Acoustic probing based on Gaussian ray tracing

Ultrasonic Testing is one of the most popular non-destructive inspection techniques. It uses acoustic transducer and receiver to find a defect inside the material. The technique usually utilizes a pulsed wave and identifies the defect based on the time-of-flight algorithm. Since it relies on the reflection, it cannot detect abnormality unless the reflection is sufficiently high. In contrast, our method introduces the concept of Gaussian beam propagation widely used in optics. A continuous ultrasonic wave is injected into the specimen and the transverse profile of the transmitted signal is analyzed in the amplitude and phase. The abnormality in the specimen is detected as the distortion in the transverse profiles. It is expected that our method is useful to applications where the conventional method is unable to identify the abnormality because the acoustic impedance is too close to the base material.