Treatment of residual stress in fracture assessment: background to the advice given in BS 7910:2013

Highlights: • Annex Q of BS 7910:2013 contains updated upper-bound residual stress profiles for a range of different weld configurations. • Information is given in the form of both equations and graphs, improving its user-friendliness compared with the earlier revision. • Two new K-solutions have been added, allowing users to translate the stress distribution into a secondary stress intensity factor. • A simplified method of calculating $K_I^s$ is given, based on resolving the stress distribution into membrane, bending and self-balancing components. • A case study illustrates the different ways in which $K_I^s$ can be calculated for a welded joint. The UK procedure for fracture mechanics-based assessment of flaws (BS 7910) was extensively updated in late 2013. This paper outlines how and why the clauses and Annexes relating to residual stresses (in particular those arising from the manufacturing of welded joints) have been expanded, and explains the origin and extent of validation of the information. A worked example of applying the guidance to fracture assessment of a welded joint is included.