TY  - JOUR
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Stefane, Primoz
AU  - Gubeljak, Nenad
AU  - Cvijović-Alagić, Ivana
AU  - Đokić, Veljko
AU  - Rakin, Marko
PY  - 2021
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/11
AB  - Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the high-pressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti-13Nb-13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti-13Nb-13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of alpha ' and beta phases in the CG TNZ alloy microstructure, while the additional omega phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer's solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.
PB  - Korean Inst Metals Materials, Seoul
T2  - Metals and Materials International
T1  - Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion
EP  - 3341
IS  - 9
SP  - 3325
VL  - 27
DO  - 10.1007/s12540-020-00837-z
ER  - 

@article{
author = "Barjaktarević, Dragana and Međo, Bojan and Stefane, Primoz and Gubeljak, Nenad and Cvijović-Alagić, Ivana and Đokić, Veljko and Rakin, Marko",
year = "2021",
abstract = "Severe plastic deformation (SPD) is a popular group of techniques applied to achieve the nanostructuring of the metallic biomaterials and improvement of their mechanical characteristics. One of the most commonly used SPD methods is the high-pressure torsion (HPT) technique which enables the obtainment of the microstructure with small grains and high strength. In the present study, the influence of the plastic deformation and surface modification treatment on the tensile and corrosion properties of the Ti-13Nb-13Zr (wt%) alloy is investigated. In that purpose, the coarse-grained (CG) Ti-13Nb-13Zr (TNZ) alloy was subjected to the HPT processing by applying a pressure of 4.1 GPa with a rotational speed of 0.2 rpm and 5 revolutions at room temperature to obtain the ultrafine-grained (UFG) microstructure. The alloy microstructure before and after HPT processing was analysed using the scanning electron microscopy (SEM) and the X-ray diffraction (XRD). The homogeneity of the UFG TNZ alloy was determined by microhardness testing and microscopic observations. The nanotubular oxide layer on the surface of the TNZ alloy, both in CG and UFG condition, was formed by electrochemical anodization in 1 M H3PO4 + NaF electrolyte for 90 min. SEM analysis was used to characterise the morphology of the anodized surfaces, while energy dispersive spectroscopy was applied to determine the chemical composition of the nanostructured layers formed at the alloy surfaces. Mechanical properties of the TNZ alloy, before and after HPT processing and electrochemical anodization, were determined by tensile testing. After tensile testing, the fractographic analysis was conducted to identify the fracture mechanisms. The potentiodynamic polarization technique was used to determine the corrosion resistance of the alloy before and after plastic deformation and surface modification treatment. The obtained results showed that the alloy is reasonably homogeneous after the HPT processing. The XRD analyses reviled the presence of alpha ' and beta phases in the CG TNZ alloy microstructure, while the additional omega phase was detected in the microstructure of the UFG TNZ alloy. The HPT obtained alloy exhibits higher hardness and improved tensile properties than the alloy in the as-received CG condition, while the electrochemical anodization leads to a decrease of its mechanical properties. Both CG and UFG alloys show excellent corrosion stability in Ringer's solution. Moreover, electrochemical anodization leads to a decrease or an increase of the corrosion resistance of these materials, depending on the morphology of the formed nanotubular surface layers. The results indicate that the anodized CG TNZ alloy is characterized by a lower modulus of elasticity and better corrosion resistance properties than the anodized UFG TNZ alloy.",
publisher = "Korean Inst Metals Materials, Seoul",
journal = "Metals and Materials International",
title = "Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion",
pages = "3341-3325",
number = "9",
volume = "27",
doi = "10.1007/s12540-020-00837-z"
}

Barjaktarević, D., Međo, B., Stefane, P., Gubeljak, N., Cvijović-Alagić, I., Đokić, V.,& Rakin, M.. (2021). Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion. in Metals and Materials International
Korean Inst Metals Materials, Seoul., 27(9), 3325-3341.
https://doi.org/10.1007/s12540-020-00837-z

Barjaktarević D, Međo B, Stefane P, Gubeljak N, Cvijović-Alagić I, Đokić V, Rakin M. Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion. in Metals and Materials International. 2021;27(9):3325-3341.
doi:10.1007/s12540-020-00837-z .

Barjaktarević, Dragana, Međo, Bojan, Stefane, Primoz, Gubeljak, Nenad, Cvijović-Alagić, Ivana, Đokić, Veljko, Rakin, Marko, "Tensile and Corrosion Properties of Anodized Ultrafine-Grained Ti-13Nb-13Zr Biomedical Alloy Obtained by High-Pressure Torsion" in Metals and Materials International, 27, no. 9 (2021):3325-3341,
https://doi.org/10.1007/s12540-020-00837-z . .

TY  - JOUR
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Sedmak, Aleksandar
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4389
AB  - Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.
PB  - Srpsko društvo za mehaniku, Beograd
T2  - Theoretical and Applied Mechanics
T1  - An overview of application of micromechanical models in ductile fracture analysis of welded joints
EP  - 62
IS  - 1
SP  - 33
VL  - 47
DO  - 10.2298/TAM200117004R
ER  - 

@article{
author = "Rakin, Marko and Međo, Bojan and Gubeljak, Nenad and Sedmak, Aleksandar",
year = "2020",
abstract = "Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.",
publisher = "Srpsko društvo za mehaniku, Beograd",
journal = "Theoretical and Applied Mechanics",
title = "An overview of application of micromechanical models in ductile fracture analysis of welded joints",
pages = "62-33",
number = "1",
volume = "47",
doi = "10.2298/TAM200117004R"
}

Rakin, M., Međo, B., Gubeljak, N.,& Sedmak, A.. (2020). An overview of application of micromechanical models in ductile fracture analysis of welded joints. in Theoretical and Applied Mechanics
Srpsko društvo za mehaniku, Beograd., 47(1), 33-62.
https://doi.org/10.2298/TAM200117004R

Rakin M, Međo B, Gubeljak N, Sedmak A. An overview of application of micromechanical models in ductile fracture analysis of welded joints. in Theoretical and Applied Mechanics. 2020;47(1):33-62.
doi:10.2298/TAM200117004R .

Rakin, Marko, Međo, Bojan, Gubeljak, Nenad, Sedmak, Aleksandar, "An overview of application of micromechanical models in ductile fracture analysis of welded joints" in Theoretical and Applied Mechanics, 47, no. 1 (2020):33-62,
https://doi.org/10.2298/TAM200117004R . .

TY  - CONF
AU  - Barjaktarević, Dragana
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Cvijović-Alagić, Ivana
AU  - Stefane, Primoz
AU  - Đokić, Veljko
AU  - Rakin, Marko
PY  - 2020
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4751
AB  - Due to their excellent mechanical properties and corrosion resistance, titanium-based materials are widely represented in aeronautics, chemical industry and medicine, where they are considered the best replacement for damaged hard tissues. In order to obtain optimal properties for medical applications, commercially pure titanium (cpTi) is often alloyed. The beta-type titanium alloys containing Nb, Zr, Ta, Mo, Sn have attracted considerable attention, due to their unique combinations of high strength, low modulus of elasticity, superior corrosion resistance and biocompatibility. Also, titanium-based materials can be processed by surface modifications, including the anodization, which belongs to the group of chemical nanostructured surface modifications. Analysis of microstructure of two-phase Ti-13Nb-13Zr (TNZ) alloy was done by Scanning Electron Microscopy (SEM). Characterisation of surface, obtained by anodization in the H3PO4 + NaF solution, during 90 minutes process, was performed by SEM. Micro Tensile Specimens (MTS) were cut from TNZ and anodized TNZ disks and were subjected to the tensile test using servo-hydraulic testing machine Instron 1255. Stereometric measurement of strain at the surface of the MTS during tension was done using the Aramis system. Results showed that anodization process led to a creation of heterogeneous layer of nanotubes. Anodized TNZ alloy had lower elastic modulus and tensile strength comparing to the initial alloy. In order to better understand tensile behaviour, numerical analysis of non-anodized alloy was done. The 3D numerical model of MTS, which simulated the tensile test, was made in Abaqus software package. Good correlation between experimental and numerical results was obtained.
C3  - Procedia Structural Integrity
T1  - Experimental and numerical analysis of tensile properties of Ti-13Nb-13Zr alloy and determination of influence of anodization process
EP  - 2194
SP  - 2187
VL  - 28
DO  - 10.1016/j.prostr.2020.11.047
ER  - 

@conference{
author = "Barjaktarević, Dragana and Međo, Bojan and Gubeljak, Nenad and Cvijović-Alagić, Ivana and Stefane, Primoz and Đokić, Veljko and Rakin, Marko",
year = "2020",
abstract = "Due to their excellent mechanical properties and corrosion resistance, titanium-based materials are widely represented in aeronautics, chemical industry and medicine, where they are considered the best replacement for damaged hard tissues. In order to obtain optimal properties for medical applications, commercially pure titanium (cpTi) is often alloyed. The beta-type titanium alloys containing Nb, Zr, Ta, Mo, Sn have attracted considerable attention, due to their unique combinations of high strength, low modulus of elasticity, superior corrosion resistance and biocompatibility. Also, titanium-based materials can be processed by surface modifications, including the anodization, which belongs to the group of chemical nanostructured surface modifications. Analysis of microstructure of two-phase Ti-13Nb-13Zr (TNZ) alloy was done by Scanning Electron Microscopy (SEM). Characterisation of surface, obtained by anodization in the H3PO4 + NaF solution, during 90 minutes process, was performed by SEM. Micro Tensile Specimens (MTS) were cut from TNZ and anodized TNZ disks and were subjected to the tensile test using servo-hydraulic testing machine Instron 1255. Stereometric measurement of strain at the surface of the MTS during tension was done using the Aramis system. Results showed that anodization process led to a creation of heterogeneous layer of nanotubes. Anodized TNZ alloy had lower elastic modulus and tensile strength comparing to the initial alloy. In order to better understand tensile behaviour, numerical analysis of non-anodized alloy was done. The 3D numerical model of MTS, which simulated the tensile test, was made in Abaqus software package. Good correlation between experimental and numerical results was obtained.",
journal = "Procedia Structural Integrity",
title = "Experimental and numerical analysis of tensile properties of Ti-13Nb-13Zr alloy and determination of influence of anodization process",
pages = "2194-2187",
volume = "28",
doi = "10.1016/j.prostr.2020.11.047"
}

