TY  - JOUR
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Stefanović, Aleksandar Z.
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4903
AB  - Continuous earthmoving machines, such as bucket-wheel excavators (BWEs), are the largest mobile terrestrial machines exposed to the working loads of a periodic character. This paper aims to launch a new idea regarding the preservation of the load-carrying structures of these machines by the means of implementing a controllable frequency-controlled drive of the excavating device. Successful implementation of this idea requires a detailed analysis of the dynamic response of the load-carrying structure in order to determine the domains of frequency of revolutions of the bucket-wheel-drive electromotor (FREM) where the dynamic response of the structure is favorable. The main goal of the presented research was the development of a unique three-step method for the identification of the FREM ranges, where the vibroactivity of the load-carrying structure is within the allowed boundaries. A methodologically original study of the dynamic response was conducted on a unique dynamic model of the BWE slewing superstructure that allows for continuous variation of the FREM, i.e., of the frequency of excitation caused by the forces resisting the excavation. Validation of the spatial reduced dynamic model of the slewing superstructure and the corresponding mathematical model, as well as the overall approach to the determination of the dynamic response, were performed by the means of vibrodiagnostics under the real exploitation conditions. Application of the developed method has yielded: (1) the resonant-free FREM domains; (2) the FREM domains, where the structure is not exposed to the excessive dynamic impacts; and (3) the frequency ratio ranges defining the resonant areas. Additionally, the results of the research have pointed out that the resonant-free state represents a necessary but insufficient condition for the proper dynamic behavior of the BWE slewing superstructure.
PB  - MDPI (Basel, Switzerland)
T2  - Mathematics
T1  - Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives
IS  - 1
SP  - 154
VL  - 11
DO  - doi.org/10.3390/math11010154
ER  - 

@article{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Stefanović, Aleksandar Z.",
year = "2023",
abstract = "Continuous earthmoving machines, such as bucket-wheel excavators (BWEs), are the largest mobile terrestrial machines exposed to the working loads of a periodic character. This paper aims to launch a new idea regarding the preservation of the load-carrying structures of these machines by the means of implementing a controllable frequency-controlled drive of the excavating device. Successful implementation of this idea requires a detailed analysis of the dynamic response of the load-carrying structure in order to determine the domains of frequency of revolutions of the bucket-wheel-drive electromotor (FREM) where the dynamic response of the structure is favorable. The main goal of the presented research was the development of a unique three-step method for the identification of the FREM ranges, where the vibroactivity of the load-carrying structure is within the allowed boundaries. A methodologically original study of the dynamic response was conducted on a unique dynamic model of the BWE slewing superstructure that allows for continuous variation of the FREM, i.e., of the frequency of excitation caused by the forces resisting the excavation. Validation of the spatial reduced dynamic model of the slewing superstructure and the corresponding mathematical model, as well as the overall approach to the determination of the dynamic response, were performed by the means of vibrodiagnostics under the real exploitation conditions. Application of the developed method has yielded: (1) the resonant-free FREM domains; (2) the FREM domains, where the structure is not exposed to the excessive dynamic impacts; and (3) the frequency ratio ranges defining the resonant areas. Additionally, the results of the research have pointed out that the resonant-free state represents a necessary but insufficient condition for the proper dynamic behavior of the BWE slewing superstructure.",
publisher = "MDPI (Basel, Switzerland)",
journal = "Mathematics",
title = "Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives",
number = "1",
pages = "154",
volume = "11",
doi = "doi.org/10.3390/math11010154"
}

Gnjatović, N., Bošnjak, S.,& Stefanović, A. Z.. (2023). Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives. in Mathematics
MDPI (Basel, Switzerland)., 11(1), 154.
https://doi.org/doi.org/10.3390/math11010154

Gnjatović N, Bošnjak S, Stefanović AZ. Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives. in Mathematics. 2023;11(1):154.
doi:doi.org/10.3390/math11010154 .

Gnjatović, Nebojša, Bošnjak, Srđan, Stefanović, Aleksandar Z., "Analysis of the Dynamic Response as a Basis for the Efficient Protection of Large Structure Health Using Controllable Frequency-Controlled Drives" in Mathematics, 11, no. 1 (2023):154,
https://doi.org/doi.org/10.3390/math11010154 . .

TY  - CONF
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Milenović, Ivan Lj.
AU  - Stefanović, Aleksandar Z.
AU  - Urošević, Marko
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5001
AB  - Stackers-reclaimers represent the mechanization backbone of high-capacity storages for granular materials. The paper presents the design of a gantry bucket chain stackers-reclaimer for handling of crushed gypsum, as well as the working technology, finite element strength calculation for the main substructures: the working device, the trolley and the gantry. Failureless operation of the presented stacker-reclaimer represent an indirect validation of not only the presented results, but also the entire project as well as the applied technology of manufacture and montage.
PB  - University of Belgrade, Faculty of Mechanical Engineering
C3  - Proceedings of the XXIV International Conference MHCL’22
T1  - Gantry Bucket Chain Stacker- Reclaimer for Crushed Gypsum
EP  - 60
SP  - 55
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5001
ER  - 

@conference{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Milenović, Ivan Lj. and Stefanović, Aleksandar Z. and Urošević, Marko",
year = "2022",
abstract = "Stackers-reclaimers represent the mechanization backbone of high-capacity storages for granular materials. The paper presents the design of a gantry bucket chain stackers-reclaimer for handling of crushed gypsum, as well as the working technology, finite element strength calculation for the main substructures: the working device, the trolley and the gantry. Failureless operation of the presented stacker-reclaimer represent an indirect validation of not only the presented results, but also the entire project as well as the applied technology of manufacture and montage.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "Proceedings of the XXIV International Conference MHCL’22",
title = "Gantry Bucket Chain Stacker- Reclaimer for Crushed Gypsum",
pages = "60-55",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5001"
}

Gnjatović, N., Bošnjak, S., Milenović, I. Lj., Stefanović, A. Z.,& Urošević, M.. (2022). Gantry Bucket Chain Stacker- Reclaimer for Crushed Gypsum. in Proceedings of the XXIV International Conference MHCL’22
University of Belgrade, Faculty of Mechanical Engineering., 55-60.
https://hdl.handle.net/21.15107/rcub_machinery_5001

Gnjatović N, Bošnjak S, Milenović IL, Stefanović AZ, Urošević M. Gantry Bucket Chain Stacker- Reclaimer for Crushed Gypsum. in Proceedings of the XXIV International Conference MHCL’22. 2022;:55-60.
https://hdl.handle.net/21.15107/rcub_machinery_5001 .

Gnjatović, Nebojša, Bošnjak, Srđan, Milenović, Ivan Lj., Stefanović, Aleksandar Z., Urošević, Marko, "Gantry Bucket Chain Stacker- Reclaimer for Crushed Gypsum" in Proceedings of the XXIV International Conference MHCL’22 (2022):55-60,
https://hdl.handle.net/21.15107/rcub_machinery_5001 .

TY  - GEN
AU  - Bošnjak, Srđan
AU  - Čolović, Vladan
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
AU  - Stefanović, Aleksandar Z.
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5046
AB  - Одлагачи, заједно са роторним багерима , припадају класи највећих копнених самоходних машина и чине окосницу система површинске експлоатације. Поменути системи представљају једно од најзначајнијих достигнућа у рударству XX века, чији је значај упоредив са значајем који је за рударе XIX века имало откриће и примена динамита.
Основни проблем који се решава применом техничког решења јесте проблем чврстоће и еластичне стабилности носеће конструкције ослоне гусенице међутранспортера одлагача (тзв. „мали транспорт“) PA 200‐2200/2000 (произвођач SANDVIK; укупна маса 1737 t; теоријски капацитет 8800 m3/h), који је у експлоатацију уведен 2016. године. У IV БТО (Багер‐Тракасти транспортер‐Одлагач) систему Површинског копа „Поље Ц“ (РБ „Колубара“) спрегнут је са роторним багером SchRs 1400 (произвођач KRUPP), теоријског капацитета 6600 m3/h. Иако је очекивани век носеће конструкције 50 година, већ након четири године експлоатације дошло је до тешке хаварије (01.07. 2020. године) носеће конструкције ослоне гусенице међутранспортера, што је праћено делимичним ослањањем на тло пријемног транспортера, као и међутранспортера. Хаварија се десила током транспорта, односно промене локације машине.
Током хаварије, најтежа оштећења доживели су елементи структуре попречног носача у зони везе са носачем круте гусенице. Са обе стране дошло је до гужвања правоугаоних вертикалних лимова и избочавања трапезних вертикалних лимова, што је праћено и пуцањем заварених веза. Истовремено, хоризонтални горњи појасни лим у потпуности је изгубио првобитну форму. Због отказа завртањске везе носача погонског мотора, дошло је до његовог пада на тло. Осим тога, код круте гусенице уочени су и ломови гусеничних чланака. Зглобна гусеница је претрпела незнатна оштећења.
Проблем који се решава техничким решењем јесте недовољна чврстоћа и еластична стабилност структуре ослоне гусенице међутранспортера одлагача савремене концепције.
Комплексност поменутог проблема проистиче из:
•	променљивости геометријске конфигурације машине, како током радног процеса, тако и
•	током транспорта;
•	релативно великог броја комбинација парцијалних оптерећења;
•	вишеструких ограничења (просторних и технолошких, пре свега) скупа могућих решења.
Осим код одлагача PA 200‐2200/2000, развијено техничко решење успешно је примењено и за парцијалну реконструкцију структуре ослоне гусенице међутранспортера одлагача PA 200‐2400/2200 (РБ „Колубара“, Површински коп „Тамнава Западно поље“, III БТО систем) истог произвођача (SANDVIK).
О значају примене техничког решења које, посебно имајући у виду актуелно стање основне рударске механизације у ЕПС‐у, изузетно доприноси стабилизацији производње откривке као предуслова за експлоатацију угља, упечатљиво говори чињеница да је у укупној производњи електричне енергије у Србији доминантно учешће (око 70% [6,7]) електричне енергије добијене из лигнита.
PB  - University of Belgrade, Faculty of Mechanical Engineering
T2  - ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
T1  - Унапређење структуре ослоне гусенице међутранспортера одлагача
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5046
ER  - 

