TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Mitrović, Nenad
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
AU  - Međo, Bojan
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7700
AB  - A global problem for industrial plants that contain process equipment operating under high pressure is the assessment of the integrity of the equipment, specifically the pipelines. Standard procedures for determining fracture mechanics parameters (ASTM E1820) for materials used in pressure piping construction cannot be applied to most thin-wall pressure components. One of the solutions to this problem is the introduction of new procedures and geometries of test specimens. In order to understand the nature of the behavior of the specimens and to determine the parameters whose critical values are important for integrity assessment of the pipeline under pressure, a detailed analysis of the model of the non-standard ring-shaped specimen is
necessary. This paper will present the results of the analysis of fracture mechanics parameters obtained by the finite element method using the Simulia Abaqus software package. The properties of the material used in the software correspond to the properties of the P235TR1 pipeline material obtained by tensile testing on cylindrical samples with initial crack. The ratio of crack length (a) to sample width (W) corresponds to standard sample geometries and varies from a/W = 0.4 to a/W = 0.6. The values obtained from SENT (Single Edge Notched Tension) models with the same cross-section and a/W ratio were taken as reference values in relation to which the comparison is made. As a result of this research, the ratio of fracture mechanics parameters of the ring-shaped model (Pipe Ring Notched Tension – PRNT specimen) with a crack and the SENT model was obtained. The values of the J-integral were also obtained, distribution of values along the crack front does not correspond to the profile obtained on the SENT model. As a result of this test, a procedure for determining the critical value of the J-integral for models corresponding to the tested P235TR1 pipe samples was established, which is an important step in establishing a new procedure for testing of pipeline materials.
PB  - University of Belgrade - Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2023
T1  - THE INFLUENCE OF CYLLINDRICAL SPECIMEN GEOMETRY ON THE VALUES OF FRACTURE MECHANICS PARAMETERS
SP  - 26
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7700
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Mitrović, Nenad and Sedmak, Aleksandar and Rakin, Marko and Međo, Bojan",
year = "2023",
abstract = "A global problem for industrial plants that contain process equipment operating under high pressure is the assessment of the integrity of the equipment, specifically the pipelines. Standard procedures for determining fracture mechanics parameters (ASTM E1820) for materials used in pressure piping construction cannot be applied to most thin-wall pressure components. One of the solutions to this problem is the introduction of new procedures and geometries of test specimens. In order to understand the nature of the behavior of the specimens and to determine the parameters whose critical values are important for integrity assessment of the pipeline under pressure, a detailed analysis of the model of the non-standard ring-shaped specimen is
necessary. This paper will present the results of the analysis of fracture mechanics parameters obtained by the finite element method using the Simulia Abaqus software package. The properties of the material used in the software correspond to the properties of the P235TR1 pipeline material obtained by tensile testing on cylindrical samples with initial crack. The ratio of crack length (a) to sample width (W) corresponds to standard sample geometries and varies from a/W = 0.4 to a/W = 0.6. The values obtained from SENT (Single Edge Notched Tension) models with the same cross-section and a/W ratio were taken as reference values in relation to which the comparison is made. As a result of this research, the ratio of fracture mechanics parameters of the ring-shaped model (Pipe Ring Notched Tension – PRNT specimen) with a crack and the SENT model was obtained. The values of the J-integral were also obtained, distribution of values along the crack front does not correspond to the profile obtained on the SENT model. As a result of this test, a procedure for determining the critical value of the J-integral for models corresponding to the tested P235TR1 pipe samples was established, which is an important step in establishing a new procedure for testing of pipeline materials.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2023",
title = "THE INFLUENCE OF CYLLINDRICAL SPECIMEN GEOMETRY ON THE VALUES OF FRACTURE MECHANICS PARAMETERS",
pages = "26",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7700"
}

Trajković, I., Milošević, M., Mitrović, N., Sedmak, A., Rakin, M.,& Međo, B.. (2023). THE INFLUENCE OF CYLLINDRICAL SPECIMEN GEOMETRY ON THE VALUES OF FRACTURE MECHANICS PARAMETERS. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2023
University of Belgrade - Faculty of Mechanical Engineering., 26.
https://hdl.handle.net/21.15107/rcub_machinery_7700

Trajković I, Milošević M, Mitrović N, Sedmak A, Rakin M, Međo B. THE INFLUENCE OF CYLLINDRICAL SPECIMEN GEOMETRY ON THE VALUES OF FRACTURE MECHANICS PARAMETERS. in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2023. 2023;:26.
https://hdl.handle.net/21.15107/rcub_machinery_7700 .

Trajković, Isaak, Milošević, Miloš, Mitrović, Nenad, Sedmak, Aleksandar, Rakin, Marko, Međo, Bojan, "THE INFLUENCE OF CYLLINDRICAL SPECIMEN GEOMETRY ON THE VALUES OF FRACTURE MECHANICS PARAMETERS" in International Conference of Experimental and Numerical Investigations and New Technologies CNN TECH 2023 (2023):26,
https://hdl.handle.net/21.15107/rcub_machinery_7700 .

TY  - JOUR
AU  - Trajković, Isaak
AU  - Rakin, Marko
AU  - Milošević, Miloš
AU  - Mitrović, Nenad
AU  - Travica, Milan
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7231
AB  - In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.
PB  - Engineering Fracture Mechanics
T2  - Engineering Fracture Mechanics
T1  - Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials
IS  - 109573
VL  - 292
DO  - 10.1016/j.engfracmech.2023.109573
ER  - 

@article{
author = "Trajković, Isaak and Rakin, Marko and Milošević, Miloš and Mitrović, Nenad and Travica, Milan and Sedmak, Aleksandar and Međo, Bojan",
year = "2023",
abstract = "In order to develop a non-standard method for determining the resistance to fracture and damage of pipeline materials, a new geometry of ring-shaped specimens with sharp notches or cracks has been defined. The need to develop a new method for testing of the specimens cut from the pipes arises due to the difficulties in determination of fracture mechanics parameters on thin-walled pressure pipelines, especially those with a smaller cross-section, by application of the standard procedures/specimens. Previous studies dealing with the topic of pipeline testing by non-standard methods are presented in the introductory part of the paper. In the experimental part of the research, tests on PRNT (Pipe Ring Notched Tension) and SENT (Single Edge Notched Tension) specimens are performed. Samples of these specimens were produced by SLS (Selective Laser Sintering) technique of additive production from PA12 (polyamide PA 2200) material. For the purpose of this study, a tool that is protected at the national level (in Serbia) as intellectual property is used for testing of the ring-shaped PRNT specimens. Tensile testing of both types of specimens is monitored by Aramis GOM 2M system; its operation is based on the method of digital image correlation, DIC. Additionally, finite element analyses are conducted on the PRNT and SENT geometries, enabling the calculation of the fracture mechanics parameter – Stress intensity factor K. It is concluded that the presented procedure based on the PRNT specimen has a good potential for use as a non-standard method for fracture resistance examination of pipeline materials. It can be performed on the specimens cut directly from the pipes (new or from exploitation). The dependence of the fracture resistance on the stress concentrator size is not pronounced, which means that the results depend dominantly on the material properties, rather than on geometry.",
publisher = "Engineering Fracture Mechanics",
journal = "Engineering Fracture Mechanics",
title = "Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials",
number = "109573",
volume = "292",
doi = "10.1016/j.engfracmech.2023.109573"
}

Trajković, I., Rakin, M., Milošević, M., Mitrović, N., Travica, M., Sedmak, A.,& Međo, B.. (2023). Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials. in Engineering Fracture Mechanics
Engineering Fracture Mechanics., 292(109573).
https://doi.org/10.1016/j.engfracmech.2023.109573

Trajković I, Rakin M, Milošević M, Mitrović N, Travica M, Sedmak A, Međo B. Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials. in Engineering Fracture Mechanics. 2023;292(109573).
doi:10.1016/j.engfracmech.2023.109573 .

Trajković, Isaak, Rakin, Marko, Milošević, Miloš, Mitrović, Nenad, Travica, Milan, Sedmak, Aleksandar, Međo, Bojan, "Selective laser sintered Pipe Ring Notched Tension specimens for examination of fracture properties of pipeline materials" in Engineering Fracture Mechanics, 292, no. 109573 (2023),
https://doi.org/10.1016/j.engfracmech.2023.109573 . .

TY  - CONF
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
AU  - Trajković, Isaak
AU  - Milošević, Miloš
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7273
AB  - This paper presents the influence of geometry on the determination of the stress intensity factor KI on specimens produced by the selective laser sintering technique.The analysis of the determination of the stress intensity factor includes experimental and numerical tests. For this purpose, two geometries of specimens were used. Flat specimens with crack loaded in tension and ring specimens loaded on the inner wall. To understand the influence of geometry, specimens and their identical models were tested with three different ratios between the width of the test specimens and the initial length of the crack. Both types of specimens used for this experiment were made from polyamide PA12 utilizing the SLS (selective laser sintering) additive manufacturing process. The specimens are tested using the Shimadzu AGS-X 100 kN universal equipment for measuring mechanical characteristics of materials. The tensile testing is complemented by the GOM Aramis 2M system, which is utilized for digital image correlation and surface displacement tracking. For the numerical analyzes, we used the finite element method (Abaqus CAE software) to determine the KI factor based on the experimentally obtained results. The values of stress intensity factor for PA12 material show some different results for different types of specimens and effects of the type of production technique. We will present all the results and detail of examination in this paper.
PB  - Serbian Ceramic Society
C3  - Serbian Ceramic Society
T1  - Experimental and numerical determination of the fracture strength of PA12 material on specimens produced by selective laser sintering
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7273
ER  - 

