TY  - JOUR
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5232
AB  - This paper contains results of tests performed in order to determine mechanical properties
of steel P460NL1, used as filler material during the execution of welded joints. Arc welding
of samples from which the specimens were taken was carried out through the application of welding process 111, because it is one of the processes for the execution of pipelines for pressure equipment. Microspecimens with diameter of 1,5 mm were tested in order to determine tensile properties of material taken from the heat-affected zone and weld metal, while specimens with diameter of 6 mm were tested in order to determine tensile properties of parent material. Standard Charpy V-notch specimens were used in order to determine impact energy. Results of metallographic tests which refer to the structure of a pipe welded joint are also presented.
PB  - Trans Tech Publications Ltd, Switzerland
T2  - Advanced Materials Research
T1  - Testing of welded joints between pipes for pressure vessels made of hot rolled fine-grained steel P460NL1
VL  - 1157
DO  - 10.4028/www.scientific.net/AMR.1157.15
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Mladenović, M. and Savić, Zoran",
year = "2020",
abstract = "This paper contains results of tests performed in order to determine mechanical properties
of steel P460NL1, used as filler material during the execution of welded joints. Arc welding
of samples from which the specimens were taken was carried out through the application of welding process 111, because it is one of the processes for the execution of pipelines for pressure equipment. Microspecimens with diameter of 1,5 mm were tested in order to determine tensile properties of material taken from the heat-affected zone and weld metal, while specimens with diameter of 6 mm were tested in order to determine tensile properties of parent material. Standard Charpy V-notch specimens were used in order to determine impact energy. Results of metallographic tests which refer to the structure of a pipe welded joint are also presented.",
publisher = "Trans Tech Publications Ltd, Switzerland",
journal = "Advanced Materials Research",
title = "Testing of welded joints between pipes for pressure vessels made of hot rolled fine-grained steel P460NL1",
volume = "1157",
doi = "10.4028/www.scientific.net/AMR.1157.15"
}

Arsić, M., Bošnjak, S., Grabulov, V., Mladenović, M.,& Savić, Z.. (2020). Testing of welded joints between pipes for pressure vessels made of hot rolled fine-grained steel P460NL1. in Advanced Materials Research
Trans Tech Publications Ltd, Switzerland., 1157.
https://doi.org/10.4028/www.scientific.net/AMR.1157.15

Arsić M, Bošnjak S, Grabulov V, Mladenović M, Savić Z. Testing of welded joints between pipes for pressure vessels made of hot rolled fine-grained steel P460NL1. in Advanced Materials Research. 2020;1157.
doi:10.4028/www.scientific.net/AMR.1157.15 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Mladenović, M., Savić, Zoran, "Testing of welded joints between pipes for pressure vessels made of hot rolled fine-grained steel P460NL1" in Advanced Materials Research, 1157 (2020),
https://doi.org/10.4028/www.scientific.net/AMR.1157.15 . .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5234
AB  - Vertical Kaplan turbines, with nominal power of 178 MW and manufactured in Russia,
have been installed in 6 hydroelectric generating units of hydro power plant ’Djerdap 1’.
Experimental tests were carried out by non-destructive methods in order to determine the turbine condition during the rehabilitation of the hydro power plant. Lack of root penetration was detected in V40 welded joints between upper and lower sleeves and bodies of guide vane apparatus vanes. Height of the lack of root penetration was in the range between 5 and 15 mm, while the allowable height of the lack of root penetration is 3 mm, according to the technical conditions. The upper sleeves were made of cast steel 25L (in accordance with GOST 977), while lower sleeves were made of steel forging St 25 (in accordance with standards GOST 1050 for chemical composition and GOST 8479 for forgings).Methodology for the repair of non-penetrated welded joints between the sleeves and body of the guide vane apparatus vane was composed taking into account the results of ultrasonic testing. By repair methodology it is necessary to, due to the structural solution and service function of guide vane apparatus vanes, specify a large number of details, consider them carefully and carry them out in order to improve safety, because if some of them get overlooked, underestimated or incorrectly perceived, significant problems in turbine operation may occur.This methodology refers solely to the repair of damaged welded joints between sleeves and bodies of guide vane apparatus vanes.
PB  - Trans Tech Publications Ltd, Switzerland
T2  - Advanced Materials Research
T1  - Repair of damages that occurred on the welded joints at the body of guide vane apparatus vanes of the vertical Kaplan turbine
VL  - 1153
DO  - 10.4028/www.scientific.net/AMR.1153.1
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Mladenović, M. and Savić, Zoran",
year = "2019",
abstract = "Vertical Kaplan turbines, with nominal power of 178 MW and manufactured in Russia,
have been installed in 6 hydroelectric generating units of hydro power plant ’Djerdap 1’.
Experimental tests were carried out by non-destructive methods in order to determine the turbine condition during the rehabilitation of the hydro power plant. Lack of root penetration was detected in V40 welded joints between upper and lower sleeves and bodies of guide vane apparatus vanes. Height of the lack of root penetration was in the range between 5 and 15 mm, while the allowable height of the lack of root penetration is 3 mm, according to the technical conditions. The upper sleeves were made of cast steel 25L (in accordance with GOST 977), while lower sleeves were made of steel forging St 25 (in accordance with standards GOST 1050 for chemical composition and GOST 8479 for forgings).Methodology for the repair of non-penetrated welded joints between the sleeves and body of the guide vane apparatus vane was composed taking into account the results of ultrasonic testing. By repair methodology it is necessary to, due to the structural solution and service function of guide vane apparatus vanes, specify a large number of details, consider them carefully and carry them out in order to improve safety, because if some of them get overlooked, underestimated or incorrectly perceived, significant problems in turbine operation may occur.This methodology refers solely to the repair of damaged welded joints between sleeves and bodies of guide vane apparatus vanes.",
publisher = "Trans Tech Publications Ltd, Switzerland",
journal = "Advanced Materials Research",
title = "Repair of damages that occurred on the welded joints at the body of guide vane apparatus vanes of the vertical Kaplan turbine",
volume = "1153",
doi = "10.4028/www.scientific.net/AMR.1153.1"
}

Arsić, M., Bošnjak, S., Grabulov, V., Mladenović, M.,& Savić, Z.. (2019). Repair of damages that occurred on the welded joints at the body of guide vane apparatus vanes of the vertical Kaplan turbine. in Advanced Materials Research
Trans Tech Publications Ltd, Switzerland., 1153.
https://doi.org/10.4028/www.scientific.net/AMR.1153.1

Arsić M, Bošnjak S, Grabulov V, Mladenović M, Savić Z. Repair of damages that occurred on the welded joints at the body of guide vane apparatus vanes of the vertical Kaplan turbine. in Advanced Materials Research. 2019;1153.
doi:10.4028/www.scientific.net/AMR.1153.1 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Mladenović, M., Savić, Zoran, "Repair of damages that occurred on the welded joints at the body of guide vane apparatus vanes of the vertical Kaplan turbine" in Advanced Materials Research, 1153 (2019),
https://doi.org/10.4028/www.scientific.net/AMR.1153.1 . .

