A simplified structural strain method for low-cycle fatigue evaluation of girth-welded pipe components

Markl's pseudo-elastic stress method has been the basis for low cycle fatigue (LCF) evaluation of girth-welded piping connections for decades, which underpins several international codes and standards. Here, we reexamine the applicability of Markl's method in correlating some recent LCF fatigue data on girth-welded pipes. To mitigate its deficiencies, a simplified structural strain method is proposed for achieving an effective correlation of the same test data. The proposed method can be conveniently used for LCF evaluation of girth-welded pipe components either as an experimental measurement technique or a post-processing procedure of elastic-plastic finite element results.