On the Features of Reflection of Shear Elastic Wave Pulses From a Vertical Crack

A computer simulation of the characteristics of pulse signals of shear waves reflected from the edge of a vertical crack coming to the surface of the control object and a bottom crack using radiated pulses of various lengths with narrow, medium width and wide spectra was carried out. Within the limits of changing the calculation parameters, a feature of pulse reflection is established – the ratio of the maxima of the envelope pulses when reflected from a crack coming to the surface of the OK and the bottom crack is approximately 3.40 (10.6 dB), which coincides with the corresponding ratio of the maxima of the spectra. Based on the results of calculations of pulse shapes with frequency spectrum of different widths when waves are reflected from a vertical crack, the recommendation is justified not to use long pulses with narrow spectra with reduced beam resolution in the time of flight diffraction method.