PREDICTION OF FATIGUE CRACK-GROWTH UNDER SINGLE OVERLOAD APPLICATION IN TI-6AL-4V

This paper is concerned with the use of a Markovian stochastic crack growth model to predict crack growth behaviour in zones affected by a single overload application. The model introduces an effective stress intensity factor in the definition of the transition intensity of the stochastic process. This in turn, generates a unified probability growth law that was used to predict scatter in single overload history. An experimental program was carried out on compact tension specimens of Ti-6A1-4V material to generate sample crack growth curves, each of which contains three single overload zones. The sample curves were then manipulated into experimental constant probability growth curves. These curves were compared with those theoretically generated using the proposed model. A good agreement was established between these two data sets.