A guide to BS 7910:2019 Annex M: starting from crack-tip stress singularity, it explains the physical meaning of the stress intensity factor K_I, the general Annex M framework and its correction factors, the semi-elliptical surface-crack solution and evaluation points, the weld-toe magnification factor Mk, and the full calculation steps β with original diagrams and a live worked example.
Across the four A533B welded-plate problems, the residual stress intensity factor K_I^Sβ46 MPaΒ·m^0.5 has always been entered directly into the FAD β but where does that number actually come from? This post uses the BS 7910 Annex M.4.2 calculator in mechCalc (finite-plate surface flaw, polynomial stress) to integrate the measured welding residual stress polynomial profile into the SIF at the deepest point of the crack, yielding 44.84 MPaΒ·m^0.5 β only 2.5% off the 46 reported by FITNET.