Barjaktarević, D., Međo, B., Gubeljak, N., Cvijović-Alagić, I., Stefane, P., Đokić, V.,& Rakin, M.. (2020). Experimental and numerical analysis of tensile properties of Ti-13Nb-13Zr alloy and determination of influence of anodization process. in Procedia Structural Integrity, 28, 2187-2194.
https://doi.org/10.1016/j.prostr.2020.11.047

Barjaktarević D, Međo B, Gubeljak N, Cvijović-Alagić I, Stefane P, Đokić V, Rakin M. Experimental and numerical analysis of tensile properties of Ti-13Nb-13Zr alloy and determination of influence of anodization process. in Procedia Structural Integrity. 2020;28:2187-2194.
doi:10.1016/j.prostr.2020.11.047 .

Barjaktarević, Dragana, Međo, Bojan, Gubeljak, Nenad, Cvijović-Alagić, Ivana, Stefane, Primoz, Đokić, Veljko, Rakin, Marko, "Experimental and numerical analysis of tensile properties of Ti-13Nb-13Zr alloy and determination of influence of anodization process" in Procedia Structural Integrity, 28 (2020):2187-2194,
https://doi.org/10.1016/j.prostr.2020.11.047 . .

TY  - JOUR
AU  - Musrati, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Stefane, Primoz
AU  - Veljić, Darko
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4055
AB  - The topic of this work is analysis of fracture behaviour and resistance of the thin-walled seamless and seam steel pipes, through application of the recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend). The main loading of these pipes in exploitation is internal pressure, which is why axial defects present a significant threat to their integrity and work safety. The ring-shaped specimen geometry is fairly simple to fabricate from a new or exploited pipeline and the specimens have the same thermo-mechanical treatment, assembly conditions, etc. as the actual structure. Experimental-numerical procedure is applied for prediction of the fracture behaviour; this included material characterisation, testing of ring specimens by bending, as well as micromechanical analysis of ductile fracture. In experimental testing, the deformation of the specimens is monitored by using the stereometric measurement system. Numerical analysis is performed in software package Simulia Abaqus, including the application of the micromechanical Complete Gurson model (CGM). The results obtained in this study, along with some previously published results, lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of cylindrical elements such as pipes.
PB  - Elsevier, Amsterdam
T2  - Theoretical and Applied Fracture Mechanics
T1  - Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens
VL  - 103
DO  - 10.1016/j.tafmec.2019.102302
ER  - 

@article{
author = "Musrati, Walid and Međo, Bojan and Gubeljak, Nenad and Stefane, Primoz and Veljić, Darko and Sedmak, Aleksandar and Rakin, Marko",
year = "2019",
abstract = "The topic of this work is analysis of fracture behaviour and resistance of the thin-walled seamless and seam steel pipes, through application of the recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend). The main loading of these pipes in exploitation is internal pressure, which is why axial defects present a significant threat to their integrity and work safety. The ring-shaped specimen geometry is fairly simple to fabricate from a new or exploited pipeline and the specimens have the same thermo-mechanical treatment, assembly conditions, etc. as the actual structure. Experimental-numerical procedure is applied for prediction of the fracture behaviour; this included material characterisation, testing of ring specimens by bending, as well as micromechanical analysis of ductile fracture. In experimental testing, the deformation of the specimens is monitored by using the stereometric measurement system. Numerical analysis is performed in software package Simulia Abaqus, including the application of the micromechanical Complete Gurson model (CGM). The results obtained in this study, along with some previously published results, lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of cylindrical elements such as pipes.",
publisher = "Elsevier, Amsterdam",
journal = "Theoretical and Applied Fracture Mechanics",
title = "Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens",
volume = "103",
doi = "10.1016/j.tafmec.2019.102302"
}

Musrati, W., Međo, B., Gubeljak, N., Stefane, P., Veljić, D., Sedmak, A.,& Rakin, M.. (2019). Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens. in Theoretical and Applied Fracture Mechanics
Elsevier, Amsterdam., 103.
https://doi.org/10.1016/j.tafmec.2019.102302

Musrati W, Međo B, Gubeljak N, Stefane P, Veljić D, Sedmak A, Rakin M. Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens. in Theoretical and Applied Fracture Mechanics. 2019;103.
doi:10.1016/j.tafmec.2019.102302 .

Musrati, Walid, Međo, Bojan, Gubeljak, Nenad, Stefane, Primoz, Veljić, Darko, Sedmak, Aleksandar, Rakin, Marko, "Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens" in Theoretical and Applied Fracture Mechanics, 103 (2019),
https://doi.org/10.1016/j.tafmec.2019.102302 . .

TY  - JOUR
AU  - Musrati, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Stefane, Primoz
AU  - Veljić, Darko
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3796
AB  - Application of pipelines is common in process industry and energetic facilities, as parts of storage and transport systems. Structural integrity and fracture resistance of the pipeline elements is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, fabrication of these geometries is often not possible for thin-walled pressurized elements, commonly used in structures of process and energetic facilities. Therefore, some proposals for non-standard specimens have been given in the literature, differing by the position of the initial defects, in circumferential or axial direction, and by the degree of complexity of procedures for fabrication and testing. Recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend) is used here to assess the fracture resistance of pressurized cylinders with defects in axial direction, critical for the internal pressure loading. The specimens are simple to fabricate and have the same material history as the actual structure, such as thermo-mechanical treatment, assembly or exploitation conditions. In this work, the ring specimens are cut from the thin-walled non-alloy steel pipes for pressure purposes. Experimental-numerical procedure is applied for prediction of fracture behavior. The methods include material characterization, fracture testing and micromechanical analysis of specimen failure. The results obtained so far lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of pipelines and small-scale vessels.
PB  - Elsevier Science Bv, Amsterdam
T2  - ECF22 - Loading and Environmental Effects on Structural Integrity
T1  - Fracture analysis of axially flawed ring-shaped bending specimen
EP  - 1833
SP  - 1828
VL  - 13
DO  - 10.1016/j.prostr.2018.12.333
ER  - 

@article{
author = "Musrati, Walid and Međo, Bojan and Gubeljak, Nenad and Stefane, Primoz and Veljić, Darko and Sedmak, Aleksandar and Rakin, Marko",
year = "2018",
abstract = "Application of pipelines is common in process industry and energetic facilities, as parts of storage and transport systems. Structural integrity and fracture resistance of the pipeline elements is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, fabrication of these geometries is often not possible for thin-walled pressurized elements, commonly used in structures of process and energetic facilities. Therefore, some proposals for non-standard specimens have been given in the literature, differing by the position of the initial defects, in circumferential or axial direction, and by the degree of complexity of procedures for fabrication and testing. Recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend) is used here to assess the fracture resistance of pressurized cylinders with defects in axial direction, critical for the internal pressure loading. The specimens are simple to fabricate and have the same material history as the actual structure, such as thermo-mechanical treatment, assembly or exploitation conditions. In this work, the ring specimens are cut from the thin-walled non-alloy steel pipes for pressure purposes. Experimental-numerical procedure is applied for prediction of fracture behavior. The methods include material characterization, fracture testing and micromechanical analysis of specimen failure. The results obtained so far lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of pipelines and small-scale vessels.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "ECF22 - Loading and Environmental Effects on Structural Integrity",
title = "Fracture analysis of axially flawed ring-shaped bending specimen",
pages = "1833-1828",
volume = "13",
doi = "10.1016/j.prostr.2018.12.333"
}

Musrati, W., Međo, B., Gubeljak, N., Stefane, P., Veljić, D., Sedmak, A.,& Rakin, M.. (2018). Fracture analysis of axially flawed ring-shaped bending specimen. in ECF22 - Loading and Environmental Effects on Structural Integrity
Elsevier Science Bv, Amsterdam., 13, 1828-1833.
https://doi.org/10.1016/j.prostr.2018.12.333

Musrati W, Međo B, Gubeljak N, Stefane P, Veljić D, Sedmak A, Rakin M. Fracture analysis of axially flawed ring-shaped bending specimen. in ECF22 - Loading and Environmental Effects on Structural Integrity. 2018;13:1828-1833.
doi:10.1016/j.prostr.2018.12.333 .

Musrati, Walid, Međo, Bojan, Gubeljak, Nenad, Stefane, Primoz, Veljić, Darko, Sedmak, Aleksandar, Rakin, Marko, "Fracture analysis of axially flawed ring-shaped bending specimen" in ECF22 - Loading and Environmental Effects on Structural Integrity, 13 (2018):1828-1833,
https://doi.org/10.1016/j.prostr.2018.12.333 . .

