NACE and CTOD
tests have been carried out with a wide range of its products.
Han  studied the effect of constraint on the critical CTOD of X65 steel using a Gurson type void model.
Eventually, by the measured parameters, the critical CTOD can be calculated, as listed in Table 1.
precisely measured the CTOD and stress intensity factor of metallic materials by employing DIC techniques [27, 28].
Then J-integral was correlated with the CTOD and the J-CTOD curve was plotted.
Most client specifications now require CTOD values of 0.
In the HAZ, the variable nature of the material sampled under the fatigue pre-crack, results in a variable performance of CTOD values.
The CTOD specimen tests nearly the full thickness of the weld (Figure 2), instead of a 10 mm or smaller Charpy sample.
The metals offer higher strength, higher CTOD toughness, and are manufactured under lot control and testing to better meet the demands of the pipeline industry.
The pipe presents the most stringent mechanical properties before and after welding: CTOD
values above 0.
Indeed, Eq 6, which is very similar to Shih's relationship between CTOD
and critical J integral (34), indicates that the fracture toughness of a material depends not only on its ability to deform extensively before fracturing (ability represented by its critical crack tip opening displacement) but also on its capacity to bear some load.
(ASTM E1290-99 Standard Test Method for Crack-Tip Opening Displacement Fracture Toughness Measurement) testing was done with engineering criteria analysis to developed flaw criteria and maximum allowable flaw size.