Influences of Hydrostatic Pressure and Stress Distribution on Rupture of Marble Cylinder in Torsion

抄録

This paper presents both the experiments and the explanations on the influences of hydrostatic pressure and the stress distribution upon the rupture of a marble cylinder in torsion. In the experiments coated and naked hollow and solid cylinders were twisted under hydrostatic pressure, and the following informations were obtained. (1) The yield point of a coated cylinder is remarkably influenced by hydrostatic pressure, and the stress at the yield point rises proportionally to hydrostatic pressure. A crack reaches near the center of the cylinder firstly at the yield point, and such a crack comes out successively as the shearing strain increases after the yield point. (2) The effects of hydrostatic pressure and the stress distribution upon the rupture of the coated cylinder are respectively accounted for by Nakanishi's theory on the rupture of brittle materials. (3) In a naked cylinder, pressure oil penetrates into the material, so the influence of hydrostatic pressure can not be recognized so much as in the coated cylinder.