@conference{
author = "Milošević, Miloš and Travica, Milan and Rakin, Marko and Sedmak, Aleksandar and Međo, Bojan and Trajković, Isaak and Milošević, Miloš",
year = "2023",
abstract = "This paper presents the influence of geometry on the determination of the stress intensity factor KI on specimens produced by the selective laser sintering technique.The analysis of the determination of the stress intensity factor includes experimental and numerical tests. For this purpose, two geometries of specimens were used. Flat specimens with crack loaded in tension and ring specimens loaded on the inner wall. To understand the influence of geometry, specimens and their identical models were tested with three different ratios between the width of the test specimens and the initial length of the crack. Both types of specimens used for this experiment were made from polyamide PA12 utilizing the SLS (selective laser sintering) additive manufacturing process. The specimens are tested using the Shimadzu AGS-X 100 kN universal equipment for measuring mechanical characteristics of materials. The tensile testing is complemented by the GOM Aramis 2M system, which is utilized for digital image correlation and surface displacement tracking. For the numerical analyzes, we used the finite element method (Abaqus CAE software) to determine the KI factor based on the experimentally obtained results. The values of stress intensity factor for PA12 material show some different results for different types of specimens and effects of the type of production technique. We will present all the results and detail of examination in this paper.",
publisher = "Serbian Ceramic Society",
journal = "Serbian Ceramic Society",
title = "Experimental and numerical determination of the fracture strength of PA12 material on specimens produced by selective laser sintering",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7273"
}

Milošević, M., Travica, M., Rakin, M., Sedmak, A., Međo, B., Trajković, I.,& Milošević, M.. (2023). Experimental and numerical determination of the fracture strength of PA12 material on specimens produced by selective laser sintering. in Serbian Ceramic Society
Serbian Ceramic Society..
https://hdl.handle.net/21.15107/rcub_machinery_7273

Milošević M, Travica M, Rakin M, Sedmak A, Međo B, Trajković I, Milošević M. Experimental and numerical determination of the fracture strength of PA12 material on specimens produced by selective laser sintering. in Serbian Ceramic Society. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_7273 .

Milošević, Miloš, Travica, Milan, Rakin, Marko, Sedmak, Aleksandar, Međo, Bojan, Trajković, Isaak, Milošević, Miloš, "Experimental and numerical determination of the fracture strength of PA12 material on specimens produced by selective laser sintering" in Serbian Ceramic Society (2023),
https://hdl.handle.net/21.15107/rcub_machinery_7273 .

TY  - JOUR
AU  - Trajkovic, Isaak
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Mladenović, Goran
AU  - Kudrjavceva, Ljudmila
AU  - Međo, Bojan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6874
AB  - This paper presents a part of development of a non-standard method for testing of cylindrical test specimens for measurement of fracture properties of pipeline materials. This method for testing of cylindrical structures working under pressure is based on determining of fracture mechanics parameters on SENT (Single Edge Notched Tension) specimens and new PRNT (Pipe Ring Notched Tension) specimens. In this work, both types of specimens required for this testing were manufactured from polyamide PA12 by using SLS (selective laser sintering) additive manufacturing method. Testing of the specimens is performed on the universal device for testing of mechanical properties of materials Shimadzu, AGS-X 100 kN. The tensile testing is accompanied by GOM Aramis 2M system, used for digital image correlation. By using these two systems, test results are obtained for ring-shaped and SENT specimens, including forces, displacements and fracture mechanics parameters CMOD (Crack Mouth Opening Displacement) and CTOD-δ5 (Crack Tip Opening Displacement obtained by δ5 technique), as well as crack growth. Repeatability of this process, along with valid result consistency, represent the basis for further development of the new method, including the determining of energy-based fracture mechanics parameters: J integral and stress intensity factor.
PB  - International Institute for the Science of Sintering
T2  - Science of Sintering
T1  - Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens
EP  - 386
SP  - 373
VL  - 54
DO  - 10.2298/SOS2203373T
ER  - 

@article{
author = "Trajkovic, Isaak and Milošević, Miloš and Travica, Milan and Rakin, Marko and Mladenović, Goran and Kudrjavceva, Ljudmila and Međo, Bojan",
year = "2022",
abstract = "This paper presents a part of development of a non-standard method for testing of cylindrical test specimens for measurement of fracture properties of pipeline materials. This method for testing of cylindrical structures working under pressure is based on determining of fracture mechanics parameters on SENT (Single Edge Notched Tension) specimens and new PRNT (Pipe Ring Notched Tension) specimens. In this work, both types of specimens required for this testing were manufactured from polyamide PA12 by using SLS (selective laser sintering) additive manufacturing method. Testing of the specimens is performed on the universal device for testing of mechanical properties of materials Shimadzu, AGS-X 100 kN. The tensile testing is accompanied by GOM Aramis 2M system, used for digital image correlation. By using these two systems, test results are obtained for ring-shaped and SENT specimens, including forces, displacements and fracture mechanics parameters CMOD (Crack Mouth Opening Displacement) and CTOD-δ5 (Crack Tip Opening Displacement obtained by δ5 technique), as well as crack growth. Repeatability of this process, along with valid result consistency, represent the basis for further development of the new method, including the determining of energy-based fracture mechanics parameters: J integral and stress intensity factor.",
publisher = "International Institute for the Science of Sintering",
journal = "Science of Sintering",
title = "Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens",
pages = "386-373",
volume = "54",
doi = "10.2298/SOS2203373T"
}

Trajkovic, I., Milošević, M., Travica, M., Rakin, M., Mladenović, G., Kudrjavceva, L.,& Međo, B.. (2022). Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens. in Science of Sintering
International Institute for the Science of Sintering., 54, 373-386.
https://doi.org/10.2298/SOS2203373T

Trajkovic I, Milošević M, Travica M, Rakin M, Mladenović G, Kudrjavceva L, Međo B. Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens. in Science of Sintering. 2022;54:373-386.
doi:10.2298/SOS2203373T .

Trajkovic, Isaak, Milošević, Miloš, Travica, Milan, Rakin, Marko, Mladenović, Goran, Kudrjavceva, Ljudmila, Međo, Bojan, "Novel Method for Measurement of Pipeline Materials Fracture Resistance-Examination on Selective Laser Sintered Cylindrical Specimens" in Science of Sintering, 54 (2022):373-386,
https://doi.org/10.2298/SOS2203373T . .

TY  - CONF
AU  - Milošević, Miloš
AU  - Rakin, Marko
AU  - Berto, Filipo
AU  - Međo, Bojan
AU  - Trajković, Isaak
AU  - Bogojević, Nebojša
AU  - Ćirić-Kostić, Snežana
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7274
AB  - Plane-strain fracture toughness is one of the main parameters in linear elastic
fracture mechanics and its purpose is to show the material capability to withstand load while
having a defect. Main validity aspect for such an assessment is to provide a wide enough crack
front to enable plane-strain condition. Nonetheless, in FDM (Fused Deposition Modeling)
polymers, due to structural anisotropy caused by material properties and Additive
Manufacturing (AM) process parameters, more validity aspects must be met. During the planestrain fracture toughness test a crack must follow a straight line from initiation cite up to the
point of structural failure. For such a purpose a DIC (Digital Image Correlation) device can be
used for crack path direction analysis. Plane-strain fracture toughness assessment is conducted
according to the ASTM D5045-14 standard for testing of polymer materials. Tests are
performed on SENB (Single Edge Notched Bend) specimens, made from two similar polymer
materials: quasi-brittle PLA and ductile PLA-X composite. Specimens are manufactured with
four different AM process parameters, i.e., layer height, infill density, printing orientation and
one batch was dried before testing. Testing is conducted using 3-point bending test fixture on
universal testing machine, with DIC dual-camera device placed ahead of the machine in order
to capture full-field deformations of front SENB specimen surface (Fig. 1).
PB  - ESIS Publishing House (ESIS-PH) European Conference on Fracture
C3  - Procedia Structural Integrity
T1  - Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7274
ER  - 

@conference{
author = "Milošević, Miloš and Rakin, Marko and Berto, Filipo and Međo, Bojan and Trajković, Isaak and Bogojević, Nebojša and Ćirić-Kostić, Snežana",
year = "2022",
abstract = "Plane-strain fracture toughness is one of the main parameters in linear elastic
fracture mechanics and its purpose is to show the material capability to withstand load while
having a defect. Main validity aspect for such an assessment is to provide a wide enough crack
front to enable plane-strain condition. Nonetheless, in FDM (Fused Deposition Modeling)
polymers, due to structural anisotropy caused by material properties and Additive
Manufacturing (AM) process parameters, more validity aspects must be met. During the planestrain fracture toughness test a crack must follow a straight line from initiation cite up to the
point of structural failure. For such a purpose a DIC (Digital Image Correlation) device can be
used for crack path direction analysis. Plane-strain fracture toughness assessment is conducted
according to the ASTM D5045-14 standard for testing of polymer materials. Tests are
performed on SENB (Single Edge Notched Bend) specimens, made from two similar polymer
materials: quasi-brittle PLA and ductile PLA-X composite. Specimens are manufactured with
four different AM process parameters, i.e., layer height, infill density, printing orientation and
one batch was dried before testing. Testing is conducted using 3-point bending test fixture on
universal testing machine, with DIC dual-camera device placed ahead of the machine in order
to capture full-field deformations of front SENB specimen surface (Fig. 1).",
publisher = "ESIS Publishing House (ESIS-PH) European Conference on Fracture",
journal = "Procedia Structural Integrity",
title = "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7274"
}

Milošević, M., Rakin, M., Berto, F., Međo, B., Trajković, I., Bogojević, N.,& Ćirić-Kostić, S.. (2022). Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity
ESIS Publishing House (ESIS-PH) European Conference on Fracture..
https://hdl.handle.net/21.15107/rcub_machinery_7274

Milošević M, Rakin M, Berto F, Međo B, Trajković I, Bogojević N, Ćirić-Kostić S. Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_7274 .

