Abstract
This paper presents a new basic nonlinear track model consisting of an infinite Euler-Bernoulli beam (rail) resting on continuous foundation with two elastic layers (rail pad and ballast bed) and intermediate inertial layer (sleepers). The two elastic layers have bilinear elastic characteristic obtained from the load-displacement characteristic of the rail pad and ballast. A time-varying load with two components - time-constant one and harmonic other, representing the wheel/rail contact force is considered as the track model input. Rail deflection due to the time-constant component of the load is obtained solving the nonlinear equations of the balance position. Subsequently, the structure of the nonhomogeneous foundation is determined. Dynamic rail response in terms of receptance due to the harmonic component of the load is calculated using the linearised track model with nonhomogeneous elastic characteristic. Influence of the time-constant component and the reflected waves due to the nonhomogeneous foundation are presented.
Highlights
Track modelling is crucial for the study of the interaction between the trains and track
The key features of the track model are the bilinear approximation of the nonlinear elastic characteristics and the manner in which the rail response is treated in the sense that it has two components corresponding to the static load due to the weight of the vehicle on the wheel, and the dynamic load caused by the wheel-rail interaction in the presence of unevenness
The elastic characteristics of the rubber rail pad and ballast are described as nonlinear functions of static load depending on deflection
Summary
Track modelling is crucial for the study of the interaction between the trains and track. The rail pads are made of rubber, ethylene propylene diene monomer (EPDM), thermoplastic polyester elastomer (TPE), high-density polyethylene (HDPE), and ethylene-vinyl acetate (EVA), as presented in Figure 2 [7, 8] Such materials are well known in industry and these are extensively studied from many view points to solve various practical issues [9,10,11,12,13,14]. The main representation of the rail pad is the Kelvin-Voigt system which consists in a linear elastic element working in parallel with a viscous damper element [2] This model can be applied in the analytical representation of the track. A new basic analytical model of the track based on the approximation of the nonlinear elastic characteristic of the rail pad using the bilinear functions is presented. Rail deflection due to the time-constant load is calculated using the nonlinear model of the track and the rail receptance is derived with the help of the linearized model with nonhomogeneous foundation
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