A closed-form solution is presented for the stress distribution in two perfectly bonded
isotropic elastic half-planes, one of which includes a fully imbedded semi-infinite
crack perpendicular to the interface. The solution is obtained in quadratures by
means of the Wiener–Hopf–Jones method. It is based on the residue expansion of
the contour integrals using the roots of the Zak–Williams characteristic
equation. The closed-form solution offers a way to derive the Green’s function
expressions for the stresses and the SIF (stress intensity factor) in a form
convenient for computation. A quantitative characterization of the SIF for various
combinations of elastic properties is presented in the form of function the
,
where
and
represent the Dundurs parameters. Together with tabulated
the
Green’s function provides a practical tool for the solution of crack-interface interaction
problems with arbitrarily distributed Mode I loading. Furthermore, in order to
characterize the stability of a crack approaching the interface, a new
interface parameter
,
is introduced, which is a simple combination of the shear moduli
and Poisson’s
ratios
of materials on both sides of the interface. It is shown that
uniquely determines the asymptotic behavior of the SIF and, consequently, the crack
stability. An estimation of the interface parameter prior to detailed computations is
proposed for a qualitative evaluation of the crack-interface interaction. The
propagation of a stable crack towards the interface with a vanishing SIF is
considered separately. Because in this case the fracture toughness approach to the
material failure is unsuitable an analysis of the complete stress distribution is
required.
Keywords
stress intensity factor, crack stability, bimaterial plane,
analytic function