Thermal Crack Propagation

Abstract

This study is concerned with the application of Griffith fracture theory to crack propagation induced by thermal means. The stress-strain field around an insulated crack, situated perpendicular to a uniform flow of heat in an elastic medium, is extracted from an isothermal configuration in which the crack surfaces are subjected to linear shear stresses. Similarly, a stress-free plane of discontinuity in heated (or cooled) solid gives rise to a pressurized crack in an otherwise traction-free solid. Adopting Griffith’s energy balance approach to brittle fracture, approximate expressions are computed for the critical temperature and critical temperature gradient pertaining to a flat elliptical crack embedded in a three-dimensional solid which is conducting heat in a steady-state manner. The results indicate that these critical parameters increase rapidly as the ratio of the major to minor semiaxes of the ellipse approaches unity.