Observation of the damage process of rolling contact fatigue using a noncontact electro-magnetic array sensor

The rolling contact fatigue between railway wheel and rail is a critical theme. It is very important to evaluate and monitor RCF damage between a railway wheel and rail to prevent derailment and increased maintenance costs. The electro-magnetic array technique was applied in rolling contact fatigue tests using a twin-disc tester under constant speed to detect the damage processing. The applied sensor provides continuous monitoring of the fatigue damage and rotation under the condition of continuous rolling contact. In the present paper, the results demonstrate the applicability of the electro-magnetic array technique to the detection and sizing of defects due to RCF damage. The usefulness of the applied sensor was verified by a twindisc test, and the measured damage sizes showed good agreement with the damage sizes estimated by the electro-magnetic array technique. The system can detect the position of the damage due to RCF and is able to provide a display of the severity of the damage and damage shape and it could provide users to monitor the information on degradation during RCF process.