Dynamic property analysis of axle shaft of high-speed train

Wheel and axle box were simplified to collective quality and inertia of moment, non-uniform axle shaft was simulated by using continuous elastic Timoshenko beam, an elastic wheelset/rail coupling vertical dynamics model was set up, and the relationships between the dynamic stiffness of axle shaft and wheel/track dynamic force, the vibratory characteristics and dynamic stress of axle shaft were analyzed. It is pointed that when the first natural frequency of wheelset reduces from 76.34 Hz to 53.68 Hz and the second natural frequency reduces from 130.03 Hz to 100.02 Hz, the first mode vibration acceleration and elastic vibration displacement of axle shaft increases by 60.12% and 92.91% respectively, wheel/track dynamic force increases by 6.23%, the dynamic stresses on the dangerous section inside wheel seat and on axle neck respectively increase by 39.30% and 34.13%. Analysis result shows that the dynamic force of wheelset and the dynamic stress of axle shaft increase with the dynamic stiffness decrease of axle shaft, so raising the dynamic stiffness of light wheelset can ensure the running safety of high-speed train and enhance the fatigue intensity of axle shaft.