Analysis of Vessel and Piping Weld Fatigue Data Using the Master S-N Curve Method

In support of the new revision of ASME Div 2 Codes, a unified master S-N curve approach has been developed using a mesh-insensitive structural stress procedure. The effectiveness of the new maser S-N curve approach has been demonstrated in a number of earlier publications for many joint types and loading conditions, including pipe and vessel welds. In this paper, additional S-N data for pipe girth welds and vessel welds are analyzed using the mesh-insensitive structural stress procedure and the master S-N curve approach. The data include full scale pipe tests for applications for deepwater risers and vessel tests in support of ASME Sec. III related applications, in which some tests incorporated welds with artificially machined flaws. In addition, a great deal more data from plate joints data in offshore and marine industries has become available to the authors. Again, both the effectiveness and the validity of the master S-N curve approach have been demonstrated by collapsing all these weld S-N data from a diverse industries with drastically different joint types, plate thicknesses, and loading modes.