Milošević, Miloš, Rakin, Marko, Berto, Filipo, Međo, Bojan, Trajković, Isaak, Bogojević, Nebojša, Ćirić-Kostić, Snežana, "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry" in Procedia Structural Integrity (2022),
https://hdl.handle.net/21.15107/rcub_machinery_7274 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Jevtić, Ivana
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6875
AB  - This work presents the fabrication and tensile testing of polyamide specimens fabricated by
selective laser sintering (SLS). Two geometries are considered: SENT (Single Edge Notched
Tension) and PRNT (Pipe Ring Notched Tension) specimens. Experimental testing of these
specimens is a step in development of a new method for testing of properties of the pipeline
materials. The samples were produced by SLS (Selective Laser Sintering) additive production
technique. The samples were made from polyamide PA12 on EOS Formiga P100 machine
(fabrication parameters: laser power 30 W, print layer height 0.1 mm, scanning speed 1.6-5
m/s, operating temperature 170⁰C). Testing was performed in the displacement control on a
universal tensile testing machine Shimadzu AGS - X. On this machine, the values of force as
well as the values of stress and strain were obtained directly from the Trapezium X software.
Special attention in this work is devoted to two important aspects: fixing of the ring specimen
for testing and influence of friction between the specimen and the tool. The results obtained
on the examined specimens indicate that this study is a valuable contribution for further
development and verification of the new fracture resistance testing procedure for different
pipeline materials.
Acknowledgement:
PB  - Serbian Ceramic Society
T1  - Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6875
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Travica, Milan and Rakin, Marko and Jevtić, Ivana and Sedmak, Aleksandar and Međo, Bojan",
year = "2022",
abstract = "This work presents the fabrication and tensile testing of polyamide specimens fabricated by
selective laser sintering (SLS). Two geometries are considered: SENT (Single Edge Notched
Tension) and PRNT (Pipe Ring Notched Tension) specimens. Experimental testing of these
specimens is a step in development of a new method for testing of properties of the pipeline
materials. The samples were produced by SLS (Selective Laser Sintering) additive production
technique. The samples were made from polyamide PA12 on EOS Formiga P100 machine
(fabrication parameters: laser power 30 W, print layer height 0.1 mm, scanning speed 1.6-5
m/s, operating temperature 170⁰C). Testing was performed in the displacement control on a
universal tensile testing machine Shimadzu AGS - X. On this machine, the values of force as
well as the values of stress and strain were obtained directly from the Trapezium X software.
Special attention in this work is devoted to two important aspects: fixing of the ring specimen
for testing and influence of friction between the specimen and the tool. The results obtained
on the examined specimens indicate that this study is a valuable contribution for further
development and verification of the new fracture resistance testing procedure for different
pipeline materials.
Acknowledgement:",
publisher = "Serbian Ceramic Society",
title = "Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6875"
}

Trajković, I., Milošević, M., Travica, M., Rakin, M., Jevtić, I., Sedmak, A.,& Međo, B.. (2022). Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries. 
Serbian Ceramic Society..
https://hdl.handle.net/21.15107/rcub_machinery_6875

Trajković I, Milošević M, Travica M, Rakin M, Jevtić I, Sedmak A, Međo B. Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_6875 .

Trajković, Isaak, Milošević, Miloš, Travica, Milan, Rakin, Marko, Jevtić, Ivana, Sedmak, Aleksandar, Međo, Bojan, "Laser sintered polyamide specimens - fabrication and tensile testing conditions on different geometries" (2022),
https://hdl.handle.net/21.15107/rcub_machinery_6875 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
AU  - Radosavljevic, Zoran
AU  - Mladenović, Goran
AU  - Međo, Bojan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6930
AB  - Examination of structures and parts of pressure equipment fabricated by additive production techniques is an insufficiently studied area. With the development of new techniques and materials, additive production is becoming increasingly important when it comes to functional replacement parts for different assemblies and devices, in addition to an already established role in rapid prototyping. In order to develop a method for testing the pressure equipment such as pipelines, prototypes of ring-shaped test specimens with a stress concentrator (new pipe ring tensile specimens) are fabricated by different techniques and from various non­ metallic and metallic materials. This work focuses on polylactic acid (PLA) specimens fabricated on a Fused Deposition Modeling (FDM) printer. The rings are produced in the axial direction so that the contours of the material obtained by extrusion through the nozzle are loaded with tension during the testing. 3D printed pipe rings are tested on Shimadzu's electro-mechanical universal testing machine. The testing is accompanied by digital image correlation (DIC) on the specimen surface; GOM Aramis system, consisting of two cameras, acquisition equipment, and software, is utilized. This way, the 3D displacement/strain field on the specimen surface is tracked. The obtained results indicate that repeatability of the testing process is possible, and the development of the methodology will be continued in the same direction. In addition  to  the  testing  results, this work  will  include a  discussion  on  the applicability and possible limitations of the proposed testing procedure in analyzing different stress concentrators on pipelines (including corrosion and stress corrosion defects).
PB  - University of Novi Sad, Faculty of Technology
C3  - 2nd International Conference on Advanced Production and Processing, The Book Of Abstracts
T1  - Additive manufacturing and characterisation using digital image correlation of tensile pipe ring specimens
EP  - 130
SP  - 130
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6930
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Sedmak, Aleksandar and Rakin, Marko and Radosavljevic, Zoran and Mladenović, Goran and Međo, Bojan",
year = "2022",
abstract = "Examination of structures and parts of pressure equipment fabricated by additive production techniques is an insufficiently studied area. With the development of new techniques and materials, additive production is becoming increasingly important when it comes to functional replacement parts for different assemblies and devices, in addition to an already established role in rapid prototyping. In order to develop a method for testing the pressure equipment such as pipelines, prototypes of ring-shaped test specimens with a stress concentrator (new pipe ring tensile specimens) are fabricated by different techniques and from various non­ metallic and metallic materials. This work focuses on polylactic acid (PLA) specimens fabricated on a Fused Deposition Modeling (FDM) printer. The rings are produced in the axial direction so that the contours of the material obtained by extrusion through the nozzle are loaded with tension during the testing. 3D printed pipe rings are tested on Shimadzu's electro-mechanical universal testing machine. The testing is accompanied by digital image correlation (DIC) on the specimen surface; GOM Aramis system, consisting of two cameras, acquisition equipment, and software, is utilized. This way, the 3D displacement/strain field on the specimen surface is tracked. The obtained results indicate that repeatability of the testing process is possible, and the development of the methodology will be continued in the same direction. In addition  to  the  testing  results, this work  will  include a  discussion  on  the applicability and possible limitations of the proposed testing procedure in analyzing different stress concentrators on pipelines (including corrosion and stress corrosion defects).",
publisher = "University of Novi Sad, Faculty of Technology",
journal = "2nd International Conference on Advanced Production and Processing, The Book Of Abstracts",
title = "Additive manufacturing and characterisation using digital image correlation of tensile pipe ring specimens",
pages = "130-130",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6930"
}

Trajković, I., Milošević, M., Sedmak, A., Rakin, M., Radosavljevic, Z., Mladenović, G.,& Međo, B.. (2022). Additive manufacturing and characterisation using digital image correlation of tensile pipe ring specimens. in 2nd International Conference on Advanced Production and Processing, The Book Of Abstracts
University of Novi Sad, Faculty of Technology., 130-130.
https://hdl.handle.net/21.15107/rcub_machinery_6930

Trajković I, Milošević M, Sedmak A, Rakin M, Radosavljevic Z, Mladenović G, Međo B. Additive manufacturing and characterisation using digital image correlation of tensile pipe ring specimens. in 2nd International Conference on Advanced Production and Processing, The Book Of Abstracts. 2022;:130-130.
https://hdl.handle.net/21.15107/rcub_machinery_6930 .

Trajković, Isaak, Milošević, Miloš, Sedmak, Aleksandar, Rakin, Marko, Radosavljevic, Zoran, Mladenović, Goran, Međo, Bojan, "Additive manufacturing and characterisation using digital image correlation of tensile pipe ring specimens" in 2nd International Conference on Advanced Production and Processing, The Book Of Abstracts (2022):130-130,
https://hdl.handle.net/21.15107/rcub_machinery_6930 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Rakin, Marko
AU  - Jevtić, Ivana
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5929
AB  - This work presents the difference in the values of fracture mechanics parameters obtained by
testing of cylindrical specimens with a sharp notch, cut on the tip of a wider groove. The
samples were obtained using two different additive manufacturing techniques. The first type
of samples was obtained by the FDM (Fused Deposition Modeling) method, on the German
REPRAP X400 device with an average accuracy of 0.25 mm. The second type of samples was
made using the SLS (Selective Laser Sintering) method on the EOS Formiga P100 device with
a production precision of 0.08 mm. Regardless of the difference in manufacturing techniques,
the direction and orientation of the samples was identical. The samples were prepared so that
during loading the fibers are loaded in tension, i.e. axially. Different lengths of the sharp
notches were fabricated axially on the samples. The values of fracture mechanics parameters
such as CMOD (Crack Mouth Opening Displacement) and CTOD-5 (Crack Tip Opening
Displacement obtained using the -5 technique) were obtained using the digital image
correlation method. The obtained parameters, except for mutual correlation, were also used
for the verification of numerical results. In the future work, a procedure for determination of
energy-based fracture mechanics parameters will be developed for this sample geometry.
PB  - Faculty of Mechanical Engineering, Univ. of Belgrade
C3  - 3rd International Workshop on Reliability and Design of Additively Manufactured Materials – RdAMM2 Belgrade, Serbia, 4th –6th October 2022
T1  - Determining fracture mechanics parameters using the digital image correlation method on cylindrical samples produced by different additive manufacturing techniques
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5929
ER  - 

