Fretting fatigue crack initiation behaviour of Ti-6Al-4V and IN-100 alloys at elevated temperatures

Abstract

Fretting fatigue is a critical concern in high temperature applications. This study presents a numerical investigation of fretting fatigue crack initiation behaviour of Ti-6Al-4 V and IN-100 alloys at elevated temperatures. Three multiaxial fatigue damage parameters are considered, namely the stress-based Findley Parameter (FP), the strain-based Fatemi–Socie (FS) parameter, and the strain energy-based Smith–Watson–Topper (SWT) parameter. A new zone-based method is proposed to estimate crack initiation parameters, based on subsurface stress averaging across discretized angular zones beneath the contact surface. The numerical predictions are validated against experimental data from the literature. FS and SWT parameters demonstrate improved predictive capability under elevated temperatures due to their ability to capture the effect of thermal strains. In contrast, FP, being purely stress-based, does not account for the strains and thus exhibits reduced accuracy at high temperatures. The zone-based method shows improved accuracy for crack orientation.