Dynamic Stability and Random Vibrations of Rigid and Elastic Wheelsets

A stability analysis and vibration studies are presented for a passenger coach model which is equipped with rigid or elastic wheels. The elastic components between wheel rim and disc act as third suspension reducing the unsprung mass and isolating the passenger coach from the high frequency motion of the wheel rim. The vertical and lateral motion by such a design requires a thorough analysis of the system dynamics. The excitation of the vertical vibrations by stochastic track irregularities results in acceleration amplitudes of the carbody that may generate droning noise. A parameter study of spring and damper coefficients of the system with radialelastic wheels leads to considerably reduced droning noise and lower force level between wheel and rail. Furthermore, the eigenmotion of a rigid and an elastic wheelset rolling on a track, the so-called hunting, is investigated. The variation of the spring and damper coefficients shows limits to guarantee the stability of the system.