TY  - JOUR
AU  - Stamenović, Marina
AU  - Putić, Slaviša
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Čikara, Dejan
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1917
AB  - The influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes is the subject of this paper. The pipes were manufactured in Corporation "Poliester" Priboj, and had a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid), to obtain knowledge about the original tensile properties of the studied composite material. Subsequently, the samples were treated by water, as well as alkaline and acidic solutions: sodium hydroxide (strong alkali), ammonium hydroxide (weak alkali), phosphoric acid (weak acid) and nitric acid (strong acid). The solutions were selected because of considerable differences in their pH values. The pipe segments were exposed to each liquid for 3, 10, 30 and 60 days, at room temperature. Then the specimens cut from these segments were subjected to tension testing by the standard procedure. A comparison of the results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of specimen breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.
PB  - Elsevier Sci Ltd, Oxford
T2  - Materials & Design
T1  - Effect of alkaline and acidic solutions on the tensile properties of glass-polyester pipes
EP  - 2461
IS  - 4
SP  - 2456
VL  - 32
DO  - 10.1016/j.matdes.2010.11.023
ER  - 

@article{
author = "Stamenović, Marina and Putić, Slaviša and Rakin, Marko and Međo, Bojan and Čikara, Dejan",
year = "2011",
abstract = "The influence of liquids on the state of stresses and tensile strengths in the longitudinal and circumferential direction of glass-polyester pipes is the subject of this paper. The pipes were manufactured in Corporation "Poliester" Priboj, and had a definite structure and known fabrication process. These analyses are of great importance for the use of glass-polyester pipes in the chemical industry. The tensile properties were tested and determined for specimens cut out of the pipes; flat specimens for the tensile properties in the longitudinal direction and ring specimens for the tensile properties in the circumferential direction. First, the tension test was performed on virgin samples (without the influence of any liquid), to obtain knowledge about the original tensile properties of the studied composite material. Subsequently, the samples were treated by water, as well as alkaline and acidic solutions: sodium hydroxide (strong alkali), ammonium hydroxide (weak alkali), phosphoric acid (weak acid) and nitric acid (strong acid). The solutions were selected because of considerable differences in their pH values. The pipe segments were exposed to each liquid for 3, 10, 30 and 60 days, at room temperature. Then the specimens cut from these segments were subjected to tension testing by the standard procedure. A comparison of the results was made based on the pH values of the aggressive media in which the examined material had been soaked, as well as based on the original tensile properties and the number of days of treatment. Micromechanical analyses of specimen breakage helped in the elucidation of the influence of the liquids on the structure of the composite pipe and enabled models and mechanisms that produced the change of strength to be proposed.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Materials & Design",
title = "Effect of alkaline and acidic solutions on the tensile properties of glass-polyester pipes",
pages = "2461-2456",
number = "4",
volume = "32",
doi = "10.1016/j.matdes.2010.11.023"
}

Stamenović, M., Putić, S., Rakin, M., Međo, B.,& Čikara, D.. (2011). Effect of alkaline and acidic solutions on the tensile properties of glass-polyester pipes. in Materials & Design
Elsevier Sci Ltd, Oxford., 32(4), 2456-2461.
https://doi.org/10.1016/j.matdes.2010.11.023

Stamenović M, Putić S, Rakin M, Međo B, Čikara D. Effect of alkaline and acidic solutions on the tensile properties of glass-polyester pipes. in Materials & Design. 2011;32(4):2456-2461.
doi:10.1016/j.matdes.2010.11.023 .

Stamenović, Marina, Putić, Slaviša, Rakin, Marko, Međo, Bojan, Čikara, Dejan, "Effect of alkaline and acidic solutions on the tensile properties of glass-polyester pipes" in Materials & Design, 32, no. 4 (2011):2456-2461,
https://doi.org/10.1016/j.matdes.2010.11.023 . .

TY  - JOUR
AU  - Cvijović, Zorica M.
AU  - Vratnica, M.
AU  - Cvijović-Alagić, Ivana
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5635
AB  - The article deals with the relations between microstructural parameters, microscopic fracture mechanisms, and resultant plane-strain fracture toughness, K(IC), of hot-forged 7000 alloy plates in overaged condition. Three industrially produced alloys with the (Zn + Mg + Cu) content of similar to 11.5 mass% and different contents of (Fe + Si) impurities (from 0.23 to 0.37 mass%) were used. The variation in alloy purity generated differences in the geometric characteristics of coarse intermetallic phase particles, exerting significant effect on fracture behavior of these alloys. To evaluate the fracture mechanism, characterization of the broken K(IC) test specimen surfaces was performed using scanning electron microscopy. Three micromechanisms governing fracture process were identified. The extent of primary voiding at coarse intermetallic phase particles increases systematically with the increase of (Fe + Si) level, whereas the extent of intergranular/transgranular fracture decreases. This observation was confirmed by a quantitative description of fractures by means of a profilometric method. It was found that morphological parameters of the fracture profiles clearly differentiate between different fracture modes and offer conclusive proof that coarse voiding at fractured intermetallic phase particles dominates fracture at low alloy purity. A higher fraction of coarse voiding is shown to result in an overall reduction of fracture toughness.
T2  - International Journal of Damage Mechanics
T1  - Effect of Alloy Purity on Fracture Behavior of Overaged 7000 Alloy Plates
EP  - 193
IS  - 2
SP  - 179
VL  - 20
DO  - 10.1177/1056789509346684
ER  - 

@article{
author = "Cvijović, Zorica M. and Vratnica, M. and Cvijović-Alagić, Ivana",
year = "2011",
abstract = "The article deals with the relations between microstructural parameters, microscopic fracture mechanisms, and resultant plane-strain fracture toughness, K(IC), of hot-forged 7000 alloy plates in overaged condition. Three industrially produced alloys with the (Zn + Mg + Cu) content of similar to 11.5 mass% and different contents of (Fe + Si) impurities (from 0.23 to 0.37 mass%) were used. The variation in alloy purity generated differences in the geometric characteristics of coarse intermetallic phase particles, exerting significant effect on fracture behavior of these alloys. To evaluate the fracture mechanism, characterization of the broken K(IC) test specimen surfaces was performed using scanning electron microscopy. Three micromechanisms governing fracture process were identified. The extent of primary voiding at coarse intermetallic phase particles increases systematically with the increase of (Fe + Si) level, whereas the extent of intergranular/transgranular fracture decreases. This observation was confirmed by a quantitative description of fractures by means of a profilometric method. It was found that morphological parameters of the fracture profiles clearly differentiate between different fracture modes and offer conclusive proof that coarse voiding at fractured intermetallic phase particles dominates fracture at low alloy purity. A higher fraction of coarse voiding is shown to result in an overall reduction of fracture toughness.",
journal = "International Journal of Damage Mechanics",
title = "Effect of Alloy Purity on Fracture Behavior of Overaged 7000 Alloy Plates",
pages = "193-179",
number = "2",
volume = "20",
doi = "10.1177/1056789509346684"
}

Cvijović, Z. M., Vratnica, M.,& Cvijović-Alagić, I.. (2011). Effect of Alloy Purity on Fracture Behavior of Overaged 7000 Alloy Plates. in International Journal of Damage Mechanics, 20(2), 179-193.
https://doi.org/10.1177/1056789509346684

Cvijović ZM, Vratnica M, Cvijović-Alagić I. Effect of Alloy Purity on Fracture Behavior of Overaged 7000 Alloy Plates. in International Journal of Damage Mechanics. 2011;20(2):179-193.
doi:10.1177/1056789509346684 .

Cvijović, Zorica M., Vratnica, M., Cvijović-Alagić, Ivana, "Effect of Alloy Purity on Fracture Behavior of Overaged 7000 Alloy Plates" in International Journal of Damage Mechanics, 20, no. 2 (2011):179-193,
https://doi.org/10.1177/1056789509346684 . .

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  - JOUR
AU  - Cvijović-Alagić, Ivana
AU  - Cvijović, Zorica
AU  - Mitrović, Slobodan
AU  - Panić, V.
AU  - Rakin, Marko
PY  - 2011
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1935
AB  - Wear and corrosion behaviour of cold-rolled Ti-13Nb-13Zr alloy, with martensitic microstructure, and Ti-6Al-4V ELI alloy, in martensitic and two-phase (alpha + beta) microstructural conditions, was studied in a Ringer's solution. The wear experiments were performed at room temperature with a normal load of 40 N and sliding speeds 0.26. 0.5 and 1.0 m/s. The corrosion behaviour was studied at 37 degrees C using open circuit potential-time measurements and potentiodynamic polarization. It was found that Ti-13Nb-13Zr alloy has a substantially lower wear resistance than Ti-6Al-4V ELI alloy in both microstructural conditions. Surface damage extent increases with sliding speed increase and is always smallest for martensitic Ti-6Al-4V ELI alloy with highest hardness. Both alloys exhibit spontaneous passivity in Ringer's solution. Corrosion potential values are similar for all three materials. However, Ti-13Nb-13Zr and martensitic Ti-6Al-4V ELI alloys show improved corrosion resistance comparatively to Ti-6Al-4V ELI alloy with (alpha + beta) microstructure. Martensitic Ti-6Al-4V ELI alloy possesses the best combination of both corrosion and wear resistance, although its corrosion resistance is found to be slightly higher than that of the Ti-13Nb-13Zr alloy.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Corrosion Science
T1  - Wear and corrosion behaviour of Ti-13Nb-13Zr and Ti-6Al-4V alloys in simulated physiological solution
EP  - 808
IS  - 2
SP  - 796
VL  - 53
DO  - 10.1016/j.corsci.2010.11.014
ER  - 

