Accession Number : AD0659306

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

Descriptive Note : Technical rept.,

Corporate Author : LEHIGH UNIV BETHLEHEM PA DEPT OF APPLIED MECHANICS

Personal Author(s) : Kassir,M. K. ; Sih,G. C.

Report Date : MAR 1967

Pagination or Media Count : 36

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)

Descriptors :   (*FRACTURE(MECHANICS), THEORY), BRITTLENESS, STRAIN(MECHANICS), ENERGY, CRACKS, ELASTIC PROPERTIES, STRESSES, BOUNDARY VALUE PROBLEMS

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE