DIFFRACTION OF ELASTIC-WAVES BY 3 COPLANAR GRIFFITH CRACKS IN AN ORTHOTROPIC MEDIUM

The dynamic response of three co-planar Griffith cracks situated in an infinite orthotropic medium due to elastic waves incident normally on the cracks has been treated. The Fourier transform technique has been used to reduce the elastodynamic problem to the solution of a set of four integral equations. These integral equations have been solved by using the finite Hilbert transform technique and Cook's result. The an alytical forms of crack opening displacement and stress intensity fact ors have been derived for low frequency vibration. Numerical results o f crack opening displacement and stress intensity factors for several orthotropic materials have been calculated and plotted graphically to display the influence of the material orthotropy.