TY  - JOUR
AU  - Bošnjak, Srđan
AU  - Zrnić, Nenad
AU  - Momčilović, Dejan
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan Lj.
PY  - 2020
UR  - http://rims.institutims.rs/handle/123456789/391
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 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., 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 D, 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, 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  - JOUR
AU  - Bošnjak, Srđan
AU  - Zrnić, Nenad
AU  - Momčilović, Dejan
AU  - Gnjatović, Nebojša
AU  - Milenović, Ivan
PY  - 2020
UR  - http://rims.institutims.rs/handle/123456789/451
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.
T2  - Engineering Structures
T1  - Bucket wheel excavators_Dynamic response as a criterion for validation of the total number of buckets
VL  - 207
DO  - 10.1016/j.engstruct.2020.110233
ER  - 

@article{
author = "Bošnjak, Srđan and Zrnić, Nenad and Momčilović, Dejan and Gnjatović, Nebojša and Milenović, Ivan",
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.",
journal = "Engineering Structures",
title = "Bucket wheel excavators_Dynamic response as a criterion for validation of the total number of buckets",
volume = "207",
doi = "10.1016/j.engstruct.2020.110233"
}

Bošnjak, S., Zrnić, N., Momčilović, D., Gnjatović, N.,& Milenović, I.. (2020). Bucket wheel excavators_Dynamic response as a criterion for validation of the total number of buckets. in Engineering Structures, 207.
https://doi.org/10.1016/j.engstruct.2020.110233

Bošnjak S, Zrnić N, Momčilović D, Gnjatović N, Milenović I. Bucket wheel excavators_Dynamic response as a criterion for validation of the total number of buckets. in Engineering Structures. 2020;207.
doi:10.1016/j.engstruct.2020.110233 .

Bošnjak, Srđan, Zrnić, Nenad, Momčilović, Dejan, Gnjatović, Nebojša, Milenović, Ivan, "Bucket wheel excavators_Dynamic response as a criterion for validation of the total number of buckets" in Engineering Structures, 207 (2020),
https://doi.org/10.1016/j.engstruct.2020.110233 . .

TY  - CONF
AU  - Arsić, Miodrag
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Sedmak, Simon
AU  - Arsić, D.
AU  - Savić, Zoran
PY  - 2018
UR  - http://rims.institutims.rs/handle/123456789/334
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  - 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 = "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 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 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 ECF22 - Loading and Environmental Effects on Structural Integrity, 13 (2018):79-84,
https://doi.org/10.1016/j.prostr.2018.12.014 . .

TY  - JOUR
AU  - Bošnjak, Srđan
AU  - Gnjatović, Nebojša
AU  - Momčilović, Dejan
AU  - Milenović, Ivan Lj.
AU  - Gašić, V.M.
PY  - 2015
UR  - http://rims.institutims.rs/handle/123456789/276
AB  - This paper presents an investigation of the accident which occurred during startup of the extending structure from the transport position. In order to clarify the causes of crack occurrence along almost the entire surface of the lever cross-section, the authors performed visual, experimental (chemical composition, tensile properties, microhardness) as well as metallographic examinations. Stress states in the critical zone are defined by applying the finite element method (FEM). Based on the investigation results it was concluded that the lever breakdown is predominantly caused by both the 'operating-in' defect (the malfunction of the limit switch) and the 'manufacturing-in' defect (poor weld quality). The investigation results presented in this paper are important because same or similar problems could arise in supporting structures of various types of transportation, construction and mining machines.
PB  - Elsevier Ltd
T2  - Case Studies in Engineering Failure Analysis
T1  - Failure analysis of the mobile elevating work platform
EP  - 87
SP  - 80
VL  - 3
DO  - 10.1016/j.csefa.2015.03.005
ER  - 

@article{
author = "Bošnjak, Srđan and Gnjatović, Nebojša and Momčilović, Dejan and Milenović, Ivan Lj. and Gašić, V.M.",
year = "2015",
abstract = "This paper presents an investigation of the accident which occurred during startup of the extending structure from the transport position. In order to clarify the causes of crack occurrence along almost the entire surface of the lever cross-section, the authors performed visual, experimental (chemical composition, tensile properties, microhardness) as well as metallographic examinations. Stress states in the critical zone are defined by applying the finite element method (FEM). Based on the investigation results it was concluded that the lever breakdown is predominantly caused by both the 'operating-in' defect (the malfunction of the limit switch) and the 'manufacturing-in' defect (poor weld quality). The investigation results presented in this paper are important because same or similar problems could arise in supporting structures of various types of transportation, construction and mining machines.",
publisher = "Elsevier Ltd",
journal = "Case Studies in Engineering Failure Analysis",
title = "Failure analysis of the mobile elevating work platform",
pages = "87-80",
volume = "3",
doi = "10.1016/j.csefa.2015.03.005"
}

