A procedure for the experimental assessment of the J-integral by means of specimens of different geometries

Abstract It is necessary to determine the elastic-plastic fracture mechanics parameter J on specimens of different loading mode and size in order to further clarify the dependence of the J- integral on these parameters. Using the fundamental equations of linear-elastic fracture mechanics and fully plastic material behaviour, the factors η el and η pl for the experimental evaluation of the J- integral for different specimen geometries are determined. The basic equations used are summarised, the relations obtained for η el and η pl are plotted. The application of these relations in the testing of large scale specimens of different specimen type and size shows the variation of the J- integral over the stable crack growth.