Investigation on the Effect of Fretting Wear on Fretting Crack Propagation of Railway Axles
In this paper,the equivalent stress intensity factors ΔKeq of fretting crack tips at different crack depths in the case of worn/unworn were calculated.Thereafter,the influence mechanism was clarified from two perspectives of contact status and stress distribution.For railway axles,ΔKeq was greater for the worn axles,which promoted the fretting crack propagation.When the crack depth was not greater than 2 mm,the relative error of ΔKeq calculated under the worn/unworn condition was greater than 7%.Owing to fretting wear,an open zone appeared near the contact edge of the wheel seat,releasing the compressive stress induced by the interference fit.In addition,the stress concentration introduced by fretting wear increased the stress field below the contact surfaces.The combined effect of these two aspects promoted thefretting cracks propagation to the depth direction of the axle.The influence of fretting wear on crack propagation cannot be neglected,and it is recommended to take the influence of fretting wear in evaluating the remaining life of fretting cracks.
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