冲角工况下列车车轮损伤机理研究

曲线通过和蛇行运动时将会在轮轨间产生一定的冲角,为探究列车车轮在冲角工况下的损伤机理,利用JD-1轮轨模拟试验机对列车车轮进行滚动接触疲劳试验.结果表明:在冲角工况下车轮试件磨痕的不同区域存在不同的损伤机理,按损伤机理的不同可以将其分为塑性堆积区、疲劳损伤区和磨损区三个区域.在应力发生剧烈变化且应力方向由高应力区指向低应力区的区域将会出现材料的塑性堆积,并且在堆积处产生疲劳裂纹.滚动接触下的疲劳裂纹可以萌生于表面和亚表面,在较强应力作用下,车轮材料的晶粒发生了明显的细化,在横截面上呈现出纤维状组织.

Damage Mechanism of Railway Wheels under Condition with Angle of Attack

There will generate an angle of attack between railway wheels and rails under curve negotiating and hunting conditions. With the aim of investigating the damage mechanisms of railway wheels under condition with angle of attack, the rolling contact fatigue test of simulate wheel was performed using a JD-1 wheel/rail simulation facility. The results indicate that different damage mechanism occurred at the different region of wheel specimen, and the regions were divided into three parts, i.e. the plastic accumulation region, the fatigue region and the worn region. Drastic changing in stress and the stress direction was from the high stress region to the lower one, it world appear the material accumulation which led to fatigue crack initiation. Rolling contact fatigue cracks initiated at surface or sub-surface in the fatigue region, and the grains of wheel material became elongated obviously under high stress, showing fibrous shape in cross section.