@conference{
author = "Trajković, Isaak and Milošević, Miloš and Travica, Milan and Rakin, Marko and Jevtić, Ivana and Sedmak, Aleksandar and Međo, Bojan",
year = "2022",
abstract = "This work presents the difference in the values of fracture mechanics parameters obtained by
testing of cylindrical specimens with a sharp notch, cut on the tip of a wider groove. The
samples were obtained using two different additive manufacturing techniques. The first type
of samples was obtained by the FDM (Fused Deposition Modeling) method, on the German
REPRAP X400 device with an average accuracy of 0.25 mm. The second type of samples was
made using the SLS (Selective Laser Sintering) method on the EOS Formiga P100 device with
a production precision of 0.08 mm. Regardless of the difference in manufacturing techniques,
the direction and orientation of the samples was identical. The samples were prepared so that
during loading the fibers are loaded in tension, i.e. axially. Different lengths of the sharp
notches were fabricated axially on the samples. The values of fracture mechanics parameters
such as CMOD (Crack Mouth Opening Displacement) and CTOD-5 (Crack Tip Opening
Displacement obtained using the -5 technique) were obtained using the digital image
correlation method. The obtained parameters, except for mutual correlation, were also used
for the verification of numerical results. In the future work, a procedure for determination of
energy-based fracture mechanics parameters will be developed for this sample geometry.",
publisher = "Faculty of Mechanical Engineering, Univ. of Belgrade",
journal = "3rd International Workshop on Reliability and Design of Additively Manufactured Materials – RdAMM2 Belgrade, Serbia, 4th –6th October 2022",
title = "Determining fracture mechanics parameters using the digital image correlation method on cylindrical samples produced by different additive manufacturing techniques",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5929"
}

Trajković, I., Milošević, M., Travica, M., Rakin, M., Jevtić, I., Sedmak, A.,& Međo, B.. (2022). Determining fracture mechanics parameters using the digital image correlation method on cylindrical samples produced by different additive manufacturing techniques. in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials – RdAMM2 Belgrade, Serbia, 4th –6th October 2022
Faculty of Mechanical Engineering, Univ. of Belgrade..
https://hdl.handle.net/21.15107/rcub_machinery_5929

Trajković I, Milošević M, Travica M, Rakin M, Jevtić I, Sedmak A, Međo B. Determining fracture mechanics parameters using the digital image correlation method on cylindrical samples produced by different additive manufacturing techniques. in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials – RdAMM2 Belgrade, Serbia, 4th –6th October 2022. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_5929 .

Trajković, Isaak, Milošević, Miloš, Travica, Milan, Rakin, Marko, Jevtić, Ivana, Sedmak, Aleksandar, Međo, Bojan, "Determining fracture mechanics parameters using the digital image correlation method on cylindrical samples produced by different additive manufacturing techniques" in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials – RdAMM2 Belgrade, Serbia, 4th –6th October 2022 (2022),
https://hdl.handle.net/21.15107/rcub_machinery_5929 .

TY  - JOUR
AU  - Trajković, Isaak
AU  - Milošević, Miloš
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Međo, Bojan
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6873
AB  - In order to define a procedure for integrity assessment of pipelines and determining the fracture mechanics parameters, a new type of specimen with a sharp notch, Pipe Ring Notched Tension (PRNT) specimen, is tested. The aim of the study is to determine the
influence of the specimen geometry (cylindrical shape, as well as number and length of stress concentrators) on parameters such
as force, Crack Mouth Opening Displacement CMOD, Crack Tip Opening Displacement CTOD and J integral. The specimens were fabricated by an additive production method - selective laser sintering (SLS). EOS Formiga P100 machine is used, and the material is polyamide PA12. In addition to Pipe Ring Notched Tension specimens, Single Edge Notched Tension (SENT)
specimens with identical cross section were also considered. All specimens were tested on a universal tensile testing machine. A
tool specially designed to apply contact pressure to the inner walls in the tension direction was used, simulating the internal pressure.
For determining the field of displacement and strain on the surface of the tested samples that occur during the loading, Aramis
GOM 2M optical measurement system was used. Aramis is applied for determination of geometry fracture mechanics parameters:
CMOD and CTOD (based on δ5 concept). In addition to the examination of fracture properties of additively manufactured PA12,
the main topic of this work is the development of the non-standard testing procedure, which will be subsequently applied to the
specimens cut from metallic or non-metallic pipes. As an important part of this procedure, the calculation of fracture parameters
will be conducted based on the results presented here.
PB  - Elsevier
T2  - Procedia Structural Integrity
T1  - Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry
EP  - 1319
SP  - 1314
VL  - 42
DO  - 10.1016/j.prostr.2022.12.167
ER  - 

@article{
author = "Trajković, Isaak and Milošević, Miloš and Rakin, Marko and Sedmak, Aleksandar and Međo, Bojan",
year = "2022",
abstract = "In order to define a procedure for integrity assessment of pipelines and determining the fracture mechanics parameters, a new type of specimen with a sharp notch, Pipe Ring Notched Tension (PRNT) specimen, is tested. The aim of the study is to determine the
influence of the specimen geometry (cylindrical shape, as well as number and length of stress concentrators) on parameters such
as force, Crack Mouth Opening Displacement CMOD, Crack Tip Opening Displacement CTOD and J integral. The specimens were fabricated by an additive production method - selective laser sintering (SLS). EOS Formiga P100 machine is used, and the material is polyamide PA12. In addition to Pipe Ring Notched Tension specimens, Single Edge Notched Tension (SENT)
specimens with identical cross section were also considered. All specimens were tested on a universal tensile testing machine. A
tool specially designed to apply contact pressure to the inner walls in the tension direction was used, simulating the internal pressure.
For determining the field of displacement and strain on the surface of the tested samples that occur during the loading, Aramis
GOM 2M optical measurement system was used. Aramis is applied for determination of geometry fracture mechanics parameters:
CMOD and CTOD (based on δ5 concept). In addition to the examination of fracture properties of additively manufactured PA12,
the main topic of this work is the development of the non-standard testing procedure, which will be subsequently applied to the
specimens cut from metallic or non-metallic pipes. As an important part of this procedure, the calculation of fracture parameters
will be conducted based on the results presented here.",
publisher = "Elsevier",
journal = "Procedia Structural Integrity",
title = "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry",
pages = "1319-1314",
volume = "42",
doi = "10.1016/j.prostr.2022.12.167"
}

Trajković, I., Milošević, M., Rakin, M., Sedmak, A.,& Međo, B.. (2022). Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity
Elsevier., 42, 1314-1319.
https://doi.org/10.1016/j.prostr.2022.12.167

Trajković I, Milošević M, Rakin M, Sedmak A, Međo B. Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry. in Procedia Structural Integrity. 2022;42:1314-1319.
doi:10.1016/j.prostr.2022.12.167 .

Trajković, Isaak, Milošević, Miloš, Rakin, Marko, Sedmak, Aleksandar, Međo, Bojan, "Additively manufactured tensile ring-shaped specimens for pipeline material fracture examination - influence of geometry" in Procedia Structural Integrity, 42 (2022):1314-1319,
https://doi.org/10.1016/j.prostr.2022.12.167 . .

TY  - JOUR
AU  - Veljić, Darko
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Radović, Nenad A.
AU  - Međo, Bojan
AU  - Mrdak, Mihailo
AU  - Bajić, Darko
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3739
AB  - The influence of friction stir welding parameters on thermo-mechanical behav-ior of the material during welding is analyzed. An aluminum alloy is considered (Al 2024 T351), and different rotating and welding speeds are applied. The finite element model consists of the working plate (Al alloy), backing plate and welding tool. The influence of the welding conditions on material behavior is taken into account the application of the Johnson-Cook material model. The rotation speed of the tool affects the results. If increased, it contributes to an increase of friction-gen-erated heat intensity. The other component of the generated heat, which stems from the plastic deformation of the material, is negligibly changed. When the welding speed, i.e. tool translation speed, is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming is becoming more pronounced. Summed, this leads to rather small change of the total genera-tion. The changes of the heat generation influence both the temperature field and reaction force. Also, the inadequate selection of welding parameters resulted in occurrence of the defects (pores) in the model.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Thermo-mechanical analysis of linear welding stage in friction stir welding influence of welding parameters
EP  - 2134
IS  - 3
SP  - 2125
VL  - 26
DO  - 10.2298/TSCI210216186V
ER  - 

@article{
author = "Veljić, Darko and Rakin, Marko and Sedmak, Aleksandar and Radović, Nenad A. and Međo, Bojan and Mrdak, Mihailo and Bajić, Darko",
year = "2022",
abstract = "The influence of friction stir welding parameters on thermo-mechanical behav-ior of the material during welding is analyzed. An aluminum alloy is considered (Al 2024 T351), and different rotating and welding speeds are applied. The finite element model consists of the working plate (Al alloy), backing plate and welding tool. The influence of the welding conditions on material behavior is taken into account the application of the Johnson-Cook material model. The rotation speed of the tool affects the results. If increased, it contributes to an increase of friction-gen-erated heat intensity. The other component of the generated heat, which stems from the plastic deformation of the material, is negligibly changed. When the welding speed, i.e. tool translation speed, is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming is becoming more pronounced. Summed, this leads to rather small change of the total genera-tion. The changes of the heat generation influence both the temperature field and reaction force. Also, the inadequate selection of welding parameters resulted in occurrence of the defects (pores) in the model.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Thermo-mechanical analysis of linear welding stage in friction stir welding influence of welding parameters",
pages = "2134-2125",
number = "3",
volume = "26",
doi = "10.2298/TSCI210216186V"
}

Veljić, D., Rakin, M., Sedmak, A., Radović, N. A., Međo, B., Mrdak, M.,& Bajić, D.. (2022). Thermo-mechanical analysis of linear welding stage in friction stir welding influence of welding parameters. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 26(3), 2125-2134.
https://doi.org/10.2298/TSCI210216186V

Veljić D, Rakin M, Sedmak A, Radović NA, Međo B, Mrdak M, Bajić D. Thermo-mechanical analysis of linear welding stage in friction stir welding influence of welding parameters. in Thermal Science. 2022;26(3):2125-2134.
doi:10.2298/TSCI210216186V .

Veljić, Darko, Rakin, Marko, Sedmak, Aleksandar, Radović, Nenad A., Međo, Bojan, Mrdak, Mihailo, Bajić, Darko, "Thermo-mechanical analysis of linear welding stage in friction stir welding influence of welding parameters" in Thermal Science, 26, no. 3 (2022):2125-2134,
https://doi.org/10.2298/TSCI210216186V . .

