ENVIRONMENTAL ATTACK ON ADHESIVE JOINTS (PART-I - TEST EQUIPMENT)

Epoxy resins are widely employed as adhesives and are being increasing ly used in engineering industries. The prediction of the strength of a dhesively bonded components is vitally important and different approac hes and methods are being used to investigate the fracture behaviour a nd predict the durability of adhesive joints when they are exposed to hostile environments. Typical accelerated ageing tests used in industr ial laboratories employ adhesive joints immersed in water and subjecte d to static tensile stresses, where the fracture stress and the time t o failure are measured in order to generate basic design data. However , in this type of work, fracture mechanics is a more useful technique. The present work is therefore concerned with the design and developme nt of new accelerated ageing test equipment employing double-torsion a dhesive joints exposed to moisture and static stresses. This allowed t he determination of the fracture energy versus crack velocity and incu bation time relations.