Based on the assumption that the shape of wheel profile is unchanged and only the wheel out-of-roundness (OOR) changes,which is more accurate than the model of equivalent track excitations,the polygonal wheels were simulated by programming.Then,the coupled model incorporating the vehicle-track system dynamics was set up.The dynamic performance of ideal wheel and polygon wheel under high-speed running were simulated and the critical range of the wheel out of roundness was determined.The simulation results showed that the wheel OOR will increase the carbody responses and affect the passenger ride comfort,and result in large wheel-rail vertical forces,which is more strongly related to the OOR order than amplitude and vehicle running speed.The safety limits for 1, 2, 3 and 4 order polygon are 1.0,0.4,0.4 and 0.3 mm.
