  The paper deals with classical problem for cracks dislocated in a certain
very specific porous elastic material, described by a Cowin-Nunziato model. We
propose a method based upon a reducing of stress concentration problem for
cracks to some integral equations. By applying Fourier integral transforms the
problem is reduced to some integral equations. For the plane-strain problem we
operate with a direct numerical treatment of a hypersingular integral equation.
In the axially symmetric case, for the penny-shaped crack, the problem is
reduced to a regular Fredholm integral equation of the second kind. In the both
cases we study stress-concentration factor, and investigate its behavior versus
porosity of the material. More in particular the stress concentration factor in
the medium with voids is always higher, under the same conditions, than in the
classical elastic medium made of material of the skeleton. Further, as can be
seen, the influence of the porosity becomes more significant for larger cracks;
that is also quite natural from a physical point of view.
