FINITE-ELEMENT NUMERICAL EVALUATION OF J-INTEGRAL FOR CRACKED DUCTILECYLINDERS

The numerical computational procedures of two independent J-integral d efinitions are described, one being the contour J-integral of Rice [J. appl. Mech. 35, 379-386 (1968)] and the other the J-integral by energ y release rate [C. Chen et al., Engineering Fracture Mechanics, Part 1 . National Defense Industry Publishing House, Beijing (1978)]. The val idity of the two procedures is confirmed in the linear elastic materia l range by comparing K(I)-values. Then, they are successfully applied in cracked ductile cylinders by using a post-processing program to the ADINA system. Numerical results show that the J-integral for a cracke d ductile cylinder still follows the path independence, even though th e material exhibits a large yield plateau in its true stress-strain cu rve, and that the two independent J-integral definitions are equivalen t to each other. These conclusions, at least from the viewpoint of num erical analysis, provide a solid foundation for the applicability of t he J-concept to the safe assessment of the ductile cylinder.