TY  - JOUR
AU  - Musraty, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Stefane, Primoz
AU  - Radosavljević, Zoran
AU  - Burzić, Zijah
AU  - Rakin, Marko
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4027
AB  - Pipelines are commonly used in process industry for transport of fluids, as well as granular solids, due to their numerous advantages in comparison to other transportation means. Pipe integrity is essential for a reliable work of the entire plant, as well as for safety assurance. Also, serious ecological consequences may follow the pipeline failure in some cases, i.e. due to the leak of toxic, flammable or otherwise dangerous fluids in a chemical or some other plant. Therefore, it is very important to examine the fracture behaviour of pipelines, which is done here by testing the recently proposed ring-shaped specimens exposed to bending. The specimens were fabricated from a seam pipe for pressure applications (allowed for usage on temperatures up to 300 degrees C). Initial defects, very narrow notches, were machined either in the base metal and weld metal (seam) or in the base metal only. Regardless of the defect position, ductile fracture mechanism is observed in all specimens. The results show that the ring-shaped specimen can be successfully used for fracture characterisation of pipeline material, especially for thin-walled pipes which are not suitable for production of standard fracture mechanics specimens due to the insufficient wall thickness.
PB  - Savez hemijskih inženjera, Beograd
T2  - Hemijska industrija
T1  - Seam pipes for process industry - Fracture analysis by using ring-shaped specimens
EP  - 46
IS  - 1
SP  - 39
VL  - 72
DO  - 10.2298/HEMIND170530014M
ER  - 

@article{
author = "Musraty, Walid and Međo, Bojan and Gubeljak, Nenad and Stefane, Primoz and Radosavljević, Zoran and Burzić, Zijah and Rakin, Marko",
year = "2018",
abstract = "Pipelines are commonly used in process industry for transport of fluids, as well as granular solids, due to their numerous advantages in comparison to other transportation means. Pipe integrity is essential for a reliable work of the entire plant, as well as for safety assurance. Also, serious ecological consequences may follow the pipeline failure in some cases, i.e. due to the leak of toxic, flammable or otherwise dangerous fluids in a chemical or some other plant. Therefore, it is very important to examine the fracture behaviour of pipelines, which is done here by testing the recently proposed ring-shaped specimens exposed to bending. The specimens were fabricated from a seam pipe for pressure applications (allowed for usage on temperatures up to 300 degrees C). Initial defects, very narrow notches, were machined either in the base metal and weld metal (seam) or in the base metal only. Regardless of the defect position, ductile fracture mechanism is observed in all specimens. The results show that the ring-shaped specimen can be successfully used for fracture characterisation of pipeline material, especially for thin-walled pipes which are not suitable for production of standard fracture mechanics specimens due to the insufficient wall thickness.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Hemijska industrija",
title = "Seam pipes for process industry - Fracture analysis by using ring-shaped specimens",
pages = "46-39",
number = "1",
volume = "72",
doi = "10.2298/HEMIND170530014M"
}

Musraty, W., Međo, B., Gubeljak, N., Stefane, P., Radosavljević, Z., Burzić, Z.,& Rakin, M.. (2018). Seam pipes for process industry - Fracture analysis by using ring-shaped specimens. in Hemijska industrija
Savez hemijskih inženjera, Beograd., 72(1), 39-46.
https://doi.org/10.2298/HEMIND170530014M

Musraty W, Međo B, Gubeljak N, Stefane P, Radosavljević Z, Burzić Z, Rakin M. Seam pipes for process industry - Fracture analysis by using ring-shaped specimens. in Hemijska industrija. 2018;72(1):39-46.
doi:10.2298/HEMIND170530014M .

Musraty, Walid, Međo, Bojan, Gubeljak, Nenad, Stefane, Primoz, Radosavljević, Zoran, Burzić, Zijah, Rakin, Marko, "Seam pipes for process industry - Fracture analysis by using ring-shaped specimens" in Hemijska industrija, 72, no. 1 (2018):39-46,
https://doi.org/10.2298/HEMIND170530014M . .

TY  - JOUR
AU  - Musraty, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Likeb, A.
AU  - Cvijović-Alagić, Ivana
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3734
AB  - Integrity of pipes is typically assessed by testing fracture mechanics specimens, such as compact tensile (CT) or single-edge notched bending (SENB). However, for some pipe dimensions it is not easy or possible to fabricate a specimen conforming to the requirements of standard procedures. A new type of specimen is proposed recently, which can be advantageous for relatively small pipe diameters and axial defects - the pipe ring notch bend specimen - PRNB. In this work, criteria for failure by ductile fracture of PRNB specimens are determined experimentally and by application of micromechanical analysis. The influence of size of the specimen, as well as size and shape of the stress concentrator, is analysed. The results of this study, along with previous authors' results, lead to the conclusion that the pipe ring specimens can be applied in integrity assessment of pipes with defects. Also, the benefits of their application include much simpler fabrication and the same material history as the pipe itself.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis
EP  - 261
SP  - 247
VL  - 175
DO  - 10.1016/j.engfracmech.2017.01.022
ER  - 

@article{
author = "Musraty, Walid and Međo, Bojan and Gubeljak, Nenad and Likeb, A. and Cvijović-Alagić, Ivana and Sedmak, Aleksandar and Rakin, Marko",
year = "2017",
abstract = "Integrity of pipes is typically assessed by testing fracture mechanics specimens, such as compact tensile (CT) or single-edge notched bending (SENB). However, for some pipe dimensions it is not easy or possible to fabricate a specimen conforming to the requirements of standard procedures. A new type of specimen is proposed recently, which can be advantageous for relatively small pipe diameters and axial defects - the pipe ring notch bend specimen - PRNB. In this work, criteria for failure by ductile fracture of PRNB specimens are determined experimentally and by application of micromechanical analysis. The influence of size of the specimen, as well as size and shape of the stress concentrator, is analysed. The results of this study, along with previous authors' results, lead to the conclusion that the pipe ring specimens can be applied in integrity assessment of pipes with defects. Also, the benefits of their application include much simpler fabrication and the same material history as the pipe itself.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Fracture Mechanics",
title = "Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis",
pages = "261-247",
volume = "175",
doi = "10.1016/j.engfracmech.2017.01.022"
}

Musraty, W., Međo, B., Gubeljak, N., Likeb, A., Cvijović-Alagić, I., Sedmak, A.,& Rakin, M.. (2017). Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis. in Engineering Fracture Mechanics
Pergamon-Elsevier Science Ltd, Oxford., 175, 247-261.
https://doi.org/10.1016/j.engfracmech.2017.01.022

Musraty W, Međo B, Gubeljak N, Likeb A, Cvijović-Alagić I, Sedmak A, Rakin M. Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis. in Engineering Fracture Mechanics. 2017;175:247-261.
doi:10.1016/j.engfracmech.2017.01.022 .

Musraty, Walid, Međo, Bojan, Gubeljak, Nenad, Likeb, A., Cvijović-Alagić, Ivana, Sedmak, Aleksandar, Rakin, Marko, "Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis" in Engineering Fracture Mechanics, 175 (2017):247-261,
https://doi.org/10.1016/j.engfracmech.2017.01.022 . .

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Musraty, Walid
AU  - Matvienko, Y.
AU  - Milošević, M.
AU  - Sedmak, Aleksandar
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3483
AB  - Integrity of cylindrical structures, such as pipes and small-scale pressure vessels, is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, their fabrication is mainly not possible for thin-walled pressurised elements, commonly used in structures of process and energetic facilities, such as hydrogen and hydrogen carriers storage and delivery systems. Recently proposed nonstandard ring-shaped specimen is used to test the fracture resistance of pressurised cylinders with defects (cracks or notches) in the most critical direction - axial. Some of the advantages of the pipe-ring notch bend specimen, PRNB, are simple fabrication and same material history as actual exploited structure. A combined experimental-numerical procedure is applied for prediction of fracture behaviour of specimens (applicable to ductile metals, mainly steels and Al alloys), with the aim to further validate the new specimen. The results obtained so far lead to conclusion that PRNB specimen can be applied in integrity assessment of cylindrical structures.
PB  - 14th International Conference on Fracture, ICF 2017
C3  - ICF 2017 - 14th International Conference on Fracture
T1  - Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures
EP  - 220
SP  - 219
VL  - 2
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3483
ER  - 

@conference{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad and Musraty, Walid and Matvienko, Y. and Milošević, M. and Sedmak, Aleksandar",
year = "2017",
abstract = "Integrity of cylindrical structures, such as pipes and small-scale pressure vessels, is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, their fabrication is mainly not possible for thin-walled pressurised elements, commonly used in structures of process and energetic facilities, such as hydrogen and hydrogen carriers storage and delivery systems. Recently proposed nonstandard ring-shaped specimen is used to test the fracture resistance of pressurised cylinders with defects (cracks or notches) in the most critical direction - axial. Some of the advantages of the pipe-ring notch bend specimen, PRNB, are simple fabrication and same material history as actual exploited structure. A combined experimental-numerical procedure is applied for prediction of fracture behaviour of specimens (applicable to ductile metals, mainly steels and Al alloys), with the aim to further validate the new specimen. The results obtained so far lead to conclusion that PRNB specimen can be applied in integrity assessment of cylindrical structures.",
publisher = "14th International Conference on Fracture, ICF 2017",
journal = "ICF 2017 - 14th International Conference on Fracture",
title = "Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures",
pages = "220-219",
volume = "2",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3483"
}

Međo, B., Rakin, M., Gubeljak, N., Musraty, W., Matvienko, Y., Milošević, M.,& Sedmak, A.. (2017). Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures. in ICF 2017 - 14th International Conference on Fracture
14th International Conference on Fracture, ICF 2017., 2, 219-220.
https://hdl.handle.net/21.15107/rcub_technorep_3483

Međo B, Rakin M, Gubeljak N, Musraty W, Matvienko Y, Milošević M, Sedmak A. Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures. in ICF 2017 - 14th International Conference on Fracture. 2017;2:219-220.
https://hdl.handle.net/21.15107/rcub_technorep_3483 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, Musraty, Walid, Matvienko, Y., Milošević, M., Sedmak, Aleksandar, "Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures" in ICF 2017 - 14th International Conference on Fracture, 2 (2017):219-220,
https://hdl.handle.net/21.15107/rcub_technorep_3483 .

