COMPUTATIONAL STRESS ANALYSIS OF RAIL-WHEEL MODEL OF INDIAN RAILWAYS

Abstract

ABSTRACT Wheel-rail contact analysis is one of the most standout problems in the modeling and analysis of railway vehicles. The wheel-rail interaction is an exceptional part of rail-vehicle progress as it accounts for the capacity of freight wagon and is being considered the most critical parameter for the freight traffic wagons on the railway tracks. In this thesis, the static response of the wheel on a rail is analyzed by modelling and analyzing the geometries of standard section of Rail and wheel through the softwares Creo parametric 2.0 and Ansys 15.0 for calculating the stresses between the Rail-wheel contact region. An analytical approach for calculating the tangent modulus has been drafted during the selection of material and its properties using the Ramberg Osgood Equation. The Hertzian contact theory gives the expression for the maximum contact shear stress value at the point of contact between the rail and the wheel. To validate the value of contact shear stresses founded in this thesis, responses of the assembled model using Ansys 15.0 are compared with the Hertzian approach as well as with the Hertzian stress calculator. Then it has been found that all the three maximum contact shear stresses achieved by different methods are less than the standard limiting values of maximum contact shear stresses in accordance to the Indian Railway Standard. Finally the effects of the results have been studied for the essence of analysis. Maximum contact shear stress between Rail-wheel is found to be 25.5 kg/mm2, 24.63 kg/mm2, 23.55 kg/mm2 by Ansys 15.0, Hertzian theory and Hertzian stress calculator respectively for 90 UTS rail of UIC 60 kg section and all are less than the limiting value of contact stress which is 27.0 kg/mm2 for 90 UTS rails and it was the prime objective of thesis. The thesis is divided into six chapters. The first chapter describes the introductory part of Indian Railways and importance of Freight traffic, followed by the scope and domain of the freight traffic. The next chapter gives an insight regarding the Railway track, rails and wheels, apart from this the chapter also focuses on theory of contact stresses as well as bending stresses. Chapter three, describes the processing of modelling of Rail UIC 60 kg (90 UTS) and wheel of BOXN standard, followed by the fourth chapter which accounts for the computational static analysis of the assembled model of rail and wheel. Chapter five, represents the result validation of contact shear stress and compares it with the limiting values in accordance to Indian Railway Standard. Chapter six delineates the conclusion.