TY  - CONF
AU  - Lazić, Vukić
AU  - Nikolić, R.
AU  - Arsić, D.
AU  - Arsić, M.
AU  - Popović, Olivera
AU  - Prokić-Cvetković, Radica
AU  - Hadzima, B.
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3631
AB  - The problem considered in this paper is the welding technology of the steel assembly of a firefighter truck rear bridge semi-housing. Since in this procedure the welding is done of the two dissimilar steels, it is necessary to analyze effects of welding on mechanical properties and microstructure of individual joint's zones. The weldability of the base metal was considered first (semi-housing tube and flange), then the welding method and the filler metal were selected and, finally, the technological parameters of welding were calculated. The computational and experimental methods were used for the base metal weldability estimate, based on the hardness measurements in the joint's critical zones and analysis of their structures. Experimental investigations performed were aimed for verification and/or eventual correction of the proposed welding technology.
PB  - Elsevier B.V.
C3  - Transportation Research Procedia
T1  - Analysis of welding of the rear bridge semi-housing assembly of a firefighter truck by the semi-automatic procedure in gas protection
EP  - 552
SP  - 544
VL  - 55
DO  - 10.1016/j.trpro.2021.07.020
ER  - 

@conference{
author = "Lazić, Vukić and Nikolić, R. and Arsić, D. and Arsić, M. and Popović, Olivera and Prokić-Cvetković, Radica and Hadzima, B.",
year = "2021",
abstract = "The problem considered in this paper is the welding technology of the steel assembly of a firefighter truck rear bridge semi-housing. Since in this procedure the welding is done of the two dissimilar steels, it is necessary to analyze effects of welding on mechanical properties and microstructure of individual joint's zones. The weldability of the base metal was considered first (semi-housing tube and flange), then the welding method and the filler metal were selected and, finally, the technological parameters of welding were calculated. The computational and experimental methods were used for the base metal weldability estimate, based on the hardness measurements in the joint's critical zones and analysis of their structures. Experimental investigations performed were aimed for verification and/or eventual correction of the proposed welding technology.",
publisher = "Elsevier B.V.",
journal = "Transportation Research Procedia",
title = "Analysis of welding of the rear bridge semi-housing assembly of a firefighter truck by the semi-automatic procedure in gas protection",
pages = "552-544",
volume = "55",
doi = "10.1016/j.trpro.2021.07.020"
}

Lazić, V., Nikolić, R., Arsić, D., Arsić, M., Popović, O., Prokić-Cvetković, R.,& Hadzima, B.. (2021). Analysis of welding of the rear bridge semi-housing assembly of a firefighter truck by the semi-automatic procedure in gas protection. in Transportation Research Procedia
Elsevier B.V.., 55, 544-552.
https://doi.org/10.1016/j.trpro.2021.07.020

Lazić V, Nikolić R, Arsić D, Arsić M, Popović O, Prokić-Cvetković R, Hadzima B. Analysis of welding of the rear bridge semi-housing assembly of a firefighter truck by the semi-automatic procedure in gas protection. in Transportation Research Procedia. 2021;55:544-552.
doi:10.1016/j.trpro.2021.07.020 .

Lazić, Vukić, Nikolić, R., Arsić, D., Arsić, M., Popović, Olivera, Prokić-Cvetković, Radica, Hadzima, B., "Analysis of welding of the rear bridge semi-housing assembly of a firefighter truck by the semi-automatic procedure in gas protection" in Transportation Research Procedia, 55 (2021):544-552,
https://doi.org/10.1016/j.trpro.2021.07.020 . .

TY  - JOUR
AU  - Milovanović, Nikola
AU  - Sedmak, Aleksandar
AU  - Arsić, M.
AU  - Sedmak, Simon
AU  - Bozić, Z.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3386
AB  - Failures of rotating equipment often cause severe consequences, so it is necessary to study their integrity and life as detailed as possible, especially when crack is detected. In the case studied here, hydro power plant turbine shaft is analysed by using fracture mechanics parameters both for static and dynamic loading in order to assess its structural integrity and life. In both cases classical engineering approach and Finite Element Method have been applied to evaluate stress state and number of cycles from a given initial crack length to its critical value. Results of analytical and numerical modelling are compared to verify both approaches.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Structural integrity and life assessment of rotating equipment
VL  - 113
DO  - 10.1016/j.engfailanal.2020.104561
ER  - 

@article{
author = "Milovanović, Nikola and Sedmak, Aleksandar and Arsić, M. and Sedmak, Simon and Bozić, Z.",
year = "2020",
abstract = "Failures of rotating equipment often cause severe consequences, so it is necessary to study their integrity and life as detailed as possible, especially when crack is detected. In the case studied here, hydro power plant turbine shaft is analysed by using fracture mechanics parameters both for static and dynamic loading in order to assess its structural integrity and life. In both cases classical engineering approach and Finite Element Method have been applied to evaluate stress state and number of cycles from a given initial crack length to its critical value. Results of analytical and numerical modelling are compared to verify both approaches.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Structural integrity and life assessment of rotating equipment",
volume = "113",
doi = "10.1016/j.engfailanal.2020.104561"
}

Milovanović, N., Sedmak, A., Arsić, M., Sedmak, S.,& Bozić, Z.. (2020). Structural integrity and life assessment of rotating equipment. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 113.
https://doi.org/10.1016/j.engfailanal.2020.104561

Milovanović N, Sedmak A, Arsić M, Sedmak S, Bozić Z. Structural integrity and life assessment of rotating equipment. in Engineering Failure Analysis. 2020;113.
doi:10.1016/j.engfailanal.2020.104561 .

Milovanović, Nikola, Sedmak, Aleksandar, Arsić, M., Sedmak, Simon, Bozić, Z., "Structural integrity and life assessment of rotating equipment" in Engineering Failure Analysis, 113 (2020),
https://doi.org/10.1016/j.engfailanal.2020.104561 . .

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  - Arsić, M.
AU  - Bošnjak, Srđan
AU  - Sedmak, Simon
AU  - Šarkoćević, Živče
AU  - Savić, Zoran
AU  - Radu, Dorin
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2289
AB  - Results of non-destructive testing of the Kaplan turbine runner manhole welded structure are presented, on the basis of which the repair methodology is defined. During repair, the welding technology for elements of the manhole is modified along with the proposal given for the modification of its structural design, because the finite element method calculation proved that the rectangular welded structure of the manhole was significantly better than round welded structure when it comes to integrity and service life.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Determination of damage and repair methodology for the runner manhole of Kaplan turbine at the hydro power plant 'Djerdap 1'
EP  - 153
IS  - 3
SP  - 149
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2289
ER  - 

@article{
author = "Arsić, M. and Bošnjak, Srđan and Sedmak, Simon and Šarkoćević, Živče and Savić, Zoran and Radu, Dorin",
year = "2016",
abstract = "Results of non-destructive testing of the Kaplan turbine runner manhole welded structure are presented, on the basis of which the repair methodology is defined. During repair, the welding technology for elements of the manhole is modified along with the proposal given for the modification of its structural design, because the finite element method calculation proved that the rectangular welded structure of the manhole was significantly better than round welded structure when it comes to integrity and service life.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Determination of damage and repair methodology for the runner manhole of Kaplan turbine at the hydro power plant 'Djerdap 1'",
pages = "153-149",
number = "3",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2289"
}

Arsić, M., Bošnjak, S., Sedmak, S., Šarkoćević, Ž., Savić, Z.,& Radu, D.. (2016). Determination of damage and repair methodology for the runner manhole of Kaplan turbine at the hydro power plant 'Djerdap 1'. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 16(3), 149-153.
https://hdl.handle.net/21.15107/rcub_machinery_2289

Arsić M, Bošnjak S, Sedmak S, Šarkoćević Ž, Savić Z, Radu D. Determination of damage and repair methodology for the runner manhole of Kaplan turbine at the hydro power plant 'Djerdap 1'. in Structural Integrity and Life. 2016;16(3):149-153.
https://hdl.handle.net/21.15107/rcub_machinery_2289 .

