Expectancy of the lifetime of bonded steel joints due to long-term shear loading

In this paper, the time-dependent behaviour, shear creep behaviour, of double lap galvanized steel joints loaded in shear by tension, is investigated at room temperature. The studied joints are assembled by bonding the galvanized steel adherends by a rigid structural adhesive (epoxy). Two thicknesses of the bondline (0.35 mm and 0.65 mm) are used. The specimens are tested under different shear stress levels. Well-known rheological and empirical models are used to describe the behaviour of the adhesive. The relevant models parameters are experimentally estimated. The time-to-failure of the studied specimens is predicted in accordance with short-term tests (rapid-loading tests) performed on similar specimens. The applied shear stresses for particular lifetimes of the bonded joints are estimated.