Review of studies on the computational diagnosis of local defects of structural elements

Rods, beams, shafts, pipelines, round plates. membranes are parts of structures in which local defects such as cracks, dents, cavities, local corrosion can be formed. Provides an overview of the research A. G. Khakimov for the diagnosis of local defects. It is received: 1. The two eigenfrequencies of the longitudinal oscillations can determine the location and the notch parameter characterizing its size. 2. The three lower eigenfrequencies of the longitudinal oscillations can determine the initial coordinate and the value of the attached distributed mass to the stepped rod, as well as the ratio of the areas. 3. The solution of the inverse problem for extended rods allows us to determine the coordinate of the incision and the parameter containing its depth and length, according to the incident and reflected waves at the observation site. 4. The reflection from the air cavity and the passage of a longitudinal damped traveling wave in a pipeline immersed in a viscous liquid are determined, and the solution of the inverse problem allows to determine the coordinate of the air cavity and its length according to the reflected wave at the observation site. 5. The initial coordinate and the length of the longitudinal through radial section of the hollow shaft are determined by the two eigenfrequencies of torsional vibrations. 6. The coordinate, length and parameter of the drill string notch are determined by the three eigenfrequencies of the torsional vibrations. 7. The reflection from the distributed mass attached to the pipeline and the passage of the flexural traveling wave are considered. The dependence of the solution on the initial coordinate of the distributed mass and its magnitude is obtained, and the inverse problem of determining the initial coordinate of the distributed mass and its magnitude from the data of the reflected wave at the observation point is solved. 8. The radius and thickness of the thin central region of the membrane are determined by the two eigenfrequencies of the transverse vibrations. 9. The radius, thickness of the thinned central area of the plate and the value of the attached distributed mass are determined by the three natural frequencies of the bending oscillations. 10. By three frequencies of bending vibrations it is possible to determine the velocity parameter, the relative mass of the product per unit length of the pipeline and the relative mass of sediments on the walls of the pipeline and, as a consequence, the mass flow of liquid through the pipeline.