Transient wave propagation in a circular annulus subjected to transient excitation on its outer surface

Abstract

The objective of this work is to investigate the propagation of guided transient waves in the circumferential direction of annular structural components. For this purpose, a two-dimensional circular annulus is considered. It is assumed that the inner surface of the annulus is traction free and the outer surface of the annulus is subjected to a time-dependent transient excitation. The guided circumferential waves induced by this transient excitation are studied in detail to understand the propagation characteristics of various wave modes. The method of eigenfunction expansion is used to solve the transient wave propagation problem. To this end, the problem of time harmonic, steady-state circumferential waves is solved first as the eigenfunctions. The time-dependent response of the annulus is then obtained by superimposing all eigenfunctions over all possible frequencies. Several numerical examples are given to illustrate the method of solution and to provide some guidelines on using guided waves to detect radial cracks in annular structural components.