Assessment of Defects Under Combined Primary and Residual Stresses

Abstract

Residual stresses can provide a significant element of the crack driving force for defects in welded components. Structural integrity assessment methods are available, such as the R6 defect assessment procedure [1], which provide detailed guidance for the assessment of such defects under the combined influence of primary and residual stresses. However, in some circumstances these methods may be unduly conservative due, in part, to an over-estimation of the crack driving force due to the residual stress, KJ s. This over-estimation can lead to a pessimistic view of actual safety margins for welded components and premature replacement or repair strategies.