This note addresses the accuracy of the J-estimation equation for shallow-c
racked single edge cracked bars, SE(B), as originally proposed by Kirk and
Dodds (1993), based on 2D finite element analysis. Our study placed particu
lar emphasis on the sensitivity of the Kirk-Dodds equation to the nature of
the material, including continuously-hardening materials and those exhibit
ing Luders strain. It was found that the Kirk-Dodds equation provides accep
table results except for specimen bars with very deep cracks such as those
with a/W = 0.7 or greater. Accordingly, based on slip line field analysis,
a modification of the original equation is suggested, which when used provi
des consistent results for all crack lengths.