TY  - CONF
AU  - Sedmak, Aleksandar
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Burzić, M.
AU  - Kozak, Drazan
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1974
AB  - Ductile damage development in welded joints of high strength low alloyed (HSLA) steel NIOMOL 490K was examined experimentally and analyzed using the micromechanical approach. Single-edge notched bend (SENB) specimens, cut from the welded plates and subsequently pre-cracked in HAZ and WM, were tested. True stress - true strain curves of the heat-affected zone (HAZ) and weld metal (WM) were determined on the smooth tensile plate specimen, by application of a combined experimental-numerical procedure which included stereometric strain measurement and finite element analysis. The complete Gurson model (CGM) was applied to estimate the fracture behavior of the analyzed zones of the joint. An important property of this model is that critical damage parameter value (used as failure criterion) is not a material constant-it is calculated in every load step, based on the stress and strain state in the structure. This feature is especially important in the examined joints, since the material heterogeneity causes pronounced stress and strain gradients. Finite element software Abaqus was used for numerical analysis. The crack growth initiation was predicted at the moment when damage parameter reaches its critical value in the element nearest to the crack tip. The advance of damage (i.e. the crack growth) was modeled by tracking the loss of load carrying capacity in the ligament (local stiffness reduction in the elements). It is concluded that the micromechanical approach can be used to assess the effects of constraint and heterogeneity on the fracture of the examined HSLA steel welded joints. HAZ fracture properties concerning both crack growth initiation and stable growth are slightly better in comparison with WM, as obtained by testing the SENB specimens with pre-cracks in these two weld zones. The influence of the finite element (FE) size on the results was also analyzed. It is found that the finite element size near the crack tip strongly influences the prediction of crack initiation and growth, and that there is a very significant difference in appropriate FE size between the WM and HAZ. For the analyzed materials, this size corresponds to the mean free path between the non-metallic inclusions in the examined welded joint zones.
PB  - 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012
C3  - 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF
T1  - Ductile fracture resistance of the weld metal and heat affected zone in a HSLA steel welded joint
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1974
ER  - 

@conference{
author = "Sedmak, Aleksandar and Younise, Bashir and Rakin, Marko and Međo, Bojan and Gubeljak, Nenad and Burzić, M. and Kozak, Drazan",
year = "2012",
abstract = "Ductile damage development in welded joints of high strength low alloyed (HSLA) steel NIOMOL 490K was examined experimentally and analyzed using the micromechanical approach. Single-edge notched bend (SENB) specimens, cut from the welded plates and subsequently pre-cracked in HAZ and WM, were tested. True stress - true strain curves of the heat-affected zone (HAZ) and weld metal (WM) were determined on the smooth tensile plate specimen, by application of a combined experimental-numerical procedure which included stereometric strain measurement and finite element analysis. The complete Gurson model (CGM) was applied to estimate the fracture behavior of the analyzed zones of the joint. An important property of this model is that critical damage parameter value (used as failure criterion) is not a material constant-it is calculated in every load step, based on the stress and strain state in the structure. This feature is especially important in the examined joints, since the material heterogeneity causes pronounced stress and strain gradients. Finite element software Abaqus was used for numerical analysis. The crack growth initiation was predicted at the moment when damage parameter reaches its critical value in the element nearest to the crack tip. The advance of damage (i.e. the crack growth) was modeled by tracking the loss of load carrying capacity in the ligament (local stiffness reduction in the elements). It is concluded that the micromechanical approach can be used to assess the effects of constraint and heterogeneity on the fracture of the examined HSLA steel welded joints. HAZ fracture properties concerning both crack growth initiation and stable growth are slightly better in comparison with WM, as obtained by testing the SENB specimens with pre-cracks in these two weld zones. The influence of the finite element (FE) size on the results was also analyzed. It is found that the finite element size near the crack tip strongly influences the prediction of crack initiation and growth, and that there is a very significant difference in appropriate FE size between the WM and HAZ. For the analyzed materials, this size corresponds to the mean free path between the non-metallic inclusions in the examined welded joint zones.",
publisher = "19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012",
journal = "19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF",
title = "Ductile fracture resistance of the weld metal and heat affected zone in a HSLA steel welded joint",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1974"
}

Sedmak, A., Younise, B., Rakin, M., Međo, B., Gubeljak, N., Burzić, M.,& Kozak, D.. (2012). Ductile fracture resistance of the weld metal and heat affected zone in a HSLA steel welded joint. in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF
19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF 2012..
https://hdl.handle.net/21.15107/rcub_technorep_1974

Sedmak A, Younise B, Rakin M, Međo B, Gubeljak N, Burzić M, Kozak D. Ductile fracture resistance of the weld metal and heat affected zone in a HSLA steel welded joint. in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF. 2012;.
https://hdl.handle.net/21.15107/rcub_technorep_1974 .