TY  - JOUR
AU  - Mladenović, M.
AU  - Arsić, Miodrag
AU  - Savić, Zoran
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5011
AB  - Hydro power plant ’Perućica’, which comprises 7 hydroelectric generating units, each with installed power of 330 MW, is the oldest hydro power plant in Montenegro and was put in service in 1960. This high pressure hydro power plant is a complex hydroenergetic system, which consists of a 3335 m long concrete tunnel, surge with a broadening and overflow and three steel pipelines with two-sided Pelton turbines with horizontal shafts installed.Five turbines have nominal power of 38 MW, while two have nominal power of 58,5 MW (307 MW overall).
The biggest problem at hydro power plant ’Perućica’ refers to the parent material and weld metal of the breeches pipe 1A located at pipeline III. Significantly lesser problems were detected at parent material and weld metal of breeches pipes 7B, 8A and 8B. Pipeline and breeches pipes were made of microalloyed steel ’Nioval 47’ (steel mill ’Jesenice’). Stresses that occur at pipelines in service during the process of execution of functional tasks (stationary and dynamic loads) and during the disturbed process of exploitation (non-stationary dynamic loads) cause severe damaging of parent material and weld metal at structural components of breeches pipes (collars and anchors), thus endangering the integrity of pipeline structure as a whole. Role of the collar, which enables the leaning of the breeches pipe on the foundation, is to receive static and dynamic loads (mean pressure of up to 61 bar in pipeline axis, specific load that occurs due to the quantity of water in the pipeline, action of the force of gravity) and displacements which happen due to non-stationary dynamic loads that occur at the pipeline, while the anchor strengthens and balances the mass of the breeches pipe.
In this paper the results of non-destructive tests carried out on parent material and weld metal (collar and anchor) of breeches pipes with designations 1A, 7A, 8A and 8B and results of destructive tests performed on parent material of the anchor are presented. Tests that were carried out include visual testing (VT), magnetic particle testing (MT) and ultrasonic testing (UT), while destructive tests included determination of chemical composition, tensile properties, impact energy and hardness. On the basis of results of test results it was determined that the main cause of occurrence of significant damages (degradation of parent material of the anchor and weld metal between the collar and anchor, as well as between the pipeline and the anchor) at the structure of the breeches pipe 1A of the pipeline III at the hydro power plant ’Perućica’ is the fact that the breeches pipe did not lean on the collar, as was predicted by design, but on the anchor which, due to the size of its cross-section, could not endure all loads that occur at the breeches pipe during service. Damages that occurred on parent material and weld metal of breeches pipes 7B, 8A and 8B are directly caused by flaws in welding technology and conditions of exploitation. Executed researches showed that degradation of parent material and weld metal does not influence the integrity of the pipeline III as a whole.
T2  - Енергија, економија, екологија
T1  - Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’
EP  - 534
SP  - 528
VL  - 1-2
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5011
ER  - 

@article{
author = "Mladenović, M. and Arsić, Miodrag and Savić, Zoran and Bošnjak, Srđan and Gnjatović, Nebojša",
year = "2018",
abstract = "Hydro power plant ’Perućica’, which comprises 7 hydroelectric generating units, each with installed power of 330 MW, is the oldest hydro power plant in Montenegro and was put in service in 1960. This high pressure hydro power plant is a complex hydroenergetic system, which consists of a 3335 m long concrete tunnel, surge with a broadening and overflow and three steel pipelines with two-sided Pelton turbines with horizontal shafts installed.Five turbines have nominal power of 38 MW, while two have nominal power of 58,5 MW (307 MW overall).
The biggest problem at hydro power plant ’Perućica’ refers to the parent material and weld metal of the breeches pipe 1A located at pipeline III. Significantly lesser problems were detected at parent material and weld metal of breeches pipes 7B, 8A and 8B. Pipeline and breeches pipes were made of microalloyed steel ’Nioval 47’ (steel mill ’Jesenice’). Stresses that occur at pipelines in service during the process of execution of functional tasks (stationary and dynamic loads) and during the disturbed process of exploitation (non-stationary dynamic loads) cause severe damaging of parent material and weld metal at structural components of breeches pipes (collars and anchors), thus endangering the integrity of pipeline structure as a whole. Role of the collar, which enables the leaning of the breeches pipe on the foundation, is to receive static and dynamic loads (mean pressure of up to 61 bar in pipeline axis, specific load that occurs due to the quantity of water in the pipeline, action of the force of gravity) and displacements which happen due to non-stationary dynamic loads that occur at the pipeline, while the anchor strengthens and balances the mass of the breeches pipe.
In this paper the results of non-destructive tests carried out on parent material and weld metal (collar and anchor) of breeches pipes with designations 1A, 7A, 8A and 8B and results of destructive tests performed on parent material of the anchor are presented. Tests that were carried out include visual testing (VT), magnetic particle testing (MT) and ultrasonic testing (UT), while destructive tests included determination of chemical composition, tensile properties, impact energy and hardness. On the basis of results of test results it was determined that the main cause of occurrence of significant damages (degradation of parent material of the anchor and weld metal between the collar and anchor, as well as between the pipeline and the anchor) at the structure of the breeches pipe 1A of the pipeline III at the hydro power plant ’Perućica’ is the fact that the breeches pipe did not lean on the collar, as was predicted by design, but on the anchor which, due to the size of its cross-section, could not endure all loads that occur at the breeches pipe during service. Damages that occurred on parent material and weld metal of breeches pipes 7B, 8A and 8B are directly caused by flaws in welding technology and conditions of exploitation. Executed researches showed that degradation of parent material and weld metal does not influence the integrity of the pipeline III as a whole.",
journal = "Енергија, економија, екологија",
title = "Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’",
pages = "534-528",
volume = "1-2",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5011"
}

Mladenović, M., Arsić, M., Savić, Z., Bošnjak, S.,& Gnjatović, N.. (2018). Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’. in Енергија, економија, екологија, 1-2, 528-534.
https://hdl.handle.net/21.15107/rcub_machinery_5011

Mladenović M, Arsić M, Savić Z, Bošnjak S, Gnjatović N. Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’. in Енергија, економија, екологија. 2018;1-2:528-534.
https://hdl.handle.net/21.15107/rcub_machinery_5011 .

Mladenović, M., Arsić, Miodrag, Savić, Zoran, Bošnjak, Srđan, Gnjatović, Nebojša, "Influence of degradation of parent-material and welded joints on the integrity of the breeches pipe located at pipeline iii of hydro power plant ‘Perućica’" in Енергија, економија, екологија, 1-2 (2018):528-534,
https://hdl.handle.net/21.15107/rcub_machinery_5011 .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Mladenović, M.
AU  - Savić, Zoran
AU  - Bošnjak, Srđan
AU  - Šarkočević, Živče
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5257
AB  - Columns of welded pipes in the oil and gas wells and pipelines for their transportation to consumers,fall into high responsible structures prone to corrosion and cracks. Therefore it is important to know the remaining strength of the pipes in the case of occurrence of any of the mentioned types of damage. Steels intended for the production of protective pipes for oil and gas drills are specified by the API 5CT standard. Premature failure or damaging of parts and components of welded pipes columns in wells, as well as pipelines for the transport of oil and gas is generally' caused by the simultaneous influence of a large number of technological, metallurgical, structural and exploitation factors. Therefore convenient structural solutions, which provide the mechanical safety of parts and the integrity of structures, can be realized only through total comprehension of their behavior in various operation regimes. The paper elaborates the importance of technical diagnostics for monitoring and analysis of protective pipes conditions in the wells and pipelines during the oil and gas transportations. Also, an analysis of the causes of failure of the pipes and pipelines is conducted and the importance of forming of database is considered.
PB  - Savez energetičara
T2  - Energija (Energija, ekonomija, ekologija)
T1  - Technical diagnostics of the conditions of drill pipes and oil and gas transport pipelines
EP  - 414
IS  - 1-2
SP  - 411
VL  - 20
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5257
ER  - 

@article{
author = "Arsić, Miodrag and Mladenović, M. and Savić, Zoran and Bošnjak, Srđan and Šarkočević, Živče",
year = "2018",
abstract = "Columns of welded pipes in the oil and gas wells and pipelines for their transportation to consumers,fall into high responsible structures prone to corrosion and cracks. Therefore it is important to know the remaining strength of the pipes in the case of occurrence of any of the mentioned types of damage. Steels intended for the production of protective pipes for oil and gas drills are specified by the API 5CT standard. Premature failure or damaging of parts and components of welded pipes columns in wells, as well as pipelines for the transport of oil and gas is generally' caused by the simultaneous influence of a large number of technological, metallurgical, structural and exploitation factors. Therefore convenient structural solutions, which provide the mechanical safety of parts and the integrity of structures, can be realized only through total comprehension of their behavior in various operation regimes. The paper elaborates the importance of technical diagnostics for monitoring and analysis of protective pipes conditions in the wells and pipelines during the oil and gas transportations. Also, an analysis of the causes of failure of the pipes and pipelines is conducted and the importance of forming of database is considered.",
publisher = "Savez energetičara",
journal = "Energija (Energija, ekonomija, ekologija)",
title = "Technical diagnostics of the conditions of drill pipes and oil and gas transport pipelines",
pages = "414-411",
number = "1-2",
volume = "20",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5257"
}

Arsić, M., Mladenović, M., Savić, Z., Bošnjak, S.,& Šarkočević, Ž.. (2018). Technical diagnostics of the conditions of drill pipes and oil and gas transport pipelines. in Energija (Energija, ekonomija, ekologija)
Savez energetičara., 20(1-2), 411-414.
https://hdl.handle.net/21.15107/rcub_machinery_5257

Arsić M, Mladenović M, Savić Z, Bošnjak S, Šarkočević Ž. Technical diagnostics of the conditions of drill pipes and oil and gas transport pipelines. in Energija (Energija, ekonomija, ekologija). 2018;20(1-2):411-414.
https://hdl.handle.net/21.15107/rcub_machinery_5257 .

