J-R and CTOD-R results were compared from multi-specimen and single-specimen procedures for toughness testing with SEN(T) specimens. Test procedures followed the multi-specimen method described in DNV-RP-F108, and a single-specimen recommended practice developed at CanmetMATERIALS. The latter uses CMOD unloading compliance to measure crack size. Tests were done in laboratories in Canada (BMT, CANMET) and in the UK (TWI). For Grade 483, BxB geometry with side grooves was adopted with the objective of comparison with results from the single-specimen method. The target fatigue precracking ao/W was about 0.5. The program employing Grade 690 used 2BxB geometry (DNV-RP-F108 & DNV-OS-F101) for the multi-specimen tests and BxB geometry with side grooves for the single-specimen tests. The target a°/W was about 0.35.
The paper describes experimental and analysis details, and compares results from the two techniques, using J expressions developed at CANMET for the BxB geometry. For the 2BxB geometry, comparison is made using both the CANMET and DNV-RP-F108 expressions for J.
