Abstract
This investigation was made in order to compare the diagram of torsional endurance limit of solid specimen with that of thin-walled hollow specimen. And it was clarified that the stress amplitude at the endurance limit is scarcely affected by the mean stress in the solid specimen as well-known and it decreases fairly with the increasing of the mean stress in the hollow specimen. This dissimilarity of the diagram of endurance limit due to the form of specimen was explained from variation of the distribution of mean stress during the fatigue test in the solid specimen.
