Influence of wheel ovalization on time-frequency characteristics of a high speed train based on improved HHT

The influence of wheel ovalization on time-frequency characteristics of a high speed train was investigated.A spatical coupled model of a vehicle-track system was presented and the dynamic response of the vehicle system due to wheel ovalization and harmonic irregularity was simulated.The Hilbert-Huang Transformation(HHT) based on an improved empirical mode decomposition(EMD) was proposed and adopted to analyze the vibration signals of the vehicle-track coupled system.Then,the time-frequency distribution and energy distribution for the dynamic response were calculated and analyzed.The simulations indicated that wheel ovalization can induce the frequency modulation of the vibration response of the vehicle system,the vehicle hunting and the nonlinear change of vibration energy distribution.