@misc{
author = "Bošnjak, Srđan and Čolović, Vladan and Gnjatović, Nebojša and Milenović, Ivan Lj. and Stefanović, Aleksandar Z.",
year = "2022",
abstract = "Одлагачи, заједно са роторним багерима , припадају класи највећих копнених самоходних машина и чине окосницу система површинске експлоатације. Поменути системи представљају једно од најзначајнијих достигнућа у рударству XX века, чији је значај упоредив са значајем који је за рударе XIX века имало откриће и примена динамита.
Основни проблем који се решава применом техничког решења јесте проблем чврстоће и еластичне стабилности носеће конструкције ослоне гусенице међутранспортера одлагача (тзв. „мали транспорт“) PA 200‐2200/2000 (произвођач SANDVIK; укупна маса 1737 t; теоријски капацитет 8800 m3/h), који је у експлоатацију уведен 2016. године. У IV БТО (Багер‐Тракасти транспортер‐Одлагач) систему Површинског копа „Поље Ц“ (РБ „Колубара“) спрегнут је са роторним багером SchRs 1400 (произвођач KRUPP), теоријског капацитета 6600 m3/h. Иако је очекивани век носеће конструкције 50 година, већ након четири године експлоатације дошло је до тешке хаварије (01.07. 2020. године) носеће конструкције ослоне гусенице међутранспортера, што је праћено делимичним ослањањем на тло пријемног транспортера, као и међутранспортера. Хаварија се десила током транспорта, односно промене локације машине.
Током хаварије, најтежа оштећења доживели су елементи структуре попречног носача у зони везе са носачем круте гусенице. Са обе стране дошло је до гужвања правоугаоних вертикалних лимова и избочавања трапезних вертикалних лимова, што је праћено и пуцањем заварених веза. Истовремено, хоризонтални горњи појасни лим у потпуности је изгубио првобитну форму. Због отказа завртањске везе носача погонског мотора, дошло је до његовог пада на тло. Осим тога, код круте гусенице уочени су и ломови гусеничних чланака. Зглобна гусеница је претрпела незнатна оштећења.
Проблем који се решава техничким решењем јесте недовољна чврстоћа и еластична стабилност структуре ослоне гусенице међутранспортера одлагача савремене концепције.
Комплексност поменутог проблема проистиче из:
•	променљивости геометријске конфигурације машине, како током радног процеса, тако и
•	током транспорта;
•	релативно великог броја комбинација парцијалних оптерећења;
•	вишеструких ограничења (просторних и технолошких, пре свега) скупа могућих решења.
Осим код одлагача PA 200‐2200/2000, развијено техничко решење успешно је примењено и за парцијалну реконструкцију структуре ослоне гусенице међутранспортера одлагача PA 200‐2400/2200 (РБ „Колубара“, Површински коп „Тамнава Западно поље“, III БТО систем) истог произвођача (SANDVIK).
О значају примене техничког решења које, посебно имајући у виду актуелно стање основне рударске механизације у ЕПС‐у, изузетно доприноси стабилизацији производње откривке као предуслова за експлоатацију угља, упечатљиво говори чињеница да је у укупној производњи електричне енергије у Србији доминантно учешће (око 70% [6,7]) електричне енергије добијене из лигнита.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)",
title = "Унапређење структуре ослоне гусенице међутранспортера одлагача",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5046"
}

Bošnjak, S., Čolović, V., Gnjatović, N., Milenović, I. Lj.,& Stefanović, A. Z.. (2022). Унапређење структуре ослоне гусенице међутранспортера одлагача. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
University of Belgrade, Faculty of Mechanical Engineering..
https://hdl.handle.net/21.15107/rcub_machinery_5046

Bošnjak S, Čolović V, Gnjatović N, Milenović IL, Stefanović AZ. Унапређење структуре ослоне гусенице међутранспортера одлагача. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82). 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_5046 .

Bošnjak, Srđan, Čolović, Vladan, Gnjatović, Nebojša, Milenović, Ivan Lj., Stefanović, Aleksandar Z., "Унапређење структуре ослоне гусенице међутранспортера одлагача" in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82) (2022),
https://hdl.handle.net/21.15107/rcub_machinery_5046 .

TY  - JOUR
AU  - Milenović, Ivan Lj.
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Obradović, Aleksandar
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3732
AB  - Identification of the basic parameters of static stability (BPSS) of the slewing superstructure is the key step in solving the problem of its static stability, as well as static stability of the entire bucket wheel excavator (BWE). Specificity of the slewing superstructure examined in this paper lies in the kinematic breakdown system (KBS) which prevents the loss of static stability on the counterweight side. Development of a unique method for the formation and two-step validation of the calculation models for this particular design concept was the main objective of the presented research. A two-step validation of the analytical models is conducted based on the experimental results. As the outcome, the final calculation model formed in such manner represents an accurate basis both for the proof of static stability and for the monitoring of the BPSS during exploitation. By comparing the results of the control weighing and the referent values of the final calculation model it was concluded that the existing double-walled bucket wheel represents a 'weak point' of the considered BWE.
PB  - Polish Maintenance Soc, Lublin
T2  - Eksploatacja I Niezawodnosc-Maintenance and Reliability
T1  - Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure
EP  - 370
IS  - 2
SP  - 359
VL  - 24
DO  - 10.17531/ein.2022.2.17
ER  - 

@article{
author = "Milenović, Ivan Lj. and Bošnjak, Srđan and Gnjatović, Nebojša and Obradović, Aleksandar",
year = "2022",
abstract = "Identification of the basic parameters of static stability (BPSS) of the slewing superstructure is the key step in solving the problem of its static stability, as well as static stability of the entire bucket wheel excavator (BWE). Specificity of the slewing superstructure examined in this paper lies in the kinematic breakdown system (KBS) which prevents the loss of static stability on the counterweight side. Development of a unique method for the formation and two-step validation of the calculation models for this particular design concept was the main objective of the presented research. A two-step validation of the analytical models is conducted based on the experimental results. As the outcome, the final calculation model formed in such manner represents an accurate basis both for the proof of static stability and for the monitoring of the BPSS during exploitation. By comparing the results of the control weighing and the referent values of the final calculation model it was concluded that the existing double-walled bucket wheel represents a 'weak point' of the considered BWE.",
publisher = "Polish Maintenance Soc, Lublin",
journal = "Eksploatacja I Niezawodnosc-Maintenance and Reliability",
title = "Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure",
pages = "370-359",
number = "2",
volume = "24",
doi = "10.17531/ein.2022.2.17"
}

Milenović, I. Lj., Bošnjak, S., Gnjatović, N.,& Obradović, A.. (2022). Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure. in Eksploatacja I Niezawodnosc-Maintenance and Reliability
Polish Maintenance Soc, Lublin., 24(2), 359-370.
https://doi.org/10.17531/ein.2022.2.17

Milenović IL, Bošnjak S, Gnjatović N, Obradović A. Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure. in Eksploatacja I Niezawodnosc-Maintenance and Reliability. 2022;24(2):359-370.
doi:10.17531/ein.2022.2.17 .

Milenović, Ivan Lj., Bošnjak, Srđan, Gnjatović, Nebojša, Obradović, Aleksandar, "Bucket wheel excavators with a kinematic breakdown system: Identification and monitoring of the basic parameters of static stability of the slewing superstructure" in Eksploatacja I Niezawodnosc-Maintenance and Reliability, 24, no. 2 (2022):359-370,
https://doi.org/10.17531/ein.2022.2.17 . .

TY  - JOUR
AU  - Bošnjak, Srđan
AU  - Zrnić, Nenad
AU  - Momčilović, Dejan B.
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3400
AB  - Tie-rods of the bucket wheel and counterweight booms are vital parts of the bucket wheel excavator slewing superstructure. This paper is dedicated to the problem of identifying the stress state of the critical cross-section ('net section') of the eye plates on these tie-rods. It presents the results of the experimental and numerical investigations carried out on the eyebar model. The results show the appearance of a plastic deformation in the zone near the contour of the hole even when the eye is subjected to the loads within the range of the permissible loads prescribed by the standard DIN 22261-2. Plastification in the eye net section occurs across the full thickness of the plate, but it does not jeopardize the integrity of the structure. The stress value in the eye net section, calculated in accordance with the standard DIN 22261-2, is significantly lower than the actual stress values around the hole and serves only as a comparative value for the static strength proof for the eye.
PB  - Elsevier Sci Ltd, Oxford
T2  - Engineering Structures
T1  - Tie-rods of the bucket wheel excavator slewing superstructure: A study of the eye plate stress state
VL  - 207
DO  - 10.1016/j.engstruct.2020.110233
ER  - 

@article{
author = "Bošnjak, Srđan and Zrnić, Nenad and Momčilović, Dejan B. and Gnjatović, Nebojša and Milenović, Ivan Lj.",
year = "2020",
abstract = "Tie-rods of the bucket wheel and counterweight booms are vital parts of the bucket wheel excavator slewing superstructure. This paper is dedicated to the problem of identifying the stress state of the critical cross-section ('net section') of the eye plates on these tie-rods. It presents the results of the experimental and numerical investigations carried out on the eyebar model. The results show the appearance of a plastic deformation in the zone near the contour of the hole even when the eye is subjected to the loads within the range of the permissible loads prescribed by the standard DIN 22261-2. Plastification in the eye net section occurs across the full thickness of the plate, but it does not jeopardize the integrity of the structure. The stress value in the eye net section, calculated in accordance with the standard DIN 22261-2, is significantly lower than the actual stress values around the hole and serves only as a comparative value for the static strength proof for the eye.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Engineering Structures",
title = "Tie-rods of the bucket wheel excavator slewing superstructure: A study of the eye plate stress state",
volume = "207",
doi = "10.1016/j.engstruct.2020.110233"
}

Bošnjak, S., Zrnić, N., Momčilović, D. B., Gnjatović, N.,& Milenović, I. Lj.. (2020). Tie-rods of the bucket wheel excavator slewing superstructure: A study of the eye plate stress state. in Engineering Structures
Elsevier Sci Ltd, Oxford., 207.
https://doi.org/10.1016/j.engstruct.2020.110233

Bošnjak S, Zrnić N, Momčilović DB, Gnjatović N, Milenović IL. Tie-rods of the bucket wheel excavator slewing superstructure: A study of the eye plate stress state. in Engineering Structures. 2020;207.
doi:10.1016/j.engstruct.2020.110233 .

Bošnjak, Srđan, Zrnić, Nenad, Momčilović, Dejan B., Gnjatović, Nebojša, Milenović, Ivan Lj., "Tie-rods of the bucket wheel excavator slewing superstructure: A study of the eye plate stress state" in Engineering Structures, 207 (2020),
https://doi.org/10.1016/j.engstruct.2020.110233 . .