TY  - JOUR
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3635
AB  - The topic of this work is assessment of ductile fracture initiation and development in different zones of welded joint of a high strength low alloyed (HSLA) steel. A combined experimental-numerical procedure is applied for determination of properties of the weld metal and the heat affected zone - HAZ. One tensile specimen with rectangular cross-section is tested, and the surface strains are determined using stereometric 3D measurement (measurement system Gom Aramis with two cameras and software solution). This methodology enabled formation of the stress-strain curves for micromechanical analysis of fracture of specimens with initial fatigue pre-cracks. Two different geometries are considered: standard single-edge notched bend (SENB) specimens and surface-cracked tensile specimens. The cracks were positioned either in weld metal or in HAZ - within the fine-grained part. Micromechanical model (complete Gurson model, by Z.L. Zhang) is applied for assessment of crack growth onset and stable growth. Higher resistance to ductile fracture initiation and crack growth in HAZ is successfully predicted, as well as constraint effect caused by different crack shapes.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment
EP  - 445
SP  - 435
VL  - 82
DO  - 10.1016/j.engfailanal.2017.08.006
ER  - 

@article{
author = "Younise, Bashir and Rakin, Marko and Gubeljak, Nenad and Međo, Bojan and Sedmak, Aleksandar",
year = "2017",
abstract = "The topic of this work is assessment of ductile fracture initiation and development in different zones of welded joint of a high strength low alloyed (HSLA) steel. A combined experimental-numerical procedure is applied for determination of properties of the weld metal and the heat affected zone - HAZ. One tensile specimen with rectangular cross-section is tested, and the surface strains are determined using stereometric 3D measurement (measurement system Gom Aramis with two cameras and software solution). This methodology enabled formation of the stress-strain curves for micromechanical analysis of fracture of specimens with initial fatigue pre-cracks. Two different geometries are considered: standard single-edge notched bend (SENB) specimens and surface-cracked tensile specimens. The cracks were positioned either in weld metal or in HAZ - within the fine-grained part. Micromechanical model (complete Gurson model, by Z.L. Zhang) is applied for assessment of crack growth onset and stable growth. Higher resistance to ductile fracture initiation and crack growth in HAZ is successfully predicted, as well as constraint effect caused by different crack shapes.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment",
pages = "445-435",
volume = "82",
doi = "10.1016/j.engfailanal.2017.08.006"
}

Younise, B., Rakin, M., Gubeljak, N., Međo, B.,& Sedmak, A.. (2017). Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 82, 435-445.
https://doi.org/10.1016/j.engfailanal.2017.08.006

Younise B, Rakin M, Gubeljak N, Međo B, Sedmak A. Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment. in Engineering Failure Analysis. 2017;82:435-445.
doi:10.1016/j.engfailanal.2017.08.006 .

Younise, Bashir, Rakin, Marko, Gubeljak, Nenad, Međo, Bojan, Sedmak, Aleksandar, "Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment" in Engineering Failure Analysis, 82 (2017):435-445,
https://doi.org/10.1016/j.engfailanal.2017.08.006 . .

TY  - JOUR
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3295
AB  - This study deals with the numerical prediction of ductile fracture initiation and development in welded joints of a high strength low alloyed steel. Having in mind the material heterogeneity in the joint zone, a combined experimental-numerical procedure is applied for determination of properties of the weld metal and heat affected zone - HAZ (both coarse-grained and fine-grained portion). Single smooth tensile specimen is tested, and the surface strains are determined during this test using stereometric measurement. Combined with numerical analysis, this enabled determination of stress-strain curves, which are subsequently used in numerical analysis of fracture of pre-cracked specimens. Two different geometries are considered: standard single-edge notched bend (SENB) specimens and surface-cracked tensile specimens. In each of them, the crack is positioned either in weld metal or between the coarse-grained and fine-grained HAZ. Micromechanical model (complete Gurson model, by Z.L. Zhang) is applied in numerical analysis. Higher resistance to ductile fracture initiation and crack growth in HAZ is successfully predicted, as well as constraint effect caused by different crack shapes.
PB  - Elsevier Science Bv, Amsterdam
T2  - 21st European Conference on Fracture, (ECF21)
T1  - Numerical prediction of ductile fracture resistance of welded joint zones
EP  - 760
SP  - 753
VL  - 2
DO  - 10.1016/j.prostr.2016.06.097
ER  - 

@article{
author = "Younise, Bashir and Rakin, Marko and Gubeljak, Nenad and Međo, Bojan and Sedmak, Aleksandar",
year = "2016",
abstract = "This study deals with the numerical prediction of ductile fracture initiation and development in welded joints of a high strength low alloyed steel. Having in mind the material heterogeneity in the joint zone, a combined experimental-numerical procedure is applied for determination of properties of the weld metal and heat affected zone - HAZ (both coarse-grained and fine-grained portion). Single smooth tensile specimen is tested, and the surface strains are determined during this test using stereometric measurement. Combined with numerical analysis, this enabled determination of stress-strain curves, which are subsequently used in numerical analysis of fracture of pre-cracked specimens. Two different geometries are considered: standard single-edge notched bend (SENB) specimens and surface-cracked tensile specimens. In each of them, the crack is positioned either in weld metal or between the coarse-grained and fine-grained HAZ. Micromechanical model (complete Gurson model, by Z.L. Zhang) is applied in numerical analysis. Higher resistance to ductile fracture initiation and crack growth in HAZ is successfully predicted, as well as constraint effect caused by different crack shapes.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "21st European Conference on Fracture, (ECF21)",
title = "Numerical prediction of ductile fracture resistance of welded joint zones",
pages = "760-753",
volume = "2",
doi = "10.1016/j.prostr.2016.06.097"
}

Younise, B., Rakin, M., Gubeljak, N., Međo, B.,& Sedmak, A.. (2016). Numerical prediction of ductile fracture resistance of welded joint zones. in 21st European Conference on Fracture, (ECF21)
Elsevier Science Bv, Amsterdam., 2, 753-760.
https://doi.org/10.1016/j.prostr.2016.06.097

Younise B, Rakin M, Gubeljak N, Međo B, Sedmak A. Numerical prediction of ductile fracture resistance of welded joint zones. in 21st European Conference on Fracture, (ECF21). 2016;2:753-760.
doi:10.1016/j.prostr.2016.06.097 .

Younise, Bashir, Rakin, Marko, Gubeljak, Nenad, Međo, Bojan, Sedmak, Aleksandar, "Numerical prediction of ductile fracture resistance of welded joint zones" in 21st European Conference on Fracture, (ECF21), 2 (2016):753-760,
https://doi.org/10.1016/j.prostr.2016.06.097 . .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Matvienko, Y.
AU  - Arsić, Miodrag
AU  - Šarkočević, Živče
AU  - Sedmak, Aleksandar
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3057
AB  - Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are also often exposed to damages at the external surface. A pipe segment exposed to internal pressure is examined experimentally and numerically, using the finite element method. Experimental setup included tracking of crack mouth opening displacement (CMOD) values, as well as J integral. Criteria for pipe failure are determined on the finite element (FE) models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. Several 3D models with different crack sizes are evaluated. 2D plane strain models are also examined, to determine the applicability limits of this simplified approach. Integrity assessment criteria for the analysed geometries are discussed. Assessment of fracture resistance of the pipeline material is also considered in this work. Besides the standard SENB specimens, Ring specimens cut from the pipe are tested, and the results are compared. Both specimen geometries are modelled using local approach to fracture, by application of the micromechanical Complete Gurson model (CGM), developed by Z.L. Zhang. It is shown that the Ring specimens have similar fracture conditions under bending load as SENB specimens. Since they are much simpler to fabricate from the pipe than standard specimens, it is concluded that they can be used for assessment of fracture of the pipes with axial cracks.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Failure resistance of drilling rig casing pipes with an axial crack
EP  - 440
SP  - 429
VL  - 58
DO  - 10.1016/j.engfailanal.2015.05.015
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad and Matvienko, Y. and Arsić, Miodrag and Šarkočević, Živče and Sedmak, Aleksandar",
year = "2015",
abstract = "Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are also often exposed to damages at the external surface. A pipe segment exposed to internal pressure is examined experimentally and numerically, using the finite element method. Experimental setup included tracking of crack mouth opening displacement (CMOD) values, as well as J integral. Criteria for pipe failure are determined on the finite element (FE) models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. Several 3D models with different crack sizes are evaluated. 2D plane strain models are also examined, to determine the applicability limits of this simplified approach. Integrity assessment criteria for the analysed geometries are discussed. Assessment of fracture resistance of the pipeline material is also considered in this work. Besides the standard SENB specimens, Ring specimens cut from the pipe are tested, and the results are compared. Both specimen geometries are modelled using local approach to fracture, by application of the micromechanical Complete Gurson model (CGM), developed by Z.L. Zhang. It is shown that the Ring specimens have similar fracture conditions under bending load as SENB specimens. Since they are much simpler to fabricate from the pipe than standard specimens, it is concluded that they can be used for assessment of fracture of the pipes with axial cracks.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Failure resistance of drilling rig casing pipes with an axial crack",
pages = "440-429",
volume = "58",
doi = "10.1016/j.engfailanal.2015.05.015"
}

Međo, B., Rakin, M., Gubeljak, N., Matvienko, Y., Arsić, M., Šarkočević, Ž.,& Sedmak, A.. (2015). Failure resistance of drilling rig casing pipes with an axial crack. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 58, 429-440.
https://doi.org/10.1016/j.engfailanal.2015.05.015

Međo B, Rakin M, Gubeljak N, Matvienko Y, Arsić M, Šarkočević Ž, Sedmak A. Failure resistance of drilling rig casing pipes with an axial crack. in Engineering Failure Analysis. 2015;58:429-440.
doi:10.1016/j.engfailanal.2015.05.015 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, Matvienko, Y., Arsić, Miodrag, Šarkočević, Živče, Sedmak, Aleksandar, "Failure resistance of drilling rig casing pipes with an axial crack" in Engineering Failure Analysis, 58 (2015):429-440,
https://doi.org/10.1016/j.engfailanal.2015.05.015 . .