Arsić, Miodrag, Mladenović, M., Savić, Zoran, Bošnjak, Srđan, Šarkočević, Živče, "Technical diagnostics of the conditions of drill pipes and oil and gas transport pipelines" in Energija (Energija, ekonomija, ekologija), 20, no. 1-2 (2018):411-414,
https://hdl.handle.net/21.15107/rcub_machinery_5257 .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5236
AB  - Technical diagnostics of hydromechanical equipment, is based on testing procedures
including the history of the exploitation with expert knowledge of structures and operating
conditions, as well as, on the analysis of results performed by experts with appropriate experience and knowledge in design, exploitation, maintenance, reliability, fracture mechanics etc. Degradation of properties of the material and/or welded joints of hydro-mechanical equipment is being caused by the simultaneous influence of a large number of factors. First of all, it is thought of technological, metallurgical, structural and conditions of exploitation. In this paper, the selection of methodology for the rehabilitation of hydro-mechanical equipment is presented based on the previously conducted assessment of state of equipment using the nondestructive testing methods. Repair welding, repair of damaged surfaces by cold metallization, corrections of existing structural solutions of metallic components in order to improve their technical characteristics and extend the service life are presented.
PB  - Trans Tech Publications Ltd, Switzerland
T2  - Advanced Materials Research
T1  - Use of Non-Destructive Tests for the Assessment of Integrity and Service Life of Hydro-Mechanical Equipment
EP  - 16
SP  - 9
VL  - 1146
DO  - 10.4028/www.scientific.net/AMR.1146.9
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Mladenović, M. and Savić, Zoran",
year = "2018",
abstract = "Technical diagnostics of hydromechanical equipment, is based on testing procedures
including the history of the exploitation with expert knowledge of structures and operating
conditions, as well as, on the analysis of results performed by experts with appropriate experience and knowledge in design, exploitation, maintenance, reliability, fracture mechanics etc. Degradation of properties of the material and/or welded joints of hydro-mechanical equipment is being caused by the simultaneous influence of a large number of factors. First of all, it is thought of technological, metallurgical, structural and conditions of exploitation. In this paper, the selection of methodology for the rehabilitation of hydro-mechanical equipment is presented based on the previously conducted assessment of state of equipment using the nondestructive testing methods. Repair welding, repair of damaged surfaces by cold metallization, corrections of existing structural solutions of metallic components in order to improve their technical characteristics and extend the service life are presented.",
publisher = "Trans Tech Publications Ltd, Switzerland",
journal = "Advanced Materials Research",
title = "Use of Non-Destructive Tests for the Assessment of Integrity and Service Life of Hydro-Mechanical Equipment",
pages = "16-9",
volume = "1146",
doi = "10.4028/www.scientific.net/AMR.1146.9"
}

Arsić, M., Bošnjak, S., Grabulov, V., Mladenović, M.,& Savić, Z.. (2018). Use of Non-Destructive Tests for the Assessment of Integrity and Service Life of Hydro-Mechanical Equipment. in Advanced Materials Research
Trans Tech Publications Ltd, Switzerland., 1146, 9-16.
https://doi.org/10.4028/www.scientific.net/AMR.1146.9

Arsić M, Bošnjak S, Grabulov V, Mladenović M, Savić Z. Use of Non-Destructive Tests for the Assessment of Integrity and Service Life of Hydro-Mechanical Equipment. in Advanced Materials Research. 2018;1146:9-16.
doi:10.4028/www.scientific.net/AMR.1146.9 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Mladenović, M., Savić, Zoran, "Use of Non-Destructive Tests for the Assessment of Integrity and Service Life of Hydro-Mechanical Equipment" in Advanced Materials Research, 1146 (2018):9-16,
https://doi.org/10.4028/www.scientific.net/AMR.1146.9 . .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Mladenović, M.
AU  - Savić, Zoran
AU  - Bošnjak, Srđan
AU  - Miković, Radovan
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5259
AB  - Vertical Kaplan turbines, with nominal power of 176 A/ITY, manufactured in Russia, have been instal-led in 6 hydroelectric generating units of hydro power plant "Djerdap 1". Turbines were designed for the lifetime of 40 years due to the required structural solution and the inability of performing periodic inspections and state analyses. Welded structure of the upper ring of guide vane apparatus is made by welding four segments made of St 3 steel together, in accordance with standard GOST 977/88. Ring segments were welded by using submerged arc welding (SAW). During the rehabilitation of turbine A6 nondestructive and destructive tests were per formed on parent material and welded joints in order to carry out the state analysis and estimation of level and causes of eventual degradation of the structure of the upper ring of guide vane apparatus at hydro power plant Djerdap I. This paper comprises results of magnetic particle tests and ultrasonic tests per formed on welded jo-ints. By ultrasonic testing it was determined that there is a lack of root penetration in welded joints, as well as lamellar tearing in parent material. Analysis of the causes of parent metal degradation and occurrence of defects in welded joints of the upper ring of guide vane apparatus was carried out on the basis of results of experimental tests.
PB  - Savez energetičara
T2  - Energija (Energija, ekonomija, ekologija)
T1  - State analisys of the upper ring of guide vane apparatus at hydro power plant Djerdap 1 carried out the basis of non destructive tests
EP  - 249
IS  - 1-2
SP  - 245
VL  - 19
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5259
ER  - 

@article{
author = "Arsić, Miodrag and Mladenović, M. and Savić, Zoran and Bošnjak, Srđan and Miković, Radovan",
year = "2017",
abstract = "Vertical Kaplan turbines, with nominal power of 176 A/ITY, manufactured in Russia, have been instal-led in 6 hydroelectric generating units of hydro power plant "Djerdap 1". Turbines were designed for the lifetime of 40 years due to the required structural solution and the inability of performing periodic inspections and state analyses. Welded structure of the upper ring of guide vane apparatus is made by welding four segments made of St 3 steel together, in accordance with standard GOST 977/88. Ring segments were welded by using submerged arc welding (SAW). During the rehabilitation of turbine A6 nondestructive and destructive tests were per formed on parent material and welded joints in order to carry out the state analysis and estimation of level and causes of eventual degradation of the structure of the upper ring of guide vane apparatus at hydro power plant Djerdap I. This paper comprises results of magnetic particle tests and ultrasonic tests per formed on welded jo-ints. By ultrasonic testing it was determined that there is a lack of root penetration in welded joints, as well as lamellar tearing in parent material. Analysis of the causes of parent metal degradation and occurrence of defects in welded joints of the upper ring of guide vane apparatus was carried out on the basis of results of experimental tests.",
publisher = "Savez energetičara",
journal = "Energija (Energija, ekonomija, ekologija)",
title = "State analisys of the upper ring of guide vane apparatus at hydro power plant Djerdap 1 carried out the basis of non destructive tests",
pages = "249-245",
number = "1-2",
volume = "19",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5259"
}

Arsić, M., Mladenović, M., Savić, Z., Bošnjak, S.,& Miković, R.. (2017). State analisys of the upper ring of guide vane apparatus at hydro power plant Djerdap 1 carried out the basis of non destructive tests. in Energija (Energija, ekonomija, ekologija)
Savez energetičara., 19(1-2), 245-249.
https://hdl.handle.net/21.15107/rcub_machinery_5259

Arsić M, Mladenović M, Savić Z, Bošnjak S, Miković R. State analisys of the upper ring of guide vane apparatus at hydro power plant Djerdap 1 carried out the basis of non destructive tests. in Energija (Energija, ekonomija, ekologija). 2017;19(1-2):245-249.
https://hdl.handle.net/21.15107/rcub_machinery_5259 .

