Transient growth of a planar crack in three dimensions: mixed mode

Transient growth in 3D of a semi-infinite, plane brittle crack in an isotropic, elastic solid is considered. Growth is mixed-mode, caused by in-plane and normal point forces on each face of an existing semi-infinite crack. An analytic solution is obtained for the case of dynamic similarity, i.e., crack edge speed is subcritical and may vary continuously with direction, but is time-invariant. The dynamic energy release rate criterion, with kinetic energy included, is imposed. A nonlinear differential equation for crack edge speed results, and allows the description of crack contour, i.e., the curve formed by the crack edge in the crack plane. Study indicates that forces of a type that increase rapidly from zero can create a fracture initiation phase in which crack growth rate indeed does not vary with time.

Keywords

3D, transient mixed mode, criteria, crack contour, kinetic energy, initiation

Milestones

Received: 15 August 2016

Accepted: 7 November 2016

Published: 9 February 2017

Authors

Louis Milton Brock
Department of Mechanical Engineering College of Engineering University of Kentucky 204 EEX Lexington, KY 40506-0038 United States

Vol. 12, No. 3, 2017

Louis Milton Brock

Abstract

Keywords

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Authors