Voytko M. Diffraction of elastic SH-waves on interface cracks

The thesis is focused on study of elastic SH-waves diffraction by interface cracks. Incident field has been modelled by either plane wave field or concentrated force source. Efficient asymptotic solutions for high-frequency range of spectrum were obtained with the use of Wiener-Hopf method. These solutions are suitable for arbitrary values of incident angle, coordinates of point of concentrated force application and mechanical properties of joint materials. The influence of problem parameters and effects of diffraction edge interaction on the formation of radiation patterns and on the behaviour of SIF dependencies has been analysed. Peculiarities of behaviour of characteristics of scattered field and SIF under critical and sliding angles of incident and observation angles were studied in detail. The scheme of their application for the determination of crack sizes has been proposed. Formulae for the calculation of SIF in vicinity of the semi-infinite interface crack tip on the basis of diffracted far field displacement were derived. Approximate solution for the problem of SH-wave diffraction on the finite interface cracks was found. Peculiarities of behaviour of radiation pattern for two interface cracks were studied.