Accession Number : AD0666127

Title :   STEADY MOVEMENT OF CRACKS AT STRAIGHT-LINE JOINT BETWEEN TWO ELASTIC MATERIALS,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Goldshtein,R. V.

Report Date : 21 JUL 1967

Pagination or Media Count : 24

Abstract : The stress distribution around the head of a crack in its steady motion along the interface of two different elastic materials bonded together is discussed by investigating the problem of motion of a 'semi-infinite' crack with a constant velocity along the rectilinear boundary of two different homogeneous isotropic, elastic half-spaces under conditions of plane deformation. It is assumed that equal concentrated forces of opposite directions are applied to the edges of the crack and are moving with the same velocity as the point of the crack so that the distance between the point and forces remains constant. The crack propagation rate is supposed to be lower than the velocity of sound (and of transverse stress waves) in the materials of both half-spaces. Fourier transformation of boundary and cohesion conditions with respect to the coordinate along the direction of crack propagation is used, and the solution is reduced (by applying the conventional technique of the Wiener-Hopf method) to that of the Riemann-Hilbert problem with piecewise-constant coefficients for a system of functions. The effects of the surface wave velocities in both half-spaces and of the crack-propagation rate on the stress intensity are analyzed in detail, and the interdependence between stresses, elastic constants of materials, and the propagation of the crack point is established. The vibratory character of stresses and displacements at the head of the crack is also discussed, as well as the finiteness of stresses, their sinusoidal distribution and singularity, the flow of energy, and the steady propagation of the crack. (Author)

Descriptors :   (*CRACK PROPAGATION, STRESSES), ELASTIC PROPERTIES, BRITTLENESS, DISTRIBUTION, CRACKS, RAYLEIGH WAVES, USSR

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE