The Fatigue Strength of Members Containing Cracks

Abstract

The significant loss of fatigue life owing to the presence of a crack, crack-like defect, or sharp notch is predicted herein from theoretical considerations. Fatigue notch factors are given as functions of the crack depth, section width, and type of loading. These values are applicable where defects of a particular depth are known to exist or where defects of a limited depth could exist without being detected. Although these values apply specifically to 100,000 psi tensile strength steels, they are conservatively high for lower strength steels, aluminum, and other materials which are less sensitive to notches. The results of this paper indicate that cracks in finite-width members may produce a greater loss of fatigue life than previous theoretical work for members of infinite width had indicated.