Fracture Mechanics Approach to Adhesive Joints

Abstract

This study investigates the problem of applying fracture mechanics to the opening mode fracture of a two-material (aluminum-epoxy-aluminum) system. The results of a finite element analysis of a two-material, single- edge-notch (SEN) plate are used with a compliance method in order to obtain strain energy rates, g, and with a displacement method to obtain stress intensity factors, K. Approximate relationships between the homo geneous system and the adhesive system for both K and g are determined. The relationship between K and g for the adhesive system is obtained. The experimental investigation provides an experimental compliance calibration for the same adhesive system and loading. Good reproducibility of the fracture toughness values obtained for the two-material system with SEN and tapered DCB specimens indicates the geometry independence of the fracture toughness. The effect of the notch root radius and proper specimen preparation are also considered.