Arsić, M., Bošnjak, Srđan, Sedmak, Simon, Šarkoćević, Živče, Savić, Zoran, Radu, Dorin, "Determination of damage and repair methodology for the runner manhole of Kaplan turbine at the hydro power plant 'Djerdap 1'" in Structural Integrity and Life, 16, no. 3 (2016):149-153,
https://hdl.handle.net/21.15107/rcub_machinery_2289 .

TY  - JOUR
AU  - Međo, Bojan
AU  - Arsić, M.
AU  - Rakin, Marko
AU  - Sedmak, Simon
AU  - Malešević, Zoranka
AU  - Savić, Zoran
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2386
AB  - Vertical Kaplan turbines with nominal power of 176 MW manufactured in Russia are installed in 6 hydroelectric generating sets at hydro power plant 'Djerdap 1' (Kladovo, Serbia). Most of the components are made of materials in accordance to GOST and ASTM standards. During rehabilitation of hydroelectric generating set, the analysis of the current state and integrity assessment of turbine regulation system pipeline required non-destructive tests on parent material and welded joints between pipes and pipes-elbows. The purpose of the regulation system, comprising of the pipeline for the turbine regulator oil supply, is to open and close vanes of the guide vane apparatus and to regulate the position of runner blades and their number of revolutions. Internal pressure in the regulation system is p = 4 MPa. Structural integrity is a recent scientific and engineering discipline which in broader sense comprises state analysis and behaviour diagnostics, service life assessment and rehabilitation of structures, meaning that beside the usual situation where structural integrity assessment is required when flaws are detected by non-destructive testing, this discipline is also includes stress state analysis. This approach is especially important for welded structures, since cracktype flaws can originate from welding and from unfavourable service conditions. In this paper, the results of non-destructive tests referring to the lack of penetration in roots of butt-welded joints between pipes and pipes-elbows, as well as tensile test results of technical specimens with reinforcements and in specimens with parallel machined sides and standard dimensions, are presented in order to carry out the integrity assessment of the turbine regulation system pipeline of hydroelectric generating set A6 at hydro power plant Djerdap 1. Results of analytical strength calculation of butt-welded joints between 2 pipes, and pipe-elbow with a lack of penetration in the root are also presented.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'djerdap 1'
EP  - 78
IS  - 2
SP  - 71
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_technorep_3159
ER  - 

@article{
author = "Međo, Bojan and Arsić, M. and Rakin, Marko and Sedmak, Simon and Malešević, Zoranka and Savić, Zoran",
year = "2016",
abstract = "Vertical Kaplan turbines with nominal power of 176 MW manufactured in Russia are installed in 6 hydroelectric generating sets at hydro power plant 'Djerdap 1' (Kladovo, Serbia). Most of the components are made of materials in accordance to GOST and ASTM standards. During rehabilitation of hydroelectric generating set, the analysis of the current state and integrity assessment of turbine regulation system pipeline required non-destructive tests on parent material and welded joints between pipes and pipes-elbows. The purpose of the regulation system, comprising of the pipeline for the turbine regulator oil supply, is to open and close vanes of the guide vane apparatus and to regulate the position of runner blades and their number of revolutions. Internal pressure in the regulation system is p = 4 MPa. Structural integrity is a recent scientific and engineering discipline which in broader sense comprises state analysis and behaviour diagnostics, service life assessment and rehabilitation of structures, meaning that beside the usual situation where structural integrity assessment is required when flaws are detected by non-destructive testing, this discipline is also includes stress state analysis. This approach is especially important for welded structures, since cracktype flaws can originate from welding and from unfavourable service conditions. In this paper, the results of non-destructive tests referring to the lack of penetration in roots of butt-welded joints between pipes and pipes-elbows, as well as tensile test results of technical specimens with reinforcements and in specimens with parallel machined sides and standard dimensions, are presented in order to carry out the integrity assessment of the turbine regulation system pipeline of hydroelectric generating set A6 at hydro power plant Djerdap 1. Results of analytical strength calculation of butt-welded joints between 2 pipes, and pipe-elbow with a lack of penetration in the root are also presented.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'djerdap 1'",
pages = "78-71",
number = "2",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_technorep_3159"
}

Međo, B., Arsić, M., Rakin, M., Sedmak, S., Malešević, Z.,& Savić, Z.. (2016). Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'djerdap 1'. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 16(2), 71-78.
https://hdl.handle.net/21.15107/rcub_technorep_3159

Međo B, Arsić M, Rakin M, Sedmak S, Malešević Z, Savić Z. Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'djerdap 1'. in Structural Integrity and Life. 2016;16(2):71-78.
https://hdl.handle.net/21.15107/rcub_technorep_3159 .

Međo, Bojan, Arsić, M., Rakin, Marko, Sedmak, Simon, Malešević, Zoranka, Savić, Zoran, "Integrity assessment of regulation system pipeline elements in hydroelectric generating set a6 of hydro power plant 'djerdap 1'" in Structural Integrity and Life, 16, no. 2 (2016):71-78,
https://hdl.handle.net/21.15107/rcub_technorep_3159 .

TY  - JOUR
AU  - Sedmak, Simon
AU  - Arsić, M.
AU  - Bošnjak, Srđan
AU  - Malešević, Zoranka
AU  - Savić, Zoran
AU  - Radu, Dorin
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2383
AB  - This paper presents the integrity and reliability evaluation of the heating system as a whole, based on results of metallographic tests performed on parent material and the ultrasonic measurement of wall thickness of elbows made of steel St 35.8.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Effect of locally damaged elbow segments on the integrity and reliability of the heating system
EP  - 170
IS  - 3
SP  - 167
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2383
ER  - 

@article{
author = "Sedmak, Simon and Arsić, M. and Bošnjak, Srđan and Malešević, Zoranka and Savić, Zoran and Radu, Dorin",
year = "2016",
abstract = "This paper presents the integrity and reliability evaluation of the heating system as a whole, based on results of metallographic tests performed on parent material and the ultrasonic measurement of wall thickness of elbows made of steel St 35.8.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Effect of locally damaged elbow segments on the integrity and reliability of the heating system",
pages = "170-167",
number = "3",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2383"
}

Sedmak, S., Arsić, M., Bošnjak, S., Malešević, Z., Savić, Z.,& Radu, D.. (2016). Effect of locally damaged elbow segments on the integrity and reliability of the heating system. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 16(3), 167-170.
https://hdl.handle.net/21.15107/rcub_machinery_2383

Sedmak S, Arsić M, Bošnjak S, Malešević Z, Savić Z, Radu D. Effect of locally damaged elbow segments on the integrity and reliability of the heating system. in Structural Integrity and Life. 2016;16(3):167-170.
https://hdl.handle.net/21.15107/rcub_machinery_2383 .

