A phenomenological fatigue damage accumulation rule based on hardness increasing, for the 2024-T42 aluminum

In this paper the problem of cummulative fatigue damage is considered. A non-linear fatigue damage accumulation rule, suitable for stepwise constant amplitude fatigue loading, is presented for the aerospace material Al-2024-T42. The proposed rule takes into account the previous damage history as well as the loading order effect. This damage function is specified with respect to damage parameters derived by the hardness increase during fatigue of the material Al-2024-T42. Theoretical results are correlated with experimental data for specimens subjected to two stage fatigue loading.