@article{
author = "Cvijović-Alagić, Ivana and Cvijović, Zorica and Mitrović, Slobodan and Panić, V. and Rakin, Marko",
year = "2011",
abstract = "Wear and corrosion behaviour of cold-rolled Ti-13Nb-13Zr alloy, with martensitic microstructure, and Ti-6Al-4V ELI alloy, in martensitic and two-phase (alpha + beta) microstructural conditions, was studied in a Ringer's solution. The wear experiments were performed at room temperature with a normal load of 40 N and sliding speeds 0.26. 0.5 and 1.0 m/s. The corrosion behaviour was studied at 37 degrees C using open circuit potential-time measurements and potentiodynamic polarization. It was found that Ti-13Nb-13Zr alloy has a substantially lower wear resistance than Ti-6Al-4V ELI alloy in both microstructural conditions. Surface damage extent increases with sliding speed increase and is always smallest for martensitic Ti-6Al-4V ELI alloy with highest hardness. Both alloys exhibit spontaneous passivity in Ringer's solution. Corrosion potential values are similar for all three materials. However, Ti-13Nb-13Zr and martensitic Ti-6Al-4V ELI alloys show improved corrosion resistance comparatively to Ti-6Al-4V ELI alloy with (alpha + beta) microstructure. Martensitic Ti-6Al-4V ELI alloy possesses the best combination of both corrosion and wear resistance, although its corrosion resistance is found to be slightly higher than that of the Ti-13Nb-13Zr alloy.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Corrosion Science",
title = "Wear and corrosion behaviour of Ti-13Nb-13Zr and Ti-6Al-4V alloys in simulated physiological solution",
pages = "808-796",
number = "2",
volume = "53",
doi = "10.1016/j.corsci.2010.11.014"
}

Cvijović-Alagić, I., Cvijović, Z., Mitrović, S., Panić, V.,& Rakin, M.. (2011). Wear and corrosion behaviour of Ti-13Nb-13Zr and Ti-6Al-4V alloys in simulated physiological solution. in Corrosion Science
Pergamon-Elsevier Science Ltd, Oxford., 53(2), 796-808.
https://doi.org/10.1016/j.corsci.2010.11.014

Cvijović-Alagić I, Cvijović Z, Mitrović S, Panić V, Rakin M. Wear and corrosion behaviour of Ti-13Nb-13Zr and Ti-6Al-4V alloys in simulated physiological solution. in Corrosion Science. 2011;53(2):796-808.
doi:10.1016/j.corsci.2010.11.014 .

Cvijović-Alagić, Ivana, Cvijović, Zorica, Mitrović, Slobodan, Panić, V., Rakin, Marko, "Wear and corrosion behaviour of Ti-13Nb-13Zr and Ti-6Al-4V alloys in simulated physiological solution" in Corrosion Science, 53, no. 2 (2011):796-808,
https://doi.org/10.1016/j.corsci.2010.11.014 . .

TY  - JOUR
AU  - Vratnica, M.
AU  - Pluvinage, G.
AU  - Jodin, P.
AU  - Cvijović, Zorica
AU  - Rakin, M.
AU  - Burzić, Z.
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5602
AB  - The influence of notch radius on the fracture behavior of two high-strength Al-Zn-Mg-Cu alloys with different Fe content in the T73 condition was investigated. The fracture toughness tests were performed on non-fatigue-precracked notched bending specimens with different notch radii ranged from 0.15 mm to 1.0 mm. The obtained data were interpreted using the concept of Notch Fracture Mechanics combined with finite-element method (FEM) calculations. It was found that both alloys are very sensitive to the notch radius. The fracture toughness increases with increasing notch radius. For a given notch radii, the increase in fracture toughness is more significant for the more pure alloy. The fracture behavior of investigated alloys with respect to microstructural features and their relation with the fracture micromechanisms were analyzed.
PB  - Elsevier
T2  - Materials and Design
T1  - Influence of notch radius and microstructure on the fracture behavior of Al-Zn-Mg-Cu alloys of different purity
EP  - 1798
IS  - 4
SP  - 1790
VL  - 31
DO  - 10.1016/j.matdes.2009.11.018
ER  - 

@article{
author = "Vratnica, M. and Pluvinage, G. and Jodin, P. and Cvijović, Zorica and Rakin, M. and Burzić, Z.",
year = "2010",
abstract = "The influence of notch radius on the fracture behavior of two high-strength Al-Zn-Mg-Cu alloys with different Fe content in the T73 condition was investigated. The fracture toughness tests were performed on non-fatigue-precracked notched bending specimens with different notch radii ranged from 0.15 mm to 1.0 mm. The obtained data were interpreted using the concept of Notch Fracture Mechanics combined with finite-element method (FEM) calculations. It was found that both alloys are very sensitive to the notch radius. The fracture toughness increases with increasing notch radius. For a given notch radii, the increase in fracture toughness is more significant for the more pure alloy. The fracture behavior of investigated alloys with respect to microstructural features and their relation with the fracture micromechanisms were analyzed.",
publisher = "Elsevier",
journal = "Materials and Design",
title = "Influence of notch radius and microstructure on the fracture behavior of Al-Zn-Mg-Cu alloys of different purity",
pages = "1798-1790",
number = "4",
volume = "31",
doi = "10.1016/j.matdes.2009.11.018"
}

Vratnica, M., Pluvinage, G., Jodin, P., Cvijović, Z., Rakin, M.,& Burzić, Z.. (2010). Influence of notch radius and microstructure on the fracture behavior of Al-Zn-Mg-Cu alloys of different purity. in Materials and Design
Elsevier., 31(4), 1790-1798.
https://doi.org/10.1016/j.matdes.2009.11.018

Vratnica M, Pluvinage G, Jodin P, Cvijović Z, Rakin M, Burzić Z. Influence of notch radius and microstructure on the fracture behavior of Al-Zn-Mg-Cu alloys of different purity. in Materials and Design. 2010;31(4):1790-1798.
doi:10.1016/j.matdes.2009.11.018 .

Vratnica, M., Pluvinage, G., Jodin, P., Cvijović, Zorica, Rakin, M., Burzić, Z., "Influence of notch radius and microstructure on the fracture behavior of Al-Zn-Mg-Cu alloys of different purity" in Materials and Design, 31, no. 4 (2010):1790-1798,
https://doi.org/10.1016/j.matdes.2009.11.018 . .

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  - Junis, Bašir
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1643
AB  - Ductile fracture initiation in high-strength low alloyed welded steel joints is predicted using micromechanical complete Gurson model (CGM). The crack tip constraint and variation of stress triaxiality in ligament are considered on single-edge notch bend SE(B) and compact tension C(T) specimens, including the effect of strength mismatching and different weld metal width. According to the analysis of stress triaxiality in front of the crack tip, transferability of fracture initiation parameter was studied. As a result of the analyses on specimens, fracture initiation parameter determined by using CGM can be transferred from one geometry to another if their triaxial conditions are found to be similar.
AB  - Nastanak žilavog loma u zavarenim spojevima niskolegiranog čelika povišene čvrstoće je predviđen primenom mikromehaničkog kompletnog Gursonovog modela (CGM). Ograničeno deformisanje oko vrha prsline (eng. 'constraint') i promena troosnosti napona u ligamentu su razmatrani na epruvetama za savijanje u tri tačke SE(B) i na kompaktnim epruvetama za zatezanje C(T), uzimajući u obzir uticaj razlike u mehaničkim osobinama (eng. 'mismatch') i širine metala šava. Analizirana je prenosivost parametra koji odgovara nastanku prsline, u zavisnosti od troosnosti napona ispred njenog vrha i zaključeno je da se dobijene vrednosti korišćenog parametra mogu koristiti za obe geometrije razmatrane u radu.
PB  - University of Belgrade - Faculty of Mechanical Engineering, Belgrade
T2  - FME Transactions
T1  - Numerical simulation for studying constraint effect on ductile fracture initiation using complete Gurson model
T1  - Uticaj ograničenog deformisanja na nastanak žilavog loma korišćenjem kompletnog Gursonovog modela - numerička simulacija
EP  - 202
IS  - 4
SP  - 197
VL  - 38
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1643
ER  - 

@article{
author = "Junis, Bašir and Rakin, Marko and Međo, Bojan and Sedmak, Aleksandar",
year = "2010",
abstract = "Ductile fracture initiation in high-strength low alloyed welded steel joints is predicted using micromechanical complete Gurson model (CGM). The crack tip constraint and variation of stress triaxiality in ligament are considered on single-edge notch bend SE(B) and compact tension C(T) specimens, including the effect of strength mismatching and different weld metal width. According to the analysis of stress triaxiality in front of the crack tip, transferability of fracture initiation parameter was studied. As a result of the analyses on specimens, fracture initiation parameter determined by using CGM can be transferred from one geometry to another if their triaxial conditions are found to be similar., Nastanak žilavog loma u zavarenim spojevima niskolegiranog čelika povišene čvrstoće je predviđen primenom mikromehaničkog kompletnog Gursonovog modela (CGM). Ograničeno deformisanje oko vrha prsline (eng. 'constraint') i promena troosnosti napona u ligamentu su razmatrani na epruvetama za savijanje u tri tačke SE(B) i na kompaktnim epruvetama za zatezanje C(T), uzimajući u obzir uticaj razlike u mehaničkim osobinama (eng. 'mismatch') i širine metala šava. Analizirana je prenosivost parametra koji odgovara nastanku prsline, u zavisnosti od troosnosti napona ispred njenog vrha i zaključeno je da se dobijene vrednosti korišćenog parametra mogu koristiti za obe geometrije razmatrane u radu.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering, Belgrade",
journal = "FME Transactions",
title = "Numerical simulation for studying constraint effect on ductile fracture initiation using complete Gurson model, Uticaj ograničenog deformisanja na nastanak žilavog loma korišćenjem kompletnog Gursonovog modela - numerička simulacija",
pages = "202-197",
number = "4",
volume = "38",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1643"
}

Junis, B., Rakin, M., Međo, B.,& Sedmak, A.. (2010). Numerical simulation for studying constraint effect on ductile fracture initiation using complete Gurson model. in FME Transactions
University of Belgrade - Faculty of Mechanical Engineering, Belgrade., 38(4), 197-202.
https://hdl.handle.net/21.15107/rcub_technorep_1643

Junis B, Rakin M, Međo B, Sedmak A. Numerical simulation for studying constraint effect on ductile fracture initiation using complete Gurson model. in FME Transactions. 2010;38(4):197-202.
https://hdl.handle.net/21.15107/rcub_technorep_1643 .

