Abstract: Influences of inclusion shapes on local stresses and crack nucleation in CRH5 wheel rim were analyzed. Results show that the sharper of inclusion, the greater stress level of inclusion. Meanwhile, the local stress increases with the decrease of inclusion thickness and the increase of inclusion radius. And it leads to increase of local stress concentration factor. It indicates that fatigue cracks are produced easier and the reliability of the wheels is reduced. The critical inclusion sizes in different operating conditions were calculated by using FEM and curve fitting method. Results also show that the critical inclusion size changes followed by changes of the operating conditions. And the critical size is relative smaller when it is the curved track. Wheel rim fatigue cracking may be initiated once the inclusion size is bigger than the critical inclusion size.

Key words: electric motor unit(EMU), crack of wheel rim, inclusion, shape factor, critical size

摘要：

以CRH5型动车组轮轴为研究对象，研究了夹杂物的形态对轮辋局部应力和轮辋裂纹成核的影响。结果显示，夹杂物棱角角度越小，夹杂物周围应力水平越高；夹杂物的厚度越小，半径越大，夹杂物周围最大等效应力越大，越易引起局部应力集中，导致疲劳裂纹易于萌生。利用有限元法和曲线拟合方法得到不同工况下夹杂物的临界尺寸，研究发现:不同工况下夹杂物的临界尺寸不同，弯道工况下的临界尺寸最小,夹杂物的尺寸超过临界尺寸时，裂纹才会萌生。

关键词: 电动车组, 车轮轮辋裂纹, 夹杂物, 形状因素, 临界尺寸