The vibration characteristics of EMU under abnormal wheel-rail wear

The abnormal wheel/rail wear is an important cause of abnormal vibration response of rail vehicles. The hollow-worn tread and wheel polygons are the most common forms in electric multiple unit (EMU) wheel wear. In order to study the vibration response of a special EMU with hollow worn or polygons, the nonlinear rail vehicle dynamics model was established, and track irregularity generated by superposition of short wave component and track spectrum, using abrasion definition parameters to generate different hollow-worn tread files, to study the vibration response characteristic under different combination conditions. The simulation results show that the wave depth of the wheel polygon has a significant effect on the vibration response of each level of the rail vehicle system. With the increasing the order of the wheel polygon, the response amplitude of each level in the frequency domain increases at first and then decreases. When the order is 7, the amplitude reaches the maximum value. Hollow-worn tread has little effect on vertical spectrum distribution of each level, but has significant effect on lateral spectrum distribution of bogie frame. With the depth of the wheel wear, the main frequency dominant of the bogie frame shifts to the right side, and the response amplitude of the 6-30 Hz frequency bandwidth increases significantly. The wheel polygon order and amplitude have no significant effect on the vertical vibration transmissibility of each EMU level, and the suspension system has a good attenuation effect on the frequency band beyond 2 Hz.