Sedmak, Simon, Arsić, M., Bošnjak, Srđan, Malešević, Zoranka, Savić, Zoran, Radu, Dorin, "Effect of locally damaged elbow segments on the integrity and reliability of the heating system" in Structural Integrity and Life, 16, no. 3 (2016):167-170,
https://hdl.handle.net/21.15107/rcub_machinery_2383 .

TY  - JOUR
AU  - Arsić, M.
AU  - Savić, Zoran
AU  - Sedmak, Aleksandar
AU  - Bošnjak, Srđan
AU  - Sedmak, Simon
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2332
AB  - This paper presents results of experimental examinations of stress concentration influence to fatigue life of butt welded joints with K-groove, produced from the most frequently used structural steel S355J2+N. One group of experiments comprised examinations carried out on the K-groove specimens with stress concentrators of edged notch type. Specimens with short cracks (limited length of initial crack), defined on the basis of the experience from fracture mechanics by the three points bending examinations, have been examined according to standard for the determination of S-N curve, and aimed to determine fatigue strengths for different lengths of initial crack and Relationship between fatigue strength and crack length. Other group of experiments comprised examinations of specimens with edge notch, prepared in accordance with ASTM E 399 for three points bending, in order to establish regularity between crack growth and range of exerted stress intensity factor aimed to determine resistance of welded joint to initial crack growth, namely fatigue threshold (ΔKth).
PB  - Gruppo Italiano Frattura
T2  - Frattura ed Integrita Strutturale
T1  - Experimental examination of fatigue life of welded joint with stress concentration
EP  - 35
IS  - 36
SP  - 27
VL  - 10
DO  - 10.3221/IGF-ESIS.36.03
ER  - 

@article{
author = "Arsić, M. and Savić, Zoran and Sedmak, Aleksandar and Bošnjak, Srđan and Sedmak, Simon",
year = "2016",
abstract = "This paper presents results of experimental examinations of stress concentration influence to fatigue life of butt welded joints with K-groove, produced from the most frequently used structural steel S355J2+N. One group of experiments comprised examinations carried out on the K-groove specimens with stress concentrators of edged notch type. Specimens with short cracks (limited length of initial crack), defined on the basis of the experience from fracture mechanics by the three points bending examinations, have been examined according to standard for the determination of S-N curve, and aimed to determine fatigue strengths for different lengths of initial crack and Relationship between fatigue strength and crack length. Other group of experiments comprised examinations of specimens with edge notch, prepared in accordance with ASTM E 399 for three points bending, in order to establish regularity between crack growth and range of exerted stress intensity factor aimed to determine resistance of welded joint to initial crack growth, namely fatigue threshold (ΔKth).",
publisher = "Gruppo Italiano Frattura",
journal = "Frattura ed Integrita Strutturale",
title = "Experimental examination of fatigue life of welded joint with stress concentration",
pages = "35-27",
number = "36",
volume = "10",
doi = "10.3221/IGF-ESIS.36.03"
}

Arsić, M., Savić, Z., Sedmak, A., Bošnjak, S.,& Sedmak, S.. (2016). Experimental examination of fatigue life of welded joint with stress concentration. in Frattura ed Integrita Strutturale
Gruppo Italiano Frattura., 10(36), 27-35.
https://doi.org/10.3221/IGF-ESIS.36.03

Arsić M, Savić Z, Sedmak A, Bošnjak S, Sedmak S. Experimental examination of fatigue life of welded joint with stress concentration. in Frattura ed Integrita Strutturale. 2016;10(36):27-35.
doi:10.3221/IGF-ESIS.36.03 .

Arsić, M., Savić, Zoran, Sedmak, Aleksandar, Bošnjak, Srđan, Sedmak, Simon, "Experimental examination of fatigue life of welded joint with stress concentration" in Frattura ed Integrita Strutturale, 10, no. 36 (2016):27-35,
https://doi.org/10.3221/IGF-ESIS.36.03 . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Bošnjak, Srđan
AU  - Arsić, M.
AU  - Sedmak, Simon
AU  - Savić, Zoran
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2319
AB  - This paper presents integrity and life estimation of turbine runner cover in a vertical pipe turbines, Kaplan 200 MW nominal output power, produced in Russia, and built in six hydro-generation units of hydroelectric power plant „Đerdap 1” in Serbia. Fatigue and corrosion-fatigue interaction have been taken into account using experimentally obtained material properties, as well as analytical and numerical calculations of stress state, to estimate appropriate safety factors. Fatigue crack growth rate, da/dN, was also calculated, indicated that internal defects of circular or elliptical shape, found out by ultrasonic testing, do not affect reliable operation of runner cover.
PB  - Gruppo Italiano Frattura
T2  - Frattura ed Integrita Strutturale
T1  - Integrity and life estimation of turbine runner cover in a hydro power plant
EP  - 68
IS  - 36
SP  - 63
VL  - 10
DO  - 10.3221/IGF-ESIS.36.07
ER  - 

@article{
author = "Sedmak, Aleksandar and Bošnjak, Srđan and Arsić, M. and Sedmak, Simon and Savić, Zoran",
year = "2016",
abstract = "This paper presents integrity and life estimation of turbine runner cover in a vertical pipe turbines, Kaplan 200 MW nominal output power, produced in Russia, and built in six hydro-generation units of hydroelectric power plant „Đerdap 1” in Serbia. Fatigue and corrosion-fatigue interaction have been taken into account using experimentally obtained material properties, as well as analytical and numerical calculations of stress state, to estimate appropriate safety factors. Fatigue crack growth rate, da/dN, was also calculated, indicated that internal defects of circular or elliptical shape, found out by ultrasonic testing, do not affect reliable operation of runner cover.",
publisher = "Gruppo Italiano Frattura",
journal = "Frattura ed Integrita Strutturale",
title = "Integrity and life estimation of turbine runner cover in a hydro power plant",
pages = "68-63",
number = "36",
volume = "10",
doi = "10.3221/IGF-ESIS.36.07"
}

Sedmak, A., Bošnjak, S., Arsić, M., Sedmak, S.,& Savić, Z.. (2016). Integrity and life estimation of turbine runner cover in a hydro power plant. in Frattura ed Integrita Strutturale
Gruppo Italiano Frattura., 10(36), 63-68.
https://doi.org/10.3221/IGF-ESIS.36.07

Sedmak A, Bošnjak S, Arsić M, Sedmak S, Savić Z. Integrity and life estimation of turbine runner cover in a hydro power plant. in Frattura ed Integrita Strutturale. 2016;10(36):63-68.
doi:10.3221/IGF-ESIS.36.07 .

