Application of ultrasonic stress measurements to nondestructive evaluation of the J integral in elastic-plastic deformation

A technique was proposed in 1] for nondestructively evaluating the J integral in cracked specimens through use of ultrasonic measurements of stress, and tested on several specimen configurations with the deformation confined to linear elastic fracture mechanics 1,2]. In this paper the application of this procedure to the evaluation of J in the presence of elastic-plastic deformation is described. Experimental results are presented for the case of an edge-cracked panel in tension, which compare favorably with numerical predictions.