TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Petrovski, Blagoj
AU  - Grbović, Aleksandar
AU  - Sedmak, Simon
AU  - Milošević, Nenad
PY  - 2024
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7778
AB  - Experimental and numerical analysis of crack growth in integral skin-stringer panels, produced by Laser Beam Welding (LBW), was performed in the scope of WELDAIR project and later on. Experiment was performed on full-scale components (four stringers, three welded clips), made of AA 6156 T6. Digital Image Correlation (DIC) was used to measure strains and construct CTOD or J crack resistance curves. It was shown that J vs. Δa can have unusual shape, indicating real component crack resistance instead of critical J value commonly obtained by comparing J-R curves with calculated Crack Driving Forces (CDFs). The applied technique is simple, practical and has no limitation in respect to material and geometry
PB  - Elsevier
T2  - Procedia Structural Integrity
T1  - Crack Resistance of AA6156 Welded Stringer Panels
EP  - 380
SP  - 376
VL  - 54
DO  - 10.1016/j.prostr.2024.01.096
ER  - 

@article{
author = "Sedmak, Aleksandar and Petrovski, Blagoj and Grbović, Aleksandar and Sedmak, Simon and Milošević, Nenad",
year = "2024",
abstract = "Experimental and numerical analysis of crack growth in integral skin-stringer panels, produced by Laser Beam Welding (LBW), was performed in the scope of WELDAIR project and later on. Experiment was performed on full-scale components (four stringers, three welded clips), made of AA 6156 T6. Digital Image Correlation (DIC) was used to measure strains and construct CTOD or J crack resistance curves. It was shown that J vs. Δa can have unusual shape, indicating real component crack resistance instead of critical J value commonly obtained by comparing J-R curves with calculated Crack Driving Forces (CDFs). The applied technique is simple, practical and has no limitation in respect to material and geometry",
publisher = "Elsevier",
journal = "Procedia Structural Integrity",
title = "Crack Resistance of AA6156 Welded Stringer Panels",
pages = "380-376",
volume = "54",
doi = "10.1016/j.prostr.2024.01.096"
}

Sedmak, A., Petrovski, B., Grbović, A., Sedmak, S.,& Milošević, N.. (2024). Crack Resistance of AA6156 Welded Stringer Panels. in Procedia Structural Integrity
Elsevier., 54, 376-380.
https://doi.org/10.1016/j.prostr.2024.01.096

Sedmak A, Petrovski B, Grbović A, Sedmak S, Milošević N. Crack Resistance of AA6156 Welded Stringer Panels. in Procedia Structural Integrity. 2024;54:376-380.
doi:10.1016/j.prostr.2024.01.096 .

Sedmak, Aleksandar, Petrovski, Blagoj, Grbović, Aleksandar, Sedmak, Simon, Milošević, Nenad, "Crack Resistance of AA6156 Welded Stringer Panels" in Procedia Structural Integrity, 54 (2024):376-380,
https://doi.org/10.1016/j.prostr.2024.01.096 . .

TY  - JOUR
AU  - Raičević, Nikola
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Sedmak, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7006
AB  - This paper deals with the damage growth in High-Pressure Turbine (HPT) cooling holes of the case assembly made of Inconel 718. Several marks (cuts) were made on cooling holes into parent material during the service due to the non-skilled use of Electrical Discharge Machining (EDM) in the workshop. After a certain time, the case assembly returned to the workshop with all EDM marks cracked. Since HPT case assembly is not repairable and the only method for fixing this issue is its replacement with the new or used one (which might be pretty expensive), it was decided to use numerical analysis to estimate Paris coefficients for used Inconel 718, since the number of cycles and crack growth from the initial position were known, based on data obtained from the workshop. Firstly, finite element method (FEM) based numerical analysis was conducted in order to simulate crack propagation to match the one observed in the workshop, and then a multi-objective genetic algorithm – The standard response surface type - full second order polynomials – was used to obtain required Paris coefficients. The objectives of this optimization were the crack length and the corresponding number of cycles of crack growth. Obtained Paris coefficients were then used to estimate the residual life of HPT case assembly.
PB  - ELSEVIER
T2  - Procedia Structural Integrity
T1  - Residual life estimation of damaged structures exposed to high pressures and temperatures
EP  - 347
SP  - 342
VL  - 48
DO  - 10.1016/j.prostr.2023.07.123
ER  - 