Junis, Bašir, Rakin, Marko, Međo, Bojan, Sedmak, Aleksandar, "Numerical simulation for studying constraint effect on ductile fracture initiation using complete Gurson model" in FME Transactions, 38, no. 4 (2010):197-202,
https://hdl.handle.net/21.15107/rcub_technorep_1643 .

TY  - JOUR
AU  - Cvijović-Alagić, Ivana
AU  - Cvijović, Zorica
AU  - Mitrović, Slobodan
AU  - Rakin, Marko
AU  - Veljović, Đorđe
AU  - Babić, Miroslav
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1665
AB  - The aim of this study is to compare the tribological behaviour of novel orthopaedic implant alloy Ti-13Nb-13Zr with that of the standard Ti-6Al-4V ELI alloy, available in four different microstructural conditions produced by variations in the heat treatments. The friction and wear tests were performed by using a block-on-disc tribometer in Ringer's solution at ambient temperature with a normal load of 20-60 N and sliding speed of 0.26-1.0 m/s. It was found that variations in microstructures produced significant variations in the wear resistance of Ti-6Al-4V ELI alloy. The wear losses of materials solution treated (ST) above the beta transus temperature are significantly lower compared with those of materials ST in the (alpha + beta) phase field and are almost insensitive to applied load and sliding speed. Wear loss of the (alpha + beta) ST Ti-6Al-4V ELI alloy continuously increased as applied load was increased and was highest at the highest sliding speed. The Ti-6Al-4V ELI alloy in all microstructural conditions possesses a much better wear resistance than cold-rolled Ti-13Nb-13Zr alloy. Friction results and morphology of worn surfaces showed that the observed behaviour is attributed to the predominant wear damage mechanism.
PB  - Springer/Plenum Publishers, New York
T2  - Tribology Letters
T1  - Tribological Behaviour of Orthopaedic Ti-13Nb-13Zr and Ti-6Al-4V Alloys
EP  - 70
IS  - 1
SP  - 59
VL  - 40
DO  - 10.1007/s11249-010-9639-8
ER  - 

@article{
author = "Cvijović-Alagić, Ivana and Cvijović, Zorica and Mitrović, Slobodan and Rakin, Marko and Veljović, Đorđe and Babić, Miroslav",
year = "2010",
abstract = "The aim of this study is to compare the tribological behaviour of novel orthopaedic implant alloy Ti-13Nb-13Zr with that of the standard Ti-6Al-4V ELI alloy, available in four different microstructural conditions produced by variations in the heat treatments. The friction and wear tests were performed by using a block-on-disc tribometer in Ringer's solution at ambient temperature with a normal load of 20-60 N and sliding speed of 0.26-1.0 m/s. It was found that variations in microstructures produced significant variations in the wear resistance of Ti-6Al-4V ELI alloy. The wear losses of materials solution treated (ST) above the beta transus temperature are significantly lower compared with those of materials ST in the (alpha + beta) phase field and are almost insensitive to applied load and sliding speed. Wear loss of the (alpha + beta) ST Ti-6Al-4V ELI alloy continuously increased as applied load was increased and was highest at the highest sliding speed. The Ti-6Al-4V ELI alloy in all microstructural conditions possesses a much better wear resistance than cold-rolled Ti-13Nb-13Zr alloy. Friction results and morphology of worn surfaces showed that the observed behaviour is attributed to the predominant wear damage mechanism.",
publisher = "Springer/Plenum Publishers, New York",
journal = "Tribology Letters",
title = "Tribological Behaviour of Orthopaedic Ti-13Nb-13Zr and Ti-6Al-4V Alloys",
pages = "70-59",
number = "1",
volume = "40",
doi = "10.1007/s11249-010-9639-8"
}

Cvijović-Alagić, I., Cvijović, Z., Mitrović, S., Rakin, M., Veljović, Đ.,& Babić, M.. (2010). Tribological Behaviour of Orthopaedic Ti-13Nb-13Zr and Ti-6Al-4V Alloys. in Tribology Letters
Springer/Plenum Publishers, New York., 40(1), 59-70.
https://doi.org/10.1007/s11249-010-9639-8

Cvijović-Alagić I, Cvijović Z, Mitrović S, Rakin M, Veljović Đ, Babić M. Tribological Behaviour of Orthopaedic Ti-13Nb-13Zr and Ti-6Al-4V Alloys. in Tribology Letters. 2010;40(1):59-70.
doi:10.1007/s11249-010-9639-8 .

Cvijović-Alagić, Ivana, Cvijović, Zorica, Mitrović, Slobodan, Rakin, Marko, Veljović, Đorđe, Babić, Miroslav, "Tribological Behaviour of Orthopaedic Ti-13Nb-13Zr and Ti-6Al-4V Alloys" in Tribology Letters, 40, no. 1 (2010):59-70,
https://doi.org/10.1007/s11249-010-9639-8 . .

TY  - JOUR
AU  - Manjgo, Mersida
AU  - Međo, Bojan
AU  - Milović, Ljubica
AU  - Rakin, Marko
AU  - Burzić, Zijah
AU  - Sedmak, Aleksandar
PY  - 2010
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1732
AB  - The behavior of the plates with a surface notch under tensile external loading is experimentally and numerically analyzed. The specimens were made of micro-alloyed steel NIO-MOL 490 K. welded by MAC (CO2) welding method. Surface notches were machined by the spark erosion method in the weld metal and heat affected zone. A finite element analysis of the specimens subjected to the tensile external loading is performed, with a simplified treatment of the heat affected zone mechanical properties. Obtained results are compared with the results of the experimental investigation, and a satisfactory agreement for the specimens containing the weld metal notch is observed. However, results for the specimen containing a notch in the heat affected zone require further investigation, including the analysis of the effects of micro structural heterogeneity.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Analysis of welded tensile plates with a surface notch in the weld metal and heat affected zone
EP  - 2970
IS  - 15
SP  - 2958
VL  - 77
DO  - 10.1016/j.engfracmech.2010.03.042
ER  - 

@article{
author = "Manjgo, Mersida and Međo, Bojan and Milović, Ljubica and Rakin, Marko and Burzić, Zijah and Sedmak, Aleksandar",
year = "2010",
abstract = "The behavior of the plates with a surface notch under tensile external loading is experimentally and numerically analyzed. The specimens were made of micro-alloyed steel NIO-MOL 490 K. welded by MAC (CO2) welding method. Surface notches were machined by the spark erosion method in the weld metal and heat affected zone. A finite element analysis of the specimens subjected to the tensile external loading is performed, with a simplified treatment of the heat affected zone mechanical properties. Obtained results are compared with the results of the experimental investigation, and a satisfactory agreement for the specimens containing the weld metal notch is observed. However, results for the specimen containing a notch in the heat affected zone require further investigation, including the analysis of the effects of micro structural heterogeneity.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Fracture Mechanics",
title = "Analysis of welded tensile plates with a surface notch in the weld metal and heat affected zone",
pages = "2970-2958",
number = "15",
volume = "77",
doi = "10.1016/j.engfracmech.2010.03.042"
}

Manjgo, M., Međo, B., Milović, L., Rakin, M., Burzić, Z.,& Sedmak, A.. (2010). Analysis of welded tensile plates with a surface notch in the weld metal and heat affected zone. in Engineering Fracture Mechanics
Pergamon-Elsevier Science Ltd, Oxford., 77(15), 2958-2970.
https://doi.org/10.1016/j.engfracmech.2010.03.042

Manjgo M, Međo B, Milović L, Rakin M, Burzić Z, Sedmak A. Analysis of welded tensile plates with a surface notch in the weld metal and heat affected zone. in Engineering Fracture Mechanics. 2010;77(15):2958-2970.
doi:10.1016/j.engfracmech.2010.03.042 .

