Effect of mean stress on the stress-controlled fatigue of a short E-glass fiber reinforced polyamide-6,6

The effect of mean stress on the fatigue strength of short E-glass fiber reinforced polyamide-6,6 composite has been investigated in this paper. Stress controlled fatigue tests were conducted in the tension–tension cycling mode and the mean stress was varied by varying the ratio of the minimum stress to the maximum stress. Creep was observed during the fatigue process. A modified Gerber equation seems to describe the effect of mean stress on the fatigue strength of this composite. In this modified Gerber equation, creep rupture strength was used along the mean stress axis instead of tensile strength.