1985 Volume 71 Issue 10 Pages 1398-1404
A single specimen method for determining fracture toughness JIC has been studied using both ultrasonic through transmission and angle beam reflection techniques. Compact tension specimens of A533B-1 steel were used. By the use of point focusing probes, the crack extension in the midthickness portion of the specimen is measured. A computer is utilized in the measuring system for controlling apparatus, recording data, and calculating J values.
The fracture processes such as blunting of precrack tip, stable crack extension and transition process between them can be revealed by this method. The JIC value obtained by ultrasonic method is in close agreement with that obtained by R-curve method.
Furthermore, crack growth resistance curve (J-R curve) can be determined because there is a linear relation between amount of relative decrease in through transmission pulse height and crack extension length.
