Author(s)

M. ROSHAN KHAN, SATYANARAYANA MURTY DASAKA

Abstract

High speed railway lines of present day operate with longer, heavier trains at super-fast speeds. The dynamic loading conditions imposed by these trains impose a large impact on the substructure, making the characterization of loads a very important aspect. Numerical modelling of railway track systems can considerably reduce the time and costs associated with performance analysis of railway tracks subjected to dynamic loading conditions. However, finely detailed numerical models expend a lot of computational resources and time for effectively simulating railway loading on tracks. A numerical model has been developed for evaluating the suitability of rigid-body simulations to model wheel-rail contact interactions and performing 3D moving load analyses. Transient analyses are performed in ANSYS, with the model simulating an Indian Railway WAP-7 locomotive wheel-set running on IRS-52 railway track section. Validation of the numerical model is done with the wheel-rail contact pressure results available from the literature, for a loaded section of Italian rail section UNI-60. Static analysis of the WAP-7 locomotive wheel-set has been done for an axle load of 20.5 tonnes and the wheel-rail contact patch has been construed with estimation of the interface contact pressures. Further, 3D transient moving load model was developed, simulating the actual wheel-rolling movement on rails, based on the interface contact friction. The analysis was performed on an Integrated Coach Factory (ICF) bogie wheel-set, simulating the coach to run at a speed of 140 km/h and an axle load of 20.3 tonnes; the maximum speed and axle load with which train coaches are allowed to operate today in Indian Railways. The model was found to have lesser computational demands and CPU time was reduced to one-twentieth in comparison with deformable-body analyses, yielding very reliable results. Rigid-body numerical modelling proved to be an effective alternative to the practice of finely meshed finite element modelling of railway track systems.

Keywords

rigid-body simulation, railway loading, wheel-rail interface, contact pressure, 3D moving load analysis