Frequency dependent stiffness and damping of railpads

Abstract

The vertical stiffness and damping of studded rubber railpads have been measured, both in a complete track and in a test rig, as functions of frequency under different static preloads. Also, for more compact polymer-based railpads, track measurements were performed. The stiffness of the studded railpads was found to increase strongly with preload, but only weakly with frequency. The loss factor of the studded railpads was found to be nearly independent of preload and to increase only slightly with frequency. A fractional derivative model of the dynamic behaviour of the railpad is proposed.