FATIGUE FAILURE MAPS OF HETEROGENEOUS MATERIALS

In this paper, so-called fatigue failure maps are studied as a functio n of initial flaw size distributions. The main cause of fatigue failur e for brittle materials, and of fatigue initiation for ductile materia ls, is that initial flaws become critical. Fatigue failure maps where the number of cycles to initiation for a given failure probability is plotted for various flaw size distributions are a means of characteriz ing the influence of the initial flaw distribution on fatigue crack in itiation. The results are applied to fatigue failure of austempered sp heroidal graphite cast iron.