Sedmak, Aleksandar, Bošnjak, Srđan, Arsić, M., Sedmak, Simon, Savić, Zoran, "Integrity and life estimation of turbine runner cover in a hydro power plant" in Frattura ed Integrita Strutturale, 10, no. 36 (2016):63-68,
https://doi.org/10.3221/IGF-ESIS.36.07 . .

TY  - JOUR
AU  - Sedmak, Simon
AU  - Arsić, M.
AU  - Bajić, Darko
AU  - Mladenović, Mladen
AU  - Savić, Zoran
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2120
AB  - Presented are results of non-destructive tests performed on the parent material and welded joints of structural parts of a breeches pipe (collar and anchor), and results of destructive tests performed on the parent material of the anchor. Non-destructive testing included visual (VT), mag-netic particle (MT), and ultrasonic testing (UT), while destructive tests included determination of chemical com-position, tensile properties, impact energy and hardness. Based on test results it is established that the major cause for the occurrence of damage in the carrying structure of the breeches pipe no.1 of pipeline III, or in other words, the degradation of anchor parent material and welded joints between the collar and anchor, and between the pipeline and anchor, is in the fact that the breeches pipe started to lean, not on the collar, as specified by design, but on the anchor that could not endure all loads occurring in service.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'
EP  - 151
IS  - 3
SP  - 147
VL  - 15
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2120
ER  - 

@article{
author = "Sedmak, Simon and Arsić, M. and Bajić, Darko and Mladenović, Mladen and Savić, Zoran",
year = "2015",
abstract = "Presented are results of non-destructive tests performed on the parent material and welded joints of structural parts of a breeches pipe (collar and anchor), and results of destructive tests performed on the parent material of the anchor. Non-destructive testing included visual (VT), mag-netic particle (MT), and ultrasonic testing (UT), while destructive tests included determination of chemical com-position, tensile properties, impact energy and hardness. Based on test results it is established that the major cause for the occurrence of damage in the carrying structure of the breeches pipe no.1 of pipeline III, or in other words, the degradation of anchor parent material and welded joints between the collar and anchor, and between the pipeline and anchor, is in the fact that the breeches pipe started to lean, not on the collar, as specified by design, but on the anchor that could not endure all loads occurring in service.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'",
pages = "151-147",
number = "3",
volume = "15",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2120"
}

Sedmak, S., Arsić, M., Bajić, D., Mladenović, M.,& Savić, Z.. (2015). Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 15(3), 147-151.
https://hdl.handle.net/21.15107/rcub_machinery_2120

Sedmak S, Arsić M, Bajić D, Mladenović M, Savić Z. Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'. in Structural Integrity and Life. 2015;15(3):147-151.
https://hdl.handle.net/21.15107/rcub_machinery_2120 .

Sedmak, Simon, Arsić, M., Bajić, Darko, Mladenović, Mladen, Savić, Zoran, "Analysis of causes of degradation of parent material and weld metal of breeches pipe at hydro power plant 'Perućica'" in Structural Integrity and Life, 15, no. 3 (2015):147-151,
https://hdl.handle.net/21.15107/rcub_machinery_2120 .

TY  - JOUR
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Matvienko, Y.
AU  - Arsić, M.
AU  - Šarkočević, Živče
AU  - Sedmak, Aleksandar
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2233
AB  - Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are also often exposed to damages at the external surface. A pipe segment exposed to internal pressure is examined experimentally and numerically, using the finite element method. Experimental setup included tracking of crack mouth opening displacement (CMOD) values, as well as J integral. Criteria for pipe failure are determined on the finite element (FE) models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. Several 3D models with different crack sizes are evaluated. 2D plane strain models are also examined, to determine the applicability limits of this simplified approach. Integrity assessment criteria for the analysed geometries are discussed. Assessment of fracture resistance of the pipeline material is also considered in this work. Besides the standard SENB specimens, Ring specimens cut from the pipe are tested, and the results are compared. Both specimen geometries are modelled using local approach to fracture, by application of the micromechanical Complete Gurson model (CGM), developed by Z.L. Zhang. It is shown that the Ring specimens have similar fracture conditions under bending load as SENB specimens. Since they are much simpler to fabricate from the pipe than standard specimens, it is concluded that they can be used for assessment of fracture of the pipes with axial cracks.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Failure resistance of drilling rig casing pipes with an axial crack
EP  - 440
SP  - 429
VL  - 58
DO  - 10.1016/j.engfailanal.2015.05.015
ER  - 

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

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

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

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

TY  - CONF
AU  - Dimić, I.
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Arsić, M.
AU  - Šarkočević, Živče
AU  - Sedmak, Aleksandar
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1874
AB  - Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a steel pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are often exposed to damages at the external surface. Analyzed crack is in axial direction, bearing in mind that this type of defect most significantly decreases the load carrying capacity of the cylindrical pressurized components. A pipe segment exposed to internal pressure is analyzed experimentally and numerically, using the finite element method. The experimental setup included the tracking of crack mouth opening displacement (CMOD) values, as well as J integral, which is determined by application of direct measurement. Criteria for pipe failure are determined on finite element models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. The size of the crack is varied in the finite element models; several 3D models with different crack sizes (length and depth) are evaluated. Dependence of maximum internal pressure on the defect size is obtained. 2D plane strain models are also examined, with an aim to determine the applicability limits of this simplified approach. Based on the obtained results, integrity assessment criteria for the analyzed geometries are discussed.
PB  - Elsevier Science Bv, Amsterdam
C3  - 20th European Conference on Fracture
T1  - Failure prediction of gas and oil drilling rig pipelines with axial defects
EP  - 960
SP  - 955
VL  - 3
DO  - 10.1016/j.mspro.2014.06.155
ER  - 

@conference{
author = "Dimić, I. and Međo, Bojan and Rakin, Marko and Arsić, M. and Šarkočević, Živče and Sedmak, Aleksandar",
year = "2014",
abstract = "Working conditions of casing pipes in drilling rigs can significantly influence the initiation and development of damage in the material, and therefore also the safe service of the entire system. In this work, an integrity assessment of a steel pipe with initial defect (machined surface crack) is presented. The position of this defect is on the external surface; unlike transport pipes, where internal surface is often endangered due to the contact with the fluid, casing pipes are often exposed to damages at the external surface. Analyzed crack is in axial direction, bearing in mind that this type of defect most significantly decreases the load carrying capacity of the cylindrical pressurized components. A pipe segment exposed to internal pressure is analyzed experimentally and numerically, using the finite element method. The experimental setup included the tracking of crack mouth opening displacement (CMOD) values, as well as J integral, which is determined by application of direct measurement. Criteria for pipe failure are determined on finite element models of the pipe; fracture initiation and plastic collapse are considered as failure mechanisms. The size of the crack is varied in the finite element models; several 3D models with different crack sizes (length and depth) are evaluated. Dependence of maximum internal pressure on the defect size is obtained. 2D plane strain models are also examined, with an aim to determine the applicability limits of this simplified approach. Based on the obtained results, integrity assessment criteria for the analyzed geometries are discussed.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "20th European Conference on Fracture",
title = "Failure prediction of gas and oil drilling rig pipelines with axial defects",
pages = "960-955",
volume = "3",
doi = "10.1016/j.mspro.2014.06.155"
}

Dimić, I., Međo, B., Rakin, M., Arsić, M., Šarkočević, Ž.,& Sedmak, A.. (2014). Failure prediction of gas and oil drilling rig pipelines with axial defects. in 20th European Conference on Fracture
Elsevier Science Bv, Amsterdam., 3, 955-960.
https://doi.org/10.1016/j.mspro.2014.06.155

Dimić I, Međo B, Rakin M, Arsić M, Šarkočević Ž, Sedmak A. Failure prediction of gas and oil drilling rig pipelines with axial defects. in 20th European Conference on Fracture. 2014;3:955-960.
doi:10.1016/j.mspro.2014.06.155 .

