TECHNIQUE DETECTING CRACKS IN SOLID BODY Russian patent published in 2003 - IPC

FIELD: nondestructive testing of solid bodies by acoustic methods. SUBSTANCE: technique detecting cracks in solid body consists in excitation of primary acoustic waves in solid body on different frequencies which interact across crack generating secondary acoustic waves on combination frequencies, in measurement of amplitudes of primary and secondary acoustic waves on which basis coefficient of crack availability is established. If it exceeds threshold value found on basis of measurements of defect-free solid body judgment on availability of cracks is passed. In this case primary acoustic waves are generated by successive excitation of ultrasonic waves on number of frequencies with simultaneous excitation of elastic vibrations on inherent frequencies by means of impact on solid body. Inherent frequencies are measured and combination frequencies are determined as sum and difference of each frequency of ultrasonic waves with each inherent frequency of elastic vibrations. Coefficient of crack availability is found by computation. EFFECT: enhanced reliability of detection of cracks in tested articles. 1 dwg