Crack depth measurement in rail steel by Rayleigh waves aided by photoelastic visualization

Abstract Stroboscopic methods of visualization of ultrasonic waves by schlieren and photoelastic methods have been introduced in recent years. The author describes work which demonstrates the application of the photoelastic technique to a problem of crack-depth sizing in steel rails by Rayleigh waves. The visualization of the interactions of ultrasonic waves in notched glass testpieces provides explanations of multiple A-scan received signals, the origins of which were not previously understood.