车轮滚动接触疲劳与磨耗耦合关系数值模拟

Simulation of Coupling Relationship between Wheel Rolling Contact Fatigue and Wear

滚动接触疲劳和磨耗是车轮失效的主要方式。通过三维弹性体非赫兹滚动接触理论得到接触斑内的法向、切向应力和材料上不同深度处的最大切应力分布,以CL60钢和贝氏体车轮钢为例,基于'layer'滚动接触疲劳失效模型和Zobory车轮磨耗模型,分析LM型车轮踏面和75 kg.m–1钢轨型面匹配时轮轨接触条件和车轮材质对车轮滚动接触疲劳和磨耗竞争关系的影响。计算结果表明,摩擦因数为0.3时,CL60钢在小蠕滑条件下会发生滚动接触疲劳损伤,在大蠕滑条件下只有轴重大于30 t时才会出现滚动接触疲劳损伤,而贝氏体车轮钢只有在大蠕滑条件且轴重为30 t时,载荷循环次数小于1×105的情况下才会出现滚动接触疲劳损伤;摩擦因数为0.6时,CL60钢和贝氏体车轮钢在各种工况下的滚动接触疲劳损伤速度都小于相同条件下的磨耗速度。

Rolling contact fatigue and wear are the main modes of wheel failure. The normal and tangential stresses at contact patch and the maximum shear stresses at different depths of material are calculated according to three dimensional elastic bodies non-hertzian rolling contact theory. In the case of CL60 and bainete steel, LM wheel profile and 75 kg · m-1 rail profile are matched, the effects of wheel/rail contact conditions and wheel materials on competition relationship between rolling contact fatigue and wear is analyzed based on ＂layer＂ rolling contact fatigue model and Zobory wheel wear model. The results indicate that, when the friction coefficient is 0.3, the rolling contact fatigue damage occurs in CL60 steel under low creepage condition, while under high creep condition the damage only occurs when axleload is over 30 t; for bainite steel, only under high creep condition and when axleload is 30 t, the damage occurs before the number of load cycles reaches 1×10^5; when the friction coefficient is 0.6, there is almost no contact fatigue damage in CL60 and bainite steel under all conditions, because the rates of wear are always higher than the contact fatigue damage.