Abstract
The impact tensile strength of structural epoxy adhesive butt joints is determined with the split Hopkinson pressure bar (SHPB) using a hat-shaped joint specimen. A two-component structural epoxy adhesive (3M Scotch weld: DP-460) and two adherends (or 7075-T6 Al alloy and 99% pure titanium) are used in the adhesion tests. The impact tensile strengths of similar (Al-to-Al and Ti-to-Ti) adhesive butt joints are evaluated from the applied maximum tensile loads. The corresponding static tensile strengths are determined on an Instron testing machine. An axisymmetric finite element analysis is performed to investigate the stress distributions in the adhesive layer of the joint specimens. The effects of adherend and adhesive layer thickness on the tensile strength of the adhesive butt joints are examined. It is shown that the joint tensile strength increases greatly with increasing loading rate, decreases with increasing adhesive layer thickness, and varies, depending on the adherend materials. Microscopic examinations are conducted to identify the dominant failure modes occurring on the joint specimen surfaces.