Arsić, Miodrag, Mladenović, M., Savić, Zoran, Bošnjak, Srđan, Miković, Radovan, "State analisys of the upper ring of guide vane apparatus at hydro power plant Djerdap 1 carried out the basis of non destructive tests" in Energija (Energija, ekonomija, ekologija), 19, no. 1-2 (2017):245-249,
https://hdl.handle.net/21.15107/rcub_machinery_5259 .

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  - Arsić, Miodrag
AU  - Mladenović, M.
AU  - Bošnjak, Srđan
AU  - Šarkočević, Živče
AU  - Savić, Zoran
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5268
AB  - Kvalitet zavarenih spojeva u procesu proizvodnje cevi postupkom visokofrekventnog kontaktnog zavarivanja definiše se karakteristikama koje cevi moraju posedovati da bi zadovoljile određene zahteve, što se postiže izborom odgovarajućih parametara zavarivanja, sprovođenjem programa kontrole svih tehnoloških operacija u njihovoj izradi i mehaničkim i tehnološkim ispitivanjima. U radu je izvršena analiza grešaka koje se javljaju u proizvodnji zaštitnih cevi za bušotine nafte i gasa, izrađenih postupkom visokofrekventnog kontaktnog zavarivanja od čelika povišene čvrstoće specificiranih standardom АРI 5СТ. Pojave greške u izradi zaštitnih zavarenih cevi u odnosu na zahteve koji su postavljeni pred zavareni spoj javljaju se kao posledica mnogobrojnih uticajnih faktora kao što је: kvalitet osnovnog materijala i međusobno usklađivanje temperature zavarivanja, pritiska valjaka i brzine zavarivanja. Segregacija nemetalnih uključaka, nastala u procesu valjanja traka od čelika povišene čvrstoće, ima značajan uticaj na integritet zaštitnih zavarenih cevi, jer u procesu proizvodnje cevi dolazi do iniciranja prsline u zavarenom spoju. U cilju analize pojave lomа cevi pri tehnološkim ispitivanjima spljoštavanjem razmotren je uticaj segregacije nemetalnih uključaka. lspitana su 43 uzorka uzeta direktno sa spljoštenih cevi iz različitih šarži.
PB  - Komitet za međulaboratorijska ispitivanja materijala
C3  - Зборник радова XXII Конференције о међулабораторијским испитивањима материјала
T1  - Утицај сегрегације неметалних укључака на интегритет цеви израђених поступком високофреквентног контактног заваривања
EP  - 111
SP  - 106
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5268
ER  - 

@conference{
author = "Arsić, Miodrag and Mladenović, M. and Bošnjak, Srđan and Šarkočević, Živče and Savić, Zoran",
year = "2016",
abstract = "Kvalitet zavarenih spojeva u procesu proizvodnje cevi postupkom visokofrekventnog kontaktnog zavarivanja definiše se karakteristikama koje cevi moraju posedovati da bi zadovoljile određene zahteve, što se postiže izborom odgovarajućih parametara zavarivanja, sprovođenjem programa kontrole svih tehnoloških operacija u njihovoj izradi i mehaničkim i tehnološkim ispitivanjima. U radu je izvršena analiza grešaka koje se javljaju u proizvodnji zaštitnih cevi za bušotine nafte i gasa, izrađenih postupkom visokofrekventnog kontaktnog zavarivanja od čelika povišene čvrstoće specificiranih standardom АРI 5СТ. Pojave greške u izradi zaštitnih zavarenih cevi u odnosu na zahteve koji su postavljeni pred zavareni spoj javljaju se kao posledica mnogobrojnih uticajnih faktora kao što је: kvalitet osnovnog materijala i međusobno usklađivanje temperature zavarivanja, pritiska valjaka i brzine zavarivanja. Segregacija nemetalnih uključaka, nastala u procesu valjanja traka od čelika povišene čvrstoće, ima značajan uticaj na integritet zaštitnih zavarenih cevi, jer u procesu proizvodnje cevi dolazi do iniciranja prsline u zavarenom spoju. U cilju analize pojave lomа cevi pri tehnološkim ispitivanjima spljoštavanjem razmotren je uticaj segregacije nemetalnih uključaka. lspitana su 43 uzorka uzeta direktno sa spljoštenih cevi iz različitih šarži.",
publisher = "Komitet za međulaboratorijska ispitivanja materijala",
journal = "Зборник радова XXII Конференције о међулабораторијским испитивањима материјала",
title = "Утицај сегрегације неметалних укључака на интегритет цеви израђених поступком високофреквентног контактног заваривања",
pages = "111-106",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5268"
}

Arsić, M., Mladenović, M., Bošnjak, S., Šarkočević, Ž.,& Savić, Z.. (2016). Утицај сегрегације неметалних укључака на интегритет цеви израђених поступком високофреквентног контактног заваривања. in Зборник радова XXII Конференције о међулабораторијским испитивањима материјала
Komitet za međulaboratorijska ispitivanja materijala., 106-111.
https://hdl.handle.net/21.15107/rcub_machinery_5268

Arsić M, Mladenović M, Bošnjak S, Šarkočević Ž, Savić Z. Утицај сегрегације неметалних укључака на интегритет цеви израђених поступком високофреквентног контактног заваривања. in Зборник радова XXII Конференције о међулабораторијским испитивањима материјала. 2016;:106-111.
https://hdl.handle.net/21.15107/rcub_machinery_5268 .

Arsić, Miodrag, Mladenović, M., Bošnjak, Srđan, Šarkočević, Živče, Savić, Zoran, "Утицај сегрегације неметалних укључака на интегритет цеви израђених поступком високофреквентног контактног заваривања" in Зборник радова XXII Конференције о међулабораторијским испитивањима материјала (2016):106-111,
https://hdl.handle.net/21.15107/rcub_machinery_5268 .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5239
AB  - Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW,
have been installed in 6 hydroelectric generating units at hydro power plant Djerdap 1.
Hydroelectric generating sets have been designed for the service life of 40 years due to structural solutions and limited possibilities of performing periodic inspections and state analyses. During the rehabilitation of the hydroelectric generating sets, non-destructive tests were performed on all components and structures in order to complete state analysis. In this paper the damages and methodology of repair welding for damaged glasses, which are the integral part of the kinematic system of runner blades, are presented.
PB  - Trans Tech Publications, Switzerland
T2  - Advanced Materials Research
T1  - Repair welding methodology for the glasses of the Kaplan turbine runner at the hydro power plant Djerdap 1
EP  - 18
SP  - 13
VL  - 1138
DO  - doi.org/10.4028/www.scientific.net/AMR.1138.13
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Mladenović, M. and Savić, Zoran",
year = "2016",
abstract = "Vertical Kaplan turbines, manufactured in Russia and with nominal power of 200 MW,
have been installed in 6 hydroelectric generating units at hydro power plant Djerdap 1.
Hydroelectric generating sets have been designed for the service life of 40 years due to structural solutions and limited possibilities of performing periodic inspections and state analyses. During the rehabilitation of the hydroelectric generating sets, non-destructive tests were performed on all components and structures in order to complete state analysis. In this paper the damages and methodology of repair welding for damaged glasses, which are the integral part of the kinematic system of runner blades, are presented.",
publisher = "Trans Tech Publications, Switzerland",
journal = "Advanced Materials Research",
title = "Repair welding methodology for the glasses of the Kaplan turbine runner at the hydro power plant Djerdap 1",
pages = "18-13",
volume = "1138",
doi = "doi.org/10.4028/www.scientific.net/AMR.1138.13"
}

