Scattering of acoustic beams by cracked composites

The scattering of elastic waves by a subsurface crack in a fiber-reinforced composite half-space immersed in a liquid is analytically studied in this paper. The composite half-space is subjected to a bounded acoustic beam, propagating at an arbitrary angle of inclination. To solve this problem, two new Green's functions are developed for unit loads acting in horizontal and vertical directions in a flawless submerged orthotropic half-space. The governing equations along with boundary, regularity, and interface conditions are reduced to a coupled set of singular integral equations in terms of the unknown crack opening displacement (COD) by using representation theorem along with Green's function. The solution of these equations is obtained by expanding the unknown COD in terms of Che-bychev polynomials. The problem is first solved in the frequency domain. Time histories are then obtained by using fast Fourier transform (FFT) routines.