Investigation on fatigue performance of adhesively bonded butt-joints and multiaxial life estimation using stress-based failure models

Uniaxial and multiaxial low-cycle fatigue experiments were conducted on the automobile sealant adhesive bonding hollow cylindrical butt-joints under stress-controlled mode, and the effects of equivalent stress amplitude, equivalent mean stress and loading frequency on the fatigue life of specimens were analyzed. The experimental results showed that the fatigue life of uniaxial tensile cycle was shorter than that one of uniaxial torsion cycle. The fatigue life of the automobile sealant adhesive bonding butt-joints decreased with the increase of equivalent stress amplitude, mean stress, loading frequency. The fatigue life of the non-proportional loading path was shorter than that of the proportional loading path. In addition, a modified stress-based fatigue life prediction model was proposed that collectively considered the effect of loading path, equivalent stress amplitude, equivalent mean stress and loading frequency on the multiaxial fatigue life. The comparisons of the predicted results and the experiment life indicated that the modified fatigue life prediction model had good prediction ability for the multiaxial fatigue life of the sealant adhesive bonding butt-joints.