FIELD: nondestructive diagnosis of materials. SUBSTANCE: method consists in that prior to applying the load, frequency of continuous ultrasonic oscillations introduced into object under test is set equal to frequency of standing-wave main resonance, and amplitude of exciting oscillations is set on level which provided for setting the standing-wave amplitude on boundary of oscillations of low and final intensities. Then signals passed through object are received, and value of standing-wave amplitude in received signal is measured. After application of load amplitudes of fundamental, second and third harmonics are measured. Relations of amplitudes of measured harmonics to oscillation amplitude prior to load application are taken as nonlinear distortion parameters, and value of chemical stresses is judged by them. Parameters of introduced continuous ultrasonic oscillations are calculated by special formulas. EFFECT: higher measurement results. 3 cl, 3 dwg , 1 tbl
