GRIFFITH'S THEORY OF BRITTLE FRACTURE IN THREE-DIMENSIONS.

Abstract

The Griffith theory of brittle fracture is extended to the three-dimensional problem of a flat elliptical crack in an otherwise uniform field of tensile and shear stresses. A method for finding the correct expressions of the change in strain energy due to the elliptical crack is developed. This is done by expressing the stresses and displacements in terms of the radius Ro of a large sphere around the crack and by imposing the condition of equilibrium that the stresses or displacements across the spherical surface should agree with the prescribed boundary conditions as R sub o approaches the limit of infinity. The strain energy due to the presence of the elliptical crack is found to be independent of the tension applied parallel to the crack plane at infinity. On the basis of the thermodynamic argument of Griffith, it is also observed that the critical tensile and shear stresses increase rapidly as the ratio of major to minor semi-axes of the ellipse approaches unity. (Author)

Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1967
Accession Number
AD0659306

Entities

People

  • George C. Sih
  • M. K. Kassir

Organizations

  • Lehigh University

Tags

Communities of Interest

  • Air Platforms

DTIC Thesaurus Topics

  • Boundaries
  • Displacement
  • Physical Properties
  • Shear Stresses
  • Stresses
  • Three Dimensional

Readers

  • Materials Science (Mechanical Engineering).
  • Mechanical Engineering/Mechanics of Materials.
  • Plasma Physics / Magnetohydrodynamics