Apparatus and method for ultrasonic stress measurement using the critically refracted longitudinal (Lcr) ultrasonic technique

摘要

The latent stress in both flat and curved materials can be measured using critically refracted longitudinal ultrasonic technique. The system uses a frame to hold a hydraulic piston. The piston is used to apply an adjustable force against the probes. A signal is initiated by a transmitting probe. The signal is angled against the piece under test so as to create a critically refracted wave along the piece. Wedge-shaped probe pads allow placement of the probes on both flat and curved surfaces with various radii and arc lengths. The delay time to receive the wave at a first and second receiving probe is measured. The delay time correlates to a stress in the piece.