Investigation on the uniaxial ratchetting and fatigue failure behaviors of silicone seal adhesive bonded butt-joints under tensile and torsional cyclic loading

Abstract In order to investigate the uniaxial ratchetting behaviors and fatigue failure of silicone seal adhesive bonded hollow cylinder butt-joints under uniaxial tensile and torsional cyclic loading, the effects of stress amplitude, mean stress, cycle time and loading history on the ratchetting strain, ratchetting strain rate and fatigue life were discussed respectively. The experimental results show that ratchetting strain appeared in both tensile and torsional cyclic loading. The ratchetting strain of tensile cycle evolved in three stages, while that of torsion cycle evolved in two stages. Furthermore, the effect of uniaxial tensile cycle on ratchetting strain is greater than that of uniaxial torsion cycle, and the fatigue life of torsion cycle is higher than that of tensile cycle. The stress amplitude, mean stress and cycle time have influence on the ratchetting strain, ratchetting strain rate and fatigue life of the adhesively bonded butt-joints. The ratchetting strain and ratchetting strain rate increase, and the fatigue life decreases with the increase of stress amplitude and mean stress, or the decrease of cycle time. In addition, it is also found that silicone seal adhesive bonded butt-joint has a strong memory of loading history for the stress amplitude. Prior stress cycle with higher stress amplitude restrains the ratchetting strain in subsequent cycle with lower stress amplitude.