Influence of rim thickness on crack initiation life of wheel web plate for freight car

The temperature and stress distribution in freight car wheel are very important to the operation life. According to the data of investigation, the relationship among the wheel service life, crack rate on web hole and rim thickness is analyzed. The loads, boundary conditions and loading processes in the finite element analysis of temperature, stress field and wheel-railway mechanical stress are discussed according to the heat transfer theory, tread braking principle of wheel and UIC standard. Based on the wheel operation conditions, the influence of different rim thickness on grade braking thermal stress and wheel-railway mechanical stress is simulated with finite element method. The prediction model of crack initiation life for the wheel web hole, which has been taken into consideration for rim thickness, is established. The results show that the high stress at the web hole edge appears under grade braking load cases combined with mechanical load cases. The stress at wheel web hole edge will be increased as the rim thickness reduces, and the increase of thermal stress is much more obvious. Mechanical stress combined with thermal stress is absolutely necessary for crack initiation on wheel web hole. With the service time increases, the rim thickness will be reduced gradually, and the fatigue damage on web hole will be accelerated. The crack initiation life prediction is close to the practical situation.