TY  - CONF
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Stefanović, Aleksandar Z.
AU  - Milenović, Ivan Lj.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4940
AB  - The design concept of temporary leaning of the gas oil storage tank bearing structure used during substitution of the worn out section of the bottom plates in the zone of the central column support is presented in the paper. On the basis of comparative analysis of the results obtained using finite element structural calculations of the designed state and the state of the central column leaning on the temporary supports, it was determined that by the implementation of the temporary support, the stress-strain state of the bearing structure, which corresponds to the designed stress-strain state of the construction, is obtained. Besides, the strength proof of the structure of temporary support including its welded joint to the central column is also presented in the paper.
PB  - SaTCIP
C3  - 20th International Conference "Research and Development in Mechanical Industry" RaDMI-2020
T1  - Temporary Leaning of the Gas Oil Storage Tank Structure During Bottom Sanation
EP  - 10
SP  - 1
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4940
ER  - 

@conference{
author = "Bošnjak, Srđan and Gnjatović, Nebojša and Stefanović, Aleksandar Z. and Milenović, Ivan Lj.",
year = "2020",
abstract = "The design concept of temporary leaning of the gas oil storage tank bearing structure used during substitution of the worn out section of the bottom plates in the zone of the central column support is presented in the paper. On the basis of comparative analysis of the results obtained using finite element structural calculations of the designed state and the state of the central column leaning on the temporary supports, it was determined that by the implementation of the temporary support, the stress-strain state of the bearing structure, which corresponds to the designed stress-strain state of the construction, is obtained. Besides, the strength proof of the structure of temporary support including its welded joint to the central column is also presented in the paper.",
publisher = "SaTCIP",
journal = "20th International Conference "Research and Development in Mechanical Industry" RaDMI-2020",
title = "Temporary Leaning of the Gas Oil Storage Tank Structure During Bottom Sanation",
pages = "10-1",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4940"
}

Bošnjak, S., Gnjatović, N., Stefanović, A. Z.,& Milenović, I. Lj.. (2020). Temporary Leaning of the Gas Oil Storage Tank Structure During Bottom Sanation. in 20th International Conference "Research and Development in Mechanical Industry" RaDMI-2020
SaTCIP., 1-10.
https://hdl.handle.net/21.15107/rcub_machinery_4940

Bošnjak S, Gnjatović N, Stefanović AZ, Milenović IL. Temporary Leaning of the Gas Oil Storage Tank Structure During Bottom Sanation. in 20th International Conference "Research and Development in Mechanical Industry" RaDMI-2020. 2020;:1-10.
https://hdl.handle.net/21.15107/rcub_machinery_4940 .

Bošnjak, Srđan, Gnjatović, Nebojša, Stefanović, Aleksandar Z., Milenović, Ivan Lj., "Temporary Leaning of the Gas Oil Storage Tank Structure During Bottom Sanation" in 20th International Conference "Research and Development in Mechanical Industry" RaDMI-2020 (2020):1-10,
https://hdl.handle.net/21.15107/rcub_machinery_4940 .

TY  - CONF
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4939
AB  - A slewing superstructure (SS) represents a key functional subsystem of bucket wheel excavators (BWEs). Identification of its basic parameters of static stability (BPSS: weight and position of the center of gravity) is of equally crucial significance in design of a BWE and in its exploitation. The BPSS dominantly determine the static stability of a BWE SS and, coupled with stiffness, its
dynamic response. This paper presents the results of research on the impact of the difference between the experimentally and analytically determined SS BPSS on the: (1) intensities of forces in the ropes of the bucket wheel boom hoisting mechanism; (2) maximum loads of the SS radiaxial slew bearing balls; (3) dynamic response of the SS. The presented research represents the initial stage in forming of the integral methodology for the assessment of impact of the mentioned differences on the key indicators which determine the lifespan and integrity, as well as reliability and safety of the SS of BWEs and related surface mining and material handling machines.
PB  - Faculty of Mechanical Engineering in Niš
C3  - Proceedings of the fifth international conference “Mechanical Engineering in XXI Century” MASING 2020
T1  - Bucket Wheel Excavators: Balancing and Dynamic Response of the Slewing Superstructure
EP  - 26
SP  - 9
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4939
ER  - 

@conference{
author = "Bošnjak, Srđan and Gnjatović, Nebojša",
year = "2020",
abstract = "A slewing superstructure (SS) represents a key functional subsystem of bucket wheel excavators (BWEs). Identification of its basic parameters of static stability (BPSS: weight and position of the center of gravity) is of equally crucial significance in design of a BWE and in its exploitation. The BPSS dominantly determine the static stability of a BWE SS and, coupled with stiffness, its
dynamic response. This paper presents the results of research on the impact of the difference between the experimentally and analytically determined SS BPSS on the: (1) intensities of forces in the ropes of the bucket wheel boom hoisting mechanism; (2) maximum loads of the SS radiaxial slew bearing balls; (3) dynamic response of the SS. The presented research represents the initial stage in forming of the integral methodology for the assessment of impact of the mentioned differences on the key indicators which determine the lifespan and integrity, as well as reliability and safety of the SS of BWEs and related surface mining and material handling machines.",
publisher = "Faculty of Mechanical Engineering in Niš",
journal = "Proceedings of the fifth international conference “Mechanical Engineering in XXI Century” MASING 2020",
title = "Bucket Wheel Excavators: Balancing and Dynamic Response of the Slewing Superstructure",
pages = "26-9",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4939"
}

Bošnjak, S.,& Gnjatović, N.. (2020). Bucket Wheel Excavators: Balancing and Dynamic Response of the Slewing Superstructure. in Proceedings of the fifth international conference “Mechanical Engineering in XXI Century” MASING 2020
Faculty of Mechanical Engineering in Niš., 9-26.
https://hdl.handle.net/21.15107/rcub_machinery_4939

Bošnjak S, Gnjatović N. Bucket Wheel Excavators: Balancing and Dynamic Response of the Slewing Superstructure. in Proceedings of the fifth international conference “Mechanical Engineering in XXI Century” MASING 2020. 2020;:9-26.
https://hdl.handle.net/21.15107/rcub_machinery_4939 .

Bošnjak, Srđan, Gnjatović, Nebojša, "Bucket Wheel Excavators: Balancing and Dynamic Response of the Slewing Superstructure" in Proceedings of the fifth international conference “Mechanical Engineering in XXI Century” MASING 2020 (2020):9-26,
https://hdl.handle.net/21.15107/rcub_machinery_4939 .

TY  - GEN
AU  - Bošnjak, Srđan
AU  - Pantelić, Milorad
AU  - Misita, Mirjana
AU  - Gnjatović, Nebojša
AU  - Stefanović, Aleksandar Z.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5042
AB  - Последице отказа свих висококапацитетних машина јесу врло велики финансијски губици и озбиљни ризици по сигурност и здравље. Када је реч о багерским јединицама, финансијски губици изазвани застојем производње због отказа основне машине у систему површинске експлоатације, односно складиштења и отпреме угља, најчешће знатно превазилазе финансијске губитке изазване директном материјалном штетом, зависно од њиховог капацитета и врсте материјала који се откопава (угаљ или јаловина) [1‐5]. О величини негативних економских ефеката изазваних отказима/хаваријама упечатљиво говори податак да у САД и Европској унији укупни трошак изазван отказима машина и система износи приближно 4% од БНП [6].
Примена техничког решења омогућава решавање следећих проблема:
•	подизање нивоа одржавања, ефективности, поузданости и сигурности роторних багера, односно БТО/Д/У система;
•	подизање нивоа економичности експлоатације БТО/Д/У система; чиме се вишетрукуко смањују ризици током експлоатације и одржавања багерских јединица.
Осим тога, применом техничког решења стварају се основе за:
•	управљање поузданошћу и сигурношћу БТО/Д/У система;
•	испуњавање критеријума ригорозне регулативе везане за заштиту животне средине и сигурност руковалаца и одржавалаца.
На значај примене техничког решења у термоенергетици Србије упућују следећечињенице:
•	највећи произвођачи елекричне енергије у Србији су термоелектране. Према [7], 2014. године 65,1% електричне енергије у Србији произведено је из лигнита, док је у 2015. години 70,3 % електричне енергије добијено из поменутог извора;
•	РБ „Колубара“ даје ≈75% производње лигнита у Србији [7];
•	у цени електричне енергије угаљ учествује са ≈60%;
•	одржавање механизације на површинским коповима учествује са 35‐40% у цени угља;
•	у односу на пројектовани номинални век (35‐40 година), просечне старости машина (31,6 год. багера за континуални ископ, 31,1 год. одлагача и самоходних транспортера) и њихових капацитета (28,3 год. багера за континуални ископ, 27,2 год. одлагача и самоходних транспортера) у РБ „Колубара“, врло су високе;
•	сат застоја БТО/Д/У у РБ „Колубара“ нормира се као индиректна материјална штета у износу од 5000‐15000 €, зависно од капацитета машине, односно материјала који се откопава/транспортује.
PB  - University of Belgrade, Faculty of Mechanical Engineering
T2  - ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
T1  - Минимизација ризика у експлоатацији и одржавању роторних багера
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5042
ER  - 

@misc{
author = "Bošnjak, Srđan and Pantelić, Milorad and Misita, Mirjana and Gnjatović, Nebojša and Stefanović, Aleksandar Z.",
year = "2020",
abstract = "Последице отказа свих висококапацитетних машина јесу врло велики финансијски губици и озбиљни ризици по сигурност и здравље. Када је реч о багерским јединицама, финансијски губици изазвани застојем производње због отказа основне машине у систему површинске експлоатације, односно складиштења и отпреме угља, најчешће знатно превазилазе финансијске губитке изазване директном материјалном штетом, зависно од њиховог капацитета и врсте материјала који се откопава (угаљ или јаловина) [1‐5]. О величини негативних економских ефеката изазваних отказима/хаваријама упечатљиво говори податак да у САД и Европској унији укупни трошак изазван отказима машина и система износи приближно 4% од БНП [6].
Примена техничког решења омогућава решавање следећих проблема:
•	подизање нивоа одржавања, ефективности, поузданости и сигурности роторних багера, односно БТО/Д/У система;
•	подизање нивоа економичности експлоатације БТО/Д/У система; чиме се вишетрукуко смањују ризици током експлоатације и одржавања багерских јединица.
Осим тога, применом техничког решења стварају се основе за:
•	управљање поузданошћу и сигурношћу БТО/Д/У система;
•	испуњавање критеријума ригорозне регулативе везане за заштиту животне средине и сигурност руковалаца и одржавалаца.
На значај примене техничког решења у термоенергетици Србије упућују следећечињенице:
•	највећи произвођачи елекричне енергије у Србији су термоелектране. Према [7], 2014. године 65,1% електричне енергије у Србији произведено је из лигнита, док је у 2015. години 70,3 % електричне енергије добијено из поменутог извора;
•	РБ „Колубара“ даје ≈75% производње лигнита у Србији [7];
•	у цени електричне енергије угаљ учествује са ≈60%;
•	одржавање механизације на површинским коповима учествује са 35‐40% у цени угља;
•	у односу на пројектовани номинални век (35‐40 година), просечне старости машина (31,6 год. багера за континуални ископ, 31,1 год. одлагача и самоходних транспортера) и њихових капацитета (28,3 год. багера за континуални ископ, 27,2 год. одлагача и самоходних транспортера) у РБ „Колубара“, врло су високе;
•	сат застоја БТО/Д/У у РБ „Колубара“ нормира се као индиректна материјална штета у износу од 5000‐15000 €, зависно од капацитета машине, односно материјала који се откопава/транспортује.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)",
title = "Минимизација ризика у експлоатацији и одржавању роторних багера",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5042"
}

Bošnjak, S., Pantelić, M., Misita, M., Gnjatović, N.,& Stefanović, A. Z.. (2020). Минимизација ризика у експлоатацији и одржавању роторних багера. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
University of Belgrade, Faculty of Mechanical Engineering..
https://hdl.handle.net/21.15107/rcub_machinery_5042

Bošnjak S, Pantelić M, Misita M, Gnjatović N, Stefanović AZ. Минимизација ризика у експлоатацији и одржавању роторних багера. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82). 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_5042 .

