METHOD OF DETERMINATION OF ACOUSTIC DENSITY Russian patent published in 2018 - IPC G01N29/04 

FIELD: defectoscopy.

SUBSTANCE: using for ultrasonic non-destructive testing of objects from structurally heterogeneous materials, mainly articles of concrete. Summary of the Invention thing is in a number of points on the surface of the monitoring object, ultrasonic probing pulses of longitudinal or transverse waves radiate, take from the same points of realization of ultrasonic oscillations caused by ultrasonic pulses, reflected from the inhomogeneities of the internal structure of the material of the object and from any interfaces between media with different acoustic densities, reconstruct the three-dimensional distribution of the amplitude of ultrasound scattered by the points of the structure of the material of the object, in the obtained three-dimensional distribution, points are distinguished with amplitudes exceeding the average level of the effective value of noise by four or more times, unite the selected distribution points into groups by the criterion of their proximity, determined by the distance between the corresponding points of the structure of the object, not exceeding half the wavelength of ultrasound, coherently summed up fragments of accepted realizations of ultrasonic oscillations containing echo signals from points of the internal structure of the object, which correspond to the points of the three-dimensional distribution belonging to each selected group, and if during the emission and reception of pulses of longitudinal ultrasonic waves the phase of the total fragment of the realizations of a certain group of points of the three-dimensional distribution differs by a factor of less than 45 degrees from the phase of the probing pulses in modulus, then this means that the medium beyond the interface is more acoustically dense than the medium to the interface, if the phase difference is in the range from 135 to 225 degrees, on the contrary, the medium outside the interface is less acoustically dense, and when the pulses of transverse ultrasonic waves are emitted and received, the ratios of the acoustic densities of the media for the indicated phase differences are inverse to the relations for longitudinal waves.

EFFECT: expansion of the range of reliable determination of the ratio of the acoustic densities of media at the interface to the region of low signal-to-noise ratios.

3 cl, 5 dwg