@article{
author = "Raičević, Nikola and Grbović, Aleksandar and Kastratović, Gordana and Vidanović, Nenad and Sedmak, Aleksandar",
year = "2023",
abstract = "This paper deals with the damage growth in High-Pressure Turbine (HPT) cooling holes of the case assembly made of Inconel 718. Several marks (cuts) were made on cooling holes into parent material during the service due to the non-skilled use of Electrical Discharge Machining (EDM) in the workshop. After a certain time, the case assembly returned to the workshop with all EDM marks cracked. Since HPT case assembly is not repairable and the only method for fixing this issue is its replacement with the new or used one (which might be pretty expensive), it was decided to use numerical analysis to estimate Paris coefficients for used Inconel 718, since the number of cycles and crack growth from the initial position were known, based on data obtained from the workshop. Firstly, finite element method (FEM) based numerical analysis was conducted in order to simulate crack propagation to match the one observed in the workshop, and then a multi-objective genetic algorithm – The standard response surface type - full second order polynomials – was used to obtain required Paris coefficients. The objectives of this optimization were the crack length and the corresponding number of cycles of crack growth. Obtained Paris coefficients were then used to estimate the residual life of HPT case assembly.",
publisher = "ELSEVIER",
journal = "Procedia Structural Integrity",
title = "Residual life estimation of damaged structures exposed to high pressures and temperatures",
pages = "347-342",
volume = "48",
doi = "10.1016/j.prostr.2023.07.123"
}

Raičević, N., Grbović, A., Kastratović, G., Vidanović, N.,& Sedmak, A.. (2023). Residual life estimation of damaged structures exposed to high pressures and temperatures. in Procedia Structural Integrity
ELSEVIER., 48, 342-347.
https://doi.org/10.1016/j.prostr.2023.07.123

Raičević N, Grbović A, Kastratović G, Vidanović N, Sedmak A. Residual life estimation of damaged structures exposed to high pressures and temperatures. in Procedia Structural Integrity. 2023;48:342-347.
doi:10.1016/j.prostr.2023.07.123 .

Raičević, Nikola, Grbović, Aleksandar, Kastratović, Gordana, Vidanović, Nenad, Sedmak, Aleksandar, "Residual life estimation of damaged structures exposed to high pressures and temperatures" in Procedia Structural Integrity, 48 (2023):342-347,
https://doi.org/10.1016/j.prostr.2023.07.123 . .

TY  - CONF
AU  - Ćosić, Petar
AU  - Petrašinović, Miloš
AU  - Grbović, Aleksandar
AU  - Petrašinović, Danilo
AU  - Petrović, Mihailo
AU  - Petrović, Veljko
AU  - Raičević, Nikola
AU  - Rašuo, Boško
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7730
AB  - Aerospace engineering, as a field in which the reduction of mass has always been one of the primary tasks of its engineers, has made significant progress as a result of numerous developments and advancements in the field of composite materials in the sense of gaining large benefits from the relatively low density that characterizes composites. In the spirit of the increasing use of composite materials on aerospace structures, in this paper we will conduct an experimental and numerical analysis of the strength of a drone arm made of a composite material. Every method of analysis, whether it is analytical, numerical, or experimental, has some advantages and disadvantages. Experimental results are easily affected by random and instrumental errors and numerical methods are highly affected by the chosen physical model. In order to obtain the most reliable analysis solution, a mixture of numerical analysis backed up by experimental data is required. In the hope of bypassing the expensive and time-consuming experiments in the future, in this paper we will conduct a numerical analysis on a drone arm made of composite materials which will then be replicated by an experiment verifying its validity.
PB  - The Serbian Society of Mechanics
C3  - 9th International Congress of the Serbian Society of Mechanics
T1  - Experimental and Numerical Analysis of the Strength of a Drone Arm Made of Composite Material
EP  - 300
SP  - 293
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7730
ER  - 

@conference{
author = "Ćosić, Petar and Petrašinović, Miloš and Grbović, Aleksandar and Petrašinović, Danilo and Petrović, Mihailo and Petrović, Veljko and Raičević, Nikola and Rašuo, Boško",
year = "2023",
abstract = "Aerospace engineering, as a field in which the reduction of mass has always been one of the primary tasks of its engineers, has made significant progress as a result of numerous developments and advancements in the field of composite materials in the sense of gaining large benefits from the relatively low density that characterizes composites. In the spirit of the increasing use of composite materials on aerospace structures, in this paper we will conduct an experimental and numerical analysis of the strength of a drone arm made of a composite material. Every method of analysis, whether it is analytical, numerical, or experimental, has some advantages and disadvantages. Experimental results are easily affected by random and instrumental errors and numerical methods are highly affected by the chosen physical model. In order to obtain the most reliable analysis solution, a mixture of numerical analysis backed up by experimental data is required. In the hope of bypassing the expensive and time-consuming experiments in the future, in this paper we will conduct a numerical analysis on a drone arm made of composite materials which will then be replicated by an experiment verifying its validity.",
publisher = "The Serbian Society of Mechanics",
journal = "9th International Congress of the Serbian Society of Mechanics",
title = "Experimental and Numerical Analysis of the Strength of a Drone Arm Made of Composite Material",
pages = "300-293",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7730"
}