Bošnjak, Srđan, Pantelić, Milorad, Misita, Mirjana, Gnjatović, Nebojša, Stefanović, Aleksandar Z., "Минимизација ризика у експлоатацији и одржавању роторних багера" in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82) (2020),
https://hdl.handle.net/21.15107/rcub_machinery_5042 .

TY  - GEN
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5041
AB  - Одговор на питање „шта радити након вагања горње градње?“ дат је једино у [7] (страна 233): „Уколико се резултати вагања разликују за више од 5% од теоријских‐прорачунских вредности усвојених за анализу стабилности, мора се проверити прорачун и поновити процедура вагања. Након тога, мора се извршити корекција баласта тако да положај тежишта одговара прорачунским вредностима.“ Дакле, одговор је начелног карактера, уз напомену да су масе обртне горње градње код роторних багера средње величине (класе), који доминирају на српским угљенокопима око 1000 t, при чему се пројектоване масе баласта крећу у распону од 175 t (роторни багер SRs 2000) до 500 t (роторни багер SchRs 1760).
С обзиром на изузетан значај проблема статичке стабилности, техничким решењем уведена је класификација модела обртне горње градње у две основне групе, модели 'а приори' и модели 'а постериори' и дат поступак трансформације прорачунског модела 'а приори' (пројектована слика обртне горње градње) у прорачунски модел 'а постериори' (стварна слика обртне градње). Основне фазе нове методе прорачуна статичке стабилности обртне горње градње ('а постериори') су:
1.	усклађивање прорачунског модела са свим изменама насталим током развоја пројекта и извођења монтаже, односно формирање прорачунског модела 'а приори';
2.	прво вагање, непосредно након завршене монтаже;
3.	израчунавање тежине и положаја тежишта модела 'а приори' за мерне положаје стреле ротора;
4.	израчунавање корективне масе, као и њеног положаја, на основу резултата првог мерења;
5.	формирање прорачунског модела 'а постериори' узимајући у обзир и утицај корективне масе;
6.	валидација прорачунског модела 'а постериори' на основу резултата првог мерења;
7.	одређивање потребне корекције масе противтега и подешених вредности сила у ужадима механизма за промену угла нагиба стреле ротора, на основу резултата прорачуна стабилности изведених на моделу 'а постериори';
8.	друго (контролно) мерење са коригованом масом противтега;
9.	израчунавање тежине и положаја тежишта модела 'а постериори' за положаје стреле ротора током мерења 2;
10.	коначна валидација модела 'а постериори' на основу резултата другог мерења;
11.	коначни прорачун минималних вредности степена сигурности против претурања, на целокупном домену угла нагиба стреле ротора, коришћењем модела 'а постериори'. 
	Модели 'а постериори' од изузетне су важности и за успешну и поуздану експлоатацију машине зато што представљају основу за:
•	подешавање и контролу граничних вредности сила у ужадима механизма за промену угла нагиба стреле ротора;
•	периодичну контролу тежине и положаја тежишта;
•	евентуалне реконструкције са циљем да се оствари оптимално прилагођавање машине условима рада;
што је посебно значајно због чињенице да су роторни багери и одлагачи машине намењене за вишедеценијску експлоатацију.
Коначно, суштину техничког решења, уз детаљан приказ механичког и математичког модела, аутори су 2018. године публиковали у часопису Eksploatacja i Niezawodnosc – Maintenance and Reliability (категорија М22, IF2018=1.806), као рад под називом „From ‘a priori’ to ‘a posteriori’ static stability of the slewing superstructure of a bucket wheel excavator“, Прилог 3 (http://dx.doi.org/10.17531/ein.2018.2.04). Наведени рад представља први рад из области статичке стабилности роторних багера и сродних машина објављен у часопису са SCI листе, што доказује научни потенцијал техничког решења.
PB  - University of Belgrade, Faculty of Mechanical Engineering
T2  - ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
T1  - Од а приори до а постериори статичке стабилности роторних багера
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5041
ER  - 

@misc{
author = "Bošnjak, Srđan and Gnjatović, Nebojša and Milenović, Ivan Lj.",
year = "2020",
abstract = "Одговор на питање „шта радити након вагања горње градње?“ дат је једино у [7] (страна 233): „Уколико се резултати вагања разликују за више од 5% од теоријских‐прорачунских вредности усвојених за анализу стабилности, мора се проверити прорачун и поновити процедура вагања. Након тога, мора се извршити корекција баласта тако да положај тежишта одговара прорачунским вредностима.“ Дакле, одговор је начелног карактера, уз напомену да су масе обртне горње градње код роторних багера средње величине (класе), који доминирају на српским угљенокопима око 1000 t, при чему се пројектоване масе баласта крећу у распону од 175 t (роторни багер SRs 2000) до 500 t (роторни багер SchRs 1760).
С обзиром на изузетан значај проблема статичке стабилности, техничким решењем уведена је класификација модела обртне горње градње у две основне групе, модели 'а приори' и модели 'а постериори' и дат поступак трансформације прорачунског модела 'а приори' (пројектована слика обртне горње градње) у прорачунски модел 'а постериори' (стварна слика обртне градње). Основне фазе нове методе прорачуна статичке стабилности обртне горње градње ('а постериори') су:
1.	усклађивање прорачунског модела са свим изменама насталим током развоја пројекта и извођења монтаже, односно формирање прорачунског модела 'а приори';
2.	прво вагање, непосредно након завршене монтаже;
3.	израчунавање тежине и положаја тежишта модела 'а приори' за мерне положаје стреле ротора;
4.	израчунавање корективне масе, као и њеног положаја, на основу резултата првог мерења;
5.	формирање прорачунског модела 'а постериори' узимајући у обзир и утицај корективне масе;
6.	валидација прорачунског модела 'а постериори' на основу резултата првог мерења;
7.	одређивање потребне корекције масе противтега и подешених вредности сила у ужадима механизма за промену угла нагиба стреле ротора, на основу резултата прорачуна стабилности изведених на моделу 'а постериори';
8.	друго (контролно) мерење са коригованом масом противтега;
9.	израчунавање тежине и положаја тежишта модела 'а постериори' за положаје стреле ротора током мерења 2;
10.	коначна валидација модела 'а постериори' на основу резултата другог мерења;
11.	коначни прорачун минималних вредности степена сигурности против претурања, на целокупном домену угла нагиба стреле ротора, коришћењем модела 'а постериори'. 
	Модели 'а постериори' од изузетне су важности и за успешну и поуздану експлоатацију машине зато што представљају основу за:
•	подешавање и контролу граничних вредности сила у ужадима механизма за промену угла нагиба стреле ротора;
•	периодичну контролу тежине и положаја тежишта;
•	евентуалне реконструкције са циљем да се оствари оптимално прилагођавање машине условима рада;
што је посебно значајно због чињенице да су роторни багери и одлагачи машине намењене за вишедеценијску експлоатацију.
Коначно, суштину техничког решења, уз детаљан приказ механичког и математичког модела, аутори су 2018. године публиковали у часопису Eksploatacja i Niezawodnosc – Maintenance and Reliability (категорија М22, IF2018=1.806), као рад под називом „From ‘a priori’ to ‘a posteriori’ static stability of the slewing superstructure of a bucket wheel excavator“, Прилог 3 (http://dx.doi.org/10.17531/ein.2018.2.04). Наведени рад представља први рад из области статичке стабилности роторних багера и сродних машина објављен у часопису са SCI листе, што доказује научни потенцијал техничког решења.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)",
title = "Од а приори до а постериори статичке стабилности роторних багера",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5041"
}

Bošnjak, S., Gnjatović, N.,& Milenović, I. Lj.. (2020). Од а приори до а постериори статичке стабилности роторних багера. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82)
University of Belgrade, Faculty of Mechanical Engineering..
https://hdl.handle.net/21.15107/rcub_machinery_5041

Bošnjak S, Gnjatović N, Milenović IL. Од а приори до а постериори статичке стабилности роторних багера. in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82). 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_5041 .

Bošnjak, Srđan, Gnjatović, Nebojša, Milenović, Ivan Lj., "Од а приори до а постериори статичке стабилности роторних багера" in ТЕХНИЧКО РЕШЕЊЕ (КАТЕГОРИЈА М82) (2020),
https://hdl.handle.net/21.15107/rcub_machinery_5041 .

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  - Pantelić, Milorad P.
AU  - Bošnjak, Srđan
AU  - Misita, Mirjana
AU  - Gnjatović, Nebojša
AU  - Stefanović, Aleksandar Z.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3285
AB  - Surface mining systems (SMSs) are among the most significant 20th century achievements in mining industry, whose significance to miners is comparable to the invention of dynamite in the 19th century. However, problems of SMS risk assessment are very scarce in relevant literature. For this reason, this paper aims to establish a consistent risk quantification approach for bucket wheel excavators (BWEs), the backbones of these systems. Based on the original structural scheme of a BWE, the risk parameters assessing criteria stemming from multidecadal experience and the database of recorded standstills (in the considered case, one hour of SMS downtime generates indirect financial losses of approximate to 15000(sic)), a study was conducted applying the Service FMECA technique to the BWE SRs2000 (one of the best-selling models from "Takraf"), with the following conclusions: (a) the material conveying subsystem is the highest contributor in the total number of mechanical and electrical failures, as well as in total downtime; (b) during the monitoring period, there were no extreme risk level failures. Besides, corrective actions for reducing risk levels of the most critical mechanical and electrical failure modes are given in the paper. The presented approach for risk quantification for a BWE can be successfully applied to other SMS subsystems, notably spreaders.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Service FMECA of a bucket wheel excavator
VL  - 108
DO  - 10.1016/j.engfailanal.2019.104289
ER  - 

@article{
author = "Pantelić, Milorad P. and Bošnjak, Srđan and Misita, Mirjana and Gnjatović, Nebojša and Stefanović, Aleksandar Z.",
year = "2020",
abstract = "Surface mining systems (SMSs) are among the most significant 20th century achievements in mining industry, whose significance to miners is comparable to the invention of dynamite in the 19th century. However, problems of SMS risk assessment are very scarce in relevant literature. For this reason, this paper aims to establish a consistent risk quantification approach for bucket wheel excavators (BWEs), the backbones of these systems. Based on the original structural scheme of a BWE, the risk parameters assessing criteria stemming from multidecadal experience and the database of recorded standstills (in the considered case, one hour of SMS downtime generates indirect financial losses of approximate to 15000(sic)), a study was conducted applying the Service FMECA technique to the BWE SRs2000 (one of the best-selling models from "Takraf"), with the following conclusions: (a) the material conveying subsystem is the highest contributor in the total number of mechanical and electrical failures, as well as in total downtime; (b) during the monitoring period, there were no extreme risk level failures. Besides, corrective actions for reducing risk levels of the most critical mechanical and electrical failure modes are given in the paper. The presented approach for risk quantification for a BWE can be successfully applied to other SMS subsystems, notably spreaders.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Service FMECA of a bucket wheel excavator",
volume = "108",
doi = "10.1016/j.engfailanal.2019.104289"
}

Pantelić, M. P., Bošnjak, S., Misita, M., Gnjatović, N.,& Stefanović, A. Z.. (2020). Service FMECA of a bucket wheel excavator. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 108.
https://doi.org/10.1016/j.engfailanal.2019.104289

Pantelić MP, Bošnjak S, Misita M, Gnjatović N, Stefanović AZ. Service FMECA of a bucket wheel excavator. in Engineering Failure Analysis. 2020;108.
doi:10.1016/j.engfailanal.2019.104289 .

