Study On Rolling Contact Behavior And Fatigue Life Of CRH5 Type EMU

In order to study the stress of the wheel rail in the actual rolling contact process of the CRH5 type EMU and the fatigue problem caused by the cyclic stress,the large-scale finite element analysis software ABAQUS is used to simulate the operation of the system under the actual operating conditions.Combination with rolling contact theory,the stress and strain responses of wheel rail contact area under different axle load gradient,different friction coefficient and different driving torque were analyzed and the influence mechanism of wheel rail rolling contact behavior is obtained.Based on the theory of rolling contact fatigue strength,the rolling contact fatigue life of the wheel was predicted by S-N curve reduction and fatigue analysis software Fe-safe.The results show that the equivalent stress of wheel rail contact area,the shear stress of wheel rail cross section,the true strain and shear strain of wheel rail contact region were all increased with the increase of axle load,however,the equivalent stress of the wheel decreases with the increase of the depth of the gauge.The maximum equivalent stress appears in the range of about 1-10 mm while the rail increases slowly and then decreases,the maximum stress appears at the depth of about 12 mm.The position of the maximum true strain does not transfer with the change of axle load,it appears in wheel rail contact area wheel depth direction about 15-20 mm range.The maximum Mises stress in wheel rail contact area is nonlinear while the vertical force increases slowly with the increase of friction coefficient.The maximum transverse,vertical and longitudinal shear stresses enlarge with the increase of friction coefficient,the difference is the maximum vertical and longitudinal shear stress are greater than the maximum transverse shear stress.At the same time,the position of the maximum vertical and longitudinal shear stress will expand to the surface with the increase of the friction coefficient,it also explains the reason why the wheel and rail is subjected to heavy stress,but it is easy to wear and crack on the surface.The change of driving torque has no influence on the maximum Mises stress,the maximum transverse shear stress and the distribution of the rolling contact area,the maximum longitudinal shear stress increases with the increase of the driving torque,and shows the trend of moving towards the wheel rail contact surface.The life cycle of the wheel under different axle load is calculated at 6×107 to9×107 times by S-N reduction method,the driving distance can meet the requirements of three or more maintenance cycles.Under the condition of wet sliding,the life of the wheel with different coefficient of friction is within 6×109 to 8.9×109 cycles,which belongs to the ultra high cycle fatigue,and the distance is up to four 107 Km,at the same time,it explains the importance of lubrication to improve the rolling contact fatigue life of wheel and rail.The calculation of the fatigue life of Fe-safe fatigue analysis software,and the calculation results are correct,getting the fatigue life of wheel rail under different axle load in 6.43× 107 to 8.10 × 107 cycles,which belongs to the high cycle fatigue.The theory driving distance of three grade to meet 106 km maintenance requirements.The numerical calculation result and the wheel fatigue lifereduction result matched.