Harmonic imaging of a defect in a flat plate using a guided wave generated by a high-intensity aerial ultrasonic wave

We propose the visualization of defects by means of guided waves generated simultaneously at multiple frequencies using the nonlinearity of a high-intensity ultrasonic wave. This report presents the use of the proposed method to visualize a slit in a thin metal plate. The results confirm that even though the multiple-frequency guided waves infiltrate the defect area in different directions, the defect can be visualized by imaging the wave propagation.