TY  - JOUR
AU  - Cvijović-Alagić, Ivana
AU  - Gubeljak, Nenad
AU  - Rakin, Marko
AU  - Cvijović, Zorica
AU  - Gerić, K.
PY  - 2014
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2766
AB  - The effects of microstructural morphology on the fracture behavior of Ti-6Al-4V ELI (extra-low impurity) alloy in two different heat treatment conditions were examined. Alloy was solution treated above (beta ST) and below (alpha + beta ST) beta transus temperature followed by furnace cooling (FC) in order to obtain the fully lamellar and equiaxed microstructures. Tensile and fracture toughness tests were conducted. The crack tip opening displacement (CTOD) and strain distribution near the crack tip were measured on the compact tension (CT) specimen surface by digital stereometric method. The crack propagation resistance (CTOD-R) curves were developed by applying the modified normalization method and critical CTOD values were determined. To identify the microstructural length scale controlling the fracture resistance of this alloy, the crack propagation path and fracture surface morphology were evaluated. It was found that the reduction in the characteristic microstructural dimension of an order of magnitude and significant change in the alpha phase aspect ratio contribute to drastic increase in the tensile properties and decrease in the crack initiation and propagation resistance. The fully lamellar microstructure displays slightly better biocompatibility because of the lower elastic modulus and superior fracture resistance. The enhanced crack propagation resistance of this microstructure is associated with the larger propensity for crack tip tortuousity, due to the coarser microstructural dimensions (lamellar colony size vs. primary alpha grain size). The difference in the crack propagation modes affects the shape and size of the actual crack tip strain distribution. These results were discussed correlating the complex multiple fracture mechanisms with the stress state in two microstructures.
PB  - Elsevier Sci Ltd, Oxford
T2  - Materials & Design
T1  - Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants
EP  - 880
SP  - 870
VL  - 53
DO  - 10.1016/j.matdes.2013.07.097
ER  - 

@article{
author = "Cvijović-Alagić, Ivana and Gubeljak, Nenad and Rakin, Marko and Cvijović, Zorica and Gerić, K.",
year = "2014",
abstract = "The effects of microstructural morphology on the fracture behavior of Ti-6Al-4V ELI (extra-low impurity) alloy in two different heat treatment conditions were examined. Alloy was solution treated above (beta ST) and below (alpha + beta ST) beta transus temperature followed by furnace cooling (FC) in order to obtain the fully lamellar and equiaxed microstructures. Tensile and fracture toughness tests were conducted. The crack tip opening displacement (CTOD) and strain distribution near the crack tip were measured on the compact tension (CT) specimen surface by digital stereometric method. The crack propagation resistance (CTOD-R) curves were developed by applying the modified normalization method and critical CTOD values were determined. To identify the microstructural length scale controlling the fracture resistance of this alloy, the crack propagation path and fracture surface morphology were evaluated. It was found that the reduction in the characteristic microstructural dimension of an order of magnitude and significant change in the alpha phase aspect ratio contribute to drastic increase in the tensile properties and decrease in the crack initiation and propagation resistance. The fully lamellar microstructure displays slightly better biocompatibility because of the lower elastic modulus and superior fracture resistance. The enhanced crack propagation resistance of this microstructure is associated with the larger propensity for crack tip tortuousity, due to the coarser microstructural dimensions (lamellar colony size vs. primary alpha grain size). The difference in the crack propagation modes affects the shape and size of the actual crack tip strain distribution. These results were discussed correlating the complex multiple fracture mechanisms with the stress state in two microstructures.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Materials & Design",
title = "Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants",
pages = "880-870",
volume = "53",
doi = "10.1016/j.matdes.2013.07.097"
}

Cvijović-Alagić, I., Gubeljak, N., Rakin, M., Cvijović, Z.,& Gerić, K.. (2014). Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants. in Materials & Design
Elsevier Sci Ltd, Oxford., 53, 870-880.
https://doi.org/10.1016/j.matdes.2013.07.097

Cvijović-Alagić I, Gubeljak N, Rakin M, Cvijović Z, Gerić K. Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants. in Materials & Design. 2014;53:870-880.
doi:10.1016/j.matdes.2013.07.097 .

Cvijović-Alagić, Ivana, Gubeljak, Nenad, Rakin, Marko, Cvijović, Zorica, Gerić, K., "Microstructural morphology effects on fracture resistance and crack tip strain distribution in Ti-6Al-4V alloy for orthopedic implants" in Materials & Design, 53 (2014):870-880,
https://doi.org/10.1016/j.matdes.2013.07.097 . .

TY  - JOUR
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Sedmak, Aleksandar
PY  - 2013
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/2462
AB  - Fracture of steel welded joints produced with one or two weld metals is analysed; the latter (double mismatched) consist of overmatched and undermatched portion. Specimens with a pre-crack in the symmetry plane of each joint are examined. In double mismatched joints, the pre-crack front passes through both weld metals. Micromechanical approach (complete Gurson model) is used for ductile damage development modelling. Influence of joint width, crack length, as well as size and formulation of finite elements, is examined. The constraint effect caused by the different joint geometry is predicted and the effect of material inhomogeneity along the crack front of the double mismatched joint is assessed by transferring the parameters from the joints with one weld metal.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Micromechanical assessment of mismatch effects on fracture of high-strength low alloyed steel welded joints
EP  - 235
SP  - 221
VL  - 109
DO  - 10.1016/j.engfracmech.2013.06.010
ER  - 

@article{
author = "Rakin, Marko and Međo, Bojan and Gubeljak, Nenad and Sedmak, Aleksandar",
year = "2013",
abstract = "Fracture of steel welded joints produced with one or two weld metals is analysed; the latter (double mismatched) consist of overmatched and undermatched portion. Specimens with a pre-crack in the symmetry plane of each joint are examined. In double mismatched joints, the pre-crack front passes through both weld metals. Micromechanical approach (complete Gurson model) is used for ductile damage development modelling. Influence of joint width, crack length, as well as size and formulation of finite elements, is examined. The constraint effect caused by the different joint geometry is predicted and the effect of material inhomogeneity along the crack front of the double mismatched joint is assessed by transferring the parameters from the joints with one weld metal.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Fracture Mechanics",
title = "Micromechanical assessment of mismatch effects on fracture of high-strength low alloyed steel welded joints",
pages = "235-221",
volume = "109",
doi = "10.1016/j.engfracmech.2013.06.010"
}

Rakin, M., Međo, B., Gubeljak, N.,& Sedmak, A.. (2013). Micromechanical assessment of mismatch effects on fracture of high-strength low alloyed steel welded joints. in Engineering Fracture Mechanics
Pergamon-Elsevier Science Ltd, Oxford., 109, 221-235.
https://doi.org/10.1016/j.engfracmech.2013.06.010

Rakin M, Međo B, Gubeljak N, Sedmak A. Micromechanical assessment of mismatch effects on fracture of high-strength low alloyed steel welded joints. in Engineering Fracture Mechanics. 2013;109:221-235.
doi:10.1016/j.engfracmech.2013.06.010 .

Rakin, Marko, Međo, Bojan, Gubeljak, Nenad, Sedmak, Aleksandar, "Micromechanical assessment of mismatch effects on fracture of high-strength low alloyed steel welded joints" in Engineering Fracture Mechanics, 109 (2013):221-235,
https://doi.org/10.1016/j.engfracmech.2013.06.010 . .

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 . .

