高速列车制动盘表面裂纹的扩展特性

The fatigue crack propagation characteristic on brake disc surface of high speed train

分析了制动盘在运行过程中的载荷特征,采用有限元法模拟制动盘在不同制动工况下的热应力分布,发现反复制动形成的拉压应力循环是裂纹扩展的主要驱动力.依据制动盘裂纹剖面的形状特征,采用三维裂纹扩展软件FRANC3D建立了裂纹扩展模型,研究了盘面裂纹的应力强度因子随裂纹长度的变化规律.结合疲劳裂纹扩展理论和裂纹扩展门槛值,估算了临界裂纹尺寸和扩展寿命,以及不同裂纹尺寸扩展到临界长度时的运营里程.研究结果可为制动盘裂纹容限的制定提供参考.

The load characteristics of the brake disc during operation are defined, and thermal stress distributions of brake disc are obtained in different conditions using the finite element method. Re- search found that the tension and compression stress caused by repeated braking is the major driving force of crack propagation. Based on the cracks profile macro-morphology of brake disc, the model is established using three-dimensional crack propagation software FRANC3D, and the relation between stress intensity factor and crack length is studied. According to the fatigue crack growth theory and crack propagation threshold, the critical crack size and extended life is estimated. Then the running distances before the crack reaches the critical crack size is also given. Research. results provide a refer- ence for the crack limits of the brake disc.