DOI: 10.14489/td.2024.12.pp.027-032

Danilov V. N.
ON THE CHANGE IN THE AMPLITUDE OF THE ECHO SIGNAL RECORDED BY A NORMAL PROBE FROM A REFLECTOR ‒ AN AX SYMMETRICALLY LOCATED FLAT-BOTTOM HOLE, DEPENDING ON THE RATIO OF THE RADII OF THE HOLE AND THE PIEZOELECTRIC PLATE OF THE PROBE
(pp. 27-32)

Abstract. Calculations of the amplitude of the echo signal recorded by a round direct converter from a reflector – an ax symmetrically located flat bottom hole in the form of an integral representation of the Fourier-Bessel type have been carried out. The calculation results, with an increase in the ratio of the radii of the piezoelectric plate of the probe and the hole, confirmed the previously established by Prof. I. N. Ermolov the presence of a maximum echo signal in the far zone of the transducer when it is located on the border of the near zone of the reflector. It was found that in the far zone of the transducer, a change in the wave parameter of the piezoelectric plate (the product of the wave number of the longitudinal wave by the radius of the piezoelectric plate) from 10 to 25 practically does not affect the dependence of the amplitude of the echo signal on the ratio of the radii of the hole and the piezoelectric plate of the probe. It is shown that an increase in the ratio of the amplitude of the echo signal at the maximum tends to the limit value - corresponding to the amplitude of the bottom echo for the radius of the hole, much larger than the radius of the piezoelectric plate with an increase in the relative range to the flat bottom hole.

Keywords: echo signal maximum, reflector, flat bottom hole, far zone, near zone, normal probe, piezoelectric plate, wave parameter, bottom signal.