Pantelić, Milorad P., Bošnjak, Srđan, Misita, Mirjana, Gnjatović, Nebojša, Stefanović, Aleksandar Z., "Service FMECA of a bucket wheel excavator" in Engineering Failure Analysis, 108 (2020),
https://doi.org/10.1016/j.engfailanal.2019.104289 . .

TY  - JOUR
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Milenović, Ivan Lj.
AU  - Stefanović, Aleksandar Z.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3337
AB  - An original method for validation of the number of buckets on the working device of a bucket wheel excavator based on the dynamic response of its slewing superstructure (SS) is presented. A set of 16 seemingly acceptable solutions which satisfied the rigid design restrictions, based on the preservation of the existing (a) bucket wheel drivetrain, (b) theoretical capacity, (c) characteristics of the excavated soil and (d) position of the superstructure centre of gravity (CoG), was analysed. Already on the basis of the limiting vertical and lateral accelerations of the bucket wheel centre, which represents a well-grounded indicator of its dynamic behaviour prescribed by the code DIN 22261-2, 14 out of 16 analysed design variants have been discarded, reducing the set of possible solutions to only two - the originally-designed variant (with 17 buckets), and the variant with 20 buckets. Conclusions on the validity of these two design variants were derived on the basis of the dynamic response analysis of the referent points of the SS. The analysis of the impact of soiling on the dynamic response of the SS has shown that negative dynamic effects, observed in the preceding analysis of the originally-designed solution, increase with the amount of the adhered material. Although the redesigned variant with 20 buckets has proven as the only suitable solution from the standpoint of dynamic behaviour of the SS, the results have to be assessed carefully due to the fact that the reduction of the mass of the bucket wheel steel structure by more than 14% leads to the appearance of unfavourable dynamic effects, even though the SS CoG position is preserved.
PB  - Elsevier Sci Ltd, Oxford
T2  - Engineering Structures
T1  - Bucket wheel excavators: Dynamic response as a criterion for validation of the total number of buckets
VL  - 225
DO  - 10.1016/j.engstruct.2020.111313
ER  - 

@article{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Milenović, Ivan Lj. and Stefanović, Aleksandar Z.",
year = "2020",
abstract = "An original method for validation of the number of buckets on the working device of a bucket wheel excavator based on the dynamic response of its slewing superstructure (SS) is presented. A set of 16 seemingly acceptable solutions which satisfied the rigid design restrictions, based on the preservation of the existing (a) bucket wheel drivetrain, (b) theoretical capacity, (c) characteristics of the excavated soil and (d) position of the superstructure centre of gravity (CoG), was analysed. Already on the basis of the limiting vertical and lateral accelerations of the bucket wheel centre, which represents a well-grounded indicator of its dynamic behaviour prescribed by the code DIN 22261-2, 14 out of 16 analysed design variants have been discarded, reducing the set of possible solutions to only two - the originally-designed variant (with 17 buckets), and the variant with 20 buckets. Conclusions on the validity of these two design variants were derived on the basis of the dynamic response analysis of the referent points of the SS. The analysis of the impact of soiling on the dynamic response of the SS has shown that negative dynamic effects, observed in the preceding analysis of the originally-designed solution, increase with the amount of the adhered material. Although the redesigned variant with 20 buckets has proven as the only suitable solution from the standpoint of dynamic behaviour of the SS, the results have to be assessed carefully due to the fact that the reduction of the mass of the bucket wheel steel structure by more than 14% leads to the appearance of unfavourable dynamic effects, even though the SS CoG position is preserved.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Engineering Structures",
title = "Bucket wheel excavators: Dynamic response as a criterion for validation of the total number of buckets",
volume = "225",
doi = "10.1016/j.engstruct.2020.111313"
}

Gnjatović, N., Bošnjak, S., Milenović, I. Lj.,& Stefanović, A. Z.. (2020). Bucket wheel excavators: Dynamic response as a criterion for validation of the total number of buckets. in Engineering Structures
Elsevier Sci Ltd, Oxford., 225.
https://doi.org/10.1016/j.engstruct.2020.111313

Gnjatović N, Bošnjak S, Milenović IL, Stefanović AZ. Bucket wheel excavators: Dynamic response as a criterion for validation of the total number of buckets. in Engineering Structures. 2020;225.
doi:10.1016/j.engstruct.2020.111313 .

Gnjatović, Nebojša, Bošnjak, Srđan, Milenović, Ivan Lj., Stefanović, Aleksandar Z., "Bucket wheel excavators: Dynamic response as a criterion for validation of the total number of buckets" in Engineering Structures, 225 (2020),
https://doi.org/10.1016/j.engstruct.2020.111313 . .

TY  - JOUR
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Milenović, Ivan Lj.
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3302
AB  - Exploitation of bucket wheel excavators (BWEs) is accompanied by an increase of mass due to transport and adherence of a large amount of the material. Technical regulations do not account for the dynamic behaviour of BWEs. Such problems are analysed as quasi-static. A procedure and results of investigation of the influence of masses of the bucket wheel (BW) incrustation and soil in a blocked BW chute on the superstructure response are presented. Analysis of sensitivity of dynamic characteristics and the response to adherence of the material is conducted. The method and results can be used in the design stages of new and in reconstructions of obsolete BWEs.
PB  - Polish Soc Theoretical & Applied Mechanics, Warszawa
T2  - Journal of Theoretical and Applied Mechanics
T1  - The influence of incrustation and chute blockage on the dynamic behaviour of a bucket wheel excavator slewing superstructure
EP  - 584
IS  - 3
SP  - 573
VL  - 58
DO  - 10.15632/jtam-pl/121942
ER  - 

@article{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Milenović, Ivan Lj.",
year = "2020",
abstract = "Exploitation of bucket wheel excavators (BWEs) is accompanied by an increase of mass due to transport and adherence of a large amount of the material. Technical regulations do not account for the dynamic behaviour of BWEs. Such problems are analysed as quasi-static. A procedure and results of investigation of the influence of masses of the bucket wheel (BW) incrustation and soil in a blocked BW chute on the superstructure response are presented. Analysis of sensitivity of dynamic characteristics and the response to adherence of the material is conducted. The method and results can be used in the design stages of new and in reconstructions of obsolete BWEs.",
publisher = "Polish Soc Theoretical & Applied Mechanics, Warszawa",
journal = "Journal of Theoretical and Applied Mechanics",
title = "The influence of incrustation and chute blockage on the dynamic behaviour of a bucket wheel excavator slewing superstructure",
pages = "584-573",
number = "3",
volume = "58",
doi = "10.15632/jtam-pl/121942"
}

Gnjatović, N., Bošnjak, S.,& Milenović, I. Lj.. (2020). The influence of incrustation and chute blockage on the dynamic behaviour of a bucket wheel excavator slewing superstructure. in Journal of Theoretical and Applied Mechanics
Polish Soc Theoretical & Applied Mechanics, Warszawa., 58(3), 573-584.
https://doi.org/10.15632/jtam-pl/121942

Gnjatović N, Bošnjak S, Milenović IL. The influence of incrustation and chute blockage on the dynamic behaviour of a bucket wheel excavator slewing superstructure. in Journal of Theoretical and Applied Mechanics. 2020;58(3):573-584.
doi:10.15632/jtam-pl/121942 .

Gnjatović, Nebojša, Bošnjak, Srđan, Milenović, Ivan Lj., "The influence of incrustation and chute blockage on the dynamic behaviour of a bucket wheel excavator slewing superstructure" in Journal of Theoretical and Applied Mechanics, 58, no. 3 (2020):573-584,
https://doi.org/10.15632/jtam-pl/121942 . .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4938
AB  - Damaging of the carrying steel structure and embedding of the rejecting drum of the stacker conveyor occurred during the exploitation of the bucket-wheel reclaimer with the belonging stacker. The analysis of the cause and level of damaging led to the conclusion that damaged parts should be replaced by new ones and that methodology of repair should be based on the application of a suitable welding technology. This paper presents the methodology of repair welding performed during the replacement of the damaged carrying structure and embedding of the rejecting drum of the stacker conveyor which consist of steel sheets and profiles that’s based on the conceptual solution for damage repair through the use of program package ’Catia’ – V5 that enabled the creation of models and graphic documentation of structural parts that should be replaced by new ones. It should also be noted that geodetic survey of the lower belt of the stacker structure was performed after the substitution of damaged parts of the structure.
PB  - University of Belgrade, Faculty of Mechanical Engineering
C3  - Proceedings of the XXIII International Conference MHCL’19
T1  - Repair methodology for the carrying structure of the rejecting drum of the bucket-wheel reclaimer stacker conveyor at coal landfill
EP  - 122
SP  - 117
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4938
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Gnjatović, Nebojša and Milenović, Ivan Lj.",
year = "2019",
abstract = "Damaging of the carrying steel structure and embedding of the rejecting drum of the stacker conveyor occurred during the exploitation of the bucket-wheel reclaimer with the belonging stacker. The analysis of the cause and level of damaging led to the conclusion that damaged parts should be replaced by new ones and that methodology of repair should be based on the application of a suitable welding technology. This paper presents the methodology of repair welding performed during the replacement of the damaged carrying structure and embedding of the rejecting drum of the stacker conveyor which consist of steel sheets and profiles that’s based on the conceptual solution for damage repair through the use of program package ’Catia’ – V5 that enabled the creation of models and graphic documentation of structural parts that should be replaced by new ones. It should also be noted that geodetic survey of the lower belt of the stacker structure was performed after the substitution of damaged parts of the structure.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "Proceedings of the XXIII International Conference MHCL’19",
title = "Repair methodology for the carrying structure of the rejecting drum of the bucket-wheel reclaimer stacker conveyor at coal landfill",
pages = "122-117",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4938"
}

Arsić, M., Bošnjak, S., Grabulov, V., Gnjatović, N.,& Milenović, I. Lj.. (2019). Repair methodology for the carrying structure of the rejecting drum of the bucket-wheel reclaimer stacker conveyor at coal landfill. in Proceedings of the XXIII International Conference MHCL’19
University of Belgrade, Faculty of Mechanical Engineering., 117-122.
https://hdl.handle.net/21.15107/rcub_machinery_4938

Arsić M, Bošnjak S, Grabulov V, Gnjatović N, Milenović IL. Repair methodology for the carrying structure of the rejecting drum of the bucket-wheel reclaimer stacker conveyor at coal landfill. in Proceedings of the XXIII International Conference MHCL’19. 2019;:117-122.
https://hdl.handle.net/21.15107/rcub_machinery_4938 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Gnjatović, Nebojša, Milenović, Ivan Lj., "Repair methodology for the carrying structure of the rejecting drum of the bucket-wheel reclaimer stacker conveyor at coal landfill" in Proceedings of the XXIII International Conference MHCL’19 (2019):117-122,
https://hdl.handle.net/21.15107/rcub_machinery_4938 .

