快速列车制动盘安全评定与寿命预测模型

Modeling of safety assessment and useful life time of high-speed passenger car brake discs

为分析含缺陷制动盘的结构完整性,应用断裂力学理论对快速列车制动盘进行了系统的寿命评估研究。根据对制动盘失效情况的调查和盘体应力变化规律计算结果,确定了制动盘失效机制,进而建立了制动盘安全评定与寿命预测模型,从工作断面、工作应力、断裂参量、计算方法、判别准则和评定步骤等方面对预测模型的理论与方法进行了阐述。结果表明:在残余拉应力和热压应力组成的疲劳应力循环驱动下,盘体内部的初始缺陷处引发裂纹并扩展至表面是导致制动盘失效的主要原因。研究结果可以为制动盘的结构设计、产品验收,以及运行大修期的确定提供参考依据,对于高速列车及其他车辆和机械的制动盘安全评定与寿命预测具有一定的指导意义。

The useful life of a passenger car brake disc design was investigated using fracture mechanics theory to analyze the structure integrity of the brake disc with a crack-like flaw. The disc failure mechanism was predicted using failure states analysis and finite element simulations of the transient stress field to develop a safety assessment model and to predict the brake disc life time. The failure mechanism is due to cycle fatigue stress including thermal stresses and residual stresses induced by the braking procedure. A fatigue crack initializes from a subsurface flaw in the brake disc and then propagates towards the brake disc surface. The detailed model includes the working plane, the operating stress, the fracture parameter, the evaluation procedure and the assessment criterion. The results show that the method can be used to design and evaluate brake discs and to determine repair periods to provide guidance for safety assessments and llfe time predictions of brake discs for high-speed passenger cars and other vehicles.