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Predan, J.
AU  - Arsić, Miodrag
AU  - Sedmak, Aleksandar
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1949
AB  - Among various micromechanical models for ductile fracture analysis using local approach, those based on the Gurson plastic flow criterion have been intensively developed in the past three decades. However, their application is still subject of many researches, with the aim to improve the assessment of ductile fracture in various, mainly metallic, materials. In this work, Gurson criterion is applied to welded joints produced with one or two different weld metals (one of these is overmatched, while the other is undermatched). Welded single-edge notched bend (SENB) specimens are examined, with an initial pre-crack located in the symmetry plane of each joint. Local approach is chosen for assessment of behaviour of the joints under the external loading, to capture the effect of material inhomogeneity and initial crack length on deformation and ductile fracture initiation in analysed specimens.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
C3  - Materials Structure & Micromechanics of Fracture
T1  - Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals
EP  - +
SP  - 578
VL  - 465
DO  - 10.4028/www.scientific.net/KEM.465.578
ER  - 

@conference{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad and Predan, J. and Arsić, Miodrag and Sedmak, Aleksandar",
year = "2011",
abstract = "Among various micromechanical models for ductile fracture analysis using local approach, those based on the Gurson plastic flow criterion have been intensively developed in the past three decades. However, their application is still subject of many researches, with the aim to improve the assessment of ductile fracture in various, mainly metallic, materials. In this work, Gurson criterion is applied to welded joints produced with one or two different weld metals (one of these is overmatched, while the other is undermatched). Welded single-edge notched bend (SENB) specimens are examined, with an initial pre-crack located in the symmetry plane of each joint. Local approach is chosen for assessment of behaviour of the joints under the external loading, to capture the effect of material inhomogeneity and initial crack length on deformation and ductile fracture initiation in analysed specimens.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Materials Structure & Micromechanics of Fracture",
title = "Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals",
pages = "+-578",
volume = "465",
doi = "10.4028/www.scientific.net/KEM.465.578"
}

Međo, B., Rakin, M., Gubeljak, N., Predan, J., Arsić, M.,& Sedmak, A.. (2011). Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals. in Materials Structure & Micromechanics of Fracture
Trans Tech Publications Ltd, Durnten-Zurich., 465, 578-+.
https://doi.org/10.4028/www.scientific.net/KEM.465.578

Međo B, Rakin M, Gubeljak N, Predan J, Arsić M, Sedmak A. Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals. in Materials Structure & Micromechanics of Fracture. 2011;465:578-+.
doi:10.4028/www.scientific.net/KEM.465.578 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, Predan, J., Arsić, Miodrag, Sedmak, Aleksandar, "Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals" in Materials Structure & Micromechanics of Fracture, 465 (2011):578-+,
https://doi.org/10.4028/www.scientific.net/KEM.465.578 . .

TY  - CONF
AU  - Gubeljak, Nenad
AU  - Rakin, Marko
AU  - Predan, J.
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1741
PB  - 28th Danubia-Adria-Symposium on Advances in Experimental Mechanics, DAS 2011
C3  - 28th Danubia - Adria - Symposium on Advances in Experimental Mechanics, DAS 2011
T1  - Weld metal tensile strength determined by testing flat micro tensile and round tensile specimens
EP  - 72
SP  - 71
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1741
ER  - 

@conference{
author = "Gubeljak, Nenad and Rakin, Marko and Predan, J. and Međo, Bojan and Sedmak, Aleksandar",
year = "2011",
publisher = "28th Danubia-Adria-Symposium on Advances in Experimental Mechanics, DAS 2011",
journal = "28th Danubia - Adria - Symposium on Advances in Experimental Mechanics, DAS 2011",
title = "Weld metal tensile strength determined by testing flat micro tensile and round tensile specimens",
pages = "72-71",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1741"
}

Gubeljak, N., Rakin, M., Predan, J., Međo, B.,& Sedmak, A.. (2011). Weld metal tensile strength determined by testing flat micro tensile and round tensile specimens. in 28th Danubia - Adria - Symposium on Advances in Experimental Mechanics, DAS 2011
28th Danubia-Adria-Symposium on Advances in Experimental Mechanics, DAS 2011., 71-72.
https://hdl.handle.net/21.15107/rcub_technorep_1741

Gubeljak N, Rakin M, Predan J, Međo B, Sedmak A. Weld metal tensile strength determined by testing flat micro tensile and round tensile specimens. in 28th Danubia - Adria - Symposium on Advances in Experimental Mechanics, DAS 2011. 2011;:71-72.
https://hdl.handle.net/21.15107/rcub_technorep_1741 .

Gubeljak, Nenad, Rakin, Marko, Predan, J., Međo, Bojan, Sedmak, Aleksandar, "Weld metal tensile strength determined by testing flat micro tensile and round tensile specimens" in 28th Danubia - Adria - Symposium on Advances in Experimental Mechanics, DAS 2011 (2011):71-72,
https://hdl.handle.net/21.15107/rcub_technorep_1741 .

TY  - JOUR
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Kozak, Drazan
AU  - Sedmak, Aleksandar
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1744
AB  - 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
PB  - Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek
T2  - Tehnicki vjesnik
T1  - Numerical analysis of constraint effect on ductile tearing in strength mismatched welded cct specimens using micromechanical approach
EP  - 340
IS  - 3
SP  - 333
VL  - 18
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1744
ER  - 

@article{
author = "Younise, Bashir and Rakin, Marko and Međo, Bojan and Gubeljak, Nenad and Kozak, Drazan and Sedmak, Aleksandar",
year = "2011",
abstract = "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",
publisher = "Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek",
journal = "Tehnicki vjesnik",
title = "Numerical analysis of constraint effect on ductile tearing in strength mismatched welded cct specimens using micromechanical approach",
pages = "340-333",
number = "3",
volume = "18",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1744"
}

Younise, B., Rakin, M., Međo, B., Gubeljak, N., Kozak, D.,& Sedmak, A.. (2011). Numerical analysis of constraint effect on ductile tearing in strength mismatched welded cct specimens using micromechanical approach. in Tehnicki vjesnik
Faculty of Mechanical Engineering in Slavonski Brod, Faculty of Electrical Engineering in Osijek, Faculty of Civil Engineering in Osijek., 18(3), 333-340.
https://hdl.handle.net/21.15107/rcub_technorep_1744

Younise B, Rakin M, Međo B, Gubeljak N, Kozak D, Sedmak A. Numerical analysis of constraint effect on ductile tearing in strength mismatched welded cct specimens using micromechanical approach. in Tehnicki vjesnik. 2011;18(3):333-340.
https://hdl.handle.net/21.15107/rcub_technorep_1744 .

Younise, Bashir, Rakin, Marko, Međo, Bojan, Gubeljak, Nenad, Kozak, Drazan, Sedmak, Aleksandar, "Numerical analysis of constraint effect on ductile tearing in strength mismatched welded cct specimens using micromechanical approach" in Tehnicki vjesnik, 18, no. 3 (2011):333-340,
https://hdl.handle.net/21.15107/rcub_technorep_1744 .

TY  - JOUR
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1838
AB  - In this paper, two micromechanical models: the Gurson-Tvergaard-Needleman (GTN) model and Complete Gurson Model (CGM) are used to predict ductile fracture initiation of two different welded specimens, SE(B) and C(T). The effect of strength mismatch and weld metal width on fracture initiation is studied also. High strength low-alloyed (HSLA) steel welded specimens are analyzed, with the precrack length/specimen width ratio a0/W = 0.32. Two different weld metals with two different widths: 6 and 12 mm are used to make strength overmatch and undermatch joints. Numerical analysis is done previously to adopt Gurson parameters and to determine the values of critical void volume fraction (fc), which are used in the prediction of crack growth initiation in the two welded specimens. Crack tip opening displacement and J-integral at crack growth initiation (CTODi and Ji) are estimated using the GTN and CGM models. Transferability of fracture initiation parameters (CTODi and Ji) between the two welded specimens is analyzed based on stress triaxiality in front of the crack tip.
AB  - U ovom radu, primenjena su dva mikromehanička modela: Gurson-Tvergard-Nidlman (GTN) model i Potpuni Gurson model (CGM) za procenu inicijacije duktilnog loma kod dve različite zavarene epruvete, SE(B) i C(T). Uticaj mismečinga čvrstoće i širine metala šava na inicijaciju loma je takođe proučen. Analizirani su zavareni uzorci od niskolegiranog čelika povišene čvrstoće (HSLA), sa izvedenom prslinom, dužina prsline/širina epruvete a0/W = 0.32. Upotrebljena su dva različita metala šava sa dve širine: 6 i 12 mm radi izvođenja overmečing i andermečing spojeva. Prethodno je urađena numerička analiza radi usvajanja Gurson parametara i određivanja vrednosti kritičnog zapreminskog udela šupljine (fc), koji su iskorišćeni za predviđanje inicijacije rasta prsline u obe zavarene epruvete. Pomeranje pri otvaranju vrha prsline i J integral pri inicijaciji rasta prsline (CTODi i Ji) su sračunati prema modelima GTN i CGM. Transferabilnost parametara inicijacije loma (CTODi i Ji) između obe zavarene epruvete je analizirana na osnovu troosnosti napona ispred vrha prsline.
PB  - Society for Structural Integrity and Life, Institute for Material Testing
T2  - Integritet i vek konstrukcija
T1  - Numerical simulation of constraint effect on fracture initiation in welded specimens using a local damage model
T1  - Numerička simulacija uticaja veze na inicijaciju loma kod zavarenih epruveta upotrebom modela lokalnog oštećenja
EP  - 56
IS  - 1
SP  - 51
VL  - 11
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1838
ER  - 

