Reliability Approach in Japanese Standard for Detect Assessment of Welded Structures

摘要

The current JWES (Japanese Welding Engineering Scoiety) Standard 2805-1983 "Method of assessment for defects in fusion welded joints with respect to brittle fracture" will be scheduled to be revised in 1997. This paper presents an outline of the revision, especially on the application of reliability approach to the defect assessment. Parameters used in defect assessment based on fracture mechanics have intrinsic uncertainty. The current standard has adopted a determinstic approach with the assumption that defect assessment could be done by conservative estimates in every stage of the procedures, and thus it does not give any explicit safety factor in the final judgement. However, to keep a constant level of reliability for the assessment, it is inevitable to give consideration to the uncertainty in the parameters which appear in fracture mechanics computations.