Bošnjak, S., Gnjatović, N., Momčilović, D., Milenović, I. Lj.,& Gašić, V.M.. (2015). Failure analysis of the mobile elevating work platform. in Case Studies in Engineering Failure Analysis
Elsevier Ltd., 3, 80-87.
https://doi.org/10.1016/j.csefa.2015.03.005

Bošnjak S, Gnjatović N, Momčilović D, Milenović IL, Gašić V. Failure analysis of the mobile elevating work platform. in Case Studies in Engineering Failure Analysis. 2015;3:80-87.
doi:10.1016/j.csefa.2015.03.005 .

Bošnjak, Srđan, Gnjatović, Nebojša, Momčilović, Dejan, Milenović, Ivan Lj., Gašić, V.M., "Failure analysis of the mobile elevating work platform" in Case Studies in Engineering Failure Analysis, 3 (2015):80-87,
https://doi.org/10.1016/j.csefa.2015.03.005 . .

TY  - JOUR
AU  - Bošnjak, Srđan
AU  - Momčilović, Dejan
AU  - Petković, Zoran D.
AU  - Pantelić, Milorad P.
AU  - Gnjatović, Nebojša
PY  - 2013
UR  - http://rims.institutims.rs/handle/123456789/218
AB  - The high mobility of open pit machines in heavy duty conditions provides fertile ground for the occurrence of various failures of the traveling mechanisms' vital parts such as chain links. The goal of the study presented in this paper was to diagnose the cause of the damage of the bucket wheel excavator crawler chain links. In order to identify the reasons behind chain link failures, stress state calculations were performed as well as experimental investigations which, given the nature of the failure, included visual and metallographic examinations, chemical composition analysis and tests of mechanical properties. Based on the results of the numerical-experimental analyses, it was concluded that the chain link breakdowns are caused by 'manufacturing-in' defects. The results of the presented analyses also emphasize the importance of a comprehensive quality control of chain links.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Failure investigation of the bucket wheel excavator crawler chain link
EP  - 469
SP  - 462
VL  - 35
DO  - 10.1016/j.engfailanal.2013.04.025
ER  - 

@article{
author = "Bošnjak, Srđan and Momčilović, Dejan and Petković, Zoran D. and Pantelić, Milorad P. and Gnjatović, Nebojša",
year = "2013",
abstract = "The high mobility of open pit machines in heavy duty conditions provides fertile ground for the occurrence of various failures of the traveling mechanisms' vital parts such as chain links. The goal of the study presented in this paper was to diagnose the cause of the damage of the bucket wheel excavator crawler chain links. In order to identify the reasons behind chain link failures, stress state calculations were performed as well as experimental investigations which, given the nature of the failure, included visual and metallographic examinations, chemical composition analysis and tests of mechanical properties. Based on the results of the numerical-experimental analyses, it was concluded that the chain link breakdowns are caused by 'manufacturing-in' defects. The results of the presented analyses also emphasize the importance of a comprehensive quality control of chain links.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Failure investigation of the bucket wheel excavator crawler chain link",
pages = "469-462",
volume = "35",
doi = "10.1016/j.engfailanal.2013.04.025"
}

Bošnjak, S., Momčilović, D., Petković, Z. D., Pantelić, M. P.,& Gnjatović, N.. (2013). Failure investigation of the bucket wheel excavator crawler chain link. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 35, 462-469.
https://doi.org/10.1016/j.engfailanal.2013.04.025

Bošnjak S, Momčilović D, Petković ZD, Pantelić MP, Gnjatović N. Failure investigation of the bucket wheel excavator crawler chain link. in Engineering Failure Analysis. 2013;35:462-469.
doi:10.1016/j.engfailanal.2013.04.025 .

Bošnjak, Srđan, Momčilović, Dejan, Petković, Zoran D., Pantelić, Milorad P., Gnjatović, Nebojša, "Failure investigation of the bucket wheel excavator crawler chain link" in Engineering Failure Analysis, 35 (2013):462-469,
https://doi.org/10.1016/j.engfailanal.2013.04.025 . .