@article{
author = "Younise, Bashir and Rakin, Marko and Gubeljak, Nenad and Međo, Bojan and Sedmak, Aleksandar",
year = "2011",
abstract = "In this paper, two micromechanical models: the Gurson-Tvergaard-Needleman (GTN) model and Complete Gurson Model (CGM) are used to predict ductile fracture initiation of two different welded specimens, SE(B) and C(T). The effect of strength mismatch and weld metal width on fracture initiation is studied also. High strength low-alloyed (HSLA) steel welded specimens are analyzed, with the precrack length/specimen width ratio a0/W = 0.32. Two different weld metals with two different widths: 6 and 12 mm are used to make strength overmatch and undermatch joints. Numerical analysis is done previously to adopt Gurson parameters and to determine the values of critical void volume fraction (fc), which are used in the prediction of crack growth initiation in the two welded specimens. Crack tip opening displacement and J-integral at crack growth initiation (CTODi and Ji) are estimated using the GTN and CGM models. Transferability of fracture initiation parameters (CTODi and Ji) between the two welded specimens is analyzed based on stress triaxiality in front of the crack tip., U ovom radu, primenjena su dva mikromehanička modela: Gurson-Tvergard-Nidlman (GTN) model i Potpuni Gurson model (CGM) za procenu inicijacije duktilnog loma kod dve različite zavarene epruvete, SE(B) i C(T). Uticaj mismečinga čvrstoće i širine metala šava na inicijaciju loma je takođe proučen. Analizirani su zavareni uzorci od niskolegiranog čelika povišene čvrstoće (HSLA), sa izvedenom prslinom, dužina prsline/širina epruvete a0/W = 0.32. Upotrebljena su dva različita metala šava sa dve širine: 6 i 12 mm radi izvođenja overmečing i andermečing spojeva. Prethodno je urađena numerička analiza radi usvajanja Gurson parametara i određivanja vrednosti kritičnog zapreminskog udela šupljine (fc), koji su iskorišćeni za predviđanje inicijacije rasta prsline u obe zavarene epruvete. Pomeranje pri otvaranju vrha prsline i J integral pri inicijaciji rasta prsline (CTODi i Ji) su sračunati prema modelima GTN i CGM. Transferabilnost parametara inicijacije loma (CTODi i Ji) između obe zavarene epruvete je analizirana na osnovu troosnosti napona ispred vrha prsline.",
publisher = "Society for Structural Integrity and Life, Institute for Material Testing",
journal = "Integritet i vek konstrukcija",
title = "Numerical simulation of constraint effect on fracture initiation in welded specimens using a local damage model, Numerička simulacija uticaja veze na inicijaciju loma kod zavarenih epruveta upotrebom modela lokalnog oštećenja",
pages = "56-51",
number = "1",
volume = "11",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1838"
}

Younise, B., Rakin, M., Gubeljak, N., Međo, B.,& Sedmak, A.. (2011). Numerical simulation of constraint effect on fracture initiation in welded specimens using a local damage model. in Integritet i vek konstrukcija
Society for Structural Integrity and Life, Institute for Material Testing., 11(1), 51-56.
https://hdl.handle.net/21.15107/rcub_technorep_1838

Younise B, Rakin M, Gubeljak N, Međo B, Sedmak A. Numerical simulation of constraint effect on fracture initiation in welded specimens using a local damage model. in Integritet i vek konstrukcija. 2011;11(1):51-56.
https://hdl.handle.net/21.15107/rcub_technorep_1838 .

Younise, Bashir, Rakin, Marko, Gubeljak, Nenad, Međo, Bojan, Sedmak, Aleksandar, "Numerical simulation of constraint effect on fracture initiation in welded specimens using a local damage model" in Integritet i vek konstrukcija, 11, no. 1 (2011):51-56,
https://hdl.handle.net/21.15107/rcub_technorep_1838 .

TY  - CONF
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Maneski, Taško
AU  - Sedmak, Aleksandar
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1737
AB  - In this paper, a brief overview is given of two projects concerning structural integrity assessment, including on-line software based on SINTAP procedure. An example of the software usage is presented, and the obtained results are compared with the experimental data and discussed.
PB  - 3rd International Multi-Conference on Engineering and Technological Innovation, IMETI 2010
C3  - IMETI 2010 - 3rd International Multi-Conference on Engineering and Technological Innovation, Proceed
T1  - Application of a Structural Integrity Assessment Software
EP  - 249
SP  - 246
VL  - 1
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1737
ER  - 

@conference{
author = "Rakin, Marko and Gubeljak, Nenad and Međo, Bojan and Maneski, Taško and Sedmak, Aleksandar",
year = "2010",
abstract = "In this paper, a brief overview is given of two projects concerning structural integrity assessment, including on-line software based on SINTAP procedure. An example of the software usage is presented, and the obtained results are compared with the experimental data and discussed.",
publisher = "3rd International Multi-Conference on Engineering and Technological Innovation, IMETI 2010",
journal = "IMETI 2010 - 3rd International Multi-Conference on Engineering and Technological Innovation, Proceed",
title = "Application of a Structural Integrity Assessment Software",
pages = "249-246",
volume = "1",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1737"
}

Rakin, M., Gubeljak, N., Međo, B., Maneski, T.,& Sedmak, A.. (2010). Application of a Structural Integrity Assessment Software. in IMETI 2010 - 3rd International Multi-Conference on Engineering and Technological Innovation, Proceed
3rd International Multi-Conference on Engineering and Technological Innovation, IMETI 2010., 1, 246-249.
https://hdl.handle.net/21.15107/rcub_technorep_1737

Rakin M, Gubeljak N, Međo B, Maneski T, Sedmak A. Application of a Structural Integrity Assessment Software. in IMETI 2010 - 3rd International Multi-Conference on Engineering and Technological Innovation, Proceed. 2010;1:246-249.
https://hdl.handle.net/21.15107/rcub_technorep_1737 .

Rakin, Marko, Gubeljak, Nenad, Međo, Bojan, Maneski, Taško, Sedmak, Aleksandar, "Application of a Structural Integrity Assessment Software" in IMETI 2010 - 3rd International Multi-Conference on Engineering and Technological Innovation, Proceed, 1 (2010):246-249,
https://hdl.handle.net/21.15107/rcub_technorep_1737 .

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Arsić, Miodrag
AU  - Sedmak, Aleksandar
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1550
AB  - Local approach is applied to analysis of ductile fracture in steel welded joints. Welded single-edge notched bend (SENBspecimens with joints containing one or two weld metals are investigated. The Gurson plastic flow criterion is used, and the crack growth is modelled by observing damage in elements in front of the crack tip. The effect of various factors: microstructural parameters, joint width, initial crack length, as well as size and formulation of finite elements in the ligament, is examined. Special consideration is given to the connection between material microstructure and fracture behaviour, and it is found that initial porosity and finite element size that correspond to the microstructural quantities (volume fraction of non-metallic inclusions and mean free path between them, determined using quantitative microstructural analysisgive the most appropriate results. It is concluded that local approach enables estimation of ductile fracture initiation in analysed welded joints, also capturing the constraint effect caused by the different joint widths and effect of material inhomogeneity along the crack front of the joints with two different weld metals.
PB  - 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale, ECF 2010
C3  - 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale
T1  - Local approach to analysis of ductile fracture in welded joints-Influence factors
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1550
ER  - 

@conference{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad and Arsić, Miodrag and Sedmak, Aleksandar",
year = "2010",
abstract = "Local approach is applied to analysis of ductile fracture in steel welded joints. Welded single-edge notched bend (SENBspecimens with joints containing one or two weld metals are investigated. The Gurson plastic flow criterion is used, and the crack growth is modelled by observing damage in elements in front of the crack tip. The effect of various factors: microstructural parameters, joint width, initial crack length, as well as size and formulation of finite elements in the ligament, is examined. Special consideration is given to the connection between material microstructure and fracture behaviour, and it is found that initial porosity and finite element size that correspond to the microstructural quantities (volume fraction of non-metallic inclusions and mean free path between them, determined using quantitative microstructural analysisgive the most appropriate results. It is concluded that local approach enables estimation of ductile fracture initiation in analysed welded joints, also capturing the constraint effect caused by the different joint widths and effect of material inhomogeneity along the crack front of the joints with two different weld metals.",
publisher = "18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale, ECF 2010",
journal = "18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale",
title = "Local approach to analysis of ductile fracture in welded joints-Influence factors",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1550"
}

Međo, B., Rakin, M., Gubeljak, N., Arsić, M.,& Sedmak, A.. (2010). Local approach to analysis of ductile fracture in welded joints-Influence factors. in 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale
18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale, ECF 2010..
https://hdl.handle.net/21.15107/rcub_technorep_1550

Međo B, Rakin M, Gubeljak N, Arsić M, Sedmak A. Local approach to analysis of ductile fracture in welded joints-Influence factors. in 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale. 2010;.
https://hdl.handle.net/21.15107/rcub_technorep_1550 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, Arsić, Miodrag, Sedmak, Aleksandar, "Local approach to analysis of ductile fracture in welded joints-Influence factors" in 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale (2010),
https://hdl.handle.net/21.15107/rcub_technorep_1550 .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1539
AB  - The 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.
PB  - 2009 ASME Pressure Vessels and Piping Conference, PVP 2009
T2  - American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
T1  - Micromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded joints
EP  - 415
SP  - 409
VL  - 5
DO  - 10.1115/PVP2009-77475
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad",
year = "2010",
abstract = "The 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.",
publisher = "2009 ASME Pressure Vessels and Piping Conference, PVP 2009",
journal = "American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP",
title = "Micromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded joints",
pages = "415-409",
volume = "5",
doi = "10.1115/PVP2009-77475"
}

Međo, B., Rakin, M.,& Gubeljak, N.. (2010). Micromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded joints. in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
2009 ASME Pressure Vessels and Piping Conference, PVP 2009., 5, 409-415.
https://doi.org/10.1115/PVP2009-77475

