On dynamic stress analysis for cracks in elastic materials with voids

The present paper is concerned with the development of a semi-analytical approach to the dynamic problem of the concentration of stresses near the edges of a crack located in a porous elastic space (two-dimensional problem) and subjected to a normal oscillating load applied to the crack faces. Our analysis is made in the context of the Goodman– Cowin–Nunziato (G–C–N) theory for porous media. In previous work we studied static crack problems for such materials; now we introduce an analysis of the relevant dynamic aspects. By using the Fourier transform, the problem is reduced in explicit form to a hyper-singular integral equation with a convolution kernel valid over the crack length. Then, we apply a collocation technique developed in our previous work to solve this equation, and study the stress intensity factor. The principal goal is to compare the stress intensity factor for the static and dynamic cases. We also compare our results with the case of an ordinary linear elastic medium.