On experimental J estimation equations based on CMOD for SE(B) specimens

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.