TY  - CONF
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
AU  - Stefanović, Aleksandar Z.
AU  - Urošević, Marko
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4936
AB  - A bucket wheel with drive represents a vital subsystem of any bucket wheel excavator. A multidecadal experience in the exploitation and maintenance of bucket wheel excavators SRs 2000 has imposed a need for modernization and unification of the excavating devices of four of such machines, used for the excavation of overburden in Serbian open pit mines. This paper presents a portion of the research dedicated to the problems of strength and dynamic properties of the bucket wheel boom, static stability of the superstructure as well as installation of the unified design solution for the bucket wheel drive of the bucket wheel excavator SRs 2000. By
installing a modernized design solution of the bucket wheel with drive, i.e. by the means of partial revitalization of the bucket wheel excavator, its exploitational life span is prolonged and, additionally, the level of reliability and availability of the overburden systems is increased, and a
significant reduction in maintenance expenses is achieved.
PB  - University of Belgrade, Faculty of Mechanical Engineering
C3  - Proceedings of the XXIII International Conference MHCL’19
T1  - Modernization and unification of the excavating devices of bucket wheel excavators SRs 2000 deployed in Serbian open pit mines
EP  - 182
SP  - 175
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4936
ER  - 

@conference{
author = "Bošnjak, Srđan and Gnjatović, Nebojša and Milenović, Ivan Lj. and Stefanović, Aleksandar Z. and Urošević, Marko",
year = "2019",
abstract = "A bucket wheel with drive represents a vital subsystem of any bucket wheel excavator. A multidecadal experience in the exploitation and maintenance of bucket wheel excavators SRs 2000 has imposed a need for modernization and unification of the excavating devices of four of such machines, used for the excavation of overburden in Serbian open pit mines. This paper presents a portion of the research dedicated to the problems of strength and dynamic properties of the bucket wheel boom, static stability of the superstructure as well as installation of the unified design solution for the bucket wheel drive of the bucket wheel excavator SRs 2000. By
installing a modernized design solution of the bucket wheel with drive, i.e. by the means of partial revitalization of the bucket wheel excavator, its exploitational life span is prolonged and, additionally, the level of reliability and availability of the overburden systems is increased, and a
significant reduction in maintenance expenses is achieved.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "Proceedings of the XXIII International Conference MHCL’19",
title = "Modernization and unification of the excavating devices of bucket wheel excavators SRs 2000 deployed in Serbian open pit mines",
pages = "182-175",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4936"
}

Bošnjak, S., Gnjatović, N., Milenović, I. Lj., Stefanović, A. Z.,& Urošević, M.. (2019). Modernization and unification of the excavating devices of bucket wheel excavators SRs 2000 deployed in Serbian open pit mines. in Proceedings of the XXIII International Conference MHCL’19
University of Belgrade, Faculty of Mechanical Engineering., 175-182.
https://hdl.handle.net/21.15107/rcub_machinery_4936

Bošnjak S, Gnjatović N, Milenović IL, Stefanović AZ, Urošević M. Modernization and unification of the excavating devices of bucket wheel excavators SRs 2000 deployed in Serbian open pit mines. in Proceedings of the XXIII International Conference MHCL’19. 2019;:175-182.
https://hdl.handle.net/21.15107/rcub_machinery_4936 .

Bošnjak, Srđan, Gnjatović, Nebojša, Milenović, Ivan Lj., Stefanović, Aleksandar Z., Urošević, Marko, "Modernization and unification of the excavating devices of bucket wheel excavators SRs 2000 deployed in Serbian open pit mines" in Proceedings of the XXIII International Conference MHCL’19 (2019):175-182,
https://hdl.handle.net/21.15107/rcub_machinery_4936 .

TY  - CONF
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Milenović, Ivan Lj.
AU  - Stefanović, Aleksandar Z.
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4934
AB  - The method for validation of the number of buckets on the working device of a bucket wheel excavator from the aspect of dynamic behaviour of the system, partially presented in this paper, was developed on the basis of the original spatial reduced dynamic model of the bucket wheel excavator with two masts, which enables modal analysis and analysis of the dynamic
response of the system for continuous variation of constructional parameters and parameters of excitation. The set of 16 seemingly acceptable solutions, all of which satisfied the rigid design restrictions which were: (a) use of the same bucket wheel drivetrain, (b) preservation of the theoretical capacity, (c) possibility of the excavation of soil of the fourth category and (d) preservation of the superstructure centre of gravity position, was analyzed. On the basis of limiting vertical and lateral accelerations, derived from dynamic coefficients prescribed by the code DIN 22261-2, of the bucket wheel centre, which for a proper geometrically-designed bucket wheel excavator structure represents a well grounded indicator of its dynamic behaviour, 14 out of 16 analyzed solutions were discarded, yielding the set of possible solutions to only 2, the originally designed one (with 17 buckets) and the solution with 20 buckets installed on the bucket wheel.
PB  - University of Belgrade, Faculty of Mechanical Engineering
C3  - Proceedings of the XXIII International Conference MHCL’19
T1  - Validation of the number of buckets on the working device of a bucket wheel
EP  - 196
SP  - 187
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4934
ER  - 

@conference{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Milenović, Ivan Lj. and Stefanović, Aleksandar Z.",
year = "2019",
abstract = "The method for validation of the number of buckets on the working device of a bucket wheel excavator from the aspect of dynamic behaviour of the system, partially presented in this paper, was developed on the basis of the original spatial reduced dynamic model of the bucket wheel excavator with two masts, which enables modal analysis and analysis of the dynamic
response of the system for continuous variation of constructional parameters and parameters of excitation. The set of 16 seemingly acceptable solutions, all of which satisfied the rigid design restrictions which were: (a) use of the same bucket wheel drivetrain, (b) preservation of the theoretical capacity, (c) possibility of the excavation of soil of the fourth category and (d) preservation of the superstructure centre of gravity position, was analyzed. On the basis of limiting vertical and lateral accelerations, derived from dynamic coefficients prescribed by the code DIN 22261-2, of the bucket wheel centre, which for a proper geometrically-designed bucket wheel excavator structure represents a well grounded indicator of its dynamic behaviour, 14 out of 16 analyzed solutions were discarded, yielding the set of possible solutions to only 2, the originally designed one (with 17 buckets) and the solution with 20 buckets installed on the bucket wheel.",
publisher = "University of Belgrade, Faculty of Mechanical Engineering",
journal = "Proceedings of the XXIII International Conference MHCL’19",
title = "Validation of the number of buckets on the working device of a bucket wheel",
pages = "196-187",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4934"
}

Gnjatović, N., Bošnjak, S., Milenović, I. Lj.,& Stefanović, A. Z.. (2019). Validation of the number of buckets on the working device of a bucket wheel. in Proceedings of the XXIII International Conference MHCL’19
University of Belgrade, Faculty of Mechanical Engineering., 187-196.
https://hdl.handle.net/21.15107/rcub_machinery_4934

Gnjatović N, Bošnjak S, Milenović IL, Stefanović AZ. Validation of the number of buckets on the working device of a bucket wheel. in Proceedings of the XXIII International Conference MHCL’19. 2019;:187-196.
https://hdl.handle.net/21.15107/rcub_machinery_4934 .

Gnjatović, Nebojša, Bošnjak, Srđan, Milenović, Ivan Lj., Stefanović, Aleksandar Z., "Validation of the number of buckets on the working device of a bucket wheel" in Proceedings of the XXIII International Conference MHCL’19 (2019):187-196,
https://hdl.handle.net/21.15107/rcub_machinery_4934 .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Grabulov, Vencislav
AU  - Arsić, Dušan
AU  - Savić, Zoran
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5237
AB  - During the rehabilitation of turbine and hydromechanical equipment at hydro power plant 'Djerdap 1' results of tests and researches carried out in order to analyze the condition of vital components and structures during service led to the conclusion that the components and structures could be made only if parameters of fracture mechanics were applied during the design and prototyping phase, because by doing so the occurrence of fatigue fracture and/or degradation of parent material and welded joints due to variable loading, corrosion, erosion and cavitation would be prevented, therefore the integrity of material would be maintained. Experimental determination of the fatigue crack propagation rate as an important property of development of the fatigue process during the action of the variable load, from the initial to the critical length, enables the prediction of the stable crack propagation period, or in other words of the service life of vital components and structures of turbine and hydromechanical equipment. Taking into account the fact that cracks are most severe of all defects, the results obtained for cracks could safely be applied for other types of defects which often occur in welded joints. This
paper contains the methodological approaches for the assessment of integrity and evaluation of service life of components and structures of turbine and hydromechanical equipment during the design, prototyping and service period based on history of fatigue loading and application of fracture mechanics parameters.
PB  - University of Banja Luka-Faculty of Mechanical Engineering
C3  - Proceedings of the 14th International conference on accomplishments in mechanical and industrial engineering „DEMI 2019”
T1  - Prediction of service life of components and structures of hydro power plants during the design, prototyping and service period
EP  - 188
SP  - 183
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5237
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Grabulov, Vencislav and Arsić, Dušan and Savić, Zoran",
year = "2019",
abstract = "During the rehabilitation of turbine and hydromechanical equipment at hydro power plant 'Djerdap 1' results of tests and researches carried out in order to analyze the condition of vital components and structures during service led to the conclusion that the components and structures could be made only if parameters of fracture mechanics were applied during the design and prototyping phase, because by doing so the occurrence of fatigue fracture and/or degradation of parent material and welded joints due to variable loading, corrosion, erosion and cavitation would be prevented, therefore the integrity of material would be maintained. Experimental determination of the fatigue crack propagation rate as an important property of development of the fatigue process during the action of the variable load, from the initial to the critical length, enables the prediction of the stable crack propagation period, or in other words of the service life of vital components and structures of turbine and hydromechanical equipment. Taking into account the fact that cracks are most severe of all defects, the results obtained for cracks could safely be applied for other types of defects which often occur in welded joints. This
paper contains the methodological approaches for the assessment of integrity and evaluation of service life of components and structures of turbine and hydromechanical equipment during the design, prototyping and service period based on history of fatigue loading and application of fracture mechanics parameters.",
publisher = "University of Banja Luka-Faculty of Mechanical Engineering",
journal = "Proceedings of the 14th International conference on accomplishments in mechanical and industrial engineering „DEMI 2019”",
title = "Prediction of service life of components and structures of hydro power plants during the design, prototyping and service period",
pages = "188-183",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5237"
}

Arsić, M., Bošnjak, S., Grabulov, V., Arsić, D.,& Savić, Z.. (2019). Prediction of service life of components and structures of hydro power plants during the design, prototyping and service period. in Proceedings of the 14th International conference on accomplishments in mechanical and industrial engineering „DEMI 2019”
University of Banja Luka-Faculty of Mechanical Engineering., 183-188.
https://hdl.handle.net/21.15107/rcub_machinery_5237

Arsić M, Bošnjak S, Grabulov V, Arsić D, Savić Z. Prediction of service life of components and structures of hydro power plants during the design, prototyping and service period. in Proceedings of the 14th International conference on accomplishments in mechanical and industrial engineering „DEMI 2019”. 2019;:183-188.
https://hdl.handle.net/21.15107/rcub_machinery_5237 .

