Tubular Adhesive Joints Under Axial Load

Abstract

In this paper a general study on tubular adhesive joint under axial load is presented. We focus our attention on both static and dynamic behavior of the joint, including shear and normal stresses and strains in the adhesive layer, joint optimization, failure load for brittle crack propagation, and crack detection based on free vibrations. First, we have considered the shear and normal stresses and strains in the adhesive layer to propose an optimization to uniform axial strength (UAS) and to reduce the stress peaks in the bond. The stress analysis confirms that the maximum shear stresses are attained at the ends of the adhesive and that the peak of maximum shear stress is reached at the end of the stiffer tube and does not tend to zero as the adhesive length approaches infinity. A fracture energy criterion to predict brittle crack propagation for conventional and optimized joint is presented. The stability of brittle crack propagation and the strength of the joint, as well as the ductile-brittle failure transition, are analyzed. A detection method to predict crack severity, based on joint dynamic behavior, is also proposed. The crack detection is achieved through the determination of the axial natural frequencies of the joint as a function of the crack length, by determining the roots of a determinantal equation.