The Stress-Strain Behaviour of Axially-Loaded Butt Joints

Abstract

The effects of the stress distribution in the adhesive layer of axially loaded butt joints have been examined theoretically and experimentally. It has been shown that the measured stress–strain behaviour of a butt joint is dependent on the triaxial stress state induced in the adhesive by the restraint of the adherends. This causes a butt joint to yield at a stress which is greater than the uniaxial yield stress of the adhesive. Conversely, the presence of stress concentrations can cause a butt joint to fail at a lower tensile stress than the failure stress of a bulk specimen tested in uniaxial tension. Therefore, the relationship between the strength of a butt joint and that of a bulk specimen of the same adhesive depends on the ductility of the adhesive. Furthermore, if the adhesive obeys a pressure-dependent yield criterion, the compressive yield stress of a butt joint can be much greater than the tensile yield stress of a similar joint and, under some circumstances, compressive yielding of a butt joint may be suppressed completely.