Arsić, Miodrag, Bošnjak, Srđan, Grabulov, Vencislav, Arsić, Dušan, Savić, Zoran, "Prediction of service life of components and structures of hydro power plants during the design, prototyping and service period" in Proceedings of the 14th International conference on accomplishments in mechanical and industrial engineering „DEMI 2019” (2019):183-188,
https://hdl.handle.net/21.15107/rcub_machinery_5237 .

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  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Sedmak, Simon
AU  - Vistać, Brane
AU  - Savić, Zoran
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3211
AB  - During the revitalization of the hydroelectric generating station A4 at the hydro power plant 'Djerdap 1', all of its parts are subjected to non-destructive testing. Cracks are detected in cast part of generator rotor hub, in the flange area toward the turbine shaft. Cracks were 10-500 mm long (determined by magnetic particle tests) and 60-100 mm deep (ultrasonic tests). The generator rotor hub is made of cast steel 25L, in accordance with the standard 977-75. The welding/surface welding repair technology in the detected crack zones of the cast part of generator rotor hub includes a large number of details, due to the structural solution and generator rotor function in service. It was also necessary to provide the carefully undertaken activities in order to enable safe operation and continuous use of the rotor hub. Failing to notice, underestimation or incorrect perception of important details could cause significant problems in hydroelectric generating station operation. The paper, due to specifics of reparation technology, contains arranged preparatory activities for the procedure apart from the welding/surface welding technology. It is of importance to mention a huge amount of money savings, The manufacture of a new generator rotor would cost over 4 million EUR (generator mass is over 300 tonnes), not taking into account the time needed for its making (6-12 months), which is directly related to the amount of energy a hydroelectric generating station can produce during that period. This technology of repair welding is also applicable for other components and structures of the turbine and the hydromechanical equipment subjected to various causes of damage during exploitation.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Repair of cracks detected in cast components of vertical kaplan turbine rotor hub
EP  - 250
IS  - 3
SP  - 243
VL  - 19
UR  - https://hdl.handle.net/21.15107/rcub_machinery_3211
ER  - 

@article{
author = "Arsić, Miodrag and Bošnjak, Srđan and Sedmak, Simon and Vistać, Brane and Savić, Zoran",
year = "2019",
abstract = "During the revitalization of the hydroelectric generating station A4 at the hydro power plant 'Djerdap 1', all of its parts are subjected to non-destructive testing. Cracks are detected in cast part of generator rotor hub, in the flange area toward the turbine shaft. Cracks were 10-500 mm long (determined by magnetic particle tests) and 60-100 mm deep (ultrasonic tests). The generator rotor hub is made of cast steel 25L, in accordance with the standard 977-75. The welding/surface welding repair technology in the detected crack zones of the cast part of generator rotor hub includes a large number of details, due to the structural solution and generator rotor function in service. It was also necessary to provide the carefully undertaken activities in order to enable safe operation and continuous use of the rotor hub. Failing to notice, underestimation or incorrect perception of important details could cause significant problems in hydroelectric generating station operation. The paper, due to specifics of reparation technology, contains arranged preparatory activities for the procedure apart from the welding/surface welding technology. It is of importance to mention a huge amount of money savings, The manufacture of a new generator rotor would cost over 4 million EUR (generator mass is over 300 tonnes), not taking into account the time needed for its making (6-12 months), which is directly related to the amount of energy a hydroelectric generating station can produce during that period. This technology of repair welding is also applicable for other components and structures of the turbine and the hydromechanical equipment subjected to various causes of damage during exploitation.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Repair of cracks detected in cast components of vertical kaplan turbine rotor hub",
pages = "250-243",
number = "3",
volume = "19",
url = "https://hdl.handle.net/21.15107/rcub_machinery_3211"
}

Arsić, M., Bošnjak, S., Sedmak, S., Vistać, B.,& Savić, Z.. (2019). Repair of cracks detected in cast components of vertical kaplan turbine rotor hub. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 19(3), 243-250.
https://hdl.handle.net/21.15107/rcub_machinery_3211

Arsić M, Bošnjak S, Sedmak S, Vistać B, Savić Z. Repair of cracks detected in cast components of vertical kaplan turbine rotor hub. in Structural Integrity and Life. 2019;19(3):243-250.
https://hdl.handle.net/21.15107/rcub_machinery_3211 .

Arsić, Miodrag, Bošnjak, Srđan, Sedmak, Simon, Vistać, Brane, Savić, Zoran, "Repair of cracks detected in cast components of vertical kaplan turbine rotor hub" in Structural Integrity and Life, 19, no. 3 (2019):243-250,
https://hdl.handle.net/21.15107/rcub_machinery_3211 .

TY  - CHAP
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
AU  - Zrnić, Nenad
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3238
AB  - A holistic approach to analyzing the dynamic behaviour of a bucket wheel excavator (BWE) superstructure, which is practically neglected by technical regulations but nowadays widely used during their design and redesign, is presented in the paper. The procedure for determining the potential and kinetic energy and the vector of generalized non-potential forces of the system, leading to the development of a reduced spatial dynamic (RD) model of the BWE with two masts is presented in detail. Direct validation of the established model has been performed by comparing the values obtained for the first ten natural frequencies (NFs) of the finite element (FE) model to those obtained by the RD model. Percent deviations of values of the NFs obtained for the RD model are very low compared to those obtained by the FE model (~1% for three fundamental NFs). Indirect validation of the RD model used in this research i.e. validation of values of the NFs which have been obtained by calculation and the respective modal deflection shapes has been achieved by comparing them to the studies containing the results of numerical-experimental research on the dynamic characteristics of BWEs of the same design concept. The values of NFs are of the same order of magnitude and the corresponding deflection shapes are in full compliance with those of the experimentally-analyzed BWEs.
PB  - Pleiades journals
T2  - Lecture Notes in Mechanical Engineering
T1  - Spatial reduced dynamic model of a bucket wheel excavator with two masts
EP  - 235
SP  - 215
DO  - 10.1007/978-3-030-04975-1_26
ER  - 

@inbook{
author = "Gnjatović, Nebojša and Bošnjak, Srđan and Zrnić, Nenad",
year = "2019",
abstract = "A holistic approach to analyzing the dynamic behaviour of a bucket wheel excavator (BWE) superstructure, which is practically neglected by technical regulations but nowadays widely used during their design and redesign, is presented in the paper. The procedure for determining the potential and kinetic energy and the vector of generalized non-potential forces of the system, leading to the development of a reduced spatial dynamic (RD) model of the BWE with two masts is presented in detail. Direct validation of the established model has been performed by comparing the values obtained for the first ten natural frequencies (NFs) of the finite element (FE) model to those obtained by the RD model. Percent deviations of values of the NFs obtained for the RD model are very low compared to those obtained by the FE model (~1% for three fundamental NFs). Indirect validation of the RD model used in this research i.e. validation of values of the NFs which have been obtained by calculation and the respective modal deflection shapes has been achieved by comparing them to the studies containing the results of numerical-experimental research on the dynamic characteristics of BWEs of the same design concept. The values of NFs are of the same order of magnitude and the corresponding deflection shapes are in full compliance with those of the experimentally-analyzed BWEs.",
publisher = "Pleiades journals",
journal = "Lecture Notes in Mechanical Engineering",
booktitle = "Spatial reduced dynamic model of a bucket wheel excavator with two masts",
pages = "235-215",
doi = "10.1007/978-3-030-04975-1_26"
}

Gnjatović, N., Bošnjak, S.,& Zrnić, N.. (2019). Spatial reduced dynamic model of a bucket wheel excavator with two masts. in Lecture Notes in Mechanical Engineering
Pleiades journals., 215-235.
https://doi.org/10.1007/978-3-030-04975-1_26

Gnjatović N, Bošnjak S, Zrnić N. Spatial reduced dynamic model of a bucket wheel excavator with two masts. in Lecture Notes in Mechanical Engineering. 2019;:215-235.
doi:10.1007/978-3-030-04975-1_26 .

Gnjatović, Nebojša, Bošnjak, Srđan, Zrnić, Nenad, "Spatial reduced dynamic model of a bucket wheel excavator with two masts" in Lecture Notes in Mechanical Engineering (2019):215-235,
https://doi.org/10.1007/978-3-030-04975-1_26 . .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Sedmak, Simon
AU  - Arsić, D.
AU  - Savić, Zoran
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2918
AB  - This paper presents a methodological approach for the assessment of service life of vital welded structures of a bucket-wheel excavator Sch Rs 650/5x24 ('Thyssen Krupp', Germany) boom, subjected to cyclic loading with a variable amplitude through the use of experimental tests carried out in order to determine operational strength and growth of a fatigue crack. Realized researches and results presented in this paper offer great possibilities for the analyses of behaviour of vital welded structures of the bucket-wheel boom. By the application of the measurement device with 8 channels for registration and processing of electric signals HBM Spider 8 and measurement tapes HBM 6/350xXY31 deformations were measured at vital welded structures of the boom in the area of the bucket-wheel, made of steels St 37.2 and St 52.3 in accordance with standard DIN 17100, or steels S235J2G3 and S355J2G3 in accordance with standard EN 10025-2. The objective of the test is to determine if there is a possibility of occurrence of plastic deformations or initial cracks due to fatigue at vital welded structures. Tests that refer to the growth of the fatigue crack located at the welded joint have been carried out by bending at three points with asymmetric load R = 0.5 (R = sigma(min) / sigma(max)) at the specimen with a single edge notch. Tests were performed through the use of controlled force, ranging between F-max and F-min at the high frequency pulsator 'Cracktronic', while obtainment of data regarding the crack growth was carried out through the use of measurement gauge ARM A-10.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
T1  - Determination of Residual Fatigue Life of Welded Structures at Bucket-Wheel Excavators through the Use of Fracture Mechanics
EP  - 84
SP  - 79
VL  - 13
DO  - 10.1016/j.prostr.2018.12.014
ER  - 

