汽车通风式盘式制动器热—结构耦合分析及结构的优化设计

发布时间：2018-06-08 06:14

  本文选题：通风盘式制动器 + 热-结构耦合　； 参考：《华南理工大学》2016年硕士论文

【摘要】：车辆的制动性一直以来都是汽车设计中最重要的性能指标,它直接影响到交通安全性,而制动器作为车辆制动系统最终的执行部件,则直接决定着汽车的制动性。车辆制动时,制动器摩擦副间由于快速的相互摩擦而产生大量的热,使得制动器的温度迅速升高,过高的温度会使得制动器在制动时出现热衰退现象从而影响汽车的制动性,同时也会导致制动盘表面易出现热疲劳裂纹而降低其使用寿命。因此对制动器在制动过程中出现的热-结构耦合现象进行研究和分析,有助于改善汽车的制动性能并提高其使用寿命。本文以某乘用车前轮所使用的通风盘式制动器为研究对象,根据其实际尺寸建立三维模型,并进行适当的简化,随后将简化后的三维模型导入有限元分析软件中建立其热-结构耦合有限元仿真模型,并根据整车相关参数确定分析所需的边界条件和载荷。最后对所建立的有限元模型进行仿真计算,并对所获得的温度场和应力场结果进行分析。通过对制动盘温度场的分析可知:制动过程中整个制动盘温度场的分布并不是呈轴对称的,在径向、周向和轴向三个方向上均存在一定的温差,其中径向方向最大温差达到了201℃,轴向方向上最大温差也达到了178℃,周向方向上的温差相比径向和轴向则相对较小,在整个制动过程中不超过25℃,且随着制动的持续整个制动盘的温度场由于内部热传导的作用而趋于均匀分布;通过对制动盘应力场的分析可知:制动时制动盘的应力主要以热应力为主,且在制动过程中其变化趋势与温度场的变化趋势基本一致。同时本文还对所研究的通风盘式制动器进行了紧急制动、多次连续制动和下长坡持续制动三种工况下的台架实验,通过对所得的实验数据进行分析发现各测温点的温度变化趋势同有限元的分析结果是一致的,且将紧急制动工况下所测得的径向5个测温点的温度值同有限元的计算值进行对比,其最大误差仅为14℃,且两者的相关系数均大于0.9,充分证明了本文所建立的通风盘式制动器热-结构耦合有限元模型的正确性。最后以建立的有限元模型为基础,以制动盘的质量和热疲劳寿命为优化目标,对该通风盘式制动器的结构进行多目标优化。同时为了降低优化成本,通过采用遗传算法优化的神经网络来构建相关设计变量与响应函数之间的近似模型,并在此近似模型的基础上采用基于遗传算法的多目标优化法来对制动器的结构进行优化设计,最后根据优化后的设计变量重新建立有限元模型并进行仿真计算,其计算结果证明了优化的有效性。
[Abstract]:The braking property of vehicle is always the most important performance index in the automobile design. It directly affects the traffic safety, and the brake, as the final executive part of the vehicle braking system, directly determines the braking property of the vehicle. When the vehicle is braking, a large amount of heat is produced between the brake friction pairs because of the rapid mutual friction, which makes the temperature of the brake rise rapidly, and the excessive temperature will make the brake appear the phenomenon of heat decline during braking, thus affecting the braking performance of the car. At the same time, it will lead to thermal fatigue crack on the brake disc surface and reduce its service life. Therefore, the study and analysis of the thermo-structural coupling phenomenon in the braking process is helpful to improve the braking performance and prolong the service life of the automobile. In this paper, the ventilation disc brake used in the front wheel of a passenger car is taken as the research object. According to its actual size, a three-dimensional model is established and properly simplified. Then, the simplified 3D model is introduced into the finite element analysis software to establish the thermal-structural coupling finite element simulation model, and the boundary conditions and loads for the analysis are determined according to the relevant parameters of the whole vehicle. Finally, the finite element model is simulated, and the results of temperature field and stress field are analyzed. Through the analysis of the temperature field of the brake disc, it can be seen that the distribution of the temperature field of the whole brake disc is not axisymmetric during the braking process, and there is a certain temperature difference in the radial, circumferential and axial directions. The maximum temperature difference in the radial direction is 201 鈩，

本文编号：1994880