Optimized modeling of fracture-critical structural components and connections
requires the application of elastic-plastic fracture mechanics. However, such
applications can require sophisticated analytical techniques that require time
and/or resources beyond those available to the designer. One of the first
engineering tools to address this dilemma was The Welding Institute CTOD Design
Curve and was included in the first edition of the British Standards Institution
(BSI) fitness-for-purpose guidance PD 6493. The engineering tool receiving
attention currently is the Failure Assessment Diagram (FAD). This approach has
been used, primarily, in the electric power industry both in Great Britain as
the R6 criteria and the U.S. as both the Failure Assessment Diagram and the
Deformation Plasticity Failure Assessment Diagram (DPFAD). Both the R6 and
DPFAD approaches utilize the J-integral criteria for fracture driving force and
resistance (i.e., toughness). Also, The second edition of the BSI PD 6493
presents failure assessments in the form of FAD's using crack-tip opening
displacement (CTOD)as crack-driving force.
"Engineering Approaches to Elastic-Plastic Failure Assessment," Bethlehem Steel
Corporation, Bethlehem, Pa., November 7, 1994.