Arsić, M., Bošnjak, S., Grabulov, V., Mladenović, M.,& Savić, Z.. (2016). Repair welding methodology for the glasses of the Kaplan turbine runner at the hydro power plant Djerdap 1. in Advanced Materials Research
Trans Tech Publications, Switzerland., 1138, 13-18.
https://doi.org/doi.org/10.4028/www.scientific.net/AMR.1138.13

Arsić M, Bošnjak S, Grabulov V, Mladenović M, Savić Z. Repair welding methodology for the glasses of the Kaplan turbine runner at the hydro power plant Djerdap 1. in Advanced Materials Research. 2016;1138:13-18.
doi:doi.org/10.4028/www.scientific.net/AMR.1138.13 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Mladenović, M., Savić, Zoran, "Repair welding methodology for the glasses of the Kaplan turbine runner at the hydro power plant Djerdap 1" in Advanced Materials Research, 1138 (2016):13-18,
https://doi.org/doi.org/10.4028/www.scientific.net/AMR.1138.13 . .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Sedmak, Aleksandar
AU  - Bošnjak, Srđan
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5250
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 hydroelectric generating sets A4, A5 and A6, non-destructive and destructive tests were carried out on parent material and weld metal in order to complete the state analysis and assessment of damage level and causes of damage occurrence at vital structures and components, which showed that the selection of suitable material has a crucial role regarding the safe operation of hydroelectric power plants. This paper contains comparative results of mechanical tests performed in order to obtain mechanical properties of materials used for the fabrication of the upper rings of guide vane apparatus installed in 1973 and made of steel St 3 (GOST 977-88) and those recently made through the use of steel S 235 (EN 10025-2), as well as for turbine covers, made of steels S 355 NL (EN 10025-2) and S 355 NL + Z25 + N (EN 10025-3).
PB  - Faculty of Mechanical Engineering, University of Belgrade
C3  - Proceedings of TEAM 2015, 7th International Scientific and Expert Conference of the International TEAM Society
T1  - Selection of steels for vital structures and turbine components of the hydro power plant ’Djerdap 1’
EP  - 564
SP  - 558
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5250
ER  - 

@conference{
author = "Arsić, Miodrag and Sedmak, Aleksandar and Bošnjak, Srđan and Mladenović, M. and Savić, Zoran",
year = "2015",
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 hydroelectric generating sets A4, A5 and A6, non-destructive and destructive tests were carried out on parent material and weld metal in order to complete the state analysis and assessment of damage level and causes of damage occurrence at vital structures and components, which showed that the selection of suitable material has a crucial role regarding the safe operation of hydroelectric power plants. This paper contains comparative results of mechanical tests performed in order to obtain mechanical properties of materials used for the fabrication of the upper rings of guide vane apparatus installed in 1973 and made of steel St 3 (GOST 977-88) and those recently made through the use of steel S 235 (EN 10025-2), as well as for turbine covers, made of steels S 355 NL (EN 10025-2) and S 355 NL + Z25 + N (EN 10025-3).",
publisher = "Faculty of Mechanical Engineering, University of Belgrade",
journal = "Proceedings of TEAM 2015, 7th International Scientific and Expert Conference of the International TEAM Society",
title = "Selection of steels for vital structures and turbine components of the hydro power plant ’Djerdap 1’",
pages = "564-558",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5250"
}

Arsić, M., Sedmak, A., Bošnjak, S., Mladenović, M.,& Savić, Z.. (2015). Selection of steels for vital structures and turbine components of the hydro power plant ’Djerdap 1’. in Proceedings of TEAM 2015, 7th International Scientific and Expert Conference of the International TEAM Society
Faculty of Mechanical Engineering, University of Belgrade., 558-564.
https://hdl.handle.net/21.15107/rcub_machinery_5250

Arsić M, Sedmak A, Bošnjak S, Mladenović M, Savić Z. Selection of steels for vital structures and turbine components of the hydro power plant ’Djerdap 1’. in Proceedings of TEAM 2015, 7th International Scientific and Expert Conference of the International TEAM Society. 2015;:558-564.
https://hdl.handle.net/21.15107/rcub_machinery_5250 .

Arsić, Miodrag, Sedmak, Aleksandar, Bošnjak, Srđan, Mladenović, M., Savić, Zoran, "Selection of steels for vital structures and turbine components of the hydro power plant ’Djerdap 1’" in Proceedings of TEAM 2015, 7th International Scientific and Expert Conference of the International TEAM Society (2015):558-564,
https://hdl.handle.net/21.15107/rcub_machinery_5250 .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5249
AB  - Turbine and hydro mechanical equipment at hydro power plant ’Djerdap 1’ is subjected to service conditions that lead to degradation of material of components and structures. Taking into
account the rate of occurrence of failures (damages, accidents) and experience gained through long-term performing of tests it was established that main causes of material degradation are fatigue, corrosion, erosion and cavitation. Results of performed tests and researches carried out in order to identify the causes of material degradation, damaging and fracture of components and structures of turbine and hydro mechanical equipment during the rehabilitation of the hydro
power plant ’Djerdap 1’ showed that material degradation, damages and fractures occur due to
the simultaneous influence of a large number of technological, metallurgical, structural and exploitational factors and that convenient structural solutions which would ensure mechanical reliability of components and structural integrity could be achieved only through absolute knowledge of their behaviour under various regimes of operation. On the basis of those results new system for maintenance of components and structures of turbine and hydro mechanical equipment was recommended.
PB  - Faculty of Mechanical Engineering, Belgrade
C3  - Proceedings of the 6th International Symposium on Industrial Engineering – SIE 2015
T1  - Recommendation for a new model of the maintenance system of turbine and hydromechanical equipment at the hydro power plant Djerdap 1
EP  - 333
SP  - 330
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5249
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Mladenović, M. and Savić, Zoran",
year = "2015",
abstract = "Turbine and hydro mechanical equipment at hydro power plant ’Djerdap 1’ is subjected to service conditions that lead to degradation of material of components and structures. Taking into
account the rate of occurrence of failures (damages, accidents) and experience gained through long-term performing of tests it was established that main causes of material degradation are fatigue, corrosion, erosion and cavitation. Results of performed tests and researches carried out in order to identify the causes of material degradation, damaging and fracture of components and structures of turbine and hydro mechanical equipment during the rehabilitation of the hydro
power plant ’Djerdap 1’ showed that material degradation, damages and fractures occur due to
the simultaneous influence of a large number of technological, metallurgical, structural and exploitational factors and that convenient structural solutions which would ensure mechanical reliability of components and structural integrity could be achieved only through absolute knowledge of their behaviour under various regimes of operation. On the basis of those results new system for maintenance of components and structures of turbine and hydro mechanical equipment was recommended.",
publisher = "Faculty of Mechanical Engineering, Belgrade",
journal = "Proceedings of the 6th International Symposium on Industrial Engineering – SIE 2015",
title = "Recommendation for a new model of the maintenance system of turbine and hydromechanical equipment at the hydro power plant Djerdap 1",
pages = "333-330",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5249"
}

Arsić, M., Bošnjak, S., Mladenović, M.,& Savić, Z.. (2015). Recommendation for a new model of the maintenance system of turbine and hydromechanical equipment at the hydro power plant Djerdap 1. in Proceedings of the 6th International Symposium on Industrial Engineering – SIE 2015
Faculty of Mechanical Engineering, Belgrade., 330-333.
https://hdl.handle.net/21.15107/rcub_machinery_5249

Arsić M, Bošnjak S, Mladenović M, Savić Z. Recommendation for a new model of the maintenance system of turbine and hydromechanical equipment at the hydro power plant Djerdap 1. in Proceedings of the 6th International Symposium on Industrial Engineering – SIE 2015. 2015;:330-333.
https://hdl.handle.net/21.15107/rcub_machinery_5249 .

