Mixed Mode Loading of an Interface Crack Between Graded Creeping Solids

Abstract

Interface cracks are seldom subjected to pure Mode I conditions. Stationary cracks between two distinct, bonded elastic-creep materials subjected to remotely applied mixed mode loading are simulated using the finite element method (FEM). Plane strain conditions are assumed. In most cases a functionally graded transition layer is included between two homogeneous, yet distinctive, materials. Examples of such systems include bonded structures or repaired components subjected to elevated temperatures. Numerical solutions based on the asymptotic fields of the homogeneous and heterogeneous Arcan-type specimens are presented. Creep ductility-based damage models are used to predict the initial crack propagation trajectory. Incorporation of functionally graded transition layer regions was determined to affect the evolution of time-dependent stress components in the vicinity of the crack tip. The magnitude and direction of crack tip propagation can then be optimized with respect to interface properties.