Dimić, I., Međo, Bojan, Rakin, Marko, Arsić, M., Šarkočević, Živče, Sedmak, Aleksandar, "Failure prediction of gas and oil drilling rig pipelines with axial defects" in 20th European Conference on Fracture, 3 (2014):955-960,
https://doi.org/10.1016/j.mspro.2014.06.155 . .

TY  - CONF
AU  - Arsić, M.
AU  - Vistać, Brane
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Savić, Zoran
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1962
AB  - Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW, have been installed in 6 hydroelectric generating units at ’Djerdap 1’. During the refurbishment of hydropower plant experimental non-destructive tests were performed in order to determine the state of turbine components. During the course of testing damage was detected at sleeves and welded shields of guide vanes, which occurred as a consequence of turbine shaft vibrations. 1782 mm long guide vane sleeves were made of cast steel 25L (GOST standard), 260 mm long sleeve was made of forged steel St 25 (GOST standard), while welded shields of guide vanes were made of austenitic steel 08X18H10T (GOST standard). Results of experimental tests and methodology for reparation of damaged surfaces of sleeves and welded shields of guide vanes are presented in this paper. It was necessary, due to the structural solution used for the design of guide vanes and their function during service, to define a large number of details, carefully reconsider them and carry out all activities with extreme care in order to enable the safe operation and continuous use of vanes through the use of reparation methodology for welding/surface welding of sleeves and welded shields. Overlooking, underestimation or incorrect perception of important details could cause significant problems during turbine operation.
PB  - Trans Tech Publications Ltd
C3  - Advanced Materials Research
T1  - Methodology for reparation of damaged sleeves and welded shield sections of guide vanes at hydropower plant DJERDAP 1
EP  - 13
SP  - 8
VL  - 1029
DO  - 10.4028/www.scientific.net/AMR.1029.8
ER  - 

@conference{
author = "Arsić, M. and Vistać, Brane and Bošnjak, Srđan and Grabulov, Vencislav and Savić, Zoran",
year = "2014",
abstract = "Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW, have been installed in 6 hydroelectric generating units at ’Djerdap 1’. During the refurbishment of hydropower plant experimental non-destructive tests were performed in order to determine the state of turbine components. During the course of testing damage was detected at sleeves and welded shields of guide vanes, which occurred as a consequence of turbine shaft vibrations. 1782 mm long guide vane sleeves were made of cast steel 25L (GOST standard), 260 mm long sleeve was made of forged steel St 25 (GOST standard), while welded shields of guide vanes were made of austenitic steel 08X18H10T (GOST standard). Results of experimental tests and methodology for reparation of damaged surfaces of sleeves and welded shields of guide vanes are presented in this paper. It was necessary, due to the structural solution used for the design of guide vanes and their function during service, to define a large number of details, carefully reconsider them and carry out all activities with extreme care in order to enable the safe operation and continuous use of vanes through the use of reparation methodology for welding/surface welding of sleeves and welded shields. Overlooking, underestimation or incorrect perception of important details could cause significant problems during turbine operation.",
publisher = "Trans Tech Publications Ltd",
journal = "Advanced Materials Research",
title = "Methodology for reparation of damaged sleeves and welded shield sections of guide vanes at hydropower plant DJERDAP 1",
pages = "13-8",
volume = "1029",
doi = "10.4028/www.scientific.net/AMR.1029.8"
}

Arsić, M., Vistać, B., Bošnjak, S., Grabulov, V.,& Savić, Z.. (2014). Methodology for reparation of damaged sleeves and welded shield sections of guide vanes at hydropower plant DJERDAP 1. in Advanced Materials Research
Trans Tech Publications Ltd., 1029, 8-13.
https://doi.org/10.4028/www.scientific.net/AMR.1029.8

Arsić M, Vistać B, Bošnjak S, Grabulov V, Savić Z. Methodology for reparation of damaged sleeves and welded shield sections of guide vanes at hydropower plant DJERDAP 1. in Advanced Materials Research. 2014;1029:8-13.
doi:10.4028/www.scientific.net/AMR.1029.8 .

Arsić, M., Vistać, Brane, Bošnjak, Srđan, Grabulov, Vencislav, Savić, Zoran, "Methodology for reparation of damaged sleeves and welded shield sections of guide vanes at hydropower plant DJERDAP 1" in Advanced Materials Research, 1029 (2014):8-13,
https://doi.org/10.4028/www.scientific.net/AMR.1029.8 . .

TY  - CONF
AU  - Arsić, M.
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Veljović, Aleksandar
AU  - Savić, Zoran
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1961
AB  - Stable supply tank, with volume V = 250 m3 and operating pressure p = 1,5 MPa, of generation unit 6 at thermal power plant 'Nikola Tesla A' in Obrenovac, is designed for water-steam working fluid. It was made of steel Č 1204 as a single-part welded structure with a single wall. Cylindrical tank shell consists of 8 segments, while torispherical deep bottoms consist of 3 segments. The tank is in the horizontal position and it lays on 4 supports. There are five manometers installed at the tank for pressure control, as well as 5 spring-loaded safety valves. In this paper results of non-destructive tests performed on the tank are presented. Mechanical damages on parent material, up to 1.5 mm deep, were detected at the outer surface of the cylindrical section of the right bottom (as seen from the boiler) and on the inner surface of the shell, as well as sporadic pitting corrosion, up to 0.5 mm deep, and 2 mm misalignment of sheet metals in areas where shell segments are joined. Crack type linear indications were detected on the surface of welded joints through the use of magnetic particle testing. Through ultrasonic and radiographic testing it was determined that the homogeneity of welded joints is satisfactory. Hardness testing was performed on all segments of the tank, and obtained values were in the range between 118 and 130 HB. Metallographic examination, performed on specimens of all segments of the tank, showed that microstructure of material is either fine-grained or striped ferrite-pearlite. On the basis of test results the repair technology for shell and bottom segments was made, while on the basis of the analytical calculation of tank strength the integrity evaluation was carried out for the upcoming period of service, depending on the category of the vessel.
PB  - Trans Tech Publications Ltd
C3  - Advanced Materials Research
T1  - Analysis of current state and integrity evaluation for the supply tank of generation unit 6 of thermal power plant Nikola Tesla ”A”, Obrenovac
EP  - 19
SP  - 14
VL  - 1029
DO  - 10.4028/www.scientific.net/AMR.1029.14
ER  - 

