Non-Contact Measurement of Defect in the Backside of Steel Plate by Electromagnetic Force Vibration

Railcar bogie may develop internal or backside cracks due to cyclic loading. Ultrasonic testing is the main method used to detect these fatigue cracks. However, ultrasonic testing needs to remove paint and requires contact catalysts. Therefore, in this research, a non-destructive inspection method using electromagnetic vibration is proposed as a non-contact measurement method for backside cracks on ferromagnetic materials such as railcar bogies. Results of verification tests on a 5 mm thick S235JR steel plate show that backside cracks of 1 mm, 2mm and 3 mm depths can be inspected non-contact.