Finite thickness cracked layer bonded to viscoelastic substrate subjected to antiplane shear

An antiplane problem of a finite thickness cracked layer bonded to a viscoe lastic substrate is considered. Complex potential function is derived via t he application of the Laplace transform and a special technique of analytic al continuation associated with the image method. A dislocation function is introduced to solve the boundary condition along the crack border by means of singular integral equations. Some typical viscoelastic models and its c orresponding stress intensity factors are also discussed.. The results show that, subjected to constant load, the time-dependent stress intensity fact or may increase or decrease with time evolution. This is affected by the or ientation of crack as well as the relative strength of the layer and substr ate. (C) 1998 Elsevier Science Ltd. All rights reserved.