TY  - CONF
AU  - Trajković, Isaak
AU  - Međo, Bojan
AU  - Milošević, Miloš
AU  - Travica, Milan
AU  - Mitrović, Nenad
AU  - Rakin, Marko
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7702
AB  - U ovom radu biće prikazan razvoj dizajna epruveta oblika prstena sa dve prsline kao i optimizacija parametara izrade. Epruvete su izrađene tehnikama aditivne proizvodnje tipa SLA (Stereolitography Apparatus) i FDM ( Fused Deposition Modeling). Odabrane tehnike omogućuju
veoma brz razvoj i izradu epruveta oblika prstena za zatezanje - PRNT (Pipe Ring Notched Tension). Epruvete izrađene navedenim tehnikama su ispitivane u okviru razvoja metode za ispitivanje PRNT epruveta i određivanja parametara mehanike loma kod uzoraka izrađenih od PLA premium filamenta firme German RepRap i fotopolimernog materijala tipa Photopolymer resin Gray ( FLGPGR04) firme FormLabs. Cilj ovog rada je optimizacija parametara 3D štampe u cilju dobijanja specijalno oblikovanih epruveta oblika prstena sa dve prsline za ispitivanje zatezanjem u obimnom pravcu. Ponovljivost procesa, mogućnost praćenja parametara mehanike loma: otvaranje usta prsline CMOD (Crack Mouth Opening Displacement), otvaranje vrha prsline CTOD (Crack Tip Opening Displacement) a kasnije i numerički proračun vrednosti J integrala, omogućila je izrada epruveta ovim tehnikama.
PB  - Akademija tehničkih strukovnih studija Beograd
C3  - Politehnika 2021
T1  - RAZVOJ DIZAJNA EPRUVETA OBLIKA PRSTENA SA DVE PRSLINE ZA ISPITIVANJE PARAMETARA MEHANIKE LOMA
EP  - 570
SP  - 565
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7702
ER  - 

@conference{
author = "Trajković, Isaak and Međo, Bojan and Milošević, Miloš and Travica, Milan and Mitrović, Nenad and Rakin, Marko",
year = "2021",
abstract = "U ovom radu biće prikazan razvoj dizajna epruveta oblika prstena sa dve prsline kao i optimizacija parametara izrade. Epruvete su izrađene tehnikama aditivne proizvodnje tipa SLA (Stereolitography Apparatus) i FDM ( Fused Deposition Modeling). Odabrane tehnike omogućuju
veoma brz razvoj i izradu epruveta oblika prstena za zatezanje - PRNT (Pipe Ring Notched Tension). Epruvete izrađene navedenim tehnikama su ispitivane u okviru razvoja metode za ispitivanje PRNT epruveta i određivanja parametara mehanike loma kod uzoraka izrađenih od PLA premium filamenta firme German RepRap i fotopolimernog materijala tipa Photopolymer resin Gray ( FLGPGR04) firme FormLabs. Cilj ovog rada je optimizacija parametara 3D štampe u cilju dobijanja specijalno oblikovanih epruveta oblika prstena sa dve prsline za ispitivanje zatezanjem u obimnom pravcu. Ponovljivost procesa, mogućnost praćenja parametara mehanike loma: otvaranje usta prsline CMOD (Crack Mouth Opening Displacement), otvaranje vrha prsline CTOD (Crack Tip Opening Displacement) a kasnije i numerički proračun vrednosti J integrala, omogućila je izrada epruveta ovim tehnikama.",
publisher = "Akademija tehničkih strukovnih studija Beograd",
journal = "Politehnika 2021",
title = "RAZVOJ DIZAJNA EPRUVETA OBLIKA PRSTENA SA DVE PRSLINE ZA ISPITIVANJE PARAMETARA MEHANIKE LOMA",
pages = "570-565",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7702"
}

Trajković, I., Međo, B., Milošević, M., Travica, M., Mitrović, N.,& Rakin, M.. (2021). RAZVOJ DIZAJNA EPRUVETA OBLIKA PRSTENA SA DVE PRSLINE ZA ISPITIVANJE PARAMETARA MEHANIKE LOMA. in Politehnika 2021
Akademija tehničkih strukovnih studija Beograd., 565-570.
https://hdl.handle.net/21.15107/rcub_machinery_7702

Trajković I, Međo B, Milošević M, Travica M, Mitrović N, Rakin M. RAZVOJ DIZAJNA EPRUVETA OBLIKA PRSTENA SA DVE PRSLINE ZA ISPITIVANJE PARAMETARA MEHANIKE LOMA. in Politehnika 2021. 2021;:565-570.
https://hdl.handle.net/21.15107/rcub_machinery_7702 .

Trajković, Isaak, Međo, Bojan, Milošević, Miloš, Travica, Milan, Mitrović, Nenad, Rakin, Marko, "RAZVOJ DIZAJNA EPRUVETA OBLIKA PRSTENA SA DVE PRSLINE ZA ISPITIVANJE PARAMETARA MEHANIKE LOMA" in Politehnika 2021 (2021):565-570,
https://hdl.handle.net/21.15107/rcub_machinery_7702 .

TY  - CONF
AU  - Trajković, Isaak
AU  - Milovanović, Aleksa
AU  - Jevtić, Ivana
AU  - Travica, Milan
AU  - Marsavina, Liviu
AU  - Međo, Bojan
AU  - Náhlík, Luboš
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7366
AB  - In order to characterize the fracture toughness of single edge notched tension (SENT) specimens, this paper describes the experimental determination of fracture mechanics parameters such as crack mouth opening displacement (CMOD) and crack type opening displacement (CTOD) on SENT specimen samples. Additive production techniques were used to make these specimens. This is an FDM (Fused Deposition Modeling) technique and the material used is polylactide amide (PLA, German RepRap Premium Filament). The experiment was performed on two models of test specimens that differed in geometry. The specimens differed in the length of the notche and crack, while the cross-sectional area of the specimens was equal. The experiment was performed at room temperature and relative humidity of 40%, a few days after production. Universal machine for testing the mechanical properties of materials (Shimadzu AGS-X 100kN) in the control of displacement at a speed of 0.5mm / min was used. Using the Aramis 2M system, digital image correlation was used to obtain CMOD and CTOD (δ-5) values according to a standard procedure using a point-point distance command that measures the distance between points with an accuracy of one thousandth of a millimeter. The repeatability of the results indicates the same trend in the fracture of SENT specimens made by this technique of additive production and from this material as the results with low values of standard deviation.
C3  - International conference of experimental and numerical investigations and new technologies (2021 ; Zlatibor)
T1  - Monitoring of fracture mechanics parameters on single edge notched tension specimens made of PLA material
SP  - 18
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7366
ER  - 

@conference{
author = "Trajković, Isaak and Milovanović, Aleksa and Jevtić, Ivana and Travica, Milan and Marsavina, Liviu and Međo, Bojan and Náhlík, Luboš",
year = "2021",
abstract = "In order to characterize the fracture toughness of single edge notched tension (SENT) specimens, this paper describes the experimental determination of fracture mechanics parameters such as crack mouth opening displacement (CMOD) and crack type opening displacement (CTOD) on SENT specimen samples. Additive production techniques were used to make these specimens. This is an FDM (Fused Deposition Modeling) technique and the material used is polylactide amide (PLA, German RepRap Premium Filament). The experiment was performed on two models of test specimens that differed in geometry. The specimens differed in the length of the notche and crack, while the cross-sectional area of the specimens was equal. The experiment was performed at room temperature and relative humidity of 40%, a few days after production. Universal machine for testing the mechanical properties of materials (Shimadzu AGS-X 100kN) in the control of displacement at a speed of 0.5mm / min was used. Using the Aramis 2M system, digital image correlation was used to obtain CMOD and CTOD (δ-5) values according to a standard procedure using a point-point distance command that measures the distance between points with an accuracy of one thousandth of a millimeter. The repeatability of the results indicates the same trend in the fracture of SENT specimens made by this technique of additive production and from this material as the results with low values of standard deviation.",
journal = "International conference of experimental and numerical investigations and new technologies (2021 ; Zlatibor)",
title = "Monitoring of fracture mechanics parameters on single edge notched tension specimens made of PLA material",
pages = "18",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7366"
}

Trajković, I., Milovanović, A., Jevtić, I., Travica, M., Marsavina, L., Međo, B.,& Náhlík, L.. (2021). Monitoring of fracture mechanics parameters on single edge notched tension specimens made of PLA material. in International conference of experimental and numerical investigations and new technologies (2021 ; Zlatibor), 18.
https://hdl.handle.net/21.15107/rcub_machinery_7366

Trajković I, Milovanović A, Jevtić I, Travica M, Marsavina L, Međo B, Náhlík L. Monitoring of fracture mechanics parameters on single edge notched tension specimens made of PLA material. in International conference of experimental and numerical investigations and new technologies (2021 ; Zlatibor). 2021;:18.
https://hdl.handle.net/21.15107/rcub_machinery_7366 .

Trajković, Isaak, Milovanović, Aleksa, Jevtić, Ivana, Travica, Milan, Marsavina, Liviu, Međo, Bojan, Náhlík, Luboš, "Monitoring of fracture mechanics parameters on single edge notched tension specimens made of PLA material" in International conference of experimental and numerical investigations and new technologies (2021 ; Zlatibor) (2021):18,
https://hdl.handle.net/21.15107/rcub_machinery_7366 .

