基于mixed Lagrangian/Eulerian方法的轮轨滚动接触特性分析

为了缩短有限元方法显式计算轮轨滚动接触的时间,采用mixed Lagrangian/Eulerian方法建立了轮轨滚动接触有限元模型.应用该模型对轮轨接触区的单元进行细化,计算了列车在启动、运行和制动工况下轮轨的接触特性.计算结果表明:不同工况下,轮轨滚动接触区最大Mises应力、最大接触应力和接触斑面积等法向特性变化幅度均在2%以内,但接触区纵向截面中Mises应力分布及纵向剪切应力分布有较大变化;启动和制动工况下,最大Mises应力和最大纵向剪切应力位置均比自由滚动时更接近于轮轨表面;不同工况下,摩擦力大小和方向发生变化,在列车牵引和制动工况中,摩擦力达到极限时轮轨间出现完全滑动,摩擦力方向与滑动方向相反,且不同速度等级下的纵向摩擦力变化幅度也在2%以内. 

Analysis of Characteristics of Wheel/Rail Rolling Contact Based on Mixed Lagrangian/Eulerian Method

To overcome the long time consumption of the explicit finite element calculation of wheel/rail rolling contact, the mixed Lagrangian/Eulerian method is used to establish a wheel/rail rolling contact finite element model. Through this model, the elements of the wheel/rail contact region are refined, and the wheel/rail contact characteristics are investigated in trains' starting, running, and braking conditions. The results show that under the different conditions, the maximum Mises stress, and the maximum contact stress, and the area of wheel/rail contact patches vary in the range of 2%, but the Mises stress distribution of the longitudinal section in the contact region and the longitudinal shear stress distribution vary greatly. Positions of the maximum Mises stress and the maximum longitudinal shear stress in starting and braking conditions are closer to the surfaces of wheel/rail than in free rolling. Especially it can be found that the size and direction of friction within the contact patch vary with different conditions, and pure sliding occurs when the friction reaches the limit between wheel and rail in the train traction and braking. In addition, the longitudinal friction force also varies within 2%when the train is in different speed grades.