Wheel-rail Interaction Analysis

Sammanfattning: A general approach to numerically simulating wear in rollingand sliding contacts is presented in this thesis. A simulationscheme is developed that calculates the wear at a detailedlevel. The removal of material follows Archard?s wear law,which states that the reduction of volume is linearlyproportional to the sliding distance, the normal load and thewear coefficient. The target application is the wheel-railcontact.Careful attention is paid to stress properties in the normaldirection of the contact. A Winkler method is used to calculatethe normal pressure. The model is calibrated either withresults from Finite Element simulations (which can include aplastic material model) or a linear-elastic contact model. Thetangential tractions and the sliding distances are calculatedusing a method that incorporates the effect of rigid bodymotion and tangential deformations in the contact zone.Kalker?s Fastsim code is used to validate the tangentialcalculation method. Results of three different sorts ofexperiments (full-scale, pin-on-disc and disc-on-disc) wereused to establish the wear and friction coefficients underdifferent operating conditions.The experimental results show that the sliding velocity andcontact pressure in the contact situation strongly influencethe wear coefficient. For the disc-on-disc simulation, therewas good agreement between experimental results and thesimulation in terms of wear and rolling friction underdifferent operating conditions. Good agreement was alsoobtained in regard to form change of the rollers. In thefull-scale simulations, a two-point contact was analysed wherethe differences between the contacts on rail-head to wheeltread and rail edge to wheel flange can be attributed primarilyto the relative velocity differences in regard to bothmagnitude and direction. Good qualitative agreement was foundbetween the simulated wear rate and the full-scale test resultsat different contact conditions.Keywords:railway rail, disc-on-disc, pin-on-disc,Archard, wear simulation, Winkler, rolling, sliding