Assessing the nonlinear static stiffness of rail pad using finite element method

Abstract

The unintended vibrations and sound emerging from train operation have an enormous impact on the surroundings, including the deterioration of the way, buildings, and structures. One proposed strategy to mitigate this issue is the installation of a rail pad inserted between the steel rail and concrete sleeper to provide flexibility to the track and cushion the shocks and vibrations generated by the train wheels’ movement. These materials have nonlinear, dissipative properties influenced by service conditions like temperature and toe load. This work aimed to investigate the static stiffness of different materials of the rail pad under the influence of temperature and toe load. The rail pads were categorized as soft, medium, or hard based on static stiffness. A 3D model of the rail pad, steel rail, and concrete sleeper was simulated and analyzed using ANSYS FEM software. The neo-Hookean model was used to model the rail pad, and the isotropic elasticity model was used for the steel rail and concrete sleeper. The static stiffness of the ethylene propylene diene monomer (EPDM) pad was 85.42 kN/mm, lower than that of thermoplastic elastomers (TPEs, 138.98 kN/mm) and ethylene vinyl acetate (EVA, 303.70 kN/mm) under reference conditions (20 °C), without including toe load effects. Increasing the temperature decreased the rail pad’s static stiffness, with the highest reduction of 53.49 %. However, increasing the toe load contributed up to a 23.53 % increase in the static stiffness of the rail pad.

Prediction of Fatigue in Rail Pad Using Simulation

“…CATIA V5 was implemented to construct geometric models for the steel rail, rail pad, and concrete sleeper. The item's dimensions were established using the existing design following previous literature research [18]. Figure 1 shows the isometric geometry of a steel rail, rail pad, and concrete sleeper.…”

“…Elements of track constructions' stiffness and attenuation were examined in the simulation test shown in Table 2 [18]. The outcomes of the simulation tests may be affected by adjusting the parameters.…”

“…Othman et al characterized the static stiffness of different materials of rail pad ethylene propylene diene monomer (EPDM), thermoplastic elastomers (TPEs), and ethylene vinyl acetate (EVA). Each of these materials shows different conditions of static stiffness under the effect of temperature and toe load [18].…”

Evaluating the Nonlinear Dynamic Stiffness of Rail Pad using Finite Element Method

“…In solid materials like steel and concrete, linear elasticity is a normal technique for modelling the mechanical behaviour of very small strains [20]- [21]. The rail constructions' characteristics and attenuation factors are stated in Othman et al [22]. The figures were gathered from various scientific journals and the web's typical material attributes.…”

“…Figure 2: Boundary condition for fastening system railway track [22] The contact between two surfaces also impacts the simulation results. The location of the interaction was therefore established.…”