Time domain simulation of railway noise

Abstract

The most difficult problem concerned with railway noise generation is the process occurring in the contact region during rolling. The following computation efficient time domain model determines the vertical rail deflection by use of Green’s function of a periodically supported beam. Nonlinear Hertzian contact mechanics are used, less realistic, however, than a discretized contact region allowing for rough surfaces. The wheel is as yet a rigid mass. More advanced contact and wheel models can readily be included later. Calculation results include the following observations. The contact force peaks sharply precisely above the support points, followed by a short loss of rail–wheel contact, also for smooth rails. Vibrations of the rail pinned–pinned mode are impossible to eliminate by removing surface roughnesses, because the excitation is above all caused by forward wheel velocity together with discrete supports. The response amplitude increases with forward velocity. Optimum pad stiffness depends on corrugation amplitude. These new findings should be considered when trying to noise optimize track constructions.