The R6 procedure : recent developments and comparison with alternative approaches

The R6 defect assessment procedure has been continually developed since 1976. It is currently at Revision 3 and a major new release, Revision 4, is planned for 2000. Recent developments in R6 include the incorporation of new appendices on crack arrest methods, weld mismatch effects, local approach and finite element methods. These additions to R6 and other recent developments are briefly described in this paper. The overall aim has been to provide additional advice, which can reduce conservatism in the basic procedure, to increase validation, and to maintain R6 up-to-date with progress in fracture mechanics. R6 has had a major influence on the development of other codes and standards, including the new BS guide BS7910:1999 and the SINTAP procedure. The relationship between these other approaches and R6 is discussed. The paper concludes with a brief outline of the intended framework of R6 Revision 4.