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ABSTRACT

Mokryy О. M. Methodological background of diagnostics of the state of

materials and structural elements by the velocity distribution of surface acoustic

waves. – Qualification scientific work as a manuscript.

Thesis for the Doctor’s degreein Engineering Science by specialty 05.02.10 ‒

diagnostics of materials and structures (132 materials science). ‒ Karpenko Physico-

Mechanical Institute of National Academy of Science of Ukraine, Lviv, 2020.

The dissertation is devoted to the solution of the scientific and technical

problem, which consists in the development of methodological bases for diagnosing

materials and structures based on the creation of methods for measuring the velocity

distribution of acoustic waves adapted to the problems of non - destructive testing.

Diagnosis and evaluation of the condition of the material long before its damage

is an important task of non-destructive testing. Degradation processes that occur in a

material under the influence of various external factors lead to changes in their

physical properties, which can serve as a parameter for the evaluation of the state of

the material. The magnitude of the acoustic wave velocity is sensitive to many

important characteristics and can be used to evaluate the state of the material. To

effectively use it for this purpose, it is necessary to develop the existing ones and to

develop new methods of measuring it.

The following results are based on the developed methodology for estimating

the state of materials by the velocity of surface acoustic waves.

A new non-contact laser technique for measuring the local velocity of surface

acoustic waves has been created. The technique allows you to combine high

resolution and precision measurements. A feature of the proposed technique is to

reduce the measurement error of the distance by displaying the acoustic field on the

surface of the object of control by the optical field of the probe laser radiation. A
numerical simulation of the distribution of the change in the intensity of optical