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dc.creatorMeđo, Bojan
dc.creatorRakin, Marko
dc.creatorGubeljak, Nenad
dc.date.accessioned2021-03-10T11:12:30Z
dc.date.available2021-03-10T11:12:30Z
dc.date.issued2010
dc.identifier.issn0277-027X
dc.identifier.urihttp://TechnoRep.tmf.bg.ac.rs/handle/123456789/1539
dc.description.abstractThe aim of this paper is prediction of ductile fracture initiation in mismatched and double mismatched welded joints. The micromechanical approach is very well-suited for this purpose, because it describes the process of fracture in a way close to the actual phenomena in the material. Micromechanical models based on the Gurson plastic flow criterion are often used for ductile fracture analysis. One of these models, the Complete Gurson Model (CGM) is used here, because the critical value of the damage parameter can be calculated during the analysis. In many other models, the value of this parameter must be predefined. Experimental and numerical analysis of ductile fracture of pre-cracked single-edge notched bend (SENB) specimens is presented. These specimens contain mismatched or double mismatched (undermatched - OM, and overmatched - UM) welded joints. The crack is located in the weld metal (WM), and in case of double mismatched joints it runs through both weld metals. Numerical analysis is conducted using ABAQUS, with user material subroutine for the CGM created by Z.L. Zhang. Three-dimensional models of double mismatched welded joints are analysed, because they cannot be regarded as plane strain or plane stress. To attain the best possible computational efficiency, the submodelling technique is used in the crack front region. With submodelling, it is possible to have sufficiently refined mesh around the crack front (which is very important, as will be discussed in the paper), without excessive computational cost. Microstructural observation is used to quantify the volume fractions of non-metallic inclusions in base metal (BM) and overmatched and undermatched weld metals. Based on these data, initial void volume fractions and mean free paths between the inclusions for all materials are determined. Crack tip opening displacement (CTOD) at the crack growth initiation is measured experimentally and calculated using the CGM, and different values are obtained in overmatched weld metal in comparison with the undermatched weld metal (for double mismatched joints). The size of the elements near the crack tip strongly influences the prediction of the crack growth initiation, and the best results are obtained for the size of the element similar to the mean free path between non-metallic inclusions. The results are also sensitive to the change of the initial void volume fraction, and the best agreement with the experimental data is obtained for the value determined by quantitative microstructural analysis. It is concluded that the CGM enables determination of the crack growth initiation in analysed welded joints and successfully captures the effect of the inhomogeneity.en
dc.publisher2009 ASME Pressure Vessels and Piping Conference, PVP 2009
dc.relationinfo:eu-repo/grantAgreement/MESTD/MPN2006-2010/14052/RS//
dc.relationinfo:eu-repo/grantAgreement/MESTD/MPN2006-2010/144027/RS//
dc.rightsrestrictedAccess
dc.sourceAmerican Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
dc.subjectDuctile fractureen
dc.subjectWelded jointen
dc.subjectMismatch effecten
dc.subjectMicromechanical approachen
dc.subjectComplete Gurson modelen
dc.titleMicromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded jointsen
dc.typearticle
dc.rights.licenseARR
dc.citation.epage415
dc.citation.other5: 409-415
dc.citation.spage409
dc.citation.volume5
dc.identifier.doi10.1115/PVP2009-77475
dc.identifier.pmid
dc.identifier.rcubconv_6754
dc.identifier.scopus2-s2.0-77953194008
dc.identifier.wos000282195600050
dc.type.versionpublishedVersion


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