Development of a Low-Constraint SE(T) Toughness Test

摘要

CANMET-MTL has developed a low-constraint test designed to reduce unnecessary conservatism in the measurement of toughness for use in the assessment of flaws in pipeline girth welds. The design is based on tension loading using fixed (clamped) grips of a single-edge-notched BxB SE(T) specimen, side-grooved to promote plane-strain conditions. Equations have been developed to derive J-integral, CTOD and crack growth from measurement of load and crack-mouth opening displacement. Loading conditions (essentially distance between the grips) have been chosen to reproduce the crack-tip constraint of a circumferential surface flaw in a pipe in service under tensile or bending loads. In this paper, the development of the test and the principal findings from its use will be described.