Numerical analysis of constraint effect on ductile tearing in strength mismatched welded CCT specimens using micromechanical approach

摘要

In this paper, constraint effect on ductile fracture initiation and propagation has been studied. Three-dimensional finite element analyses of mismatched welded joints made of high strength steel, have been performed for centre-cracked tensile (CCT) specimens. Different weld widths and material mismatching ratios have been considered. Ductile fracture parameter, crack tip opening displacement at crack growth initiation (CTODi), has been obtained for centre-cracked tensile (CCT) specimens using local approach to fracture and compared with experimental results of single edge bend specimens. Micromechanical complete Gurson model has been applied to investigate fracture behaviour of cracked welded joints. Crack tip constraint has been analysed through stress triaxiality in order to study transferability of fracture parameters from one geometry to another.