Manjgo, Mersida, Međo, Bojan, Milović, Ljubica, Rakin, Marko, Burzić, Zijah, Sedmak, Aleksandar, "Analysis of welded tensile plates with a surface notch in the weld metal and heat affected zone" in Engineering Fracture Mechanics, 77, no. 15 (2010):2958-2970,
https://doi.org/10.1016/j.engfracmech.2010.03.042 . .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Zrilić, Milorad
AU  - Putić, Slaviša
AU  - Sedmak, Aleksandar
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1460
AB  - We analyze the level of damage to 14MoV63 steel for steam pipelines under the conditions of crack-growth initiation according to the mechanism of ductile fracture. The state of the material after service for about 100,000 h at the power plant is estimated by using a combined experimental and numerical procedure based on the local approach to fracture. The level of damage is determined by analyzing the material taken from the pipeline (aged) and new (virgin) material of the same grade (for the sake of comparison). The critical values of the J-integral are determined on single-edge notched bend (SENB) specimens both experimentally and by using a simplified procedure of local approach without knowing the microstructural parameters. Two micromechanical models are applied: the Rice - Tracey models modified by Beremin (uncoupled) and the complete Gurson model (coupled).
PB  - Springer, New York
T2  - Materials Science
T1  - Micromechanical estimates of the critical values of j-integral for the steel of steam pipelines
EP  - 531
IS  - 4
SP  - 523
VL  - 45
DO  - 10.1007/s11003-010-9210-7
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Zrilić, Milorad and Putić, Slaviša and Sedmak, Aleksandar",
year = "2009",
abstract = "We analyze the level of damage to 14MoV63 steel for steam pipelines under the conditions of crack-growth initiation according to the mechanism of ductile fracture. The state of the material after service for about 100,000 h at the power plant is estimated by using a combined experimental and numerical procedure based on the local approach to fracture. The level of damage is determined by analyzing the material taken from the pipeline (aged) and new (virgin) material of the same grade (for the sake of comparison). The critical values of the J-integral are determined on single-edge notched bend (SENB) specimens both experimentally and by using a simplified procedure of local approach without knowing the microstructural parameters. Two micromechanical models are applied: the Rice - Tracey models modified by Beremin (uncoupled) and the complete Gurson model (coupled).",
publisher = "Springer, New York",
journal = "Materials Science",
title = "Micromechanical estimates of the critical values of j-integral for the steel of steam pipelines",
pages = "531-523",
number = "4",
volume = "45",
doi = "10.1007/s11003-010-9210-7"
}

Međo, B., Rakin, M., Zrilić, M., Putić, S.,& Sedmak, A.. (2009). Micromechanical estimates of the critical values of j-integral for the steel of steam pipelines. in Materials Science
Springer, New York., 45(4), 523-531.
https://doi.org/10.1007/s11003-010-9210-7

Međo B, Rakin M, Zrilić M, Putić S, Sedmak A. Micromechanical estimates of the critical values of j-integral for the steel of steam pipelines. in Materials Science. 2009;45(4):523-531.
doi:10.1007/s11003-010-9210-7 .

Međo, Bojan, Rakin, Marko, Zrilić, Milorad, Putić, Slaviša, Sedmak, Aleksandar, "Micromechanical estimates of the critical values of j-integral for the steel of steam pipelines" in Materials Science, 45, no. 4 (2009):523-531,
https://doi.org/10.1007/s11003-010-9210-7 . .

TY  - JOUR
AU  - Šarkočević, Živče
AU  - Arsić, Miodrag
AU  - Međo, Bojan
AU  - Kozak, Drazan
AU  - Rakin, Marko
AU  - Burzić, Zijah
AU  - Sedmak, Aleksandar
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1360
AB  - The subject of this paper is investigation of the damage level of API J55 steel, used for manufacturing casing pipes by high frequency (HF) contact welding. The analysed pipe was withdrawn after about 70 000 hours of service in an oil drilling rig. Experimental analysis included determining the mechanical properties of the base material and welded joint, in particular the tensile and impact toughness testing. Fracture behaviour is examined by testing the modified compact tension (CT) specimens machined with a pre-crack in the base metal, weld metal and heat affected zone (HAZ). The critical value of the stress intensity factor K(Ic) is determined using the critical value of the J integral J(Ic). Fatigue crack growth rate and fatigue threshold stress intensity factor range are determined by three point bending tests of the Charpy specimens with a V-notch. The investigation conducted on specimens cut from the exploited pipe and the new pipe of the same grade revealed that material properties were not seriously altered during the analysed period of service.
T2  - Strojarstvo
T1  - Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes
EP  - 311
IS  - 4
SP  - 303
VL  - 51
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1360
ER  - 

@article{
author = "Šarkočević, Živče and Arsić, Miodrag and Međo, Bojan and Kozak, Drazan and Rakin, Marko and Burzić, Zijah and Sedmak, Aleksandar",
year = "2009",
abstract = "The subject of this paper is investigation of the damage level of API J55 steel, used for manufacturing casing pipes by high frequency (HF) contact welding. The analysed pipe was withdrawn after about 70 000 hours of service in an oil drilling rig. Experimental analysis included determining the mechanical properties of the base material and welded joint, in particular the tensile and impact toughness testing. Fracture behaviour is examined by testing the modified compact tension (CT) specimens machined with a pre-crack in the base metal, weld metal and heat affected zone (HAZ). The critical value of the stress intensity factor K(Ic) is determined using the critical value of the J integral J(Ic). Fatigue crack growth rate and fatigue threshold stress intensity factor range are determined by three point bending tests of the Charpy specimens with a V-notch. The investigation conducted on specimens cut from the exploited pipe and the new pipe of the same grade revealed that material properties were not seriously altered during the analysed period of service.",
journal = "Strojarstvo",
title = "Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes",
pages = "311-303",
number = "4",
volume = "51",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1360"
}

Šarkočević, Ž., Arsić, M., Međo, B., Kozak, D., Rakin, M., Burzić, Z.,& Sedmak, A.. (2009). Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes. in Strojarstvo, 51(4), 303-311.
https://hdl.handle.net/21.15107/rcub_technorep_1360

Šarkočević Ž, Arsić M, Međo B, Kozak D, Rakin M, Burzić Z, Sedmak A. Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes. in Strojarstvo. 2009;51(4):303-311.
https://hdl.handle.net/21.15107/rcub_technorep_1360 .

Šarkočević, Živče, Arsić, Miodrag, Međo, Bojan, Kozak, Drazan, Rakin, Marko, Burzić, Zijah, Sedmak, Aleksandar, "Damage Level Estimate of API J55 Steel for Welded Seam Casing Pipes" in Strojarstvo, 51, no. 4 (2009):303-311,
https://hdl.handle.net/21.15107/rcub_technorep_1360 .

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  - Međo, Bojan
AU  - Rakin, Marko
AU  - Kolednik, O.
AU  - Simha, N K.
AU  - Fischer, F.D.
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1402
AB  - Residual stresses in many structural components are often produced during the fabrication or bonding processes, due to the cooling from elevated temperatures. Examples for such behavior are: welded and soldered joints, composites, functionally graded materials, coatings, etc. The residual stresses in these materials affect the stress and strain fields in the vicinity of the crack tip, thus making the crack driving force to become different compared to a material without residual stresses. In this paper, the influence of residual stresses is analyzed using FEM software ABAQUS and post processing routine based on the method of configurationally forces. A previous application of this method has included investigations on the influence of mechanical in homogeneities (Young's modulus, yield stress, hardening coefficient) in welded joints of high-strength low-alloyed steels (HSLA). However, these analyses did not include the effect of in homogeneity in thermal properties (coefficient of thermal expansion). The main goal of this paper is to find out the effect of thermally induced residual stresses on the crack driving force in biomaterials and to use the obtained data to improve the integrity and work safety of welded and other inhomogeneous structures.
AB  - Zaostali naponi u mnogim konstrukcijama nastaju tokom hlađenja u procesu proizvodnje ili spajanja materijala. Primeri su: zavareni i zalemljeni spojevi, kompoziti, materijali sa izraženom anizotropijom, prevlake i dr. Zaostali naponi u slučaju ovakvih materijala utiču na polje napona i deformacija u okolini vrha prsline i dovode do promene vrednosti sile rasta prsline u odnosu na materijal bez zaostalih napona. U ovom radu, uticaj zaostalih napona je analiziran metodom konačnih elemenata, primenom programskog paketa ABAQUS, uz korišćenje postprocesorskog programa razvijenog primenom metode konfiguracionih sila. Ovaj pristup je ranije primenjen na ispitivanje uticaja nehomogenosti mehaničkih osobina (modula elastičnosti, granice tečenja, koeficijenta deformacionog ojačavanja) na spojeve niskolegiranih čelika povišene čvrstoće, ali bez uzimanja u obzir nehomogenosti koeficijenta termičkog širenja materijala. Cilj ovog rada je analiza uticaja termički unetih zaostalih napona na silu rasta prsline u bimaterijalnim spojevima i korišćenje dobijenih rezultata za obezbeđenje integriteta i sigurnog rada zavarenih konstrukcija i struktura sastavljenih od više materijala.
PB  - DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd
T2  - Zavarivanje i zavarene konstrukcije
T1  - The influence of residual stresses on welded joints and other inhomogeneous materials with cracks
T1  - Uticaj zaostalih napona na ponašanje zavarenih spojeva i drugih nehomogenih materijala sa prslinama
EP  - 49
IS  - 2
SP  - 43
VL  - 54
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1402
ER  - 

