DAMAGE EVOLUTION AHEAD OF SHARP NOTCHES UNDER CYCLIC LOADING

The evolution of cyclic damage ahead of sharp notches has been investi gated experimentally. The results are analyzed in terms of a loading p arameter Delta B-vm which is derived from averaging the calculated loc al stress and strain distribution at the notch root over some microstr ucture related size scale. This loading parameter is suggested to brid ge the gap between the stress controlled crack initiation and the stre ss intensity controlled macrocrack growth. This approach proved to be well suited in describing the striking phenomena of the fatigue behavi our of notched bodies, especially the damage evolution ahead of sharp notches till crack initiation and the growth of (mechanically) short f atigue cracks.