@conference{
author = "Arsić, M. and Bošnjak, Srđan and Grabulov, Vencislav and Veljović, Aleksandar and Savić, Zoran",
year = "2014",
abstract = "Stable supply tank, with volume V = 250 m3 and operating pressure p = 1,5 MPa, of generation unit 6 at thermal power plant 'Nikola Tesla A' in Obrenovac, is designed for water-steam working fluid. It was made of steel Č 1204 as a single-part welded structure with a single wall. Cylindrical tank shell consists of 8 segments, while torispherical deep bottoms consist of 3 segments. The tank is in the horizontal position and it lays on 4 supports. There are five manometers installed at the tank for pressure control, as well as 5 spring-loaded safety valves. In this paper results of non-destructive tests performed on the tank are presented. Mechanical damages on parent material, up to 1.5 mm deep, were detected at the outer surface of the cylindrical section of the right bottom (as seen from the boiler) and on the inner surface of the shell, as well as sporadic pitting corrosion, up to 0.5 mm deep, and 2 mm misalignment of sheet metals in areas where shell segments are joined. Crack type linear indications were detected on the surface of welded joints through the use of magnetic particle testing. Through ultrasonic and radiographic testing it was determined that the homogeneity of welded joints is satisfactory. Hardness testing was performed on all segments of the tank, and obtained values were in the range between 118 and 130 HB. Metallographic examination, performed on specimens of all segments of the tank, showed that microstructure of material is either fine-grained or striped ferrite-pearlite. On the basis of test results the repair technology for shell and bottom segments was made, while on the basis of the analytical calculation of tank strength the integrity evaluation was carried out for the upcoming period of service, depending on the category of the vessel.",
publisher = "Trans Tech Publications Ltd",
journal = "Advanced Materials Research",
title = "Analysis of current state and integrity evaluation for the supply tank of generation unit 6 of thermal power plant Nikola Tesla ”A”, Obrenovac",
pages = "19-14",
volume = "1029",
doi = "10.4028/www.scientific.net/AMR.1029.14"
}

Arsić, M., Bošnjak, S., Grabulov, V., Veljović, A.,& Savić, Z.. (2014). Analysis of current state and integrity evaluation for the supply tank of generation unit 6 of thermal power plant Nikola Tesla ”A”, Obrenovac. in Advanced Materials Research
Trans Tech Publications Ltd., 1029, 14-19.
https://doi.org/10.4028/www.scientific.net/AMR.1029.14

Arsić M, Bošnjak S, Grabulov V, Veljović A, Savić Z. Analysis of current state and integrity evaluation for the supply tank of generation unit 6 of thermal power plant Nikola Tesla ”A”, Obrenovac. in Advanced Materials Research. 2014;1029:14-19.
doi:10.4028/www.scientific.net/AMR.1029.14 .

Arsić, M., Bošnjak, Srđan, Grabulov, Vencislav, Veljović, Aleksandar, Savić, Zoran, "Analysis of current state and integrity evaluation for the supply tank of generation unit 6 of thermal power plant Nikola Tesla ”A”, Obrenovac" in Advanced Materials Research, 1029 (2014):14-19,
https://doi.org/10.4028/www.scientific.net/AMR.1029.14 . .

TY  - CONF
AU  - Rakin, Marko
AU  - Arsić, M.
AU  - Međo, Bojan
AU  - Šarkočević, Živče
AU  - Sedmak, Aleksandar
PY  - 2013
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1790
AB  - The exploitation of casing steel pipes used in oil and gas drilling rigs typically involves a corrosive atmosphere, high pressures and elevated temperatures. These conditions can affect the initiation and development of defects in the material, which can jeopardize t he s afe s ervice o f t he s ystem. I n t his work, a n assessment of the integrity of a damaged pipe, manufactured by high frequency contact welding (HF) of API J55 steel, is presented. The influence of an initial defect (machined surface crack) on the pipe structural integrity is analysed. Besides the defects at the internal surface, which is in contact with the transported fluid, casing pipes are also exposed to damage at the external surface, which is why such configuration is examined here. The analysed surface crack is in an axial direction, bearing in mind that this type of defect is the most severe for the cylindrical pressurised components. Internal pressure testing is conducted on a pipe closed by dished ends. The values of fracture parameters, crack mouth opening displacement CMOD and J integral, were tracked during the experiment. The applied procedure for J integral determination (so-called direct measurement) can be applied both on standard specimens and on structures. It includes the use of combined experimental - computational procedure. Finite element analysis is used for determining the criteria for the pipe failure, regarding both crack growth initiation and plastic collapse of the ligament. The size of the crack is varied in the finite element models, in order to determine the influence of its size on the maximum loading. Simplified 2D models are also examined, with the aim of determining the applicability of such approach. Based on the obtained results, criteria for the integrity assessment of the pipe are discussed.
C3  - WIT Transactions on the Built Environment
T1  - Structural integrity assurance of casing pipes in the oil and gas industry
EP  - 410
SP  - 401
VL  - 134
DO  - 10.2495/SAFE130361
ER  - 

@conference{
author = "Rakin, Marko and Arsić, M. and Međo, Bojan and Šarkočević, Živče and Sedmak, Aleksandar",
year = "2013",
abstract = "The exploitation of casing steel pipes used in oil and gas drilling rigs typically involves a corrosive atmosphere, high pressures and elevated temperatures. These conditions can affect the initiation and development of defects in the material, which can jeopardize t he s afe s ervice o f t he s ystem. I n t his work, a n assessment of the integrity of a damaged pipe, manufactured by high frequency contact welding (HF) of API J55 steel, is presented. The influence of an initial defect (machined surface crack) on the pipe structural integrity is analysed. Besides the defects at the internal surface, which is in contact with the transported fluid, casing pipes are also exposed to damage at the external surface, which is why such configuration is examined here. The analysed surface crack is in an axial direction, bearing in mind that this type of defect is the most severe for the cylindrical pressurised components. Internal pressure testing is conducted on a pipe closed by dished ends. The values of fracture parameters, crack mouth opening displacement CMOD and J integral, were tracked during the experiment. The applied procedure for J integral determination (so-called direct measurement) can be applied both on standard specimens and on structures. It includes the use of combined experimental - computational procedure. Finite element analysis is used for determining the criteria for the pipe failure, regarding both crack growth initiation and plastic collapse of the ligament. The size of the crack is varied in the finite element models, in order to determine the influence of its size on the maximum loading. Simplified 2D models are also examined, with the aim of determining the applicability of such approach. Based on the obtained results, criteria for the integrity assessment of the pipe are discussed.",
journal = "WIT Transactions on the Built Environment",
title = "Structural integrity assurance of casing pipes in the oil and gas industry",
pages = "410-401",
volume = "134",
doi = "10.2495/SAFE130361"
}

Rakin, M., Arsić, M., Međo, B., Šarkočević, Ž.,& Sedmak, A.. (2013). Structural integrity assurance of casing pipes in the oil and gas industry. in WIT Transactions on the Built Environment, 134, 401-410.
https://doi.org/10.2495/SAFE130361

Rakin M, Arsić M, Međo B, Šarkočević Ž, Sedmak A. Structural integrity assurance of casing pipes in the oil and gas industry. in WIT Transactions on the Built Environment. 2013;134:401-410.
doi:10.2495/SAFE130361 .

