高速动车组制动盘热力耦合分析

高速动车在紧急制动工况下，制动盘表面温度分布不均致使制动盘热胀冷缩产生热应力，进而导致制动盘出现热裂纹失效，针对上述问题，以某型号高速动车组拖车制动盘为研究对象，对其在300 km/h紧急制动工况过程开展热力耦合特性研究。综合考虑制动盘材料随温度变化而变化，且制动闸片与制动盘接触面的几何形状和分布对热流密度的影响，建立了基于微元法的摩擦面热流密度计算模型；结合热传导、对流换热和热辐射模型，建立了制动盘的应力计算模型，并对制动盘进行热力耦合分析，得到制动盘的温度和应力分布规律。结果表明，制动过程中制动盘最高温度出现摩擦区域靠近外圈位置处，需采取必要的散热措施；最大应力出现在靠近内圈的散热筋部位，设计时需优化此处结构。新方法构建了基于多物理参数和变梯度微元法的热力耦合模型，有效模拟了高速动车组的紧急制动过程，研究结果可为高速动车组制动盘的选材和结构设计优化提供理论依据。

Thermo-mechanical coupling analysis of high-speed EMU brake disc

Under the emergency braking condition of high-speed EMU,the uneven temperature distribution on the surface of the brake disc results in thermal stress caused by thermal expansion and contraction of the brake disc,which in turn leads to thermal crack failure of the brake disc.Aiming at the above problems,taking a certain type of high-speed EMU trailer brake disc as the research object,the thermo-mechanical coupling characteristics were studied in the process of emergency braking at 300 km/h.A calculation model of the friction surface heat flux density based on the micro-element method was established based on the comprehensive consideration of the change of brake disc material with temperature,and the influence of the geometric shape and distribution of the contact surface between the brake pad and the brake disc on the heat flux density.Combined with the heat conduction,convective heat transfer and heat radiation models,the stress calculation model of the brake disc was established,and the thermo-mechanical coupling analysis of the brake disc was carried out to obtain the temperature and stress distribution laws of the brake disc.The results show that the highest temperature of the brake disc occurs in the friction area near the outer ring during the braking process,and necessary heat dissipation measures need to be taken;the maximum stress occurs at the heat dissipation rib near the inner ring,and the structure here needs to be optimized during design.This method builds a thermo-mechanical coupling model based on multi-physical parameters and variable gradient micro-element method,which can effectively simulate the emergency braking process of high-speed EMUs.The research results can provide theoretical guidance for the material selection and structural design optimization of high-speed EMU brake discs.