TY  - CONF
AU  - Younise, Bashir
AU  - Sedmak, Aleksandar
AU  - Milošević, Nenad
AU  - Rakin, Marko
AU  - Međo, Bojan
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3381
AB  - True stress-strain curves of HSLA steel welded joint regions were estimated by using numerical simulation of strains measured by DIC and special iteration procedure to match the results. Strains were measured at certain level of loading in all regions of welded joint with different tensile properties, namely base metal (BM), weld metal (WM) and two subzones of Heat-Affected-Zone (fine grain, FGHAZ, and coarse grain CGHAZ). By converting engineering stress (load divided by initial cross section area) into true stress, experimental true stress-true strain curves are obtained and used as initial iteration for the Finite Element Method (FEM) simulation, after being fitted by the power law relation for stress-strain curves. Obtained results are then compared with the experimental results to fmd the differences and make appropriate correction in power law curves and make as many iterations as needed before the differences become small enough. This procedure has been verified by an example of welded tensile panel.
PB  - Elsevier, Amsterdam
C3  - Procedia Structural Integrity - 1st Virtual European Conference on Fracture - Vecf1
T1  - True Stress-strain Curves for HSLA Steel Weldment - Iteration Procedure Based on DIC and FEM
EP  - 1997
SP  - 1992
VL  - 28
DO  - 10.1016/j.prostr.2020.11.023
ER  - 

@conference{
author = "Younise, Bashir and Sedmak, Aleksandar and Milošević, Nenad and Rakin, Marko and Međo, Bojan",
year = "2020",
abstract = "True stress-strain curves of HSLA steel welded joint regions were estimated by using numerical simulation of strains measured by DIC and special iteration procedure to match the results. Strains were measured at certain level of loading in all regions of welded joint with different tensile properties, namely base metal (BM), weld metal (WM) and two subzones of Heat-Affected-Zone (fine grain, FGHAZ, and coarse grain CGHAZ). By converting engineering stress (load divided by initial cross section area) into true stress, experimental true stress-true strain curves are obtained and used as initial iteration for the Finite Element Method (FEM) simulation, after being fitted by the power law relation for stress-strain curves. Obtained results are then compared with the experimental results to fmd the differences and make appropriate correction in power law curves and make as many iterations as needed before the differences become small enough. This procedure has been verified by an example of welded tensile panel.",
publisher = "Elsevier, Amsterdam",
journal = "Procedia Structural Integrity - 1st Virtual European Conference on Fracture - Vecf1",
title = "True Stress-strain Curves for HSLA Steel Weldment - Iteration Procedure Based on DIC and FEM",
pages = "1997-1992",
volume = "28",
doi = "10.1016/j.prostr.2020.11.023"
}

Younise, B., Sedmak, A., Milošević, N., Rakin, M.,& Međo, B.. (2020). True Stress-strain Curves for HSLA Steel Weldment - Iteration Procedure Based on DIC and FEM. in Procedia Structural Integrity - 1st Virtual European Conference on Fracture - Vecf1
Elsevier, Amsterdam., 28, 1992-1997.
https://doi.org/10.1016/j.prostr.2020.11.023

Younise B, Sedmak A, Milošević N, Rakin M, Međo B. True Stress-strain Curves for HSLA Steel Weldment - Iteration Procedure Based on DIC and FEM. in Procedia Structural Integrity - 1st Virtual European Conference on Fracture - Vecf1. 2020;28:1992-1997.
doi:10.1016/j.prostr.2020.11.023 .

Younise, Bashir, Sedmak, Aleksandar, Milošević, Nenad, Rakin, Marko, Međo, Bojan, "True Stress-strain Curves for HSLA Steel Weldment - Iteration Procedure Based on DIC and FEM" in Procedia Structural Integrity - 1st Virtual European Conference on Fracture - Vecf1, 28 (2020):1992-1997,
https://doi.org/10.1016/j.prostr.2020.11.023 . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Arsić, M.
AU  - Šarkoćević, Živče
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Arsić, D.
AU  - Lazić, Vukić
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3349
AB  - Experimental investigation of the integrity of casing pipes, used in the oil drilling rigs, withdrawn after about 70,000 h of service, has been conducted, together with numerical simulation. Pipes were manufactured by the high frequency contact welding (HF) of API J55 steel. The influence of corrosion damage is investigated by means of pressure test of a pipe with different damage levels made by machining the circular holes. The finite element analysis of the damaged pipe subjected to internal pressure is conducted to simulate the stress state in the pipe and to establish the criteria for the maximum pressure that a damaged pipe can withstand. Several analytical expressions were used to estimate the maximum pressure in a damaged pipeline, and the solutions were compared to predictions of finite element models and experimental results.
PB  - Elsevier Sci Ltd, Oxford
T2  - International Journal of Pressure Vessels and Piping
T1  - Remaining strength of API J55 steel casing pipes damaged by corrosion
VL  - 188
DO  - 10.1016/j.ijpvp.2020.104230
ER  - 

@article{
author = "Sedmak, Aleksandar and Arsić, M. and Šarkoćević, Živče and Međo, Bojan and Rakin, Marko and Arsić, D. and Lazić, Vukić",
year = "2020",
abstract = "Experimental investigation of the integrity of casing pipes, used in the oil drilling rigs, withdrawn after about 70,000 h of service, has been conducted, together with numerical simulation. Pipes were manufactured by the high frequency contact welding (HF) of API J55 steel. The influence of corrosion damage is investigated by means of pressure test of a pipe with different damage levels made by machining the circular holes. The finite element analysis of the damaged pipe subjected to internal pressure is conducted to simulate the stress state in the pipe and to establish the criteria for the maximum pressure that a damaged pipe can withstand. Several analytical expressions were used to estimate the maximum pressure in a damaged pipeline, and the solutions were compared to predictions of finite element models and experimental results.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "International Journal of Pressure Vessels and Piping",
title = "Remaining strength of API J55 steel casing pipes damaged by corrosion",
volume = "188",
doi = "10.1016/j.ijpvp.2020.104230"
}

Sedmak, A., Arsić, M., Šarkoćević, Ž., Međo, B., Rakin, M., Arsić, D.,& Lazić, V.. (2020). Remaining strength of API J55 steel casing pipes damaged by corrosion. in International Journal of Pressure Vessels and Piping
Elsevier Sci Ltd, Oxford., 188.
https://doi.org/10.1016/j.ijpvp.2020.104230

Sedmak A, Arsić M, Šarkoćević Ž, Međo B, Rakin M, Arsić D, Lazić V. Remaining strength of API J55 steel casing pipes damaged by corrosion. in International Journal of Pressure Vessels and Piping. 2020;188.
doi:10.1016/j.ijpvp.2020.104230 .

Sedmak, Aleksandar, Arsić, M., Šarkoćević, Živče, Međo, Bojan, Rakin, Marko, Arsić, D., Lazić, Vukić, "Remaining strength of API J55 steel casing pipes damaged by corrosion" in International Journal of Pressure Vessels and Piping, 188 (2020),
https://doi.org/10.1016/j.ijpvp.2020.104230 . .

TY  - JOUR
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Sedmak, Aleksandar
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3291
AB  - Fracture of welded joints has been an important research and industrial topic for a long time, having in mind the key role of welded joints in ensuring the safe operation and integrity of welded structures. This work contains an overview of application of micromechanical models to ductile fracture of welded joints. The main benefit of these models, in comparison with the classical fracture mechanics approach, is consideration of the local quantities (stress and strain) in prediction of damage development. The damage is quantified through the value of the damage parameter, which is typically related to the void nucleation, growth and coalescence for ductile fracture of metallic materials, i.e. the description of the material can be related to the actual material behaviour during fracture. Most of the presented studies, including those published by the present authors, are performed on steel as the base material, and the rest deal with aluminium alloys.
PB  - Srpsko društvo za mehaniku, Beograd
T2  - Theoretical and Applied Mechanics
T1  - An overview of application of micromechanical models in ductile fracture analysis of welded joints
EP  - 62
IS  - 1
SP  - 33
VL  - 47
DO  - 10.2298/TAM200117004R
ER  - 

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

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

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

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

TY  - JOUR
AU  - Veljić, Darko
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Mrdak, Mihailo
AU  - Sedmak, Aleksandar
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3190
AB  - Friction stir welding is one of the procedures for joining the parts in solid state. Thermo-mechanical simulation of the friction stir welding of high-strength aluminium alloys 2024 T3 and 2024 T351 is considered in this work. Numerical models corresponding to the linear welding stage are developed in Abaqus software package. The material behaviour is modelled by Johnson-Cook law (which relates the yield stress with temperature, strain and strain rate), and the Arbitrary Lagrangian-Eulerian technique is applied. The difference in thermo-mechanical behaviour between the two materials has been analysed and commented. The main quantities which are considered are the temperature in the weld area, plastic strain, as well as the rate of heat generation during the welding process.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Temperature fields in linear stage of friction stir welding effect of different material properties
EP  - 3992
IS  - 6
SP  - 3985
VL  - 23
DO  - 10.2298/TSCI181015264V
ER  - 

@article{
author = "Veljić, Darko and Rakin, Marko and Međo, Bojan and Mrdak, Mihailo and Sedmak, Aleksandar",
year = "2019",
abstract = "Friction stir welding is one of the procedures for joining the parts in solid state. Thermo-mechanical simulation of the friction stir welding of high-strength aluminium alloys 2024 T3 and 2024 T351 is considered in this work. Numerical models corresponding to the linear welding stage are developed in Abaqus software package. The material behaviour is modelled by Johnson-Cook law (which relates the yield stress with temperature, strain and strain rate), and the Arbitrary Lagrangian-Eulerian technique is applied. The difference in thermo-mechanical behaviour between the two materials has been analysed and commented. The main quantities which are considered are the temperature in the weld area, plastic strain, as well as the rate of heat generation during the welding process.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Temperature fields in linear stage of friction stir welding effect of different material properties",
pages = "3992-3985",
number = "6",
volume = "23",
doi = "10.2298/TSCI181015264V"
}

Veljić, D., Rakin, M., Međo, B., Mrdak, M.,& Sedmak, A.. (2019). Temperature fields in linear stage of friction stir welding effect of different material properties. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 23(6), 3985-3992.
https://doi.org/10.2298/TSCI181015264V

Veljić D, Rakin M, Međo B, Mrdak M, Sedmak A. Temperature fields in linear stage of friction stir welding effect of different material properties. in Thermal Science. 2019;23(6):3985-3992.
doi:10.2298/TSCI181015264V .

