Об использовании пазов для моделирования трещин при ультразвуковой дефектоскопии

Abstract

An analysis of the possibility of a rigorous theoretical solution of the three-dimensional problem of elastic wave scattering at the tip of a vertical crack in a welded joint was carried out. It was shown that in the general case of ultrasound scattering on a flat target, the three-dimensional problem can be reduced to a two-dimensional one. On this basis, for an arbitrary direction of sounding a crack in a weld, the dependence assessment of the signal from the crack tip on the direction to the receiver was made. It is noted that the wave size of the crack tip is much smaller than the wave size of the notches tip that can be machined to simulate defects in welded joints. As a result, it is shown that the nature of the scattering of elastic waves at the tip of the crack differs from the nature of scattering on the notches, including in cases where the opening of the notches is minimal based on the possibility of their manufacture. The results of an experimental verification of the obtained theoretical estimates on steel and aluminum samples were presented. It was shown that, in contrast to the tip of the cracks, at the tips of the notches, even with their minimal openings, conditions are created for the formation of a scattered field by the type of specular reflection from a volumetric cavity - a side cylindrical reflector.