Sedmak, Aleksandar, Younise, Bashir, Rakin, Marko, Međo, Bojan, Gubeljak, Nenad, Burzić, M., Kozak, Drazan, "Ductile fracture resistance of the weld metal and heat affected zone in a HSLA steel welded joint" in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF (2012),
https://hdl.handle.net/21.15107/rcub_technorep_1974 .

TY  - JOUR
AU  - Younise, Bashir
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Burzić, M.
AU  - Zrilić, Milorad
PY  - 2012
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2198
AB  - The objective of this study is determination of the effect of mechanical heterogeneity on ductile crack initiation and propagation in weldments using micromechanical approach. Welded single-edge notched bend (SENB) specimens were experimentally and numerically analysed. Material properties of welded joint zones were estimated using a combined experimental and numerical procedure; strains on a smooth tensile specimen were determined using ARAMIS stereometric measuring system in order to obtain true stress - true strain curves. High-strength low-alloyed steel was used as base metal, in quenched and tempered condition. J-R curves and crack growth initiation values of fracture mechanics parameter were experimentally and numerically obtained for specimens with a pre-crack in the heat-affected zone (HAZ) and weld metal (WM). The complete Gurson model (CGM) was used in prediction of J-R curves and crack growth initiation. It is shown that the resistance to crack initiation and growth can be predicted using micromechanical analysis, and that the results are significantly affected by mechanical heterogeneity of the weldment.
PB  - Elsevier Sci Ltd, Oxford
T2  - Materials & Design
T1  - Micromechanical analysis of mechanical heterogeneity effect on the ductile tearing of weldments
EP  - 201
SP  - 193
VL  - 37
DO  - 10.1016/j.matdes.2012.01.001
ER  - 

@article{
author = "Younise, Bashir and Sedmak, Aleksandar and Rakin, Marko and Gubeljak, Nenad and Međo, Bojan and Burzić, M. and Zrilić, Milorad",
year = "2012",
abstract = "The objective of this study is determination of the effect of mechanical heterogeneity on ductile crack initiation and propagation in weldments using micromechanical approach. Welded single-edge notched bend (SENB) specimens were experimentally and numerically analysed. Material properties of welded joint zones were estimated using a combined experimental and numerical procedure; strains on a smooth tensile specimen were determined using ARAMIS stereometric measuring system in order to obtain true stress - true strain curves. High-strength low-alloyed steel was used as base metal, in quenched and tempered condition. J-R curves and crack growth initiation values of fracture mechanics parameter were experimentally and numerically obtained for specimens with a pre-crack in the heat-affected zone (HAZ) and weld metal (WM). The complete Gurson model (CGM) was used in prediction of J-R curves and crack growth initiation. It is shown that the resistance to crack initiation and growth can be predicted using micromechanical analysis, and that the results are significantly affected by mechanical heterogeneity of the weldment.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Materials & Design",
title = "Micromechanical analysis of mechanical heterogeneity effect on the ductile tearing of weldments",
pages = "201-193",
volume = "37",
doi = "10.1016/j.matdes.2012.01.001"
}

Younise, B., Sedmak, A., Rakin, M., Gubeljak, N., Međo, B., Burzić, M.,& Zrilić, M.. (2012). Micromechanical analysis of mechanical heterogeneity effect on the ductile tearing of weldments. in Materials & Design
Elsevier Sci Ltd, Oxford., 37, 193-201.
https://doi.org/10.1016/j.matdes.2012.01.001

Younise B, Sedmak A, Rakin M, Gubeljak N, Međo B, Burzić M, Zrilić M. Micromechanical analysis of mechanical heterogeneity effect on the ductile tearing of weldments. in Materials & Design. 2012;37:193-201.
doi:10.1016/j.matdes.2012.01.001 .

Younise, Bashir, Sedmak, Aleksandar, Rakin, Marko, Gubeljak, Nenad, Međo, Bojan, Burzić, M., Zrilić, Milorad, "Micromechanical analysis of mechanical heterogeneity effect on the ductile tearing of weldments" in Materials & Design, 37 (2012):193-201,
https://doi.org/10.1016/j.matdes.2012.01.001 . .