@conference{
author = "Arsić, Miodrag and Bošnjak, Srđan and Gnjatović, Nebojša and Sedmak, Simon and Arsić, D. and Savić, Zoran",
year = "2018",
abstract = "This paper presents a methodological approach for the assessment of service life of vital welded structures of a bucket-wheel excavator Sch Rs 650/5x24 ('Thyssen Krupp', Germany) boom, subjected to cyclic loading with a variable amplitude through the use of experimental tests carried out in order to determine operational strength and growth of a fatigue crack. Realized researches and results presented in this paper offer great possibilities for the analyses of behaviour of vital welded structures of the bucket-wheel boom. By the application of the measurement device with 8 channels for registration and processing of electric signals HBM Spider 8 and measurement tapes HBM 6/350xXY31 deformations were measured at vital welded structures of the boom in the area of the bucket-wheel, made of steels St 37.2 and St 52.3 in accordance with standard DIN 17100, or steels S235J2G3 and S355J2G3 in accordance with standard EN 10025-2. The objective of the test is to determine if there is a possibility of occurrence of plastic deformations or initial cracks due to fatigue at vital welded structures. Tests that refer to the growth of the fatigue crack located at the welded joint have been carried out by bending at three points with asymmetric load R = 0.5 (R = sigma(min) / sigma(max)) at the specimen with a single edge notch. Tests were performed through the use of controlled force, ranging between F-max and F-min at the high frequency pulsator 'Cracktronic', while obtainment of data regarding the crack growth was carried out through the use of measurement gauge ARM A-10.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity",
title = "Determination of Residual Fatigue Life of Welded Structures at Bucket-Wheel Excavators through the Use of Fracture Mechanics",
pages = "84-79",
volume = "13",
doi = "10.1016/j.prostr.2018.12.014"
}

Arsić, M., Bošnjak, S., Gnjatović, N., Sedmak, S., Arsić, D.,& Savić, Z.. (2018). Determination of Residual Fatigue Life of Welded Structures at Bucket-Wheel Excavators through the Use of Fracture Mechanics. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
Elsevier Science Bv, Amsterdam., 13, 79-84.
https://doi.org/10.1016/j.prostr.2018.12.014

Arsić M, Bošnjak S, Gnjatović N, Sedmak S, Arsić D, Savić Z. Determination of Residual Fatigue Life of Welded Structures at Bucket-Wheel Excavators through the Use of Fracture Mechanics. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity. 2018;13:79-84.
doi:10.1016/j.prostr.2018.12.014 .

Arsić, Miodrag, Bošnjak, Srđan, Gnjatović, Nebojša, Sedmak, Simon, Arsić, D., Savić, Zoran, "Determination of Residual Fatigue Life of Welded Structures at Bucket-Wheel Excavators through the Use of Fracture Mechanics" in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity, 13 (2018):79-84,
https://doi.org/10.1016/j.prostr.2018.12.014 . .

TY  - CONF
AU  - Jovančić, Predrag
AU  - Ignjatović, Dragan
AU  - Gnjatović, Nebojša
AU  - Bošnjak, Srđan
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5047
AB  - Na površinskim kopovima EPS trenutno je u funkciji 4 rotorna bagera tipa SRs 2000. Bageri
su nabavljani i montirani u različitim periodima što je uslovilo da ovi bageri imaju različita
konstruktivna rešenja najvitalnijeg dela - glave rotora. Tokom dosadašnje eksploatacije ovih
bagera na našim površinskim kopovima, kao najslabija mesta pokazali su se sistemi za pogon
rotornog točka i sam rotor. To iziskuje optimalno definisanje modernizacije i revitalizacije
odnosno unifikacije pogonske grupe rotora, što bi trebalo da obezbedi povećanje pouzdanosti
bagera, a time i povećanje vremenskog i kapacitetnog iskorišćenja. Na osnovu sistematizovanja
zapažanja i primedbi korisnika i održavalaca ovih rotornih bagera kao i hronologije problema
u radu, vrši se analiza pogona kopanja na svim bagerima i donosi krajnji stav o mogućim daljim
aktivnostima sa ciljem unifikacije.
PB  - Jugoslovenski komitet za površinsku eksploataciju
C3  - Зборник радова XIII међународне конференције „OMC 2018“
T1  - Анализа погонских система на багерима SRs 2000 са циљем унификације
EP  - 71
SP  - 63
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5047
ER  - 

@conference{
author = "Jovančić, Predrag and Ignjatović, Dragan and Gnjatović, Nebojša and Bošnjak, Srđan",
year = "2018",
abstract = "Na površinskim kopovima EPS trenutno je u funkciji 4 rotorna bagera tipa SRs 2000. Bageri
su nabavljani i montirani u različitim periodima što je uslovilo da ovi bageri imaju različita
konstruktivna rešenja najvitalnijeg dela - glave rotora. Tokom dosadašnje eksploatacije ovih
bagera na našim površinskim kopovima, kao najslabija mesta pokazali su se sistemi za pogon
rotornog točka i sam rotor. To iziskuje optimalno definisanje modernizacije i revitalizacije
odnosno unifikacije pogonske grupe rotora, što bi trebalo da obezbedi povećanje pouzdanosti
bagera, a time i povećanje vremenskog i kapacitetnog iskorišćenja. Na osnovu sistematizovanja
zapažanja i primedbi korisnika i održavalaca ovih rotornih bagera kao i hronologije problema
u radu, vrši se analiza pogona kopanja na svim bagerima i donosi krajnji stav o mogućim daljim
aktivnostima sa ciljem unifikacije.",
publisher = "Jugoslovenski komitet za površinsku eksploataciju",
journal = "Зборник радова XIII међународне конференције „OMC 2018“",
title = "Анализа погонских система на багерима SRs 2000 са циљем унификације",
pages = "71-63",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5047"
}

Jovančić, P., Ignjatović, D., Gnjatović, N.,& Bošnjak, S.. (2018). Анализа погонских система на багерима SRs 2000 са циљем унификације. in Зборник радова XIII међународне конференције „OMC 2018“
Jugoslovenski komitet za površinsku eksploataciju., 63-71.
https://hdl.handle.net/21.15107/rcub_machinery_5047

Jovančić P, Ignjatović D, Gnjatović N, Bošnjak S. Анализа погонских система на багерима SRs 2000 са циљем унификације. in Зборник радова XIII међународне конференције „OMC 2018“. 2018;:63-71.
https://hdl.handle.net/21.15107/rcub_machinery_5047 .

Jovančić, Predrag, Ignjatović, Dragan, Gnjatović, Nebojša, Bošnjak, Srđan, "Анализа погонских система на багерима SRs 2000 са циљем унификације" in Зборник радова XIII међународне конференције „OMC 2018“ (2018):63-71,
https://hdl.handle.net/21.15107/rcub_machinery_5047 .

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  - Đorđević, Miloš
AU  - Mladenović, Goran
AU  - Zrnić, Nenad
AU  - Bošnjak, Srđan
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2780
AB  - Sprovedena je procena životnog ciklusa malog trakastog transportera. Analizirana je faza proizvodnje sa aspekata uticaja na životnu sredinu i potrošnje energije. Najveći uticaj na životnu sredinu u većini kategorija uticaja za osnovni model kategorija uticaja potiče od proizvodnje niskolegiranih čelika i potrošnje električne energije tokom faze proizvodnje, praćen uticajem transporta. U radu su takođe predloženi načini uštede energije u proizvodnoj praksi uz primenu adekvatnih tehnologija.
AB  - A cradle-to-gate LCA analysis of a small belt conveyor was conducted. Manufacturing stage was analysed from the aspects of environmental impacts and energy consumption. The biggest environmental impact in majority of baseline impact categories is obtained from low-alloyed steel production and electricity consumption during the manufacturing stage, followed by impact of the transport. Ways for possible energy savings regarding manufacturing practice and technologies were proposed later on.
PB  - Univerzitet u Beogradu - Mašinski fakultet, Beograd
T2  - FME Transactions
T1  - Analiza faze proizvodnje pri proceni životnog ciklusa laboratorijskog trakastog transportera
T1  - LCA of the manufacturing stage of the laboratory belt conveyor
EP  - 417
IS  - 3
SP  - 410
VL  - 46
DO  - 10.5937/fmet1803410D
ER  - 

@article{
author = "Đorđević, Miloš and Mladenović, Goran and Zrnić, Nenad and Bošnjak, Srđan",
year = "2018",
abstract = "Sprovedena je procena životnog ciklusa malog trakastog transportera. Analizirana je faza proizvodnje sa aspekata uticaja na životnu sredinu i potrošnje energije. Najveći uticaj na životnu sredinu u većini kategorija uticaja za osnovni model kategorija uticaja potiče od proizvodnje niskolegiranih čelika i potrošnje električne energije tokom faze proizvodnje, praćen uticajem transporta. U radu su takođe predloženi načini uštede energije u proizvodnoj praksi uz primenu adekvatnih tehnologija., A cradle-to-gate LCA analysis of a small belt conveyor was conducted. Manufacturing stage was analysed from the aspects of environmental impacts and energy consumption. The biggest environmental impact in majority of baseline impact categories is obtained from low-alloyed steel production and electricity consumption during the manufacturing stage, followed by impact of the transport. Ways for possible energy savings regarding manufacturing practice and technologies were proposed later on.",
publisher = "Univerzitet u Beogradu - Mašinski fakultet, Beograd",
journal = "FME Transactions",
title = "Analiza faze proizvodnje pri proceni životnog ciklusa laboratorijskog trakastog transportera, LCA of the manufacturing stage of the laboratory belt conveyor",
pages = "417-410",
number = "3",
volume = "46",
doi = "10.5937/fmet1803410D"
}

Đorđević, M., Mladenović, G., Zrnić, N.,& Bošnjak, S.. (2018). Analiza faze proizvodnje pri proceni životnog ciklusa laboratorijskog trakastog transportera. in FME Transactions
Univerzitet u Beogradu - Mašinski fakultet, Beograd., 46(3), 410-417.
https://doi.org/10.5937/fmet1803410D

Đorđević M, Mladenović G, Zrnić N, Bošnjak S. Analiza faze proizvodnje pri proceni životnog ciklusa laboratorijskog trakastog transportera. in FME Transactions. 2018;46(3):410-417.
doi:10.5937/fmet1803410D .

Đorđević, Miloš, Mladenović, Goran, Zrnić, Nenad, Bošnjak, Srđan, "Analiza faze proizvodnje pri proceni životnog ciklusa laboratorijskog trakastog transportera" in FME Transactions, 46, no. 3 (2018):410-417,
https://doi.org/10.5937/fmet1803410D . .