Research On The Influence Of Cyclic Load Conditions On The Damage Of Wheel Seat Of 1:4 Scaled Axle

In order to understand the law of the influence of load conditions on the fretting damage of wheel seats of railway axle,fatigue tests were conducted on 1:4 scaled axles,and the width of wear zone,slip zone,the maximum depth of wear zone of wheel seats and the location information of the fretting cracks under various working conditions were observed and tested.The experimental results show that the wear profile of the contact edge of the wheel seat will be changed when the load increases and the cycle remain the same,which shows that the width of the wear zone,slip zone and the maximum wear depth increase accordingly.When the cycle increase and the load stress remain the same,the wear profile also changes,which shows that the width of the wear zone and the maximum wear depth increase,but the width of the slip zone does not change.The influence of load amplitude on fretting wear is greater than that of load cycles,and fretting cracks appear near the boundary between wear and unwear.In order to obtain the mechanical conditions of axle wheel seat damage,clarify the law of the influence of fretting wear on fatigue,Abaqus was used to calculate and compare the contact parameters,SWT parameters and axial stress concentration coefficients of the contact edge of the wheel seat under various load conditions,and the test and simulation results were compared.All the results about the scaled-axle will be compared to the full-scale axles.The results show that: wear will significantly affect the stress distribution on wheel seat and aggravate the stress concentration of the axle;the local maximum of the contact stress,the friction shear stress and the axial stress concentration coefficient appears at the boundary between worn and unworn.Contact parameters are significantly affected by the load amplitude.The more severe the wear is,the greater the peak value of the SWT parameter and the axial stress concentration coefficient is,and the peak value of them appear at the boundary between the wear and the unwear;The dispersivity of SWT parameters and the axial stress concentration coefficient of the failed axles is small,which,to a certain extent,can reflect whether there is a cracks on the wheel axle.From the above research results,it can be seen that the failure of large-load and low-cycle specimens is stress-dominated fatigue failure accompanied by slight wear,and the low-load and high-cycle specimens are wear-dominated fatigue failures,which are caused by contour changes caused by fretting wear.The resulting stress concentration caused the axle to fail.There is a certain equivalent relationship between the damage caused by large-load and lowcycle and small-load and high-cycle,but a large-load and low-cycle condition cannot replace the stress concentration caused by the wear of small-load and high-cycle,so it is not objective to understand the damage of the actual axle with a long-time work according to the result obtained from the test with a large-load and low-cycle condition.The results of this thesis can provide reference for the research of the actual railway wheel axle fretting fatigue test and the combination of fretting fatigue test and simulation.