Veljić, Darko, Rakin, Marko, Međo, Bojan, Mrdak, Mihailo, Sedmak, Aleksandar, "Temperature fields in linear stage of friction stir welding effect of different material properties" in Thermal Science, 23, no. 6 (2019):3985-3992,
https://doi.org/10.2298/TSCI181015264V . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Younise, Bashir
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3237
AB  - Micromechanical modelling of ductile fracture by using the local approach has been presented as the review of previously obtained results for welded joints made of low alloyed high strength steel. Experimental work was performed on 3PB specimens and tensile panels, which were then modelled by finite element method, using two- and three-dimensional meshes, respectively. The local approach was used to simulate both for crack initiation and growth during ductile fracture process.
PB  - Savez inženjera metalurgije Srbije, Beograd
T2  - Metallurgical & Materials Engineering
T1  - Micromechanical modelling of ductile fracture - local approach
EP  - 286
IS  - 4
SP  - 265
VL  - 25
DO  - 10.30544/459
ER  - 

@article{
author = "Sedmak, Aleksandar and Rakin, Marko and Međo, Bojan and Younise, Bashir",
year = "2019",
abstract = "Micromechanical modelling of ductile fracture by using the local approach has been presented as the review of previously obtained results for welded joints made of low alloyed high strength steel. Experimental work was performed on 3PB specimens and tensile panels, which were then modelled by finite element method, using two- and three-dimensional meshes, respectively. The local approach was used to simulate both for crack initiation and growth during ductile fracture process.",
publisher = "Savez inženjera metalurgije Srbije, Beograd",
journal = "Metallurgical & Materials Engineering",
title = "Micromechanical modelling of ductile fracture - local approach",
pages = "286-265",
number = "4",
volume = "25",
doi = "10.30544/459"
}

Sedmak, A., Rakin, M., Međo, B.,& Younise, B.. (2019). Micromechanical modelling of ductile fracture - local approach. in Metallurgical & Materials Engineering
Savez inženjera metalurgije Srbije, Beograd., 25(4), 265-286.
https://doi.org/10.30544/459

Sedmak A, Rakin M, Međo B, Younise B. Micromechanical modelling of ductile fracture - local approach. in Metallurgical & Materials Engineering. 2019;25(4):265-286.
doi:10.30544/459 .

Sedmak, Aleksandar, Rakin, Marko, Međo, Bojan, Younise, Bashir, "Micromechanical modelling of ductile fracture - local approach" in Metallurgical & Materials Engineering, 25, no. 4 (2019):265-286,
https://doi.org/10.30544/459 . .

TY  - JOUR
AU  - Musrati, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Stefane, Primoz
AU  - Veljić, Darko
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3030
AB  - The topic of this work is analysis of fracture behaviour and resistance of the thin-walled seamless and seam steel pipes, through application of the recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend). The main loading of these pipes in exploitation is internal pressure, which is why axial defects present a significant threat to their integrity and work safety. The ring-shaped specimen geometry is fairly simple to fabricate from a new or exploited pipeline and the specimens have the same thermo-mechanical treatment, assembly conditions, etc. as the actual structure. Experimental-numerical procedure is applied for prediction of the fracture behaviour; this included material characterisation, testing of ring specimens by bending, as well as micromechanical analysis of ductile fracture. In experimental testing, the deformation of the specimens is monitored by using the stereometric measurement system. Numerical analysis is performed in software package Simulia Abaqus, including the application of the micromechanical Complete Gurson model (CGM). The results obtained in this study, along with some previously published results, lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of cylindrical elements such as pipes.
PB  - Elsevier, Amsterdam
T2  - Theoretical and Applied Fracture Mechanics
T1  - Fracture assessment of seam and seamless steel pipes by application of the ring-shaped bending specimens
VL  - 103
DO  - 10.1016/j.tafmec.2019.102302
ER  - 

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

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

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

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

TY  - CONF
AU  - Doncheva, Elisaveta
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Trajanoska, Bojana
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2942
AB  - The industrial application of high-strength low-alloyed steel (HSLA) in welded structures has increased the demand for understanding fracture behavior and structural integrity assessment of this type of steel and produced welded joints. The aim of this paper is to simulate the experimental evaluation of the fracture mechanics specimens by using the micromechanical model. The investigation is performed on two standard single edge notch bend (SENB) specimens with imposed crack in the central region. Numerical analysis was carried out by using Simulia Abaqus software package on 2D models used to simulate the damage development on the local level. The comparison between numerical and experimental results is presented through measured values of J-integral, load-line displacement vu and crack growth resistance (J-Aa) curves. This paper shows that numerical simulations are promising in respect to their accuracy. The application of this model enables to decrease the amount of expensive experiments for determination of the load level that causes crack propagation.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
T1  - Numerical simulation of crack propagation in high-strength low-alloyed welded steel
EP  - 488
SP  - 483
VL  - 13
DO  - 10.1016/j.prostr.2018.12.080
ER  - 

@conference{
author = "Doncheva, Elisaveta and Međo, Bojan and Rakin, Marko and Sedmak, Simon and Trajanoska, Bojana",
year = "2018",
abstract = "The industrial application of high-strength low-alloyed steel (HSLA) in welded structures has increased the demand for understanding fracture behavior and structural integrity assessment of this type of steel and produced welded joints. The aim of this paper is to simulate the experimental evaluation of the fracture mechanics specimens by using the micromechanical model. The investigation is performed on two standard single edge notch bend (SENB) specimens with imposed crack in the central region. Numerical analysis was carried out by using Simulia Abaqus software package on 2D models used to simulate the damage development on the local level. The comparison between numerical and experimental results is presented through measured values of J-integral, load-line displacement vu and crack growth resistance (J-Aa) curves. This paper shows that numerical simulations are promising in respect to their accuracy. The application of this model enables to decrease the amount of expensive experiments for determination of the load level that causes crack propagation.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity",
title = "Numerical simulation of crack propagation in high-strength low-alloyed welded steel",
pages = "488-483",
volume = "13",
doi = "10.1016/j.prostr.2018.12.080"
}

Doncheva, E., Međo, B., Rakin, M., Sedmak, S.,& Trajanoska, B.. (2018). Numerical simulation of crack propagation in high-strength low-alloyed welded steel. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
Elsevier Science Bv, Amsterdam., 13, 483-488.
https://doi.org/10.1016/j.prostr.2018.12.080

Doncheva E, Međo B, Rakin M, Sedmak S, Trajanoska B. Numerical simulation of crack propagation in high-strength low-alloyed welded steel. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity. 2018;13:483-488.
doi:10.1016/j.prostr.2018.12.080 .

Doncheva, Elisaveta, Međo, Bojan, Rakin, Marko, Sedmak, Simon, Trajanoska, Bojana, "Numerical simulation of crack propagation in high-strength low-alloyed welded steel" in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity, 13 (2018):483-488,
https://doi.org/10.1016/j.prostr.2018.12.080 . .

TY  - CONF
AU  - Musrati, Walid
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Stefane, Primoz
AU  - Veljić, Darko
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2892
AB  - Application of pipelines is common in process industry and energetic facilities, as parts of storage and transport systems. Structural integrity and fracture resistance of the pipeline elements is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, fabrication of these geometries is often not possible for thin-walled pressurized elements, commonly used in structures of process and energetic facilities. Therefore, some proposals for non-standard specimens have been given in the literature, differing by the position of the initial defects, in circumferential or axial direction, and by the degree of complexity of procedures for fabrication and testing. Recently proposed ring-shaped specimen (PRNB - Pipe Ring Notched Bend) is used here to assess the fracture resistance of pressurized cylinders with defects in axial direction, critical for the internal pressure loading. The specimens are simple to fabricate and have the same material history as the actual structure, such as thermo-mechanical treatment, assembly or exploitation conditions. In this work, the ring specimens are cut from the thin-walled non-alloy steel pipes for pressure purposes. Experimental-numerical procedure is applied for prediction of fracture behavior. The methods include material characterization, fracture testing and micromechanical analysis of specimen failure. The results obtained so far lead to conclusion that PRNB specimen is a good option for testing of fracture resistance of pipelines and small-scale vessels.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
T1  - Fracture analysis of axially flawed ring-shaped bending specimen
EP  - 1833
SP  - 1828
VL  - 13
DO  - 10.1016/j.prostr.2018.12.333
ER  - 

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

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

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

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

TY  - JOUR
AU  - Međo, Bojan
AU  - Arsić, Miodrag
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Savić, Zoran
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2961
AB  - Vital components of the beam that enable conjoint operation of two bridge cranes are braces and threaded spindle. The beam connects two bridge cranes with overall lifting capacity of 500 t (2 x 250 t) and enables their simultaneous conjoint operation during the rehabilitation or major overhaul of hydroelectric generating set equipment at the hydro power plant ''Djerdap 2'. Two braces are being installed instead of two hooks when this situation occurs. The threaded spindle is loaded with 500 t (5 MN), while braces are loaded with 250 t (2.5 MN) each. Integrity of structures is a relatively new scientific and engineering discipline which in a broader sense comprises condition analysis, behaviour diagnostics, service life evaluation and rehabilitation of structures, which means that beside the usual situation in which it is necessary to evaluate the integrity of a structure when a flaw is detected by means of non-destructive tests, this discipline also comprises stress condition analysis for the crackless structure, most often through the use of finite element method. This is the way to obtain precise and detailed distribution of displacements, deformations and stresses, which enables determination of weak spots on the structure, even before crack initiation. Non-destructive tests are performed in order to analyse the current condition of braces and the threaded spindle. On the basis of performed analytical calculations it is determined that the integrity is not threatened, although some internal non-homogeneities are detected by ultrasonic testing.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes
EP  - 59
IS  - 1
SP  - 53
VL  - 18
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3791
ER  - 