@article{
author = "Međo, Bojan and Rakin, Marko and Kolednik, O. and Simha, N K. and Fischer, F.D.",
year = "2009",
abstract = "Residual stresses in many structural components are often produced during the fabrication or bonding processes, due to the cooling from elevated temperatures. Examples for such behavior are: welded and soldered joints, composites, functionally graded materials, coatings, etc. The residual stresses in these materials affect the stress and strain fields in the vicinity of the crack tip, thus making the crack driving force to become different compared to a material without residual stresses. In this paper, the influence of residual stresses is analyzed using FEM software ABAQUS and post processing routine based on the method of configurationally forces. A previous application of this method has included investigations on the influence of mechanical in homogeneities (Young's modulus, yield stress, hardening coefficient) in welded joints of high-strength low-alloyed steels (HSLA). However, these analyses did not include the effect of in homogeneity in thermal properties (coefficient of thermal expansion). The main goal of this paper is to find out the effect of thermally induced residual stresses on the crack driving force in biomaterials and to use the obtained data to improve the integrity and work safety of welded and other inhomogeneous structures., Zaostali naponi u mnogim konstrukcijama nastaju tokom hlađenja u procesu proizvodnje ili spajanja materijala. Primeri su: zavareni i zalemljeni spojevi, kompoziti, materijali sa izraženom anizotropijom, prevlake i dr. Zaostali naponi u slučaju ovakvih materijala utiču na polje napona i deformacija u okolini vrha prsline i dovode do promene vrednosti sile rasta prsline u odnosu na materijal bez zaostalih napona. U ovom radu, uticaj zaostalih napona je analiziran metodom konačnih elemenata, primenom programskog paketa ABAQUS, uz korišćenje postprocesorskog programa razvijenog primenom metode konfiguracionih sila. Ovaj pristup je ranije primenjen na ispitivanje uticaja nehomogenosti mehaničkih osobina (modula elastičnosti, granice tečenja, koeficijenta deformacionog ojačavanja) na spojeve niskolegiranih čelika povišene čvrstoće, ali bez uzimanja u obzir nehomogenosti koeficijenta termičkog širenja materijala. Cilj ovog rada je analiza uticaja termički unetih zaostalih napona na silu rasta prsline u bimaterijalnim spojevima i korišćenje dobijenih rezultata za obezbeđenje integriteta i sigurnog rada zavarenih konstrukcija i struktura sastavljenih od više materijala.",
publisher = "DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd",
journal = "Zavarivanje i zavarene konstrukcije",
title = "The influence of residual stresses on welded joints and other inhomogeneous materials with cracks, Uticaj zaostalih napona na ponašanje zavarenih spojeva i drugih nehomogenih materijala sa prslinama",
pages = "49-43",
number = "2",
volume = "54",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1402"
}

Međo, B., Rakin, M., Kolednik, O., Simha, N. K.,& Fischer, F.D.. (2009). The influence of residual stresses on welded joints and other inhomogeneous materials with cracks. in Zavarivanje i zavarene konstrukcije
DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd., 54(2), 43-49.
https://hdl.handle.net/21.15107/rcub_technorep_1402

Međo B, Rakin M, Kolednik O, Simha NK, Fischer F. The influence of residual stresses on welded joints and other inhomogeneous materials with cracks. in Zavarivanje i zavarene konstrukcije. 2009;54(2):43-49.
https://hdl.handle.net/21.15107/rcub_technorep_1402 .

Međo, Bojan, Rakin, Marko, Kolednik, O., Simha, N K., Fischer, F.D., "The influence of residual stresses on welded joints and other inhomogeneous materials with cracks" in Zavarivanje i zavarene konstrukcije, 54, no. 2 (2009):43-49,
https://hdl.handle.net/21.15107/rcub_technorep_1402 .

TY  - JOUR
AU  - Rakin, Marko
AU  - Kolednik, O.
AU  - Međo, Bojan
AU  - Simha, N. K.
AU  - Fischer, F.D.
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1412
AB  - The effect of thermal residual stresses in bimaterial structure with initial crack located near a sharp interface is discussed in this paper. Bimaterial compact tension (CT) specimen is used in the analysis, and the residual stresses are introduced by cooling of the specimen. The residual stresses affect the stress and strain fields near the crack tip, and the crack-driving force is different compared with that in the homogeneous material without residual stresses. This difference can be quantitatively expressed through an additional crack-driving force term-the material inhomogeneity term, Cinh. In this paper, it is evaluated using the post-processing procedure based on the concept of configurational forces, following a finite-element analysis. The results indicate that accurate numerical analysis of pre-cracked bimaterials should include the effect of thermally induced residual stresses. This effect cannot be neglected, even for bimaterials with homogeneous mechanical properties and inhomogeneity in thermal properties only (e.g. welded joints of ferritic and austenitic steel). Based on the obtained results, data from this study can be used in engineering practice to improve integrity and work safety of various inhomogeneous structures.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - International Journal of Mechanical Sciences
T1  - A case study on the effect of thermal residual stresses on the crack-driving force in linear-elastic bimaterials
EP  - 540
IS  - 7
SP  - 531
VL  - 51
DO  - 10.1016/j.ijmecsci.2009.05.006
ER  - 

@article{
author = "Rakin, Marko and Kolednik, O. and Međo, Bojan and Simha, N. K. and Fischer, F.D.",
year = "2009",
abstract = "The effect of thermal residual stresses in bimaterial structure with initial crack located near a sharp interface is discussed in this paper. Bimaterial compact tension (CT) specimen is used in the analysis, and the residual stresses are introduced by cooling of the specimen. The residual stresses affect the stress and strain fields near the crack tip, and the crack-driving force is different compared with that in the homogeneous material without residual stresses. This difference can be quantitatively expressed through an additional crack-driving force term-the material inhomogeneity term, Cinh. In this paper, it is evaluated using the post-processing procedure based on the concept of configurational forces, following a finite-element analysis. The results indicate that accurate numerical analysis of pre-cracked bimaterials should include the effect of thermally induced residual stresses. This effect cannot be neglected, even for bimaterials with homogeneous mechanical properties and inhomogeneity in thermal properties only (e.g. welded joints of ferritic and austenitic steel). Based on the obtained results, data from this study can be used in engineering practice to improve integrity and work safety of various inhomogeneous structures.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "International Journal of Mechanical Sciences",
title = "A case study on the effect of thermal residual stresses on the crack-driving force in linear-elastic bimaterials",
pages = "540-531",
number = "7",
volume = "51",
doi = "10.1016/j.ijmecsci.2009.05.006"
}

Rakin, M., Kolednik, O., Međo, B., Simha, N. K.,& Fischer, F.D.. (2009). A case study on the effect of thermal residual stresses on the crack-driving force in linear-elastic bimaterials. in International Journal of Mechanical Sciences
Pergamon-Elsevier Science Ltd, Oxford., 51(7), 531-540.
https://doi.org/10.1016/j.ijmecsci.2009.05.006

Rakin M, Kolednik O, Međo B, Simha NK, Fischer F. A case study on the effect of thermal residual stresses on the crack-driving force in linear-elastic bimaterials. in International Journal of Mechanical Sciences. 2009;51(7):531-540.
doi:10.1016/j.ijmecsci.2009.05.006 .

Rakin, Marko, Kolednik, O., Međo, Bojan, Simha, N. K., Fischer, F.D., "A case study on the effect of thermal residual stresses on the crack-driving force in linear-elastic bimaterials" in International Journal of Mechanical Sciences, 51, no. 7 (2009):531-540,
https://doi.org/10.1016/j.ijmecsci.2009.05.006 . .

TY  - JOUR
AU  - Cvijović-Alagić, Ivana
AU  - Mitrović, Slobodan
AU  - Cvijović, Zorica
AU  - Veljović, Đorđe
AU  - Babić, Miroslav
AU  - Rakin, Marko
PY  - 2009
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1424
AB  - The influence of diverse heat treatments on micro-structural and tribological characteristics of Ti-6Al-4V ELI (mass%) alloy, which is used as implant material in biomedical engineering, was investigated on a block-on-disc tribometer. Aim of the present study was to explore the possibility of Ti-6Al-4V ELI alloy wear resistance improvement, examining the effects of different heat treatments on alloy microstructure, as well as on alloy wear characteristics in simulated body conditions using light optical microscopy (LOM) and scanning electron microscopy (SEM). Results presented in this paper show that the influence of heat treatment on micro-structural and tribological characteristics of the investigated Ti-based alloy is significant and that it can be used for further wear resistance improvement of this widely used implant material. .
PB  - Univerzitet u Kragujevcu - Fakultet inženjerskih nauka, Kragujevac
T2  - Tribology in Industry
T1  - Influence of the heat treatment on the tribological characteristics of the Ti-based alloy for biomedical applications
EP  - 22
IS  - 3-4
SP  - 17
VL  - 31
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1424
ER  - 

@article{
author = "Cvijović-Alagić, Ivana and Mitrović, Slobodan and Cvijović, Zorica and Veljović, Đorđe and Babić, Miroslav and Rakin, Marko",
year = "2009",
abstract = "The influence of diverse heat treatments on micro-structural and tribological characteristics of Ti-6Al-4V ELI (mass%) alloy, which is used as implant material in biomedical engineering, was investigated on a block-on-disc tribometer. Aim of the present study was to explore the possibility of Ti-6Al-4V ELI alloy wear resistance improvement, examining the effects of different heat treatments on alloy microstructure, as well as on alloy wear characteristics in simulated body conditions using light optical microscopy (LOM) and scanning electron microscopy (SEM). Results presented in this paper show that the influence of heat treatment on micro-structural and tribological characteristics of the investigated Ti-based alloy is significant and that it can be used for further wear resistance improvement of this widely used implant material. .",
publisher = "Univerzitet u Kragujevcu - Fakultet inženjerskih nauka, Kragujevac",
journal = "Tribology in Industry",
title = "Influence of the heat treatment on the tribological characteristics of the Ti-based alloy for biomedical applications",
pages = "22-17",
number = "3-4",
volume = "31",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1424"
}

Cvijović-Alagić, I., Mitrović, S., Cvijović, Z., Veljović, Đ., Babić, M.,& Rakin, M.. (2009). Influence of the heat treatment on the tribological characteristics of the Ti-based alloy for biomedical applications. in Tribology in Industry
Univerzitet u Kragujevcu - Fakultet inženjerskih nauka, Kragujevac., 31(3-4), 17-22.
https://hdl.handle.net/21.15107/rcub_technorep_1424

Cvijović-Alagić I, Mitrović S, Cvijović Z, Veljović Đ, Babić M, Rakin M. Influence of the heat treatment on the tribological characteristics of the Ti-based alloy for biomedical applications. in Tribology in Industry. 2009;31(3-4):17-22.
https://hdl.handle.net/21.15107/rcub_technorep_1424 .

