The scope of the work described in this report mainly involved a review of the current practices for making an assessment of the acceptability in time. In ASME Section XI terminology@?snap shot?? of a flaw@ at one specific end of evaluation?? this is analogous to making a flaw assessment using the flaw size. Aspects related to flaw growth@ whether it be due to fatigue@?period creep@ or some other mechanism@ are not rigorously covered in this document. The main conclusion drawn as a result of this effort is that for the most part the existing flaw evaluation criteria are conservative when compared with experimental data. Even so@ there are a number of limitations associated with the application of these criteria which must be considered. These include the following: High R/t Ratio Components@ Undermatching Welds@ Questionable Choice of Material Data@ Poorly Defined Flaw Size@ The following recommendations are made as a result of this effort. 1. It is recommended that any new FFS criteria that evolve as a result of the ASME Post Construction Committee activities should be based on the failure assessment diagram (FAD) approach. 2. To use such an FAD-based approach@ a stress intensity factor (K) solution and limit-load solution must be available for the geometry of interest. 3. It is recommended that FFS assessment procedures allow assessments at multiple levels of complexity and accuracy. 4. It is recommended that the FFS assessment procedures that evolve allow flaw assessments to be performed either deterministically or probabilistically. Publication of this document - WRC Bulletin No. 430 was sponsored by the Pressure Vessel Research Council of the Welding Research Council.
BULLETIN 430-1998 history
1998BULLETIN 430-1998 REVIEW OF EXISTING FITNESS-FOR-SERVICE CRITERIA FOR CRACK-LIKE FLAWS