考虑接触热阻的高速列车制动盘热机耦合行为分析

Analysis of Thermal-mechanical Coupling Behavior of Brake Disc of High Speed Trains Considering Thermal Contact Resistance

接触界面间存在的接触热阻对制动盘内部热流传递过程有重要影响,进而影响制动盘热机耦合仿真分析的准确性。通过建立考虑接触热阻的有限元模型,结合制动台架试验,系统分析某高速列车轮装制动盘在紧急制动过程中的温度分布、盘面变形、螺栓载荷以及螺栓孔边应力等热机耦合行为。结果表明,选定的接触热阻模型得到的仿真结果与台架试验结果在较大的速度范围内吻合较好。制动系统内的温度梯度导致制动盘体产生较大的热应力并发生离面变形,是导致螺栓载荷增大的主要原因。制动盘面螺栓孔边沿制动盘半径方向的0°和180°位置附近的周向应力变化量较大,且处在较高的平均应力水平,是最容易产生制动热疲劳裂纹的两个方向。

The contact thermal resistance at contact interface plays an important role in the heat transfer process inside the brake disc,which affects the accuracy of simulating the thermal-mechanical coupling behavior of brake disc.A finite element model is established by integrating the model for contact thermal resistance considering the contact pressure and interface roughness.The temperature distribution and deformation of brake disc,bolt load,and loop stress around bolt hole are investigated and compared with the results from bench test during emergency braking process.The simulation results show good agreement with the bench test within a wide range of speed.The temperature gradient in the braking system results in large thermal stress and out-of-plane displacement of brake disc,which is the main reason for the increase of bolt load.The change of loop stress near the 0°and 180°of bolt hole along the radial direction of the brake disc surface is larger during the braking process,which makes thermal fatigue crack easily appear at those two locations.