Determination of dimensionless stress intensity factor of plate-to-plate butt welds between axially aligned members of different thickness

British Standard 7910:2013 (BS 7910:2013) includes a set of equations for estimating the effect of misalignment on different types of welded joints with a semi-elliptical surface crack. In this study, extensive finite element (FE) analyses are carried out to determine the dimensionless stress intensity factor (Y) of plate-to-plate butt-welded joints between axially aligned members of different thickness. The Y values at the crack deepest points and the crack ends are determined. It is observed that BS 7910:2013 underestimates the Y results of misaligned butt welds for shallow cracks with percentage difference in values being as high as 56%. An overestimation percentage difference of 26% for deep cracks is given by BS 7910:2013. The new Y equations for misaligned butt welds are proposed using multiple regression analyses.