Variance-Based Wheel/Rail Contact Sensitivity Analysis in Respect of Wheelset Dynamics

To get a deep insight into bogie suspension design, it is important to identify those wheelset dynamics states and running conditions that can influence contact mechanics and wear, remarkably. In this regard, global sensitivity analysis of wheel/rail contact creepages, forces, and wear with respect to wheelset dynamics states, vehicle speed, and normal contact force is scrutinized. The Gaussian quadrature integrals together with multiplicative dimension reduction method (M-DRM) are employed to approximate the global sensitivity indices of wheel/rail contact mechanics. Using simulation results of a one car railway vehicle model, a feasible state vector is chosen as the cut center for sensitivity analysis of a single rigid wheelset with 6 degrees of freedom. The state vector, speed, and normal contact force are varied around the cut center according to a predefined set of independent and identically distributed random numbers. A computational model is developed to attain the contact point positions on wheel and rail as well as nonlinear creepages. The corresponding contact stimuli vector is obtained using FASTSIM algorithm and wear is modelled as the energy dissipation in the contact patch. The wheelset dynamics effects on wheel/rail contact mechanics are then explored. The results showed wear is mostly sensitive with respect to yaw motion and lateral speed of the wheelset. Such an analysis provides informative data that can be used in vibration control and suspension design in railway applications.