Rakin, Marko, Arsić, M., Međo, Bojan, Šarkočević, Živče, Sedmak, Aleksandar, "Structural integrity assurance of casing pipes in the oil and gas industry" in WIT Transactions on the Built Environment, 134 (2013):401-410,
https://doi.org/10.2495/SAFE130361 . .

TY  - CONF
AU  - Rakin, Marko
AU  - Arsić, M.
AU  - Šarkočević, Živče
AU  - Međo, Bojan
AU  - Tomović, N.
AU  - Sedmak, Aleksandar
PY  - 2012
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1592
AB  - The paper deals with the integrity assessment of API J55 steel casing pipes for drilling rigs, manufactured by high frequency contact welding procedure. The influence of corrosion defects on the pipeline load carrying capacity is determined through pressure test of a pipe with corrosion damages simulated by machining the circular holes. Finite element analysis of the damaged pipe subjected to internal pressure is used for determining the stress/strain conditions in the damaged area of the pipe. Also, numerical model was used for establishing the load carrying capacity of the pipe with different damage levels (i.e. defect depth and length). Several expressions from the literature are used for estimation of the maximum pressure in the damaged section of the pipe, and the solutions are compared with the predictions of finite element models and experimental results.
PB  - European Conference on Fracture, ECF
C3  - 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF
T1  - Damaged welded pipes for oil and gas rigs exposed to internal pressure - Failure estimation
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1975
ER  - 

@conference{
author = "Rakin, Marko and Arsić, M. and Šarkočević, Živče and Međo, Bojan and Tomović, N. and Sedmak, Aleksandar",
year = "2012",
abstract = "The paper deals with the integrity assessment of API J55 steel casing pipes for drilling rigs, manufactured by high frequency contact welding procedure. The influence of corrosion defects on the pipeline load carrying capacity is determined through pressure test of a pipe with corrosion damages simulated by machining the circular holes. Finite element analysis of the damaged pipe subjected to internal pressure is used for determining the stress/strain conditions in the damaged area of the pipe. Also, numerical model was used for establishing the load carrying capacity of the pipe with different damage levels (i.e. defect depth and length). Several expressions from the literature are used for estimation of the maximum pressure in the damaged section of the pipe, and the solutions are compared with the predictions of finite element models and experimental results.",
publisher = "European Conference on Fracture, ECF",
journal = "19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF",
title = "Damaged welded pipes for oil and gas rigs exposed to internal pressure - Failure estimation",
url = "https://hdl.handle.net/21.15107/rcub_technorep_1975"
}

Rakin, M., Arsić, M., Šarkočević, Ž., Međo, B., Tomović, N.,& Sedmak, A.. (2012). Damaged welded pipes for oil and gas rigs exposed to internal pressure - Failure estimation. in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF
European Conference on Fracture, ECF..
https://hdl.handle.net/21.15107/rcub_technorep_1975

Rakin M, Arsić M, Šarkočević Ž, Međo B, Tomović N, Sedmak A. Damaged welded pipes for oil and gas rigs exposed to internal pressure - Failure estimation. in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF. 2012;.
https://hdl.handle.net/21.15107/rcub_technorep_1975 .

Rakin, Marko, Arsić, M., Šarkočević, Živče, Međo, Bojan, Tomović, N., Sedmak, Aleksandar, "Damaged welded pipes for oil and gas rigs exposed to internal pressure - Failure estimation" in 19th European Conference on Fracture: Fracture Mechanics for Durability, Reliability and Safety, ECF (2012),
https://hdl.handle.net/21.15107/rcub_technorep_1975 .

TY  - CONF
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Arsić, M.
AU  - Šarkočević, Živče
AU  - Ivanović, Ivana
AU  - Sedmak, Aleksandar
PY  - 2012
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1396
AB  - Seam casing pipe used in an oil drilling rig, manufactured by high frequency (HF) contact welding of API J55 steel, is tested. The influence of an initial defect (machined surface crack) is analysed, by performing pressure test of a pipe segment closed at both ends. Besides the damages at the internal surface, casing pipes are exposed to damage at the external surface, which is why such configuration is analysed here. Measurement of strains and crack mouth opening displacement (CMOD) enabled the application of direct method for J integral evaluation. This procedure is based on the path independence of the J integral and can be applied both in laboratory conditions (on specimens) and on structures. However, it requires a demanding experimental - computational procedure, which is accomplished here using the developed routine. Additionally, the behaviour of the pipe under internal pressure, including fracture mechanics parameters determination, is modelled numerically (by finite element method) in software package Abaqus. The pressure is applied as distributed load acting on the inner surface of the three-dimensional model, and axial tension is applied at the end of the pipe to simulate the closed end. J integral values determined numerically and using direct method are used for estimation of the critical pressure corresponding to the crack growth initiation. Additionally, plastic limit load, i.e. pressure which causes yielding of the ligament, is determined. Based on the results, criteria for pipe integrity assessment are discussed.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
C3  - Advances in Fracture and Damage Mechanics X
T1  - API J55 Steel Casing Pipe with an Initial Surface Crack under Internal Pressure - Determination of Fracture Parameters
EP  - +
SP  - 577
VL  - 488-489
DO  - 10.4028/www.scientific.net/KEM.488-489.577
ER  - 

@conference{
author = "Rakin, Marko and Međo, Bojan and Arsić, M. and Šarkočević, Živče and Ivanović, Ivana and Sedmak, Aleksandar",
year = "2012",
abstract = "Seam casing pipe used in an oil drilling rig, manufactured by high frequency (HF) contact welding of API J55 steel, is tested. The influence of an initial defect (machined surface crack) is analysed, by performing pressure test of a pipe segment closed at both ends. Besides the damages at the internal surface, casing pipes are exposed to damage at the external surface, which is why such configuration is analysed here. Measurement of strains and crack mouth opening displacement (CMOD) enabled the application of direct method for J integral evaluation. This procedure is based on the path independence of the J integral and can be applied both in laboratory conditions (on specimens) and on structures. However, it requires a demanding experimental - computational procedure, which is accomplished here using the developed routine. Additionally, the behaviour of the pipe under internal pressure, including fracture mechanics parameters determination, is modelled numerically (by finite element method) in software package Abaqus. The pressure is applied as distributed load acting on the inner surface of the three-dimensional model, and axial tension is applied at the end of the pipe to simulate the closed end. J integral values determined numerically and using direct method are used for estimation of the critical pressure corresponding to the crack growth initiation. Additionally, plastic limit load, i.e. pressure which causes yielding of the ligament, is determined. Based on the results, criteria for pipe integrity assessment are discussed.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Advances in Fracture and Damage Mechanics X",
title = "API J55 Steel Casing Pipe with an Initial Surface Crack under Internal Pressure - Determination of Fracture Parameters",
pages = "+-577",
volume = "488-489",
doi = "10.4028/www.scientific.net/KEM.488-489.577"
}

Rakin, M., Međo, B., Arsić, M., Šarkočević, Ž., Ivanović, I.,& Sedmak, A.. (2012). API J55 Steel Casing Pipe with an Initial Surface Crack under Internal Pressure - Determination of Fracture Parameters. in Advances in Fracture and Damage Mechanics X
Trans Tech Publications Ltd, Durnten-Zurich., 488-489, 577-+.
https://doi.org/10.4028/www.scientific.net/KEM.488-489.577

Rakin M, Međo B, Arsić M, Šarkočević Ž, Ivanović I, Sedmak A. API J55 Steel Casing Pipe with an Initial Surface Crack under Internal Pressure - Determination of Fracture Parameters. in Advances in Fracture and Damage Mechanics X. 2012;488-489:577-+.
doi:10.4028/www.scientific.net/KEM.488-489.577 .