Cvijović-Alagić, Ivana, Mitrović, Slobodan, Cvijović, Zorica, Veljović, Đorđe, Babić, Miroslav, Rakin, Marko, "Influence of the heat treatment on the tribological characteristics of the Ti-based alloy for biomedical applications" in Tribology in Industry, 31, no. 3-4 (2009):17-22,
https://hdl.handle.net/21.15107/rcub_technorep_1424 .

TY  - JOUR
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Dobrojević, M.
AU  - Sedmak, Aleksandar
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5569
AB  - In this paper, the effect of strength mismatch and width of the welded joints oil the stress-strain distribution in the crack tip region has been discussed. The single-edge notched bend (SENB) specimens (precrack length a(0)/W= 0.32) were experimentally and numerically analysed. The model of local approach to fracture, proposed by Gurson, Tvergaard and Needleman, was used. High-strength low-alloyed (HSLA) steel was used as a base metal in quenched and tempered condition. The flux-cored arc-welding process in shielding gas was used. Two different fillers were selected to make over- and undermatched weld metal. The experimental analysis of fracture behaviour of the over- and undermatched welded joints was followed by numerical computations of void volume fraction in front of the crack tip. The critical void volume fraction, f(c), used in prediction of the crack growth initiation on the SENB specimen had been previously determined on a round smooth specimen. Three widths of weld metal were considered: 6,12 and 18 mm. A comparison of the crack tip opening displacement (CTOD) values corresponding to crack initiation in the SENB specimens is given, as determined both experimentally and using the GTN model.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Modelling of ductile fracture initiation in strength mismatched welded joint
EP  - 3510
IS  - 11
SP  - 3499
VL  - 75
DO  - 10.1016/j.engfracmech.2007.04.026
ER  - 

@article{
author = "Rakin, Marko and Gubeljak, Nenad and Dobrojević, M. and Sedmak, Aleksandar",
year = "2008",
abstract = "In this paper, the effect of strength mismatch and width of the welded joints oil the stress-strain distribution in the crack tip region has been discussed. The single-edge notched bend (SENB) specimens (precrack length a(0)/W= 0.32) were experimentally and numerically analysed. The model of local approach to fracture, proposed by Gurson, Tvergaard and Needleman, was used. High-strength low-alloyed (HSLA) steel was used as a base metal in quenched and tempered condition. The flux-cored arc-welding process in shielding gas was used. Two different fillers were selected to make over- and undermatched weld metal. The experimental analysis of fracture behaviour of the over- and undermatched welded joints was followed by numerical computations of void volume fraction in front of the crack tip. The critical void volume fraction, f(c), used in prediction of the crack growth initiation on the SENB specimen had been previously determined on a round smooth specimen. Three widths of weld metal were considered: 6,12 and 18 mm. A comparison of the crack tip opening displacement (CTOD) values corresponding to crack initiation in the SENB specimens is given, as determined both experimentally and using the GTN model.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Fracture Mechanics",
title = "Modelling of ductile fracture initiation in strength mismatched welded joint",
pages = "3510-3499",
number = "11",
volume = "75",
doi = "10.1016/j.engfracmech.2007.04.026"
}

Rakin, M., Gubeljak, N., Dobrojević, M.,& Sedmak, A.. (2008). Modelling of ductile fracture initiation in strength mismatched welded joint. in Engineering Fracture Mechanics
Pergamon-Elsevier Science Ltd, Oxford., 75(11), 3499-3510.
https://doi.org/10.1016/j.engfracmech.2007.04.026

Rakin M, Gubeljak N, Dobrojević M, Sedmak A. Modelling of ductile fracture initiation in strength mismatched welded joint. in Engineering Fracture Mechanics. 2008;75(11):3499-3510.
doi:10.1016/j.engfracmech.2007.04.026 .

Rakin, Marko, Gubeljak, Nenad, Dobrojević, M., Sedmak, Aleksandar, "Modelling of ductile fracture initiation in strength mismatched welded joint" in Engineering Fracture Mechanics, 75, no. 11 (2008):3499-3510,
https://doi.org/10.1016/j.engfracmech.2007.04.026 . .

TY  - JOUR
AU  - Zrilić, Milorad
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Cvijović, Zorica
AU  - Sedmak, Aleksandar
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1207
AB  - In the paper, the level of damage of steam pipeline steel after about 100,000 hours at 540 degrees C (1004 degrees F) under pressure of 42 bars (609 PSI) is analyzed. Material degradation is estimated using a combined experimental and numerical procedure based on micromechanical or local approach to fracture. Detailed analysis is conducted on the samples taken from exploited used steel and from unused new steel of the same designation. Damage parameter void growth ratio - is determined using round notched specimens, (including various notch radii). A comparison of the values for critical void growth ratio, computed for tested steels is made. Based on the values obtained, the possibility of prolongation of the operating life Of used steel is discussed.
PB  - ASME 2008 Pressure Vessels and Piping Conference, PVP2008
T2  - American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
T1  - Evaluation of damage of steam pipeline steel using local approach to fracture
EP  - 12
SP  - 7
VL  - 7
DO  - 10.1115/PVP2008-61265
ER  - 

@article{
author = "Zrilić, Milorad and Rakin, Marko and Međo, Bojan and Cvijović, Zorica and Sedmak, Aleksandar",
year = "2008",
abstract = "In the paper, the level of damage of steam pipeline steel after about 100,000 hours at 540 degrees C (1004 degrees F) under pressure of 42 bars (609 PSI) is analyzed. Material degradation is estimated using a combined experimental and numerical procedure based on micromechanical or local approach to fracture. Detailed analysis is conducted on the samples taken from exploited used steel and from unused new steel of the same designation. Damage parameter void growth ratio - is determined using round notched specimens, (including various notch radii). A comparison of the values for critical void growth ratio, computed for tested steels is made. Based on the values obtained, the possibility of prolongation of the operating life Of used steel is discussed.",
publisher = "ASME 2008 Pressure Vessels and Piping Conference, PVP2008",
journal = "American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP",
title = "Evaluation of damage of steam pipeline steel using local approach to fracture",
pages = "12-7",
volume = "7",
doi = "10.1115/PVP2008-61265"
}

Zrilić, M., Rakin, M., Međo, B., Cvijović, Z.,& Sedmak, A.. (2008). Evaluation of damage of steam pipeline steel using local approach to fracture. in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
ASME 2008 Pressure Vessels and Piping Conference, PVP2008., 7, 7-12.
https://doi.org/10.1115/PVP2008-61265

Zrilić M, Rakin M, Međo B, Cvijović Z, Sedmak A. Evaluation of damage of steam pipeline steel using local approach to fracture. in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 2008;7:7-12.
doi:10.1115/PVP2008-61265 .

Zrilić, Milorad, Rakin, Marko, Međo, Bojan, Cvijović, Zorica, Sedmak, Aleksandar, "Evaluation of damage of steam pipeline steel using local approach to fracture" in American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 7 (2008):7-12,
https://doi.org/10.1115/PVP2008-61265 . .

TY  - JOUR
AU  - Cvijović, Zorica
AU  - Vratnica, Maja
AU  - Rakin, Marko
AU  - Cvijović-Alagić, Ivana
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1292
AB  - An attempt has been made to model the plane-strain fracture toughness, KIc, in Al-Zn-Mg-Cu alloy forgings subjected to overageing. The proposed model, based on the multiple micromechanisms, reveals the quantitative relations between fracture toughness, fraction of all fracture modes and microstructural parameters associated with multiscale-sized second-phase particles and precipitate-free zones. The new model is validated by the present quantitative data of microstructural and fractographic analysis performed along with mechanical tests on hot-forged plates in T73 condition. The relevant parameters changed by the compositional variations were determined in two orientations. It was found that the predicted KIc values represent the tendency of fracture toughness change well. The new model provides better agreement for the case of dominant transgranular fracture mode.
PB  - Taylor & Francis Ltd, Abingdon
T2  - Philosophical Magazine
T1  - Micromechanical model for fracture toughness prediction in Al-Zn-Mg-Cu alloy forgings
EP  - 3179
IS  - 27
SP  - 3153
VL  - 88
DO  - 10.1080/14786430802502559
ER  - 

@article{
author = "Cvijović, Zorica and Vratnica, Maja and Rakin, Marko and Cvijović-Alagić, Ivana",
year = "2008",
abstract = "An attempt has been made to model the plane-strain fracture toughness, KIc, in Al-Zn-Mg-Cu alloy forgings subjected to overageing. The proposed model, based on the multiple micromechanisms, reveals the quantitative relations between fracture toughness, fraction of all fracture modes and microstructural parameters associated with multiscale-sized second-phase particles and precipitate-free zones. The new model is validated by the present quantitative data of microstructural and fractographic analysis performed along with mechanical tests on hot-forged plates in T73 condition. The relevant parameters changed by the compositional variations were determined in two orientations. It was found that the predicted KIc values represent the tendency of fracture toughness change well. The new model provides better agreement for the case of dominant transgranular fracture mode.",
publisher = "Taylor & Francis Ltd, Abingdon",
journal = "Philosophical Magazine",
title = "Micromechanical model for fracture toughness prediction in Al-Zn-Mg-Cu alloy forgings",
pages = "3179-3153",
number = "27",
volume = "88",
doi = "10.1080/14786430802502559"
}

Cvijović, Z., Vratnica, M., Rakin, M.,& Cvijović-Alagić, I.. (2008). Micromechanical model for fracture toughness prediction in Al-Zn-Mg-Cu alloy forgings. in Philosophical Magazine
Taylor & Francis Ltd, Abingdon., 88(27), 3153-3179.
https://doi.org/10.1080/14786430802502559

Cvijović Z, Vratnica M, Rakin M, Cvijović-Alagić I. Micromechanical model for fracture toughness prediction in Al-Zn-Mg-Cu alloy forgings. in Philosophical Magazine. 2008;88(27):3153-3179.
doi:10.1080/14786430802502559 .

