Electromagnetic stimulation of the ultrasonic signal for nondestructive detection of ferromagnetic inclusions and flaws

In this paper, the method of nondestructive detection based on electromagnetic modulation of the ultrasonic signal scattered from the inclusions or defects has been reported. The electromagnetically induced high-density current pulse generates transient stress fields which alter the ultrasonic waves scanning the part with the defect and modulate the ultrasonic signal due to magnetoelastic coupling, magnetostriction, or the "crack closure" effect. The results of applying electromagnetic transient modulation of the ultrasonic echo pulse tone-burst suggest that this method could be used to enhance detection of small cracks and ferromagnetic inclusions in thin-walled metallic structures.