THE APPLICATION OF CONSTRAINT-BASED FRACTURE-MECHANICS TO ENGINEERINGSTRUCTURES

Elastic-plastic crack tip fields can be characterised by two parameter s, J and T/Q which describes crack tip constraint. This forms the foun dation of a constraint based fracture mechanics in which toughness is expressed as a function of constraint in the form of a J-(T/Q) locus. The enhanced toughness associated with shallow cracks and defects can be used in a systematic manner by constraint matching, and implemented through a simple modification to a failure assessment diagram. This m ethodology enables the conservatism associated with the use of deeply cracked fracture toughness measurements to be relaxed. In this work th ese methods have been applied to a tubular welded joint. (C) 1998 Else vier Science S.A. All rights reserved.