Development of Experimental Procedure Based on the Load Separation Method to Measure the Fracture Toughness of Zr-2.5Nb Tubes

摘要

The load separation method was employed to measure the η{sub}(pl)-factor, the growing crack length and the applied J-integral during the course of the test of small curved CT specimen of Z-2.5Nb pressure tube material. The effect of the notch tip radius of the notched (reference) CT specimen on the separation parameter was analyzed to predict the crack growing length in the precracked specimen. To avoid the effect of load relaxation in the reference specimen on the separation parameter and the crack growing length estimation, the load was assumed to be maximum and constant value behind the peak load in the reference curve.