A bridged crack perpendicular to a bimaterial interface

Abstract

We consider the contribution of fully or partially crack bridging to a mode I or mode II crack perpendicular to a bimaterial interface. The crack faces are subjected to both shear and normal bridging forces, and the bridging stiffnesses are allowed to vary arbitrarily along the crack. The resulting singular integral equations are solved numerically by combining the Chebyshev polynomials and the collocation method. The proposed method is proved reliable and efficient for the bridged crack problem under consideration. It is observed that the stress intensity factors at the two crack tips and the crack opening displacement are suppressed due to the toughening and stiffening effects of crack bridging, respectively. In particular, when the crack is embedded in the right stiffer (or softer) half-plane and is only partially bridged at its left (or right) portion, new phenomena can be observed. More specifically, with suitably chosen bridging zone and bridging stiffness, the behavior of the stress intensity factors and the crack opening displacement for a bridged crack can be quite different from those for an unbridged crack, and the crack can even propagate toward the opposite direction to that for an unbridged crack.