An Alternative Rail Pad Tester for Measuring Dynamic Properties of Rail Pads Under Large Preloads

Abstract

Kaewunruen, S. and Remennikov, A. M. (2008). An alternative rail pad tester for measuring dynamic properties of rail pads under large preloads. Experimental mechanics, 48 55-64. Abstract One of the main components in ballasted railway track systems is the rail pad. It is installed between the rail and the sleeper to attenuate wheel/rail interaction loads, preventing the underlying railway sleepers from excessive stress waves. Generally, the dynamic design of tracks relies on the available data, which are mostly focused on the structural condition at a specific toe load. Recent findings show that track irregularities could significantly amplify the loads on railway tracks. This phenomenon gives rise to a concern that the rail pads may experience higher effective preloading than anticipated in the past. On this ground, this paper highlights the significance of accounting for effects of preloading on dynamic properties of polymeric rail pads. An innovative test rig for controlling preloads on rail pads has been devised. A non-destructive methodology for evaluating and monitoring the dynamic properties of the rail pads has been developed based on an instrumented hammer impact technique and an equivalent single degreeof-freedom system approximation. Based on the impactexcitation responses, some of the selected rail pads have been tested to determine such modal parameters as dynamic stiffness and damping constants in the laboratory. The influence of large preloads on dynamic properties of both new and worn rail pads is demonstrated in this paper. Additionally, the design criteria, which has been used to take into account the influence of the level of preload on dynamic properties of generic rail pads, are discussed.

Axle box acceleration for health monitoring of insulated joints: A case study in the Netherlands

“…Furthermore, by examining the frequency response, insight into the condition of the track can be gained [22][23][24][25]. The measurement consists of exciting the rail with a hammer and measuring the response with accelerometers at the location of interest.…”

Nonlinear Modelling and Analysis of Moving Train Loads on Interspersed Railway Tracks

“…The nonlinear iteration (Newton Raphson) has been used to compute the ballast contact and support. The model has been validated earlier using experimental parameters, field data and previous laboratory results [9][10][11][12][13][14][15].…”

Health condition monitoring of insulated joints based on axle box acceleration measurements

“…By examining the frequency response measured via the hammer test, insight into the condition of the track can be gained [32,12,25]. A schematic representation of the hammer test is shown in Fig.…”