Fatigue Strength on Reduced Stress Concentration Holes

Abstract

In case of considering fatigue strength of ship structure S-N curves are fundamental factor. And stress concentration is also a important factor related to them. We here assume plates with a hole under tensile loading and examine stress concentration. We first introduce a optimized hole with the minimum stress concentration ration according to Mano's theory. Next we approximate the hole by straight lines and ellipsis. Plates with the approximated hole has enough low stress concentration ratio. The effect of this hole is also evalueted through bending problems. Its characteristics are shown through tensile and bending fatigue tests as compared with conventional holes.