Rakin, Marko, Međo, Bojan, Arsić, M., Šarkočević, Živče, Ivanović, Ivana, Sedmak, Aleksandar, "API J55 Steel Casing Pipe with an Initial Surface Crack under Internal Pressure - Determination of Fracture Parameters" in Advances in Fracture and Damage Mechanics X, 488-489 (2012):577-+,
https://doi.org/10.4028/www.scientific.net/KEM.488-489.577 . .

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Predan, J.
AU  - Arsić, M.
AU  - Sedmak, Aleksandar
PY  - 2011
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1181
AB  - Among various micromechanical models for ductile fracture analysis using local approach, those based on the Gurson plastic flow criterion have been intensively developed in the past three decades. However, their application is still subject of many researches, with the aim to improve the assessment of ductile fracture in various, mainly metallic, materials. In this work, Gurson criterion is applied to welded joints produced with one or two different weld metals (one of these is overmatched, while the other is undermatched). Welded single-edge notched bend (SENB) specimens are examined, with an initial pre-crack located in the symmetry plane of each joint. Local approach is chosen for assessment of behaviour of the joints under the external loading, to capture the effect of material inhomogeneity and initial crack length on deformation and ductile fracture initiation in analysed specimens.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
C3  - Materials Structure & Micromechanics of Fracture
T1  - Influence of crack length on ductile fracture initiation in welded joints with one and two weld metals
EP  - +
SP  - 578
VL  - 465
DO  - 10.4028/www.scientific.net/KEM.465.578
ER  - 

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

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

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

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

TY  - CONF
AU  - Međo, Bojan
AU  - Rakin, Marko
AU  - Gubeljak, Nenad
AU  - Arsić, M.
AU  - Sedmak, Aleksandar
PY  - 2010
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/1018
AB  - Local approach is applied to analysis of ductile fracture in steel welded joints. Welded single-edge notched bend (SENBspecimens with joints containing one or two weld metals are investigated. The Gurson plastic flow criterion is used, and the crack growth is modelled by observing damage in elements in front of the crack tip. The effect of various factors: microstructural parameters, joint width, initial crack length, as well as size and formulation of finite elements in the ligament, is examined. Special consideration is given to the connection between material microstructure and fracture behaviour, and it is found that initial porosity and finite element size that correspond to the microstructural quantities (volume fraction of non-metallic inclusions and mean free path between them, determined using quantitative microstructural analysisgive the most appropriate results. It is concluded that local approach enables estimation of ductile fracture initiation in analysed welded joints, also capturing the constraint effect caused by the different joint widths and effect of material inhomogeneity along the crack front of the joints with two different weld metals.
C3  - 18th European Conference on Fracture: Fracture of Materials and Structures from Micro to Macro Scale
T1  - Local approach to analysis of ductile fracture in welded joints-Influence factors
UR  - https://hdl.handle.net/21.15107/rcub_technorep_1550
ER  - 

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

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

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

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

TY  - JOUR
AU  - Zrilić, Milorad
AU  - Rakin, Marko
AU  - Sedmak, Aleksandar
AU  - Aleksić, R.
AU  - Cvijović, Z.
AU  - Arsić, M.
PY  - 2006
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/629
AB  - Considering the conditions to which steels used for the manufacture of steam pipelines are exposed, the micromechanism of their destruction in exploitation is exclusively the ductile one. In order to make an estimation of the level of the damage that occurs in exploitation, in this paper a combined experimental and numerical procedure has been developed based on micromechanical or local approach to the fracture mechanics of metallic materials. After the analysis of the results obtained for micromechanical criterion of failure for virgin steel and that used in the steam pipeline, a proposal for prolongation of the working life of tested steel for steam pipelines until the next overhaul is given.
PB  - Trans Tech Publications Ltd, Durnten-Zurich
T2  - Recent Developments in Advanced Materials and Processes
T1  - Ductile fracture prediction of steam pipeline steel
EP  - 542
SP  - 537
VL  - 518
DO  - 10.4028/www.scientific.net/MSF.518.537
ER  - 

@article{
author = "Zrilić, Milorad and Rakin, Marko and Sedmak, Aleksandar and Aleksić, R. and Cvijović, Z. and Arsić, M.",
year = "2006",
abstract = "Considering the conditions to which steels used for the manufacture of steam pipelines are exposed, the micromechanism of their destruction in exploitation is exclusively the ductile one. In order to make an estimation of the level of the damage that occurs in exploitation, in this paper a combined experimental and numerical procedure has been developed based on micromechanical or local approach to the fracture mechanics of metallic materials. After the analysis of the results obtained for micromechanical criterion of failure for virgin steel and that used in the steam pipeline, a proposal for prolongation of the working life of tested steel for steam pipelines until the next overhaul is given.",
publisher = "Trans Tech Publications Ltd, Durnten-Zurich",
journal = "Recent Developments in Advanced Materials and Processes",
title = "Ductile fracture prediction of steam pipeline steel",
pages = "542-537",
volume = "518",
doi = "10.4028/www.scientific.net/MSF.518.537"
}

Zrilić, M., Rakin, M., Sedmak, A., Aleksić, R., Cvijović, Z.,& Arsić, M.. (2006). Ductile fracture prediction of steam pipeline steel. in Recent Developments in Advanced Materials and Processes
Trans Tech Publications Ltd, Durnten-Zurich., 518, 537-542.
https://doi.org/10.4028/www.scientific.net/MSF.518.537

Zrilić M, Rakin M, Sedmak A, Aleksić R, Cvijović Z, Arsić M. Ductile fracture prediction of steam pipeline steel. in Recent Developments in Advanced Materials and Processes. 2006;518:537-542.
doi:10.4028/www.scientific.net/MSF.518.537 .

Zrilić, Milorad, Rakin, Marko, Sedmak, Aleksandar, Aleksić, R., Cvijović, Z., Arsić, M., "Ductile fracture prediction of steam pipeline steel" in Recent Developments in Advanced Materials and Processes, 518 (2006):537-542,
https://doi.org/10.4028/www.scientific.net/MSF.518.537 . .