Author(s)

A. Plumtree. N. Untermann & J. Petermann

Abstract

A model is presented that predicts the fatigue limit of a metal by determining the threshold stress and critical length of short cracks. Once this length is exceeded, fatigue cracks continue to grow, causing eventual failure. The threshold stress range for short fatigue crack is related to the strain intensity factor range by considering surface strain distribution and crack closure. The surface strains decrease whereas closure increases with crack length. The resulting threshold stress for short crack growth increases to a maximum that corresponds to the endurance limit stress. This occurs at the critical crack length corresponding to a depth of about four grain diameters. In

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