Investigating the Effect of Displacement Rate on Deformation and Failure Mechanism in Bonded Elastomers

摘要

Bonded sandwich laminates are being used widely in various industries. They have been successfully used in aircraft and space structures, pipes, chemical tanks, ship hulls, and in other structural applications in which a high strength-to-weight ratio is a desirable feature. Joining structural components with adhesives provides a number of advantages. Bonding does not require rivet holes, which are stress raisers and may cause premature failure either under static or fatigue loading. In fact, it has been shown that the fatigue strength of a stiffened panel in an aircraft structure is considerably improved when the stiffeners are bonded to the panel. The bonding of damping materials to metal sheets, to form a sandwich structure, currently is being considered as an effective way to control noise-induced fatigue (sonic fatigue) of airframes. In solid rocket motor design, the bonding of insulation materials to motor casings is used to protect the casing from high temperature after the motor is fired. In this study, the effects of displacement rate on strain distributions and the failure behavior in a bonded bi-material specimen under three displacement rates, 0.0254 cm/min, 0.254 cm/min, and 2.54 cm/min, were determined using the computer aided speckle interferometry (CASI) technique. Two different viscoelastic materials were used to make sandwiched specimens. The experimental data were analyzed and the effect of applied displacement rate on strain distributions and interfacial failure mechanisms, consisting of interfacial crack initiation and propagation, in the bonded specimen are discussed.