Arsić, Miodrag, Bošnjak, Srđan, Mladenović, M., Savić, Zoran, "Recommendation for a new model of the maintenance system of turbine and hydromechanical equipment at the hydro power plant Djerdap 1" in Proceedings of the 6th International Symposium on Industrial Engineering – SIE 2015 (2015):330-333,
https://hdl.handle.net/21.15107/rcub_machinery_5249 .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Mladenović, M.
AU  - Minić, M.
PY  - 2015
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5244
AB  - Hydro power plant Pirot, which was built in 1990, is an accumulation-derivative power plant, which consists of 2 above - ground vertical hydroelectric generating sets that contain Francis turbines with nominal power of 41,5 MW, manufactured in Czech Republic, a tunnel and a sunken pipeline with overall length of 2.030 m and diameter that ranges from 3.000 to 3.500 m. Pipes have been made of S275J2G3 steel. [1] Pipe wall is 22 mm thick. Maximum pressure of 2.5 MPa occurs in front of the turbine cover. [2]
Pipeline has been designed and built without anchor blocks at curvatures, which is rarity elsewhere. Geodetic measurements have been conducted permanently from the day the assembly was finished and pipeline was put into service, both when pipeline is empty and unloaded by hydrostatic pressure and when it is full. Analysis of obtained data regards the movements along the pipeline route showed that from year 2003 there are significantly higher differences in movements comparing the situations when the pipeline is full and when it is empty in comparison with the previous period.
Those differences primarily refers to tangential movements of vertices marked with numbers 6, 7 and 8, which, compared to the period until year 2002, are in the range from 3 mm for vertex 8 to 5 mm for vertex 6. Apart from geodetic measurements, the measurement of pipe diameter in 2 directions is also being carried out permanently. Those data show that from year 2003. the diameter in horizontal direction started to increase significantly, while at the same time the diameter in vertical direction started to decrease less significantly.
This paper contains the analysis of current state and integrity evaluation of the pipeline as a whole on the basis of results of non - destructive tests performed on the vital butt - welded joint in the curvature area at chainage 1+263 m (visual testing, magnetic particle testing, penetrant testing, ultrasonic testing, radiographic testing, metallographic replication testing).
PB  - Mechanical Engineering Faculty in Slavonski Brod
C3  - Proceedings of the 8th International Scientific-Professional Conference Design, Production and Service of Welded Constructions and Products – SBZ 2015
T1  - Analysis of current state and integrity evaluation of the pipeline at hydro power plant "Pirot"
EP  - 12
SP  - 5
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5244
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Mladenović, M. and Minić, M.",
year = "2015",
abstract = "Hydro power plant Pirot, which was built in 1990, is an accumulation-derivative power plant, which consists of 2 above - ground vertical hydroelectric generating sets that contain Francis turbines with nominal power of 41,5 MW, manufactured in Czech Republic, a tunnel and a sunken pipeline with overall length of 2.030 m and diameter that ranges from 3.000 to 3.500 m. Pipes have been made of S275J2G3 steel. [1] Pipe wall is 22 mm thick. Maximum pressure of 2.5 MPa occurs in front of the turbine cover. [2]
Pipeline has been designed and built without anchor blocks at curvatures, which is rarity elsewhere. Geodetic measurements have been conducted permanently from the day the assembly was finished and pipeline was put into service, both when pipeline is empty and unloaded by hydrostatic pressure and when it is full. Analysis of obtained data regards the movements along the pipeline route showed that from year 2003 there are significantly higher differences in movements comparing the situations when the pipeline is full and when it is empty in comparison with the previous period.
Those differences primarily refers to tangential movements of vertices marked with numbers 6, 7 and 8, which, compared to the period until year 2002, are in the range from 3 mm for vertex 8 to 5 mm for vertex 6. Apart from geodetic measurements, the measurement of pipe diameter in 2 directions is also being carried out permanently. Those data show that from year 2003. the diameter in horizontal direction started to increase significantly, while at the same time the diameter in vertical direction started to decrease less significantly.
This paper contains the analysis of current state and integrity evaluation of the pipeline as a whole on the basis of results of non - destructive tests performed on the vital butt - welded joint in the curvature area at chainage 1+263 m (visual testing, magnetic particle testing, penetrant testing, ultrasonic testing, radiographic testing, metallographic replication testing).",
publisher = "Mechanical Engineering Faculty in Slavonski Brod",
journal = "Proceedings of the 8th International Scientific-Professional Conference Design, Production and Service of Welded Constructions and Products – SBZ 2015",
title = "Analysis of current state and integrity evaluation of the pipeline at hydro power plant "Pirot"",
pages = "12-5",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5244"
}

Arsić, M., Bošnjak, S., Grabulov, V., Mladenović, M.,& Minić, M.. (2015). Analysis of current state and integrity evaluation of the pipeline at hydro power plant "Pirot". in Proceedings of the 8th International Scientific-Professional Conference Design, Production and Service of Welded Constructions and Products – SBZ 2015
Mechanical Engineering Faculty in Slavonski Brod., 5-12.
https://hdl.handle.net/21.15107/rcub_machinery_5244

Arsić M, Bošnjak S, Grabulov V, Mladenović M, Minić M. Analysis of current state and integrity evaluation of the pipeline at hydro power plant "Pirot". in Proceedings of the 8th International Scientific-Professional Conference Design, Production and Service of Welded Constructions and Products – SBZ 2015. 2015;:5-12.
https://hdl.handle.net/21.15107/rcub_machinery_5244 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Mladenović, M., Minić, M., "Analysis of current state and integrity evaluation of the pipeline at hydro power plant "Pirot"" in Proceedings of the 8th International Scientific-Professional Conference Design, Production and Service of Welded Constructions and Products – SBZ 2015 (2015):5-12,
https://hdl.handle.net/21.15107/rcub_machinery_5244 .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Vistać, Brane
AU  - Bošnjak, Srđan
AU  - Mladenović, M.
AU  - Savić, Zoran
PY  - 2014
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5264
AB  - Vertical Kaplan turbines with nominal power of 200 MW, made in Russia, have been installed at 6 hydroelectric generating sets of "Djerdap 1". Most of the components were made of steel in accor-dance with GOST and ASTM- standards. During the rehabilitation of the hydroelectric generating set A6 non-destructive testing methods were performed on parent material and welded joints of the main oil/air tank and air tank with the auxiliary oil/air tank, which acts as pressure accumulator in the regulation system, in order to carry out the analysis of the current state and integrity evaluation for the regulation system- of the turbine. Shells of all 3 tanks were made of steel Č 1205, while bottoms were made of russian steel St 20K Tests were also performed on pipeline elements (pipes and elbows). The results of non-destructive tests performed on air tank are presented in this paper Mechanical damages were detected by visual inspection at parent material of the shell and at the upper bottom, as well as discontinuous and incompletely welded joints on the inside and outside of the tank. Sur-face linear crack type indications were detected through magnetic particle testing at intersections of welded joints on the inside of the tank. Internal crack type defects were detected through ultrasonic testing of welded joints On the basis of test results the technology of reparatory welding / surface welding of parent mate-rial and welded joints was created, while on the basis of the analytical calculation of tank strength the evaluation of its integrity for the following 40 years of operation was obtained.
PB  - Savez energetičara
T2  - Energija (Energija, ekonomija, ekologija)
T1  - Analysis of current state and integrity evaluation for the air tank of the regulation system of turbine A6 at hydropower plant Djerdap 1
EP  - 391
IS  - 1-2
SP  - 385
VL  - 16
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5264
ER  - 

