侧面结构强度相对薄弱且空间较小,侧面碰撞过程中乘员容易受到严重的损伤,而常规的安全带无法提供应对侧向冲击的缓冲作用,因此侧气囊的保护作用就显得尤为重要。随着我国汽车研发技术的不断积累和对自主知识的重视,新车型的研制越来越多地采用正向开发。安全气囊的正向开发过程涉及诸多的因素:车身强度、乘员空间和约束系统零部件等,而不同的因素对气囊保护作用的影响程度不尽相同,研究气囊的各项特性有助于提高约束系统的工作效能,减少乘员在侧面碰撞中的损伤。本文基于非线性分析软件LS-DYNA研究侧气囊的建模及仿真方法,通过动态冲击试验结果修正仿真模型,提高了数值仿真计算的精度,同时引入乘员损伤评价准则,使得侧气囊的仿真计算结果更符合实际的工况。在分析了目前主要气囊模型的基础上,详细研究了应用控制体积方法的Hybrid模型。从建模方法上分析网格划分对模型质量的影响,研究模型中参数的设置方法,并结合多种前后处理软件进行建模和分析结果数据。针对侧气囊在开发过程中应用的试验进行有限元模拟,通过将试验数据与仿真数据对比,优化了有限元模型参数,获得了与试验各项特性相吻合的有限元模型。本研究项目中,气囊的试验有压力容器试验、静态展开试验和动态冲击试验三个部分组成,这是气囊开发过程中确定有限元模型参数的关键环节。通过压力容器试验获得发生器参数,确定发生器产生气体随时间的变化量。静态展开试验使用高速摄像机记录来判定气囊充气时间,分析气囊折叠方式对气囊展开的影响。动态冲击试验是通过具有一定速度的冲击锤撞击气囊,模拟了实际碰撞侧面碰撞过程中人与气囊之间的缓冲作用,通过这种试验方法获得气囊的泄气特性。在上述研究的基础上,进一步开展了侧气囊在乘员约束系统中的作用研究,这可以更真实的评估约束系统的安全性能,通过运动损伤生物力学研究乘员损伤机理和损伤准则的制定方法,其中NCAP(新车碰撞测试)法规是应用最为广泛的损伤准则。通过研究表明,侧气囊的气孔直径在一定范围内数值越大乘员胸部位移量越小,而超过一定数值易造成气囊过量泄气,乘员与车门之间还有相对速度的现象。侧面车身强度直接影响车身入侵量的大小,侧气囊作为车身与乘员之间的缓冲中介,通过交叉对比试验表明,合理的选择侧气囊的型号有助于降低乘员的损伤程度。
[Abstract]:The moment occurred in the car crash, sensor signal, feel the collision safety belts, airbags and other safety equipment all started working to prevent damage to passengers, these devices and systems called passive safety system. The traffic situation of city of our country makes the intersection of side collision probability is higher, the inherent need for special pay attention to occupant protection in vehicle side impact. Due to the side of the body structure strength is relatively weak and the space is small, in the process of side collision of occupant vulnerable to serious damage, and the safety belt can not provide cushioning effect with conventional lateral impact, so the protective effect of the side airbag is particularly important. With the automotive research and development technology of our country continue to accumulate and the intellectual attention, more and more development of new type with positive development. The development process of the airbag is involved Many of the factors: the strength of the body, and the occupant space constraint system components, and the influence of different factors on the airbag protective effect is not the same, helps to improve the working efficiency of the characteristics of the airbag restraint system, reduce the passenger injury in side impact. In this paper, the nonlinear analysis method for modeling and simulation software of LS-DYNA the side airbag based on dynamic impact test results through the modified simulation model, to improve the numerical simulation accuracy, while the introduction of occupant injury evaluation criteria, the simulation calculation results of side airbag accord with the actual conditions. Based on the analysis of the current main airbag model, studies the application of Hybrid model with control volume method analysis of impact of grid on the quality of the model from modeling method, setting method of parameters in the model, combined with a variety of post-processing software Modeling and analysis of the results of data. Finite element simulation for the test application of side airbag in the development process, through the comparison between experimental data and simulation data, a finite element model parameters optimization, the finite element is consistent with the characteristics of the test model. This research project, the airbag test pressure vessel test. The three part static deployment test and dynamic impact test, which is the key link to determine the parameters of the finite element model of the airbag development process. Generator parameters obtained by pressure vessel test, determine the generator gas quantity changing with time. The static deployment test to determine the air time are recorded using a high speed camera, analysis of the impact of airbag folding patterns on the airbag deployment. The dynamic impact test by impact hammer with a certain velocity impact airbags, simulated the actual impact in the process of side collision of people With the buffer between the balloons, get discouraged by the characteristic of airbag test method. On the basis of the above research, we carried out further research in the role of the side airbag occupant restraint system, which can evaluate the safety performance of restraint system more realistic, methods developed through sports injury biomechanics research of occupant injury mechanism and damage criterion among them, NCAP (NCAP) regulations is the most widely used damage criterion. The research shows that the pore diameter of the side airbag in a certain range of value the greater the occupant chest displacement is smaller, but more than a certain value caused by excessive air between the occupant and the door are discouraged, the relative speed of body weight intrusion phenomenon. The size of the direct impact of the strength of the side body, the side airbag buffer as intermediary between the body and the crew, through cross contrast experiment shows that the reasonable selection of side gas The model of the capsule helps to reduce the degree of damage to the crew.

【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U491.61

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