Dynamic stress intensity factors of a semi-infinite crack in an orthotropic functionally graded material

The plane strain problems of semi-infinite cracks in an infinite functionally graded orthotropic material are studied. Two uniform impact loading modes are considered, i.e. opening and in-plane shear. Laplace and Fourier transforms along with the Winner-Hopf technique are employed to solve the displacement formulation of the equations of motion. Closed-form solutions of the dynamic stress intensity factors are obtained. It is observed that the stress intensity factors are not all proportional to the square root of time as expected. The results can be reduced to the known solutions derived independently for orthotropic or isotropic materials. (C) 2007 Elsevier Ltd. All rights reserved.