Determination of Pipe Girth Weld Fracture Toughness Using Sent Specimens

This paper reviews the basis for the use of SENT or SE(T) specimens as described in DNV RP F108, their limitations and aspects about specimen preparation testing and analysis procedures that need to be addressed in order to standardise the test better. Examples are given comparing the effect of crack tip constraint in a SE(T) specimen with a circumferential crack in a pipe subjected to axial straining and axial strain plus internal pressure. The variations in crack front straightness, the effect of specimen geometry on the J resistance curve as well as the accuracy of the J estimation procedure are presented. The use and limitations of CTOD estimation procedure based on measurement of crack mouth opening displacement as a fracture toughness parameter is discussed.