Assessment of the integrity of structures containing defects

A number of methods are now available for assessing the integrity of structures containing flaws in all loading regimes. In this paper one of these methods is used to define a route for establishing the integrity of a structure containing defects. It should not be inferred that the approach selected is the only satisfactory one. Other methods of analysis are mentioned in this paper and in some cases these may be preferable to the one described. In developing this route, care has been taken to ensure that, wherever possible, the techniques used have been fully validated. In instances where validation is not available, the suggested methods represent the best judgement of the drafting panel. The status notes in Section 14 of this paper describe the extent of validation of the different steps in the analysis. The user is cautioned against following this paper without first reading that section. The paper contains 14 main sections and a number of appendices. The sections detail the major steps which have to be followed when using this procedure, in some cases giving a number of different options. Since all sections must be followed to perform an R6 analysis, they are obligatory. On the other hand, the appendices are advisory, since they are intended only to give guidance on how to perform the different aspects of the analysis. Techniques other than those contained in the appendices may be used in the analysis provided they are validated. This third revision of R/H/R6, originally published in 1976, supersedes all earlier revisions. It takes cognisance of developments in elastic-plastic fracture mechanics which have taken place up to April 1987. In particular, the failure assessment diagrams given in Addenda 1 and 2 of R/H/R6 Rev. 2 have been incorporated, as have modified methods for dealing with ductile tearing and residual and thermal stresses. This paper has been prepared by the R6 drafting panel in consultation with fracture experts within the CEGB. Their contributions are gratefully acknowledged.