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紧急制动时的制动盘温度状况与其使用寿命密切相关,而如何准确预测制动盘摩擦表面的温度及温度场分布成为研究摩擦制动盘表面磨损、金相转变及热裂纹的关键技术。本文提出了一种把热辐射系数折算成对流换热系数的方法,建立了锻钢制动盘三维循环对称有限元模型、热输入数学模型及对流散热数学模型。用平均轴制动功率法,对高速列车“中华之星”在270 km/h紧急制动时制动盘温度场分布进行仿真。仿真结果表明,高速列车实施紧急制动时,制动盘摩擦升温最高可达935℃,且高温区域集中在制动盘摩擦表面的中部区域。在1∶1制动动力台进行紧急制动试验,试验结果与仿真数据比较接近,从而验证了该模型的有效性,为制动盘应力场分析及其结构参数优化提供了直接依据。
The temperature of brake disc during emergency braking is closely related to its service life. How to accurately predict the temperature and temperature distribution of brake disc friction surface is the key technology to study the surface wear, metallurgical transformation and hot crack of friction brake disc. In this paper, a method to convert heat radiation coefficient to convective heat transfer coefficient is proposed. Three-dimensional circular symmetrical finite element model, heat input mathematical model and convection heat dissipation mathematical model of the forged steel brake disc are established. Using the method of average shaft braking power, the temperature field distribution of brake disc at “Zhonghua Star” of high speed train during emergency braking at 270 km / h was simulated. The simulation results show that when emergency braking is applied to high-speed trains, the friction temperature of the brake disc can reach as high as 935 ° C, and the high temperature region is concentrated in the central region of the friction surface of the brake disc. The emergency brake test is carried out on the 1: 1 brake power station. The test results are close to those of the simulation data, which verifies the effectiveness of the model and provides a direct basis for the stress field analysis and structural parameter optimization of the brake disc.