轮轨接触应力对U71Mn钢轨磨损-疲劳劣化行为影响研究

Effect of Wheel-Rail Contact Stress on Wear-Fatigue Deterioration Behavior of U71Mn Rail

利用实验室摩擦磨损试验与双盘接触有限元仿真计算,初步研究U71Mn钢轨材料在法向接触应力为900 MPa、滑差率分别为0.5%、2.0%、4.0%条件下,切向接触应力对钢轨材料磨损-疲劳劣化行为的影响。结果表明:轮轨试样间法向接触应力在900 MPa条件下,当滑差率由0.5%提高至2.0%时,轮轨试样间的切向接触应力、钢轨材料的平均摩擦系数、磨损率均呈增大趋势,钢轨材料的疲劳裂纹长度更长、深度更大,损伤表面起皮更为严重,此时轮轨试样间的磨损-疲劳竞争耦合关系中疲劳作用成为了劣化行为的主导;当滑差率由2.0%提高至4.0%时,钢轨材料的平均摩擦系数、磨损率均呈增大趋势,损伤表面起皮更为严重,但轮轨试样间的切向接触应力增加十分有限,钢轨材料的疲劳裂纹长度和深度均略有降低,此时轮轨试样间的磨损-疲劳竞争耦合关系中磨损作用成为了劣化行为的主导。

Based on laboratory friction and wear test and two-disc contact finite element simulation,the effect of tangential contact stress on wear-fatigue degradation of U71Mn rail material under the conditions of normal contact stress of 900 MPa and slip rate of 0.5%,2.0%and 4.0%respectively were studied.The results show that when the normal contact stress between wheel and rail is 900 MPa and the slip ratio is increased from 0.5%to 2.0%,the tangential contact stress between wheel and rail specimens,the average friction coefficient of rail material and the wear rate all show an increasing trend.The fatigue crack length and depth of rail material are longer and deeper,and the damaged surface peeling is more serious.At this time,the fatigue action becomes the dominant degradation behavior in the wear-fatigue competitive coupling relationship between wheel and rail specimens.When the normal contact stress between wheel and rail specimens is 900 MPa,the average friction coefficient and wear rate of rail material increase from 2.0%to 4.0%,and the damage surface peeling is more serious,but the increase of tangential contact stress between wheel and rail specimens is very limited,and the fatigue crack length and depth of rail material decrease slightly.At this time,the wear action becomes the dominant degradation behavior in the coupling relationship of wear-fatigue competition between wheel and rail specimens.