Abstract: Through fatigue experiments, the growth law of short cracks both on the surface of smooth steel 45 specimens and on the edge of holed steel 16Mn specimens was obtained. The relation of short crack growth rate with stress level and crack size was established. From the test data of the holed specimen of steel 16Mn, the distrbution of the short crack size is found to be logarithm normal. The evolution of the probabilistic density function of short crack sizes is studied, and the results show that it is consistent with the crack size evolution in durability design.

Key words: crack around hole, crack size distribution, durability design