影响系数研究

This research study provides background information that may be used to revise the Fitness-For-Service (FFS) document, API 579-1/ASME FFS-1 2021 (aka “API 579”), more specifically the Part 9 Level 2 Assessment, along with a new Level 3 option for Part 9. he Part 9 Level 2 crack-like flaw FFS procedure relies on the Failure Assessment Diagram (FAD) approach, which is the most widely used crack assessment methodology in the world. Several industry standards for crack assessment implement the FAD approach, including BS 7910 from the British Standards Institute and the R6 document from the British nuclear power generation industry. The FAD approach was first introduced in 1976 as a simple approximation for fracture stability assessment of structural components that experience plastic deformation prior to failure. Modern industry standards use improved versions of the FAD, but the approach still contains approximations and simplifications.