Cvijović, Zorica, Vratnica, Maja, Rakin, Marko, Cvijović-Alagić, Ivana, "Micromechanical model for fracture toughness prediction in Al-Zn-Mg-Cu alloy forgings" in Philosophical Magazine, 88, no. 27 (2008):3153-3179,
https://doi.org/10.1080/14786430802502559 . .

TY  - JOUR
AU  - Cvijović, Zorica
AU  - Rakin, Marko
AU  - Vratnica, Maja
AU  - Cvijović, Ivana
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1320
AB  - The effects of microstructural parameters associated with the coarse intermetallic phases particles and precipitates on the fracture toughness of the overaged 7000 alloy forgings are investigated. Detailed microstructural and fractographic analysis together with fracture toughness tests are carried out using three alloys with different (Fe + Si) contents. The fracture mechanisms are identified and area fractions of different fracture modes are assessed. The data are then quantitatively correlated to plane-strain fracture toughness, K-Ic, and the bulk microstructural attributes estimated via image analysis. A multiple micromechanism-based model is developed, which accurately describes the dependence of K-Ic on individual microstructural parameters.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Microstructural dependence of fracture toughness in high-strength 7000 forging alloys
EP  - 2129
IS  - 8
SP  - 2115
VL  - 75
DO  - 10.1016/j.engfracmech.2007.10.010
ER  - 

@article{
author = "Cvijović, Zorica and Rakin, Marko and Vratnica, Maja and Cvijović, Ivana",
year = "2008",
abstract = "The effects of microstructural parameters associated with the coarse intermetallic phases particles and precipitates on the fracture toughness of the overaged 7000 alloy forgings are investigated. Detailed microstructural and fractographic analysis together with fracture toughness tests are carried out using three alloys with different (Fe + Si) contents. The fracture mechanisms are identified and area fractions of different fracture modes are assessed. The data are then quantitatively correlated to plane-strain fracture toughness, K-Ic, and the bulk microstructural attributes estimated via image analysis. A multiple micromechanism-based model is developed, which accurately describes the dependence of K-Ic on individual microstructural parameters.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Fracture Mechanics",
title = "Microstructural dependence of fracture toughness in high-strength 7000 forging alloys",
pages = "2129-2115",
number = "8",
volume = "75",
doi = "10.1016/j.engfracmech.2007.10.010"
}

Cvijović, Z., Rakin, M., Vratnica, M.,& Cvijović, I.. (2008). Microstructural dependence of fracture toughness in high-strength 7000 forging alloys. in Engineering Fracture Mechanics
Pergamon-Elsevier Science Ltd, Oxford., 75(8), 2115-2129.
https://doi.org/10.1016/j.engfracmech.2007.10.010

Cvijović Z, Rakin M, Vratnica M, Cvijović I. Microstructural dependence of fracture toughness in high-strength 7000 forging alloys. in Engineering Fracture Mechanics. 2008;75(8):2115-2129.
doi:10.1016/j.engfracmech.2007.10.010 .

Cvijović, Zorica, Rakin, Marko, Vratnica, Maja, Cvijović, Ivana, "Microstructural dependence of fracture toughness in high-strength 7000 forging alloys" in Engineering Fracture Mechanics, 75, no. 8 (2008):2115-2129,
https://doi.org/10.1016/j.engfracmech.2007.10.010 . .

TY  - JOUR
AU  - Šumarac, Dragoslav
AU  - Međo, Bojan
AU  - Trišović, Nataša
PY  - 2008
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1289
AB  - In the present paper the Preisach model of hysteresis is applied to model cyclic behavior of elasto-plastic material. Rate of loading and viscous effects will not be considered. The problem of axial loading of rectangular cross section and cyclic bending of rectangular tube (box) will be studied in details. Hysteretic stress-strain loop for prescribed history of stress change is plotted for material modeled by series connection of three unite element. Also moment-curvature hysteretic loop is obtained for a prescribed curvature change of rectangular tube (box). One chapter of the paper is devoted to results obtained by FEM using Finite Element Code ABAQUS. All obtained results clearly show advantages of the Preisach model for describing cyclic behavior of elasto-plastic material.
AB  - U posmatranom radu Prajzakov model histerezisa je primenjen na modeliranje cikličnog ponašanja elasto-plastičnih materijala. Pri tome brzina nanošenja opterećenja i viskozni efekti se ne uzimaju u obzir. U radu se detaljno proučava problem aksijalnog naprezanja pravougaonog poprečnog preseka i ciklično savijanje pravougaone čelične cevi. Konstruisana je histerezisna petlja za zadatu promenu cikličnog opterećenja za materijal modeliran sa tri osnovna elementa. Takođe, histerezis momenat-krivina za čeličnu pravougaonu cev je konstruisan za zadatu istoriju promene krivine. U posebnom poglavlju se obrađuju rezultati dobijeni primenom MKE korišćenjem programa ABAQUS. Svi dobijeni rezultati jasno pokazuju prednost Prajzakovog modela kod opisivanja cikličnog ponašanja elasto-plastičnih materijala.
PB  - Serbian Society of Mechanics & Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade
T2  - Theoretical and Applied Mechanics
T1  - Hysteretic behavior modeling of elastoplastic materials
T1  - Modeliranje histerezisnog ponašanja elastoplastičnih materijala
EP  - 304
IS  - 1-3
SP  - 287
VL  - 35
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1289
ER  - 

@article{
author = "Šumarac, Dragoslav and Međo, Bojan and Trišović, Nataša",
year = "2008",
abstract = "In the present paper the Preisach model of hysteresis is applied to model cyclic behavior of elasto-plastic material. Rate of loading and viscous effects will not be considered. The problem of axial loading of rectangular cross section and cyclic bending of rectangular tube (box) will be studied in details. Hysteretic stress-strain loop for prescribed history of stress change is plotted for material modeled by series connection of three unite element. Also moment-curvature hysteretic loop is obtained for a prescribed curvature change of rectangular tube (box). One chapter of the paper is devoted to results obtained by FEM using Finite Element Code ABAQUS. All obtained results clearly show advantages of the Preisach model for describing cyclic behavior of elasto-plastic material., U posmatranom radu Prajzakov model histerezisa je primenjen na modeliranje cikličnog ponašanja elasto-plastičnih materijala. Pri tome brzina nanošenja opterećenja i viskozni efekti se ne uzimaju u obzir. U radu se detaljno proučava problem aksijalnog naprezanja pravougaonog poprečnog preseka i ciklično savijanje pravougaone čelične cevi. Konstruisana je histerezisna petlja za zadatu promenu cikličnog opterećenja za materijal modeliran sa tri osnovna elementa. Takođe, histerezis momenat-krivina za čeličnu pravougaonu cev je konstruisan za zadatu istoriju promene krivine. U posebnom poglavlju se obrađuju rezultati dobijeni primenom MKE korišćenjem programa ABAQUS. Svi dobijeni rezultati jasno pokazuju prednost Prajzakovog modela kod opisivanja cikličnog ponašanja elasto-plastičnih materijala.",
publisher = "Serbian Society of Mechanics & Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade",
journal = "Theoretical and Applied Mechanics",
title = "Hysteretic behavior modeling of elastoplastic materials, Modeliranje histerezisnog ponašanja elastoplastičnih materijala",
pages = "304-287",
number = "1-3",
volume = "35",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1289"
}

Šumarac, D., Međo, B.,& Trišović, N.. (2008). Hysteretic behavior modeling of elastoplastic materials. in Theoretical and Applied Mechanics
Serbian Society of Mechanics & Mathematical Institute of the Serbian Academy of Sciences and Arts, Belgrade., 35(1-3), 287-304.
https://hdl.handle.net/21.15107/rcub_technorep_1289

Šumarac D, Međo B, Trišović N. Hysteretic behavior modeling of elastoplastic materials. in Theoretical and Applied Mechanics. 2008;35(1-3):287-304.
https://hdl.handle.net/21.15107/rcub_technorep_1289 .

Šumarac, Dragoslav, Međo, Bojan, Trišović, Nataša, "Hysteretic behavior modeling of elastoplastic materials" in Theoretical and Applied Mechanics, 35, no. 1-3 (2008):287-304,
https://hdl.handle.net/21.15107/rcub_technorep_1289 .

