EVALUATION OF THE J-INTEGRAL FOR SURFACE CRACKS USING THE LINE-SPRINGMODEL

The line-spring model for the analysis of surface cracks is discussed in this paper. The complementary energy method [J. Press. Vess. Techno l. 108, 305 (1986)] is extended to derive the fully plastic solutions of a single edge cracked plate in combinations of tension and bending. A simple method is proposed to specify the undetermined factors in co mplementary energy by making use of Shih's [J. appl. Mech. 51, 48 (198 4)] finite element results. The obtained fully plastic solutions are i n a quasi-analytic form, and suitable for arbitrary combinations of te nsion and bending. Finally, the present line-spring model is incorpora ted into a plate-shell finite element code, and the semi-elliptical su rface cracked plates in tension are analyzed. The estimated stress int ensity factors and J-integral are in keeping with those of three-dimen sional finite element analysis.