Crack driving force of specimens with shallow crack in the undermatched welded joint

摘要

This paper deals with numerical finite elementcalculations of the crack driving force CTOD-#delta#_5 forstrength-mismatch welded joints. The crack driving force, i.e.the parameter CTOD-#delta#_5, for bending specimens withshallow cracks in mismatch welded joints is determined at thepoint of instability when the first ductile or brittle fractureappeared using a numerical model with plane strain conditionsat the crack tip. Yield strengths of different microstructuresaround the crack tip and its actual mechanical properties aretaken into account in the finite element model of the specimen.It was shown that by calculated crack driving force, it ispossible to predict brittle or ductile fracture initiation ofbending specimens with shallow cracks in the weld metal ofstrength-mismatch welded joints.