当铁路机车车辆沿钢轨运行时,在其主要的零部件中产生相当大的动应力,这种动应力频率在1～250赫之间变化着。因此,疲劳裂纹的产生和发展是机车车辆零件最为普遍的破损形式。脆性折损只在某些情况下于焊接结构中发生,通常,只有当低温时,在具有较大的残余应力和剧烈的应力集中的地方才发生。这是车体和转向架零件的特点。因此, When a rolling stock vehicle runs along a rail, considerable dynamic stresses are generated in its major components, which fluctuate between 1 and 250 Hz. Therefore, the generation and development of fatigue cracks are the most common forms of damage to rolling stock parts. Fragile loss occurs only in the welded structure in some cases, and usually only occurs at low temperatures, where there is greater residual stress and intense stress concentration. This is a feature of bodywork and bogie parts. therefore,