Fretting Fatigue Life Estimation of Al 7075-T6 Using Plain Fatigue Test

Fretting fatigue occurs in many engineering applications. Fretting fatigue life is estimated by experiment, which is tedious and requires special equipment and instrumentation. In this study, we attempt to introduce a method for estimation of fretting fatigue life from plain fatigue (normal fatigue without fretting) experiments. The method employs the critical distance theory for estimation of fretting fatigue life of Al7075-T6 under rotary bending loading. The approach uses the Fatemi-Socie parameter (FSP) as a multiaxial criterion to account for the stress multiaxiality on focus path. A comparison between the predictions of the new approach with the experimental results shows that the approach is quite accurate for low stress or high cycle fatigue regimes but for high stresses it is slightly conservative. This method considers only elastic behavior for materials and two characteristic diagrams that are obtained simply by testing two simple notched specimens under plain fatigue conditions. The method is therefore an applicable approach that can be used in the context of finite fretting fatigue life estimation with no need for fretting fatigue tests.