Application of Torsion Ce Factor for Piping Non-Planar Through-Wall Flaws

Solution for multi-axis loading on piping non-planar flaws has been studied by many authors (Hoang 2010, 2011), (Kunio 2012, 2014), (Li, 2010, 2012) and ( Bezensek, 2010) to provide a technical basis for an equivalent moment in applications of ASME Section XI, Appendix C limit load approach for pipe flaw evaluation. The equivalent moment is defined as the square root of the sum of the squares (SRSS) of bending moment and torsion with a multiplier of C_e. It has been shown that C_e=1 is applicable for piping with crack-like planar flaws and for part-through-wall non-planar flaws subjected to some limitations. However, the C_e factor for through-wall non-planar flaws has not been investigated. Since Code Case 513-3 allows the use of Section XI, Appendix C procedure for non-planar through-wall flaws, the C_e factor is studied in this paper to support the applications with torsion loading.