Calibration of the Directivity of Ultrasonic Stress Meter Transducer Using Semi-Cylindrical Block Method

In recent years, ultrasonic stress gauges have been widely used in residual stress measurement of steel plates, pressure vessels and other materials and components with low cost, better resolution and penetration. Studies have shown that the measurement accuracy is best when the ultrasonic waves are in the same direction as the stress. The directionality of the transducer is very important for the measurement of ultrasonic stress. At present, the calibration of the sound beam directionality of ultrasonic transducers is mainly based on the hydrophone method, but some ultrasonic stress transducers may not be placed in water due to waterproof problems, and some electromagnetic ultrasonic transducers cannot emit sound in water. The hydrophone method is no longer suitable for directional calibration of these transducers. Therefore, in order to fully understand the directivity properties of the transducer, a semi-cylindrical block method is proposed in this paper, which is suitable for the calibration of the directivity of ultrasonic stress transducers without any limitation.