Study On Fatigue Reliability Of Wheel Axle Under Surface Damage

Wheel and axle is one of the key components to insure the operation safety of high speed train.With the speed of the high speed train improved,the fatigue of wheel and axle is proposed more strict requirements;Running in a vicious environment,the axle will inevitably encounter some unexpected situations,such as the axle is struck by ballast or debris on the track,leaving a deep gap on its surface.Under this condition cracks can initiate and grow to the critical size,which will bring a great hide safe trouble,causing casualties and loss of public property.In order to ensure the safety of the train axle This paper focuses on the fatigue life,which is very importment for the axles examine and repair management.The mainly work are follows:(1)Investigate the shape of the defects caused by the debris hitting the axle.Get the fatigue property parameters of axle steel by consulting literatures,including the S-N curve of the axle steel,the threshold value of crack propagation,the crack growth rate parameter and the calculation method of the notched S-N curve.(2)Refer to UIC510-5 standard,through the calculation of finite element simulation of the wheel axle to get the force state,Selecting dangerous cross section to arrange bridge road and then test.Get the stress spectrum by processing the measured data.(3)Establishing a finite element model with gaps in wheel axle hazardous locations.Get the force state and stress concentration coefficient through the calculation of finite element.Estimate the S-N curve of the notch by the smooth S-N curve.Calculate crack initiation life at different notches based on Miner rule.(4)Get the stress intensity factor by analytical method and simulation method.Calculate the strength factor by the formula;Calculate the simulation solution of stress intensity factors by FRANC3D and ANSYS.Determine the reliability of the finite element simulation method by comparing the calculation results of the two methods.Judge whether the crack will be extended by comparing the value of the intensity factor and the threshold value.