Abstract: The traditional linear damage model cannot accurately describe the relationship between damage and load in the fatigue study of the aero-engine blade, thus causing unsatisfactory calculation result. The common non-linear damage model is easy to bring in error in the calculation due to neglecting the influence of torsional vibration. Therefore, based on the continuum damage theory, the non-linear damage model proposed by CHABOCHE is modified according to the blade material S-N curve obtained from the TC4(Ti-6Al-4V)fatigue testing, and the non-linear continuum damage model is proposed and its correctness is verified. In comparison with the experimental data and the linear damage model results, the non-linear continuum damage model shows better accuracy in reflecting the damage accumulation process. Finally, the non-linear continuum damage model is used to predict the fatigue life of a certain aero engine blade.

Key words: Fatigue life, Fatigue testing, Model modifying, Non-linear continuum damage