TY  - JOUR
AU  - Cvijović, Zorica M.
AU  - Cvijović, Ivana
AU  - Vratnic, M.
PY  - 2007
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5490
AB  - Micromechanisms controlling the fracture damage in 7000 alloy forgings are studied for T73-type heat treatments. Insight into the fracture modes are obtained by varying the microstructural attributes associated with the coarse intermetallic (IM) particles and precipitates. To identify the fracture micromechanisms, extensive fractographic analysis by scanning electron microscopy (SEM) observation of the broken plane-strain fracture-toughness test specimen surfaces are carried out. The relative fractions of the various fracture modes as a function of microstructural features are quantitatively determined. The relationships between these data and values of fracture toughness are then established. It was found that multiple-fracture micromechanisms occur and the fracture toughness degradation is consistent with a change in the dominant fracture mode governed by variations in the alloy purity. (C) 2006 Elsevier B.V. All rights reserved.
T2  - Journal of Alloys and Compounds
T1  - Fracture micromechanisms in overaged 7000 alloy forgings
EP  - 75
IS  - 1-2
SP  - 66
VL  - 441
DO  - 10.1016/j.jallcom.2006.09.061
ER  - 

@article{
author = "Cvijović, Zorica M. and Cvijović, Ivana and Vratnic, M.",
year = "2007",
abstract = "Micromechanisms controlling the fracture damage in 7000 alloy forgings are studied for T73-type heat treatments. Insight into the fracture modes are obtained by varying the microstructural attributes associated with the coarse intermetallic (IM) particles and precipitates. To identify the fracture micromechanisms, extensive fractographic analysis by scanning electron microscopy (SEM) observation of the broken plane-strain fracture-toughness test specimen surfaces are carried out. The relative fractions of the various fracture modes as a function of microstructural features are quantitatively determined. The relationships between these data and values of fracture toughness are then established. It was found that multiple-fracture micromechanisms occur and the fracture toughness degradation is consistent with a change in the dominant fracture mode governed by variations in the alloy purity. (C) 2006 Elsevier B.V. All rights reserved.",
journal = "Journal of Alloys and Compounds",
title = "Fracture micromechanisms in overaged 7000 alloy forgings",
pages = "75-66",
number = "1-2",
volume = "441",
doi = "10.1016/j.jallcom.2006.09.061"
}

Cvijović, Z. M., Cvijović, I.,& Vratnic, M.. (2007). Fracture micromechanisms in overaged 7000 alloy forgings. in Journal of Alloys and Compounds, 441(1-2), 66-75.
https://doi.org/10.1016/j.jallcom.2006.09.061

Cvijović ZM, Cvijović I, Vratnic M. Fracture micromechanisms in overaged 7000 alloy forgings. in Journal of Alloys and Compounds. 2007;441(1-2):66-75.
doi:10.1016/j.jallcom.2006.09.061 .

Cvijović, Zorica M., Cvijović, Ivana, Vratnic, M., "Fracture micromechanisms in overaged 7000 alloy forgings" in Journal of Alloys and Compounds, 441, no. 1-2 (2007):66-75,
https://doi.org/10.1016/j.jallcom.2006.09.061 . .

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 . .

TY  - JOUR
AU  - Vratnica, Maja
AU  - Cvijović, Zorica
AU  - Rakin, Marko
AU  - Cvijović, Ivana
PY  - 2007
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/1046
AB  - An attempt to develop a multiple micromechanism-based model for predicting plane-strain fracture toughness, KIc, of overaged 7000 alloy forgings has been made. The proposed model reveals the quantitative relations between the fracture toughness, fraction of the main fracture modes and parameters such as volume fraction, size and density of differently sized second-phase particles and precipitate-free zones. The new model is validated by the present quantitative data of microstructural and fractographic analysis performed along with mechanical tests on hot-forged plates subjected to the T73 temper. The relative parameters changed by the compositional variations were determined in the R-L and L-R orientations. It was found that the predicted KIc values well represent the tendency of fracture toughness change. The new model provides better agreement for the case of dominant transgranular fracture mode represented in the R-L orientation. .
PB  - Savez inženjera metalurgije Srbije, Beograd
T2  - Metalurgija
T1  - A model for predicting fracture toughness in overaged 7000 alloy forgings
EP  - 300
IS  - 4
SP  - 293
VL  - 13
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1046
ER  - 

@article{
author = "Vratnica, Maja and Cvijović, Zorica and Rakin, Marko and Cvijović, Ivana",
year = "2007",
abstract = "An attempt to develop a multiple micromechanism-based model for predicting plane-strain fracture toughness, KIc, of overaged 7000 alloy forgings has been made. The proposed model reveals the quantitative relations between the fracture toughness, fraction of the main fracture modes and parameters such as volume fraction, size and density of differently sized second-phase particles and precipitate-free zones. The new model is validated by the present quantitative data of microstructural and fractographic analysis performed along with mechanical tests on hot-forged plates subjected to the T73 temper. The relative parameters changed by the compositional variations were determined in the R-L and L-R orientations. It was found that the predicted KIc values well represent the tendency of fracture toughness change. The new model provides better agreement for the case of dominant transgranular fracture mode represented in the R-L orientation. .",
publisher = "Savez inženjera metalurgije Srbije, Beograd",
journal = "Metalurgija",
title = "A model for predicting fracture toughness in overaged 7000 alloy forgings",
pages = "300-293",
number = "4",
volume = "13",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1046"
}

Vratnica, M., Cvijović, Z., Rakin, M.,& Cvijović, I.. (2007). A model for predicting fracture toughness in overaged 7000 alloy forgings. in Metalurgija
Savez inženjera metalurgije Srbije, Beograd., 13(4), 293-300.
https://hdl.handle.net/21.15107/rcub_technorep_1046

Vratnica M, Cvijović Z, Rakin M, Cvijović I. A model for predicting fracture toughness in overaged 7000 alloy forgings. in Metalurgija. 2007;13(4):293-300.
https://hdl.handle.net/21.15107/rcub_technorep_1046 .

Vratnica, Maja, Cvijović, Zorica, Rakin, Marko, Cvijović, Ivana, "A model for predicting fracture toughness in overaged 7000 alloy forgings" in Metalurgija, 13, no. 4 (2007):293-300,
https://hdl.handle.net/21.15107/rcub_technorep_1046 .

TY  - JOUR
AU  - Vratnica, M.
AU  - Cvijović, Zorica
AU  - Degische, H.P.
AU  - Requena, G.C.
PY  - 2006
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5469
AB  - The effect of coarse intermetallic particles on the fracture process in 7000 alloy forgings was investigated using three alloys with different (Fe + Si) impurity levels. The intermetallic particles were identified by selective etching and energy dispersive spectroscopy analysis conducted on a scanning electron microscope. Their geometrical parameters were estimated by image analysis and then correlated with area fractions of different fracture modes on the broken fracture toughness test specimens. It was found that the dominant fracture mode varies with the (Fe + Si) content. The coarse voiding at large intermetallic particles increases systematically with an increase of the impurity level, which in turn increases the amount and size of particles containing Fe and Si while decreasing their spacing. That the crack nucleation and propagation are accelerated by these particles was revealed by in situ scanning electron microscopy observation of the fracture process.
PB  - Wiley-Blackwell
T2  - Journal of Microscopy
T1  - The effect of coarse intermetallic particles on the fracture process in forged 7000 alloys
EP  - 120
IS  - 1
SP  - 117
VL  - 224
DO  - 10.1111/j.1365-2818.2006.01683.x
ER  - 

@article{
author = "Vratnica, M. and Cvijović, Zorica and Degische, H.P. and Requena, G.C.",
year = "2006",
abstract = "The effect of coarse intermetallic particles on the fracture process in 7000 alloy forgings was investigated using three alloys with different (Fe + Si) impurity levels. The intermetallic particles were identified by selective etching and energy dispersive spectroscopy analysis conducted on a scanning electron microscope. Their geometrical parameters were estimated by image analysis and then correlated with area fractions of different fracture modes on the broken fracture toughness test specimens. It was found that the dominant fracture mode varies with the (Fe + Si) content. The coarse voiding at large intermetallic particles increases systematically with an increase of the impurity level, which in turn increases the amount and size of particles containing Fe and Si while decreasing their spacing. That the crack nucleation and propagation are accelerated by these particles was revealed by in situ scanning electron microscopy observation of the fracture process.",
publisher = "Wiley-Blackwell",
journal = "Journal of Microscopy",
title = "The effect of coarse intermetallic particles on the fracture process in forged 7000 alloys",
pages = "120-117",
number = "1",
volume = "224",
doi = "10.1111/j.1365-2818.2006.01683.x"
}

Vratnica, M., Cvijović, Z., Degische, H.P.,& Requena, G.C.. (2006). The effect of coarse intermetallic particles on the fracture process in forged 7000 alloys. in Journal of Microscopy
Wiley-Blackwell., 224(1), 117-120.
https://doi.org/10.1111/j.1365-2818.2006.01683.x

Vratnica M, Cvijović Z, Degische H, Requena G. The effect of coarse intermetallic particles on the fracture process in forged 7000 alloys. in Journal of Microscopy. 2006;224(1):117-120.
doi:10.1111/j.1365-2818.2006.01683.x .

Vratnica, M., Cvijović, Zorica, Degische, H.P., Requena, G.C., "The effect of coarse intermetallic particles on the fracture process in forged 7000 alloys" in Journal of Microscopy, 224, no. 1 (2006):117-120,
https://doi.org/10.1111/j.1365-2818.2006.01683.x . .