Accession Number : AD0696983

Title :   DYNAMIC ASPECTS OF CRACK PROPAGATION.

Descriptive Note : Technical rept.,

Corporate Author : LEHIGH UNIV BETHLEHEM PA DEPT OF MECHANICAL ENGINEERING AND MECHANICS

Personal Author(s) : Sih,George C.

Report Date : SEP 1969

Pagination or Media Count : 43

Abstract : The rate at which elastic and kinetic energies are released by a uniformly moving crack can be calculated from a line integral derived from energy-balance consideration. With the aid of the equations of motion, the divergence of the integrand is shown to vanish for certain closed path and thus indicating that the path of integration can be deformed arbitrarily without affecting the value of this integral which applies to linear or nonlinear materials. In view of this path independent property, the rate of energy release per unit crack extension can be evaluated simply from a knowledge of the local dynamic stress and displacement fields. As in the static theory of fracture, the detailed structure of the dynamic crack tip stresses and displacements are expressed independently of the crack geometry and loading conditions. This permits a general definition of the dynamic energy rates as related to the stress-intensity factors for elastic materials. (Author)

Descriptors :   (*CRACK PROPAGATION, ANALYSIS), CRACKS, INTEGRAL EQUATIONS, ELONGATION, STRESSES, STRAIN(MECHANICS), ELASTIC PROPERTIES, KINETIC ENERGY, FRACTURE(MECHANICS), CONTINUUM MECHANICS, EQUATIONS OF MOTION, LINEAR SYSTEMS, NONLINEAR SYSTEMS

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE