Experimental Investigation and Numerical Prediction of Fatigue Life in Force Fitted Fastener Holes

In this paper, the effect of interference fit on fatigue life of holed plate of mechanical joints was investigated experimentally. Fatigue tests were carried out on the holed specimens of Al-alloy 7075-T6 alloy. The interference fit process consists of force fitting a fastener into the hole with a negative clearance (diameter of the fastener is larger than of the hole) that produces beneficial tangential pre-stress at the edge of the hole. Stress and strain analysis was implemented in order to estimate the fatigue life due to interference fit process. 3D finite element simulations have been performed to obtain stress and strain histories and distributions around the hole due to interference fit and subsequent cyclic longitudinal loading using ANSYS package. The results obtained from the finite element analysis of the interference fit were employed to predict the fatigue life. The fatigue life was divided into two phases of crack initiation life and fatigue crack growth life. Fatigue initiation life was estimated using Fatemi–Socie multiaxial fatigue criterion, and the fatigue crack growth life was predicted using AFGROW computer code. The results show that there is a good agreement between the numerically predicted total fatigue life and experimental fatigue test results