Abstract

The Common Format Equation constraint factor, ?*, introduced by Donoso and Landes, is analyzed in terms of its dependence on crack length and thickness, in disk-shaped compact specimens, DC(T). Numerical analysis of the load-displacement behavior of blunt-notched DC(T) specimens, and experimental evaluation of pre-cracked DC(T) specimens of various thickness, allows one to obtain the values of ?* in terms of the thickness-to-ligament ratio, B/b, as a measure of the degree of size-induced constraint in this geometry.