Fufa, Bulcha
(The main objective of this thesis is to analyze the contact stresses developed by varying contact profile geometry of wheel-rail such as; rail profile radii, wheel profile radii, and wheel profile taper. A change in contact surface topology of wheel-rail may result in a change in contact geometry and stresses. To understand their influence profile radii are changed for seven different values. The methods used to calculate the analytical results are Hertzian contact (normal contact) method and tangential contact method. The selected materials for the analysis are R7T for wheel and UIC60 for rail as per European standard. Additionally, the corresponding finite element analysis is carried out by ANSYS software using boundary conditions of the materials. A three-dimensional finite element model for wheel-rail is developed and the load is applied to identify the stress at the contact patch. It is observed that the magnitudes of equivalent stress are 338.29 MPa from FEA and 333.31 MPa from Hertzian Contact Theory (HCT) for 330 mm and 300 mm of the wheel and rail radii of curvature respectively. Similarly, for wheel and rail radii of curvature 360 mm and 300 mm the values of equivalent stress are 329.67 MPa from FEA and 324.28 MPa from HCT. When the results of two methods HCT and FEA are compared they agree well with each other with the maximum deviation of 2.29%. This percentage difference may be due to the assumptions made in Hertzian contact theory during the analysis. The number of cycles to failure is also done analytically using tangential contact method and FEM., 2020-05-12)