Abstract:
The goal of the research is to create techniques and tools for detecting the discontinuities in metal with the help of the shadow and shadow-mirror methods of monitoring the ultrasonic flaw detection using the non-contact methods of ultrasonic wave generation and registration. To achieve this goal, studies on the diffraction of bulk elastic waves in a cylindrical cavity have been carried out on a special stand. A pulsed laser and a broadband EMA receiver are used to excite ultrasound and receive the diffracted waves. It is established that along with a decrease in the amplitude of the ultrasound pulses of longitudinal and shear waves transmitted through a discontinuity, a change in the pulse duration and frequency, which accounts for the maximum of their spectrum, can be used as the quantitative estimate of the defects.
Keywords:laser excitation of ultrasound, EMA receiver, volumetric defect, shadow method of laser-acoustic control, pulse spectrum of ultrasonic waves.