Approximate Techniques for Prediction of Size Effects on Cleavage Fracture Toughness," ASTM STP1207

This investigation examines the ability of an elastic T-stress analysis coupled with a modified boundary layer (MBL) solution to predict stresses ahead of a crack tip in a variety of planar geometries. The approxi-mate stresses are used as input to estimate the effective driving force for cleavage fracture (Jo) using the micromechanically based approached introduced by Dodds and Anderson. Finite element analyses for a wide variety of planar cracked geometries are conducted which have elastic biaxiality parameters (f3) ranging from-0.99 (very low constraint) to +2.96 (very high constraint). The magnitude and sign offJ indi-cate the rate at which crack-tip constraint changes with increasing applied load. All results pertain to a moderately strain hardening hardening material (strain hardening exponent(n) of 10). These analyse