A physically-based model for the prediction of long fatigue crack growth in Ti-6Al-4V

A physically-based model is presented for the prediction of fatigue crack g rowth in Ti-6Al-4V. The model assumes that the crack extension per cycle is directly proportional to the change in the crack-tip opening displacement, during cyclic loading between the maximum and minimum stress intensity fac tor. The extent of irreversibility is also assumed to exhibit a power law d ependence on the effective stress intensity factor range. A simple power la w equation is then derived for the prediction of fatigue crack growth as a function of the effective stress intensity factor range. The model is valid ated for fatigue crack growth in the near-threshold, Paris and high-AK regi mes. The fatigue crack growth mechanisms associated with the parametric com binations of stress intensity factor ranges and maximum stress intensity fa ctor are then summarized on fatigue mechanism maps. Mechanistically-based f atigue crack growth relationships are thus obtained for the prediction of f atigue crack growth in the near-threshold, Paris and high-AK regimes. (C) 2 001 Elsevier Science B.V. All rights reserved.