@article{
author = "Arsić, Miodrag and Vistać, Brane and Bošnjak, Srđan and Mladenović, M. and Savić, Zoran",
year = "2014",
abstract = "Vertical Kaplan turbines with nominal power of 200 MW, made in Russia, have been installed at 6 hydroelectric generating sets of "Djerdap 1". Most of the components were made of steel in accor-dance with GOST and ASTM- standards. During the rehabilitation of the hydroelectric generating set A6 non-destructive testing methods were performed on parent material and welded joints of the main oil/air tank and air tank with the auxiliary oil/air tank, which acts as pressure accumulator in the regulation system, in order to carry out the analysis of the current state and integrity evaluation for the regulation system- of the turbine. Shells of all 3 tanks were made of steel Č 1205, while bottoms were made of russian steel St 20K Tests were also performed on pipeline elements (pipes and elbows). The results of non-destructive tests performed on air tank are presented in this paper Mechanical damages were detected by visual inspection at parent material of the shell and at the upper bottom, as well as discontinuous and incompletely welded joints on the inside and outside of the tank. Sur-face linear crack type indications were detected through magnetic particle testing at intersections of welded joints on the inside of the tank. Internal crack type defects were detected through ultrasonic testing of welded joints On the basis of test results the technology of reparatory welding / surface welding of parent mate-rial and welded joints was created, while on the basis of the analytical calculation of tank strength the evaluation of its integrity for the following 40 years of operation was obtained.",
publisher = "Savez energetičara",
journal = "Energija (Energija, ekonomija, ekologija)",
title = "Analysis of current state and integrity evaluation for the air tank of the regulation system of turbine A6 at hydropower plant Djerdap 1",
pages = "391-385",
number = "1-2",
volume = "16",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5264"
}

Arsić, M., Vistać, B., Bošnjak, S., Mladenović, M.,& Savić, Z.. (2014). Analysis of current state and integrity evaluation for the air tank of the regulation system of turbine A6 at hydropower plant Djerdap 1. in Energija (Energija, ekonomija, ekologija)
Savez energetičara., 16(1-2), 385-391.
https://hdl.handle.net/21.15107/rcub_machinery_5264

Arsić M, Vistać B, Bošnjak S, Mladenović M, Savić Z. Analysis of current state and integrity evaluation for the air tank of the regulation system of turbine A6 at hydropower plant Djerdap 1. in Energija (Energija, ekonomija, ekologija). 2014;16(1-2):385-391.
https://hdl.handle.net/21.15107/rcub_machinery_5264 .

Arsić, Miodrag, Vistać, Brane, Bošnjak, Srđan, Mladenović, M., Savić, Zoran, "Analysis of current state and integrity evaluation for the air tank of the regulation system of turbine A6 at hydropower plant Djerdap 1" in Energija (Energija, ekonomija, ekologija), 16, no. 1-2 (2014):385-391,
https://hdl.handle.net/21.15107/rcub_machinery_5264 .

TY  - JOUR
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Mladenović, M.
AU  - Grabulov, Vencislav
AU  - Savić, Zoran
PY  - 2013
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5265
AB  - Vertical Kaplan turbines with nominal output power of 200 MW, fabricated in Russia, are installed in six hydroelectric generating units of the hydroelectric power plant 'Djerdap I'. The calculation of all basic and dynamic loads turbine parts are subjected to (runner blades, all parts of the blade rotating mechanism, runner casing, runner cover, shaft, stator cylinder of the turbine, apparatus guide etc.) has been performed during the design process, while mechanical properties of the material are just a starting point for the evaluation of the resistance to fracture. In order to perform the evaluation of integrity and estimation of service life of turbine components, it is necessary to carry out the analytical and numerical calculation of strength based on the stress state, and in some cases experimental tests in order to obtain fracture mechanics parameters. Turbine runner cover of the hydroelectric generating set A6 at HPP 'Djerdap I' has been made of cast steel 20GSL. The results of chemical composition analysis, hardness testing and metallographic tests performed on 2 samples in the longitudinal and transverse cross-section are presented in this paper, as well as mechanical tests that refer to yield strength (R0), tensile strength (R) and impact strength KCU that were carried out on four samples cut out from the turbine cover. Results of tests performed on two samples confirmed that chemical composition meets the requirements of standard GOST 977/88, and also that results of hardness tests according to Vickers (HV10) and Brinell HB (2,5/187,5/20 '), as well as that results of microhardness tests according to Vickers (HV1) meet the predefined technical requirements. It has also been established that both samples in the longitudinal cross-section have coarse grained ferrite-pearlite microstructure with large local porosity, while in the transverse cross-section both samples have dendritic ferrite-pearlite microstructure, which could cause the fracture t occur: Results of tests carried out on 4 samples showed that values of yield strength (R0,), tensile strength (&) and impact strength ICCLI for all samples meet the requirements of the standard, while values of parameters which define the plasticity of base material, elongation A5 and contraction. Z, have a large dispersion. Two samples meet the requirements of the standard (A3= 23% i A3 = 27%), while two have significantly lower values of elongation (A5 = 8% and A, = 9%), Taking into account the4fact that values ofA5and Z are not universal and that if is impossible to evaluate whether the fracture mechanism could be implemented for the runner cover material, analytical and numerical calculations ofstress state and experimental tests in order to determine the fracture mechanics parameters were carried out. Test results that referred to fatigue crack growth rate da/dN showed that internal deformations shaped as circles or ellipses (detected through ultrasonic testing), with an initial size up to 6 mm, will not disturb the reliable operation of the cover for the next 29 years.
PB  - Savez energetičara
T2  - Energija (Energija, ekonomija, ekologija)
T1  - Effect of mechanical properties of material on strength and resistance to fracture of the turbine runner cover at HPP Djerdap 1
EP  - 23
IS  - 3-4
SP  - 15
VL  - 15
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5265
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Mladenović, M. and Grabulov, Vencislav and Savić, Zoran",
year = "2013",
abstract = "Vertical Kaplan turbines with nominal output power of 200 MW, fabricated in Russia, are installed in six hydroelectric generating units of the hydroelectric power plant 'Djerdap I'. The calculation of all basic and dynamic loads turbine parts are subjected to (runner blades, all parts of the blade rotating mechanism, runner casing, runner cover, shaft, stator cylinder of the turbine, apparatus guide etc.) has been performed during the design process, while mechanical properties of the material are just a starting point for the evaluation of the resistance to fracture. In order to perform the evaluation of integrity and estimation of service life of turbine components, it is necessary to carry out the analytical and numerical calculation of strength based on the stress state, and in some cases experimental tests in order to obtain fracture mechanics parameters. Turbine runner cover of the hydroelectric generating set A6 at HPP 'Djerdap I' has been made of cast steel 20GSL. The results of chemical composition analysis, hardness testing and metallographic tests performed on 2 samples in the longitudinal and transverse cross-section are presented in this paper, as well as mechanical tests that refer to yield strength (R0), tensile strength (R) and impact strength KCU that were carried out on four samples cut out from the turbine cover. Results of tests performed on two samples confirmed that chemical composition meets the requirements of standard GOST 977/88, and also that results of hardness tests according to Vickers (HV10) and Brinell HB (2,5/187,5/20 '), as well as that results of microhardness tests according to Vickers (HV1) meet the predefined technical requirements. It has also been established that both samples in the longitudinal cross-section have coarse grained ferrite-pearlite microstructure with large local porosity, while in the transverse cross-section both samples have dendritic ferrite-pearlite microstructure, which could cause the fracture t occur: Results of tests carried out on 4 samples showed that values of yield strength (R0,), tensile strength (&) and impact strength ICCLI for all samples meet the requirements of the standard, while values of parameters which define the plasticity of base material, elongation A5 and contraction. Z, have a large dispersion. Two samples meet the requirements of the standard (A3= 23% i A3 = 27%), while two have significantly lower values of elongation (A5 = 8% and A, = 9%), Taking into account the4fact that values ofA5and Z are not universal and that if is impossible to evaluate whether the fracture mechanism could be implemented for the runner cover material, analytical and numerical calculations ofstress state and experimental tests in order to determine the fracture mechanics parameters were carried out. Test results that referred to fatigue crack growth rate da/dN showed that internal deformations shaped as circles or ellipses (detected through ultrasonic testing), with an initial size up to 6 mm, will not disturb the reliable operation of the cover for the next 29 years.",
publisher = "Savez energetičara",
journal = "Energija (Energija, ekonomija, ekologija)",
title = "Effect of mechanical properties of material on strength and resistance to fracture of the turbine runner cover at HPP Djerdap 1",
pages = "23-15",
number = "3-4",
volume = "15",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5265"
}

