Crack Size and Grain Size Dependence of the Brittle Fracture Stress

摘要

The tensile brittle fracture, sigma sub c, dependence on crack size, c, is well approximated over a range of crack sizes by the relationship sigma sub c is approximately equal to sigma sub(o sub c) + (k sub c)(c to the minus 1/2 power where sigma sub (o sub c) and k sub c are experimental constants. The positive value of sigma sub (o sub c) differentiates this relationship from the Irwin-Orowan expression. Some theoretical basis for sigma sub (o sub c) stems from the Bilby-Cottrell-Swinden expression for continuum cracking and from the Hall-Petch stress-grain size analysis for the fracture of polycrystals. (Author)