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

An antiplane problem of a finite thickness cracked layer bonded to a viscoelastic substrate is considered. Complex potential function is derived via the application of the Laplace transform and a special technique of analytical 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 corresponding stress intensity factors are also discussed.. The results show that, subjected to constant load, the time-dependent stress intensity factor may increase or decrease with time evolution. This is affected by the orientation of crack as well as the relative strength of the layer and substrate. (C) 1998 Elsevier Science Ltd. All rights reserved.