Međo B, Rakin M, Gubeljak N. Micromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded joints. in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 2010;5:409-415.
doi:10.1115/PVP2009-77475 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, "Micromechanical analysis of ductile fracture initiation in mismatched and double mismatched welded joints" in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 5 (2010):409-415,
https://doi.org/10.1115/PVP2009-77475 . .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Sedmak, Aleksandar
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1364
AB  - Ductile fracture process includes three stages: void nucleation, their growth and coalescence. The voids nucleate due to the fracture or separation of non-metallic inclusions and secondary-phase particles from the material matrix. Micromechanical models based on the Gurson plastic flow criterion are often used for analysis of ductile fracture. They consider the material as a porous medium in which the effect of voids on the stress-strain state and plastic flow cannot be neglected. Another important property of the Gurson criterion is that the hydrostatic stress component influences the plastic flow of the material.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
T2  - Key Engineering Materials
T1  - Application of Complete Gurson Model for prediction of ductile fracture in welded steel joints
EP  - 20
SP  - 13
VL  - 399
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1364
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Gubeljak, Nenad and Sedmak, Aleksandar",
year = "2009",
abstract = "Ductile fracture process includes three stages: void nucleation, their growth and coalescence. The voids nucleate due to the fracture or separation of non-metallic inclusions and secondary-phase particles from the material matrix. Micromechanical models based on the Gurson plastic flow criterion are often used for analysis of ductile fracture. They consider the material as a porous medium in which the effect of voids on the stress-strain state and plastic flow cannot be neglected. Another important property of the Gurson criterion is that the hydrostatic stress component influences the plastic flow of the material.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Key Engineering Materials",
title = "Application of Complete Gurson Model for prediction of ductile fracture in welded steel joints",
pages = "20-13",
volume = "399",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1364"
}

Međo, B., Rakin, M., Gubeljak, N.,& Sedmak, A.. (2009). Application of Complete Gurson Model for prediction of ductile fracture in welded steel joints. in Key Engineering Materials
Trans Tech Publications Ltd, Durnten-Zurich., 399, 13-20.
https://hdl.handle.net/21.15107/rcub_technorep_1364

Međo B, Rakin M, Gubeljak N, Sedmak A. Application of Complete Gurson Model for prediction of ductile fracture in welded steel joints. in Key Engineering Materials. 2009;399:13-20.
https://hdl.handle.net/21.15107/rcub_technorep_1364 .

Međo, Bojan, Rakin, Marko, Gubeljak, Nenad, Sedmak, Aleksandar, "Application of Complete Gurson Model for prediction of ductile fracture in welded steel joints" in Key Engineering Materials, 399 (2009):13-20,
https://hdl.handle.net/21.15107/rcub_technorep_1364 .

TY  - JOUR
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Dobrojević, M.
AU  - Međo, Bojan
AU  - Cvijović-Alagić, Ivana
AU  - Sedmak, Aleksandar
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1215
AB  - The integrity of welded structures depends on the load-carrying capacities of their welded joints. Having in mind that welding process produces a large microstructural gradient through the weld, resulting in variation of mechanical properties, micromechanical analysis that correlates the local stresses and strains with fracture toughness seems to be appropriate to ensure integrity. In this paper, a micromechanical model for ductile fracture has been applied for assessment of the crack growth onset in the strength-mismatched welded joints of various widths. High-strength low-alloyed (HSLA) steel is used as the base metal in quenched and tempered condition. The flux-cored arc-welding process in shielding gas is used. Two different fillers are selected to obtain over- and undermatched weld metal. Precracked (single-edged notch bend - SENB) specimens are experimentally and numerically analysed in static conditions of external loading. Computations of the void volume fraction ahead of the crack tip are performed using the FE method. Volume fraction of non-metallic inclusions in the materials forming the joint was determined using the quantitative microstructural analysis. Based on the critical value, fc, determined on round tensile specimens, CTOD at ductile crack growth initiation on SENB specimens is determined. It has been found that the micromechanical model enables determination of the constraint effect induced by different widths of the welded joints at the onset of the crack growth in tested specimens.
T2  - Welding in the World
T1  - Ductile crack growth initiation in welded joints - Micromechanical approach
EP  - 302
IS  - SPEC. ISS.
SP  - 297
VL  - 52
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1215
ER  - 

@article{
author = "Rakin, Marko and Gubeljak, Nenad and Dobrojević, M. and Međo, Bojan and Cvijović-Alagić, Ivana and Sedmak, Aleksandar",
year = "2008",
abstract = "The integrity of welded structures depends on the load-carrying capacities of their welded joints. Having in mind that welding process produces a large microstructural gradient through the weld, resulting in variation of mechanical properties, micromechanical analysis that correlates the local stresses and strains with fracture toughness seems to be appropriate to ensure integrity. In this paper, a micromechanical model for ductile fracture has been applied for assessment of the crack growth onset in the strength-mismatched welded joints of various widths. High-strength low-alloyed (HSLA) steel is used as the base metal in quenched and tempered condition. The flux-cored arc-welding process in shielding gas is used. Two different fillers are selected to obtain over- and undermatched weld metal. Precracked (single-edged notch bend - SENB) specimens are experimentally and numerically analysed in static conditions of external loading. Computations of the void volume fraction ahead of the crack tip are performed using the FE method. Volume fraction of non-metallic inclusions in the materials forming the joint was determined using the quantitative microstructural analysis. Based on the critical value, fc, determined on round tensile specimens, CTOD at ductile crack growth initiation on SENB specimens is determined. It has been found that the micromechanical model enables determination of the constraint effect induced by different widths of the welded joints at the onset of the crack growth in tested specimens.",
journal = "Welding in the World",
title = "Ductile crack growth initiation in welded joints - Micromechanical approach",
pages = "302-297",
number = "SPEC. ISS.",
volume = "52",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1215"
}

Rakin, M., Gubeljak, N., Dobrojević, M., Međo, B., Cvijović-Alagić, I.,& Sedmak, A.. (2008). Ductile crack growth initiation in welded joints - Micromechanical approach. in Welding in the World, 52(SPEC. ISS.), 297-302.
https://hdl.handle.net/21.15107/rcub_technorep_1215

Rakin M, Gubeljak N, Dobrojević M, Međo B, Cvijović-Alagić I, Sedmak A. Ductile crack growth initiation in welded joints - Micromechanical approach. in Welding in the World. 2008;52(SPEC. ISS.):297-302.
https://hdl.handle.net/21.15107/rcub_technorep_1215 .

Rakin, Marko, Gubeljak, Nenad, Dobrojević, M., Međo, Bojan, Cvijović-Alagić, Ivana, Sedmak, Aleksandar, "Ductile crack growth initiation in welded joints - Micromechanical approach" in Welding in the World, 52, no. SPEC. ISS. (2008):297-302,
https://hdl.handle.net/21.15107/rcub_technorep_1215 .

TY  - JOUR
AU  - Dobrojević, M.
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Cvijović, Ivana
AU  - Zrilić, Milorad
AU  - Krunich, N.
AU  - Sedmak, Aleksandar
PY  - 2007
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1131
AB  - In this paper the micromechanical approach to ductile fracture was applied in a study of constraint effect on crack growth initiation in mismatched welded joints. The single-edged notched bend specimens (precrack length a(0)/W=0.32) were experimentally and numerically analyzed. The coupled micromechanical model proposed by Gurson, Tvergaard and Needleman was used. Constraint effect was tested by varying widths of the welded joints (6, 12 and 18mm). High-strength low-alloyed (HSLA) steel was used as the base metal in a quenched and tempered condition. The flux-cored are-welding process in shielding gas was used. Two different fillers were selected to obtain over- and undermatched weld metal. The micromechanical parameters used in prediction of the crack growth initiation on precracked specimen were calibrated on a round smooth specimen. The difference in fracture behavior between over- and undermatched welded joints obtained in experimental results was followed by numerical computations of void volume fraction in front of the crack tip.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
T2  - Research Trends in Contemporary Materials Science
T1  - Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded
EP  - 
SP  - 571
VL  - 555
DO  - 10.4028/www.scientific.net/MSF.555.571
ER  - 

@article{
author = "Dobrojević, M. and Rakin, Marko and Gubeljak, Nenad and Cvijović, Ivana and Zrilić, Milorad and Krunich, N. and Sedmak, Aleksandar",
year = "2007",
abstract = "In this paper the micromechanical approach to ductile fracture was applied in a study of constraint effect on crack growth initiation in mismatched welded joints. The single-edged notched bend specimens (precrack length a(0)/W=0.32) were experimentally and numerically analyzed. The coupled micromechanical model proposed by Gurson, Tvergaard and Needleman was used. Constraint effect was tested by varying widths of the welded joints (6, 12 and 18mm). High-strength low-alloyed (HSLA) steel was used as the base metal in a quenched and tempered condition. The flux-cored are-welding process in shielding gas was used. Two different fillers were selected to obtain over- and undermatched weld metal. The micromechanical parameters used in prediction of the crack growth initiation on precracked specimen were calibrated on a round smooth specimen. The difference in fracture behavior between over- and undermatched welded joints obtained in experimental results was followed by numerical computations of void volume fraction in front of the crack tip.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Research Trends in Contemporary Materials Science",
title = "Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded",
pages = "-571",
volume = "555",
doi = "10.4028/www.scientific.net/MSF.555.571"
}

Dobrojević, M., Rakin, M., Gubeljak, N., Cvijović, I., Zrilić, M., Krunich, N.,& Sedmak, A.. (2007). Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded. in Research Trends in Contemporary Materials Science
Trans Tech Publications Ltd, Durnten-Zurich., 555, 571-.
https://doi.org/10.4028/www.scientific.net/MSF.555.571

Dobrojević M, Rakin M, Gubeljak N, Cvijović I, Zrilić M, Krunich N, Sedmak A. Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded. in Research Trends in Contemporary Materials Science. 2007;555:571-.
doi:10.4028/www.scientific.net/MSF.555.571 .

Dobrojević, M., Rakin, Marko, Gubeljak, Nenad, Cvijović, Ivana, Zrilić, Milorad, Krunich, N., Sedmak, Aleksandar, "Micromechanical analysis of constraint effect on fracture initiation in strength mismatched welded" in Research Trends in Contemporary Materials Science, 555 (2007):571-,
https://doi.org/10.4028/www.scientific.net/MSF.555.571 . .