A new semi-numerical method for calculation of the critical J-integral

The current research presents a semi-numerical (SN) method to obtain the critical J-integral (JC) of an Al 2024-T3 plate under plane-stress conditions. In the present method, estimation of the JC is performed by the finite element simulating a simple tensile test of a dumbbell specimen, using the true experimental stress-strain curve. To this end, a three-dimensional numerical analysis was conducted on the necking behavior of the Al 2024-T3 dumbbell specimen with a rectangular cross-section. To evaluate the results of the present method, an experimental program was conducted on double-edge notched specimens at room temperature. Also, experiments have been done to investigate the effect of notch radius on symmetrical edge U-notched specimens with and without fatigue pre-cracking at a quasi-static loading rate. The results of the present method were also compared with those of the essential work of fracture (EWF) method. The JC obtained from the present method is consistent with the laboratory data and serves as a viable alternative method for determining this fracture parameter.