In order to comprehensively consider the dynamic behavior of vehicle system and the contact forces between wheel and rail, the vehicle-track coupling model is established considering the flexible wheelset and rail modal characteristics. Guyan reduction theory is introduced to reduce the degrees of freedom of wheelset and rail and to improve the calculation speed. Due to small axle load variation of freight wagon operating on the special line for the coal transportation, the vehicles with different speeds and wheel flat lengths, whether in empty or loaded conditions, are simulated and then the mapping relations between the flat lengths and wheel/rail impact force are obtained. Subsequently, the fitting functions for the empty and loaded vehicles are fitted to quantitatively detect the wheel flat by trackside equipment. The results indicate that the fitting function of empty vehicle has a better effect on predicting the flat length within 6% error since wheel/rail contact force of empty vehicle induced by wheel flat increases with the increase of flat length, while that of loaded vehicle presents a parabola variation trend at low speed and increasing trend at higher speed.

为了综合考虑车辆系统的动态行为和轮轨接触力，建立了考虑柔性轮对和轨道模态特性的车轨耦合模型。引入Guyan减缩理论，减小轮对和钢轨的自由度，提高计算速度。由于运煤专线上的货车轴荷变化较小，对不同车速和不同轮平长度的车辆，无论是空载还是载重情况，进行模拟，得到平长与轮距的映射关系。获得轨道冲击力。随后，通过轨旁设备对空车和载车的拟合功能进行定量检测。