چكيده به لاتين
The issue of wheel and rail contact has always been one of the problems in the railway industry, because contact has a very important and undeniable role in various cases such as passenger comfort, vehicle dynamics, off-line, etc. Therefore, industry experts have always tried to simulate the problem of wheel and rail contact in different ways so that they can control wheel and rail wear in a desirable way. Therefore, in this dissertation, a three-dimensional contact model with nonlinear elastic-plastic behavior that simulates surface roughness (asperity) at the points of contact between the wheels and rails of high-speed train tracks of Japan (Shinkansen). In the case of a sliding body moving along a surface, there are areas without relative movement of surfaces (sticky areas) and areas where relative slippage occurs (slip areas). On the other hand, the law of sliding friction essentially determines the maximum tangible transferable force. Therefore, in this study, only the sliding wear status is investigated. In addition, since fatigue wear is unlikely to occur for this study, the study focused only on the abrasive mechanism. The main purpose of this study was to create a finite element model with the ability to simulate slip wear in high speed rail lines. This model includes Johnson-Cook's flexibility and dynamic failure algorithms, the Columbus friction equation, and the thermo-mechanical coupling, which simulates the phenomenon of wear assuming an adiabatic process, where the temperature increases due to plastic deformation. This model can predict local contact pressure, flexibility, local temperature, local tangential stress, local friction coefficient and adhesion coefficient. The effect of surface topography, contact conditions and speed on the adhesion coefficient and contact temperature is considered in this model. After changing parameters such as initial wheel speed and contact position between wheel and rail, outputs such as stress contours at wheel and rail contact surface, wheel and rail surface wear patterns, maximum rail temperature, wheel wear rate and adhesion coefficient between wheel and rail case Will be reviewed. One of the most important results is to reduce the adhesion by increasing the speed of the train and under surface contamination (wet surface).
