Effect of T-stress on crack growth along an interface between ductile and elastic solids

For crack growth along an interface joining an elastic-plastic solid to an elastic substrate the effect of a non-singular stress component in the crack growth direction in the elastic-plastic solid is investigated. Conditions of small scale yielding are assumed, and due to the mismatch of elastic properties across the interface the corresponding oscillating stress singularity fields are applied as boundary conditions on the outer edge of the region analysed.

The fracture process is represented in terms of a cohesive zone model. It is shown that the interface fracture toughness is significantly increased by a negative T-stress in the elastic-plastic solid, while a positive T-stress in the elastic-plastic solid leads to a reduced fracture toughness.