The Lap Joint Performance of a Structural Bonding Tape

A test program has been carried out on a pressure-sensitive tape using single lap joints. The adherend materials used were hardened steel, which is expected to remain elastic throughout the test, and mild steel, which may undergo yield. Six different overlap lengths, between 12.5 and 100 mm, were tested. Measurements were also made of the mechanical properties of the structural bonding tape. The stress-strain curve of the material showed a viscoelastic behavior at ambient temperature experiencing high strain to failure. For the joints with hardened steel adherend, a linear relationship was observed between the increasing load and overlap lengths and the tape tolerated well the strain concentrations at the ends of the overlap. The shear performance of the single lap joint was found to be in agreement with the butt joint test result. For the joints with mild steel adherend, the tape performance was controlled by the plastic deformation of the adherend leading to a poor joint strength.