Numerical Simulation of Energy-Absorbing Rubber Pads Using FEM and DEM Approaches—A Comparative Study

Abstract

AbstractTo lessen the track deterioration and the life cycle cost of ballasted railway tracks, the application of energy-absorbing rubber pads such as rail pads (RP), under sleeper pads (USP), and under ballast mats (UBM) is becoming popular in many countries. Recent experimental studies explore the ability of these rubber pads to reduce ballast layer stress, ballast degradation, and excessive track settlement through large-scale laboratory investigations. Numerical simulation of these large-scale experiments provides an efficient and cost-effective approach to extend for more investigations. Finite element method (FEM) and discrete element method (DEM) are the main approaches used in many studies to simulate the ballasted rail track behaviour. The selection of an appropriate numerical approach mainly depends on the nature of the materials, simulation type, computational cost, and the expected level of accuracy. However, limited numerical studies have been done so far to simulate the static and cyclic loading behaviour of energy-absorbing rubber pads as a solid element for railway applications using either FEM or DEM approaches. Therefore, in this study, 3D models of a rubber pad were developed using both FEM and DEM approaches and they were validated based on the experimental data from the literature for the quasi-static loading condition. Then, a parametric study was carried out by changing the thickness of the rubber pad using both numerical approaches and the results were compared. The results exhibited that the developed numerical models captured the behaviour of the rubber pad with reasonable accuracy for both FEM and DEM approaches. Therefore, the developed rubber pad models can be effectively used in numerical simulations of large-scale experiments and railway applications using either FEM or DEM approaches based on the requirement.KeywordsBallastFEMDEMEnergy-absorbing rubber padsHyper-elastic materials