Torsional shear strength of steel joined with high performance aerospace adhesives at cryogenic and elevated temperatures.

Pure torsional shear tests of joints glued with two different aerospace grade adhesives were performed using a specifically designed and constructed torsional shear test equipment. The developed test equipment allows for measuring of pure torsional shear strength under cryogenic and at elevated temperature conditions. The adhesives Hysol EA 9321 and 3M Scotch-Weld EC-9323-2 B/A were used to join steel torsional shear test specimens. Torsional shear tests were performed from -180°C to 150°C. In addition torsional shear fatigue tests were also performed at various loads and the effect of cryogenic aging (cyclic cooling and warming) on the torsional strength of the joints was investigated. The results showed that both sets of adhesive joints achieved three times higher torsional shear strength at -180°C compared to room temperature.