-Integral Values of Steels Tested Under Constant Load
SourceA stable to unstable transition phenomenon of cracking under constant load was studied. The transition phenomenon was mainly caused by initiation and growth of the ductile crack. When this fracture process was examined by means of J-integral resistance (J-R) curves, the ductile crack growth under constant load seemed to agree with the J-R curve that had been determined by the conventional multiple-specimen method. If Jg is defined as the minimum J value that causes the unstable ductile fracture under the constant load, Jg exists between Ji (corresponding to the ductile crack initiation) and Jm (corresponding to the maximum load point in displacement control test). Thus the Jg might be one of the parameters to define the unstable ductile fracture under the constant load condition, though the effect of specimen geometry on Jg is recognized.