Elastodynamic response of a cracked orthotropic medium under impact loading

In this paper the problem of elastodynamic response of an infinite orthotropic medium containing a central crack under normal impact loading is considered. Laplace and Fourier integral transforms are employed to reduce the dimensional wave propagation problem to the solution of a pair of dual integral equations in the Laplace transform plane. These integral equations are then reduced to integro-differential equations which have been solved in the low frequency domain by method of iteration. To determine time dependence, these equations are inverted to yield the dynamic stress intensity factor (SIF) for normal point force loading. Numerical results of normalized SIF for large normalized time variable and for different concentrated point force loading at arbitrary location of the crack surface have been calculated for graphite-epoxy composite material. In the present paper the method of [A. Papoulis, The method of inversion of Laplace transform, Quart. Appl. Math. 14 (1957) 405-414] is used for the inversion of the Laplace transform. Finally the results obtained are displayed graphically. (c) 2006 Elsevier B.V. All rights reserved.