Arsić, M., Bošnjak, S., Mladenović, M., Grabulov, V.,& Savić, Z.. (2013). Effect of mechanical properties of material on strength and resistance to fracture of the turbine runner cover at HPP Djerdap 1. in Energija (Energija, ekonomija, ekologija)
Savez energetičara., 15(3-4), 15-23.
https://hdl.handle.net/21.15107/rcub_machinery_5265

Arsić M, Bošnjak S, Mladenović M, Grabulov V, Savić Z. Effect of mechanical properties of material on strength and resistance to fracture of the turbine runner cover at HPP Djerdap 1. in Energija (Energija, ekonomija, ekologija). 2013;15(3-4):15-23.
https://hdl.handle.net/21.15107/rcub_machinery_5265 .

Arsić, Miodrag, Bošnjak, Srđan, Mladenović, M., Grabulov, Vencislav, Savić, Zoran, "Effect of mechanical properties of material on strength and resistance to fracture of the turbine runner cover at HPP Djerdap 1" in Energija (Energija, ekonomija, ekologija), 15, no. 3-4 (2013):15-23,
https://hdl.handle.net/21.15107/rcub_machinery_5265 .

TY  - CONF
AU  - Šarkočević, Živče
AU  - Arsić, Miodrag
AU  - Mladenović, M.
AU  - Rakin, Marko
AU  - Međo, Bojan
AU  - Radaković, Zoran
PY  - 2010
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4960
C3  - Proceedings of the 3rd International Conference "Civil Engineering – Science and Practice" GNP 2010, Žabljak, 2010
T1  - Manufacturing defects and pipe damages influencing drill well reliability and the environment
EP  - 1342
SP  - 1337
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4960
ER  - 

@conference{
author = "Šarkočević, Živče and Arsić, Miodrag and Mladenović, M. and Rakin, Marko and Međo, Bojan and Radaković, Zoran",
year = "2010",
journal = "Proceedings of the 3rd International Conference "Civil Engineering – Science and Practice" GNP 2010, Žabljak, 2010",
title = "Manufacturing defects and pipe damages influencing drill well reliability and the environment",
pages = "1342-1337",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4960"
}

Šarkočević, Ž., Arsić, M., Mladenović, M., Rakin, M., Međo, B.,& Radaković, Z.. (2010). Manufacturing defects and pipe damages influencing drill well reliability and the environment. in Proceedings of the 3rd International Conference "Civil Engineering – Science and Practice" GNP 2010, Žabljak, 2010, 1337-1342.
https://hdl.handle.net/21.15107/rcub_machinery_4960

Šarkočević Ž, Arsić M, Mladenović M, Rakin M, Međo B, Radaković Z. Manufacturing defects and pipe damages influencing drill well reliability and the environment. in Proceedings of the 3rd International Conference "Civil Engineering – Science and Practice" GNP 2010, Žabljak, 2010. 2010;:1337-1342.
https://hdl.handle.net/21.15107/rcub_machinery_4960 .

Šarkočević, Živče, Arsić, Miodrag, Mladenović, M., Rakin, Marko, Međo, Bojan, Radaković, Zoran, "Manufacturing defects and pipe damages influencing drill well reliability and the environment" in Proceedings of the 3rd International Conference "Civil Engineering – Science and Practice" GNP 2010, Žabljak, 2010 (2010):1337-1342,
https://hdl.handle.net/21.15107/rcub_machinery_4960 .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Veljović, A.
AU  - Rakin, Marko
AU  - Radaković, Zoran
AU  - Mladenović, M.
PY  - 2009
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5473
AB  - Structural reliability and integrity include analysis of state, diagnostics of structural behaviour and compliance, life assessment and revitalization of structures. Aside to assessment based on flaws detected by non-destructive methods, these disciplines also include stress state analysis. Detailed distributions of displacement, deformation and stress are acquired determining “weak” locations. This approach is important for structures exposed to complex dynamical loads as bucket wheel excavators.
Fatigue research deals with welded joints as critical locations in welded structures. Under variable loads, stress concentration effects are pronounced not only by geometry and shape, but also by flaws. Flaws originate in design and construction, or in the technology, inspection and testing. Multiple parameters become critical compared to base material. Reliability is observed with more complexity as the probability of proper functionality of responsible welded joints in prescribed working conditions and operating life. The relationship between probability of failure and the degree of overlapping and shape of critical and working stress spectra are clarified and enable reliability determination in responsible welded joints.
PB  - University of Belgrade, Faculty of Mechanical Engineering
C3  - Proc. XIX International Conference on Material Handling, Constructions and Logistics, MHCL’09, Faculty of Mechanical Engineering, University of Belgrade
T1  - Reliability of critical welded joints in responsible support structures of bucket wheel excavator
EP  - 138
SP  - 133
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5473
ER  - 

@conference{
author = "Arsić, Miodrag and Veljović, A. and Rakin, Marko and Radaković, Zoran and Mladenović, M.",
year = "2009",
abstract = "Structural reliability and integrity include analysis of state, diagnostics of structural behaviour and compliance, life assessment and revitalization of structures. Aside to assessment based on flaws detected by non-destructive methods, these disciplines also include stress state analysis. Detailed distributions of displacement, deformation and stress are acquired determining “weak” locations. This approach is important for structures exposed to complex dynamical loads as bucket wheel excavators.
Fatigue research deals with welded joints as critical locations in welded structures. Under variable loads, stress concentration effects are pronounced not only by geometry and shape, but also by flaws. Flaws originate in design and construction, or in the technology, inspection and testing. Multiple parameters become critical compared to base material. Reliability is observed with more complexity as the probability of proper functionality of responsible welded joints in prescribed working conditions and operating life. The relationship between probability of failure and the degree of overlapping and shape of critical and working stress spectra are clarified and enable reliability determination in responsible welded joints.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "Proc. XIX International Conference on Material Handling, Constructions and Logistics, MHCL’09, Faculty of Mechanical Engineering, University of Belgrade",
title = "Reliability of critical welded joints in responsible support structures of bucket wheel excavator",
pages = "138-133",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5473"
}

Arsić, M., Veljović, A., Rakin, M., Radaković, Z.,& Mladenović, M.. (2009). Reliability of critical welded joints in responsible support structures of bucket wheel excavator. in Proc. XIX International Conference on Material Handling, Constructions and Logistics, MHCL’09, Faculty of Mechanical Engineering, University of Belgrade
University of Belgrade, Faculty of Mechanical Engineering., 133-138.
https://hdl.handle.net/21.15107/rcub_machinery_5473

Arsić M, Veljović A, Rakin M, Radaković Z, Mladenović M. Reliability of critical welded joints in responsible support structures of bucket wheel excavator. in Proc. XIX International Conference on Material Handling, Constructions and Logistics, MHCL’09, Faculty of Mechanical Engineering, University of Belgrade. 2009;:133-138.
https://hdl.handle.net/21.15107/rcub_machinery_5473 .

Arsić, Miodrag, Veljović, A., Rakin, Marko, Radaković, Zoran, Mladenović, M., "Reliability of critical welded joints in responsible support structures of bucket wheel excavator" in Proc. XIX International Conference on Material Handling, Constructions and Logistics, MHCL’09, Faculty of Mechanical Engineering, University of Belgrade (2009):133-138,
https://hdl.handle.net/21.15107/rcub_machinery_5473 .