Finite Lifetime Estimation of Mechanical Assemblies Subjected to Fretting Fatigue Loading

This paper proposes a new design method for predicting the finite lifetime of mechanical assemblies subjected to constant amplitude (CA) fretting fatigue loading. The proposed methodology is based on the use of the Modified Wӧhler Curve Method (MWCM) applied in conjunction with the Theory of Critical Distance (TCD) and the Shear Stress-Maximum Variance Method (τ-MVM). In more detail, this engineering approach uses the τ-MVM to calculate the stress quantities relative to the critical plane, whose orientation is determined numerically by locating the plane containing the direction experiencing the maximum variance of the resolved shear stress. To estimate the fretting fatigue lifetime, the time-variable linear elastic stress quantities are post processed according to the MWCM applied in conjunction with the TCD. The proposed approach was checked against experimental data taken from the literature and generated by testing specimens made of aluminium alloy Al 7075-T6. The extensive validation supports the idea that the MWCM applied in conjunction with both the TCD and τ-MVM can be suitable to predict the finite lifetime of mechanical assemblies subjected to fretting fatigue loading.