Место издания: Novosibirsk , Год издания: 2023

Vibration monitoring of structures or their fragments, based on the extraction of eigenfrequencies of vibrations of various origins, are widely used in various applications. For example, to detect defects of pile structures in the underground part. However, in general, such techniques usually detect the presence or absence of changes compared to a reference. However, it is necessary to know the localization and size of the detected defects in order to make recommendations on the possibility of continued exploitation of the structure. Within the framework of this paper, a hyperbolic equation describing the change of stress-strain state in time under the load of a sinusoidal source with linear frequency modulation in the kilohertz range is considered as a mathematical model of propagation of induced vibrations in a beam. A combination of the finite element method on tetrahedral supports and the Newmark scheme in the time domain was used to solve the problem. The eigenfrequencies of beams without defects and beams with kerfs at different distances from the source were analyzed. It is obtained that the addition of a kerf in the beam generates additional eigenmodes compared to the reference. However, in this case, no clear conclusions could be made about the distance of the kerf to the source. Nevertheless, such work is necessary for a more detailed study of the interaction between materials and their characteristics under the conditions of real experimental problems.