纯电动汽车蓄电池在汽车碰撞事故中的力学安全性分析

发布时间：2018-05-11 12:41

本文选题：有限元法 + 蓄电池　；参考：《哈尔滨工业大学》2014年硕士论文

【摘要】：良好的汽车被动安全性能够在汽车碰撞事故中对汽车本身和乘员起到有效的保护作用。电动汽车的被动安全性设计可以借鉴传统燃油汽车,但也有自己的特点:蓄电池作为电动汽车重要的部件,是电动汽车被动安全必须考虑的环节。本文首先探讨了有限元方法求解冲击动力学问题的关键理论,为高效的网格划分提供了理论依据。研究内容包括冲击问题求解控制方程的数值求解形式、接触非线性、材料在冲击碰撞问题中的本构模型等问题。在本文的具体仿真中,对焊点模拟、显式算法的步长控制、单元选择、沙漏控制等问题也进行了探讨。本文着重建立了高效的整车有限元模型,用于进一步的正面碰撞仿真分析。首先,我们通过对纯电动汽车白车身进行力学简化,重点考虑车身前部吸能结构和碰撞力传递路径,建立了电动汽车整车模型。然后,通过单元类型选择,单元尺寸和形状控制,焊点仿真定义,接触类型定义等工作建立了整车有限元模型。整车碰撞仿真时间被控制在了一小时以内。最后,按照中国新车评价规程(C-NCAP)中正面100%重叠的刚性墙碰撞试验工况,对模型进行了碰撞仿真。最终得出了与试验数据较为吻合的仿真结果数据,验证了整车有限元模型的有效性。基于有效的整车有限元模型,本文进一步研究了蓄电池在汽车碰撞过程中的力学安全性问题。一方面,我们重新设计了蓄电池架结构:通过增加蓄电池架斜拉杆的方法优化蓄电池架应力分布,有效限制了蓄电池在汽车碰撞过程中的翻滚和位移。另一方面,我们将热成型钢应用于前纵梁扩展部分,有效防止了结构在汽车碰撞过程中过大的压溃和弯曲变形。仿真结果显示:蓄电池的最大加速度和平均加速度大幅度减小,蓄电池对驾驶舱的侵入量减小为零,并且避免了严重的二次碰撞的发生。研究表明:新的设计提高了蓄电池在汽车碰撞事故中的力学安全性。
[Abstract]:Good passive safety can protect the vehicle itself and occupants effectively. Passive safety design of electric vehicles can draw lessons from traditional fuel vehicles, but also has its own characteristics: batteries as an important part of electric vehicles, is the passive safety of electric vehicles must be considered. In this paper, the key theory of finite element method for solving impact dynamics problems is discussed, which provides a theoretical basis for efficient mesh generation. The research contents include the numerical solution of the governing equation, the contact nonlinearity, the constitutive model of the material in the impact problem and so on. In this paper, some problems such as solder joint simulation, step size control of explicit algorithm, unit selection and hourglass control are also discussed. In this paper, an efficient finite element model is established for further frontal impact simulation. First of all, through the mechanical simplification of the pure electric vehicle's white body, focusing on the front energy absorption structure and the collision force transfer path, the model of the electric vehicle is established. Then, the finite element model of the vehicle is established through the selection of element type, the control of element size and shape, the definition of solder joint simulation and the definition of contact type. The vehicle crash simulation time was controlled within an hour. Finally, according to the 100% overlap rigid wall crash test conditions in C-NCAP, the impact simulation of the model is carried out. Finally, the simulation results are obtained, which are in good agreement with the test data, and the validity of the finite element model of the whole vehicle is verified. Based on the effective finite element model of vehicle, the mechanical safety of battery during vehicle collision is further studied in this paper. On the one hand, we redesigned the storage battery structure: by increasing the oblique pull bar of the battery frame, the stress distribution of the storage battery is optimized, which effectively limits the rolling and displacement of the battery during the collision process. On the other hand, the hot forming steel is applied to the extension of the front longitudinal beam, which effectively prevents the excessive crushing and bending deformation of the structure during the vehicle collision. The simulation results show that the maximum acceleration and the average acceleration of the battery are greatly reduced, and the intrusion of the battery to the cockpit is reduced to zero, and the serious secondary collision is avoided. The results show that the new design improves the mechanical safety of batteries in vehicle crash.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U467.14;TM912

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