Xingguo Zhao

Failure Analysis of Connecting Plate Between Indication Rod and Switch Rail in a Turnout System

Failure analysis was conducted on a connecting plate of indication rod and switch rail in the switch system of rail. The cracking of connecting plate was detected during the periodic routing inspection after one year of service. Detailed fracture morphology examinations on the fractured connecting plate were conducted combining with the actual working condition analysis. Typical morphology of brittle fracture like cleavage and quasi-cleavage morphology was observed in the fractured surface. The results indicated that the bending stress, resulted from the lateral force during the train passing the switch rail, is the key reason leading to the cracks initiation and propagation of the connecting plate.

An Approach for Subsurface Rolling Contact Fatigue Damage Assessment of Backup Roll Material

This paper proposed an approach for the subsurface rolling contact fatigue damage assessment of the component operated under rolling contact conditions. The maximum range of orthogonal shear stress was selected as the critical stress controlling subsurface rolling contact fatigue damage. The distribution of the maximum range of orthogonal shear stress combined with the S–N curve of materials tested was used to compute the subsurface rolling contact fatigue damage. The distribution of subsurface rolling contact fatigue damage computed by theoretical model proposed was validated by the statistical analysis result of hardness test on the rolling contact fatigue test samples and distribution of the pole figure’s peak intensity tested by X-ray diffraction method in one of the reference article. The theoretical results agree well with that subsurface rolling contact fatigue damage evaluation characterized by hardness and X-ray diffraction.