@article{
author = "Međo, Bojan and Arsić, Miodrag and Rakin, Marko and Sedmak, Simon and Savić, Zoran",
year = "2018",
abstract = "Vital components of the beam that enable conjoint operation of two bridge cranes are braces and threaded spindle. The beam connects two bridge cranes with overall lifting capacity of 500 t (2 x 250 t) and enables their simultaneous conjoint operation during the rehabilitation or major overhaul of hydroelectric generating set equipment at the hydro power plant ''Djerdap 2'. Two braces are being installed instead of two hooks when this situation occurs. The threaded spindle is loaded with 500 t (5 MN), while braces are loaded with 250 t (2.5 MN) each. Integrity of structures is a relatively new scientific and engineering discipline which in a broader sense comprises condition analysis, behaviour diagnostics, service life evaluation and rehabilitation of structures, which means that beside the usual situation in which it is necessary to evaluate the integrity of a structure when a flaw is detected by means of non-destructive tests, this discipline also comprises stress condition analysis for the crackless structure, most often through the use of finite element method. This is the way to obtain precise and detailed distribution of displacements, deformations and stresses, which enables determination of weak spots on the structure, even before crack initiation. Non-destructive tests are performed in order to analyse the current condition of braces and the threaded spindle. On the basis of performed analytical calculations it is determined that the integrity is not threatened, although some internal non-homogeneities are detected by ultrasonic testing.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes",
pages = "59-53",
number = "1",
volume = "18",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3791"
}

Međo, B., Arsić, M., Rakin, M., Sedmak, S.,& Savić, Z.. (2018). Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 18(1), 53-59.
https://hdl.handle.net/21.15107/rcub_technorep_3791

Međo B, Arsić M, Rakin M, Sedmak S, Savić Z. Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes. in Structural Integrity and Life. 2018;18(1):53-59.
https://hdl.handle.net/21.15107/rcub_technorep_3791 .

Međo, Bojan, Arsić, Miodrag, Rakin, Marko, Sedmak, Simon, Savić, Zoran, "Integrity assessment of vital beam components that enable conjoint operation of two bridge cranes" in Structural Integrity and Life, 18, no. 1 (2018):53-59,
https://hdl.handle.net/21.15107/rcub_technorep_3791 .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Međo, Bojan
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5243
AB  - Cold metallization includes the powder or wire application on the cold surface of components
by electric arc, gas, plasma, supersonic, gas-detonation method. It could be applied on all metals except on pure copper, but not on glass and non-metallic materials. Thickness of the layer which is being deposited ranges from 0.05 to 5 mm. Porosity of the layer is 3-15 %. Temperature of the parent material does not exceed 250°C, and therefore it sustains its mechanical properties. Taking into account the above mentioned, for the repair of damaged surfaces of components of turbine and hydromechanical equipment, the methodology of the electric arc technique was developed. At first, research regarding the possibility of application of cold metallization at damaged samples of metal sheets and pipes made of structural steel was carried out, and afterwards the same methodology was performed and confirmed during the repair of damaged surfaces of the flange at the horizontal Kaplan turbine with nominal power of 28 MW (Djerdap 2). Functional role of the flange, made of steel X5CrNi18-10, is to prevent the water from entering the enclosed space of the turbine shaft.
PB  - University of Niš, Faculty of Mechanical Engineering and Society of Thermal Engineers of Serbia
C3  - Proceedings of the 18th  Symposium on Thermal Science and Engineering of Serbia – SIMTERM 2017
T1  - Repair of damaged surfaces of components of turbine and hydromechanical equipment through the use of cold metallization
EP  - 540
SP  - 536
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5243
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Međo, Bojan and Mladenović, M. and Savić, Zoran",
year = "2017",
abstract = "Cold metallization includes the powder or wire application on the cold surface of components
by electric arc, gas, plasma, supersonic, gas-detonation method. It could be applied on all metals except on pure copper, but not on glass and non-metallic materials. Thickness of the layer which is being deposited ranges from 0.05 to 5 mm. Porosity of the layer is 3-15 %. Temperature of the parent material does not exceed 250°C, and therefore it sustains its mechanical properties. Taking into account the above mentioned, for the repair of damaged surfaces of components of turbine and hydromechanical equipment, the methodology of the electric arc technique was developed. At first, research regarding the possibility of application of cold metallization at damaged samples of metal sheets and pipes made of structural steel was carried out, and afterwards the same methodology was performed and confirmed during the repair of damaged surfaces of the flange at the horizontal Kaplan turbine with nominal power of 28 MW (Djerdap 2). Functional role of the flange, made of steel X5CrNi18-10, is to prevent the water from entering the enclosed space of the turbine shaft.",
publisher = "University of Niš, Faculty of Mechanical Engineering and Society of Thermal Engineers of Serbia",
journal = "Proceedings of the 18th  Symposium on Thermal Science and Engineering of Serbia – SIMTERM 2017",
title = "Repair of damaged surfaces of components of turbine and hydromechanical equipment through the use of cold metallization",
pages = "540-536",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5243"
}

Arsić, M., Bošnjak, S., Grabulov, V., Međo, B., Mladenović, M.,& Savić, Z.. (2017). Repair of damaged surfaces of components of turbine and hydromechanical equipment through the use of cold metallization. in Proceedings of the 18th  Symposium on Thermal Science and Engineering of Serbia – SIMTERM 2017
University of Niš, Faculty of Mechanical Engineering and Society of Thermal Engineers of Serbia., 536-540.
https://hdl.handle.net/21.15107/rcub_machinery_5243

Arsić M, Bošnjak S, Grabulov V, Međo B, Mladenović M, Savić Z. Repair of damaged surfaces of components of turbine and hydromechanical equipment through the use of cold metallization. in Proceedings of the 18th  Symposium on Thermal Science and Engineering of Serbia – SIMTERM 2017. 2017;:536-540.
https://hdl.handle.net/21.15107/rcub_machinery_5243 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Međo, Bojan, Mladenović, M., Savić, Zoran, "Repair of damaged surfaces of components of turbine and hydromechanical equipment through the use of cold metallization" in Proceedings of the 18th  Symposium on Thermal Science and Engineering of Serbia – SIMTERM 2017 (2017):536-540,
https://hdl.handle.net/21.15107/rcub_machinery_5243 .

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Musraty, W.
AU  - Matvienko, Y.
AU  - Milošević, Miloš
AU  - Sedmak, Aleksandar
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2669
AB  - Integrity of cylindrical structures, such as pipes and small-scale pressure vessels, is typically assessed by testing fracture mechanics specimens, like compact tensile CT or single-edge notched bending, SENB. However, their fabrication is mainly not possible for thin-walled pressurised elements, commonly used in structures of process and energetic facilities, such as hydrogen and hydrogen carriers storage and delivery systems. Recently proposed nonstandard ring-shaped specimen is used to test the fracture resistance of pressurised cylinders with defects (cracks or notches) in the most critical direction - axial. Some of the advantages of the pipe-ring notch bend specimen, PRNB, are simple fabrication and same material history as actual exploited structure. A combined experimental-numerical procedure is applied for prediction of fracture behaviour of specimens (applicable to ductile metals, mainly steels and Al alloys), with the aim to further validate the new specimen. The results obtained so far lead to conclusion that PRNB specimen can be applied in integrity assessment of cylindrical structures.
PB  - International Conference on Fracture
C3  - ICF 2017 - 14th International Conference on Fracture
T1  - Numerical analysis of fracture of non-standard ring specimen for examination of axially flawed cylindrical structures
EP  - 220
SP  - 219
VL  - 2
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3483
ER  - 

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

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

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

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

TY  - JOUR
AU  - Younise, Bashir
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Međo, Bojan
AU  - Sedmak, Aleksandar
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2585
AB  - The topic of this work is assessment of ductile fracture initiation and development in different zones of welded joint of a high strength low alloyed (HSLA) steel. A combined experimental-numerical procedure is applied for determination of properties of the weld metal and the heat affected zone - HAZ. One tensile specimen with rectangular cross-section is tested, and the surface strains are determined using stereometric 3D measurement (measurement system Gom Aramis with two cameras and software solution). This methodology enabled formation of the stress-strain curves for micromechanical analysis of fracture of specimens with initial fatigue pre-cracks. Two different geometries are considered: standard single-edge notched bend (SENB) specimens and surface-cracked tensile specimens. The cracks were positioned either in weld metal or in HAZ - within the fine-grained part. Micromechanical model (complete Gurson model, by Z.L. Zhang) is applied for assessment of crack growth onset and stable growth. Higher resistance to ductile fracture initiation and crack growth in HAZ is successfully predicted, as well as constraint effect caused by different crack shapes.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Effect of material heterogeneity and constraint conditions on ductile fracture resistance of welded joint zones - Micromechanical assessment
EP  - 445
SP  - 435
VL  - 82
DO  - 10.1016/j.engfailanal.2017.08.006
ER  - 

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

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

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

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

TY  - JOUR
AU  - Musraty, W.
AU  - Međo, Bojan
AU  - Gubeljak, Nenad
AU  - Likeb, A.
AU  - Cvijović-Alagić, Ivana
AU  - Sedmak, Aleksandar
AU  - Rakin, Marko
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2539
AB  - Integrity of pipes is typically assessed by testing fracture mechanics specimens, such as compact tensile (CT) or single-edge notched bending (SENB). However, for some pipe dimensions it is not easy or possible to fabricate a specimen conforming to the requirements of standard procedures. A new type of specimen is proposed recently, which can be advantageous for relatively small pipe diameters and axial defects - the pipe ring notch bend specimen - PRNB. In this work, criteria for failure by ductile fracture of PRNB specimens are determined experimentally and by application of micromechanical analysis. The influence of size of the specimen, as well as size and shape of the stress concentrator, is analysed. The results of this study, along with previous authors' results, lead to the conclusion that the pipe ring specimens can be applied in integrity assessment of pipes with defects. Also, the benefits of their application include much simpler fabrication and the same material history as the pipe itself.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Fracture Mechanics
T1  - Ductile fracture of pipe-ring notched bend specimens - Micromechanical analysis
EP  - 261
SP  - 247
VL  - 175
DO  - 10.1016/j.engfracmech.2017.01.022
ER  - 

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

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

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

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