An In-Situ Failure Model for Adhesive Joints

Abstract In this paper, a theoretical model based on the fracture mechanics principle is built to describe the in-situ failure process of adhesive joints. The central concept of the model is that the adhesive fracture is controlled by the plastic zone developed at the crack tip. On the basis of an approximate crack tip stress distribution, a quantitative representation is found to relate the adhesive fracture energy G1c(joint) to certain bulk resin properties: fracture toughness G1c(bulk), yield stress σy, and Young's modulus E. It is found that the factor σ y 2/E is sometimes more important than G1c(bulk) in controlling G1c(joint). The in-situ failure model interprets well the temperature and loading rate dependent phenomena of adhesive joint fracture reported in the literature. A correlation between the resin material variables and the adhesive fracture is thus established.