Ćosić, P., Petrašinović, M., Grbović, A., Petrašinović, D., Petrović, M., Petrović, V., Raičević, N.,& Rašuo, B.. (2023). Experimental and Numerical Analysis of the Strength of a Drone Arm Made of Composite Material. in 9th International Congress of the Serbian Society of Mechanics
The Serbian Society of Mechanics., 293-300.
https://hdl.handle.net/21.15107/rcub_machinery_7730

Ćosić P, Petrašinović M, Grbović A, Petrašinović D, Petrović M, Petrović V, Raičević N, Rašuo B. Experimental and Numerical Analysis of the Strength of a Drone Arm Made of Composite Material. in 9th International Congress of the Serbian Society of Mechanics. 2023;:293-300.
https://hdl.handle.net/21.15107/rcub_machinery_7730 .

Ćosić, Petar, Petrašinović, Miloš, Grbović, Aleksandar, Petrašinović, Danilo, Petrović, Mihailo, Petrović, Veljko, Raičević, Nikola, Rašuo, Boško, "Experimental and Numerical Analysis of the Strength of a Drone Arm Made of Composite Material" in 9th International Congress of the Serbian Society of Mechanics (2023):293-300,
https://hdl.handle.net/21.15107/rcub_machinery_7730 .

TY  - CONF
AU  - Grbović, Aleksandar
AU  - Eldwaib, Khalid Ahmed
AU  - Kastratović, Gordana
AU  - Čolić, Katarina
AU  - Sedmak, Simon
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7109
AB  - Fatigue cracks growth in three different wing spar geometries is simulated using xFEM, as the most suitable numerical method for this purpose. The goal of this analysis was to find out how crack paths affect number of cycles, i.e. fatigue life, so that the optimal geometry can be defined. The extended finite element method was applied using Morfeo/Crack for Abaqus software. Results provided better understanding and prediction of multiple cracks propagation in complex 3D structures and provided data for the optimal design of wing spar.
C3  - Procedia Structural Integrity
T1  - Predicting fatigue crack growth in complex geometries using numerical methods
EP  - 61
SP  - 56
VL  - 46
DO  - 10.1016/j.prostr.2023.06.010
ER  - 

@conference{
author = "Grbović, Aleksandar and Eldwaib, Khalid Ahmed and Kastratović, Gordana and Čolić, Katarina and Sedmak, Simon",
year = "2023",
abstract = "Fatigue cracks growth in three different wing spar geometries is simulated using xFEM, as the most suitable numerical method for this purpose. The goal of this analysis was to find out how crack paths affect number of cycles, i.e. fatigue life, so that the optimal geometry can be defined. The extended finite element method was applied using Morfeo/Crack for Abaqus software. Results provided better understanding and prediction of multiple cracks propagation in complex 3D structures and provided data for the optimal design of wing spar.",
journal = "Procedia Structural Integrity",
title = "Predicting fatigue crack growth in complex geometries using numerical methods",
pages = "61-56",
volume = "46",
doi = "10.1016/j.prostr.2023.06.010"
}

Grbović, A., Eldwaib, K. A., Kastratović, G., Čolić, K.,& Sedmak, S.. (2023). Predicting fatigue crack growth in complex geometries using numerical methods. in Procedia Structural Integrity, 46, 56-61.
https://doi.org/10.1016/j.prostr.2023.06.010

Grbović A, Eldwaib KA, Kastratović G, Čolić K, Sedmak S. Predicting fatigue crack growth in complex geometries using numerical methods. in Procedia Structural Integrity. 2023;46:56-61.
doi:10.1016/j.prostr.2023.06.010 .

Grbović, Aleksandar, Eldwaib, Khalid Ahmed, Kastratović, Gordana, Čolić, Katarina, Sedmak, Simon, "Predicting fatigue crack growth in complex geometries using numerical methods" in Procedia Structural Integrity, 46 (2023):56-61,
https://doi.org/10.1016/j.prostr.2023.06.010 . .

TY  - JOUR
AU  - Raičević, Nikola
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Sedmak, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7007
AB  - The torque link is part of the nose landing gear of aircraft. It prevents the piston from turning inside the cylinder of the shock absorber, enabling its up and down motion during the landing and take-off. As such, its structural integrity and life are crucial for aircraft safe operation, but because of complex geometry and variable loading conditions, its fatigue life estimation represents a real challenge. In this paper, fatigue lives of two different designs of the torque links of the light aircraft are evaluated by a numerical approach based on the improved FEM. Firstly, the fatigue life of the damaged torque link was assessed for actual load conditions. Then, improved torque links, obtained through topological optimization, were analyzed and their fatigue life was calculated. Finally, the numerical simulations of the additive manufacturing (AM) process of optimized torque links were carried out, and the fatigue life of these torque links, including residual stresses from AM, were estimated too. The obtained numbers of cycles in all cases were compared and discussed for all torque links cases. This is an advanced approach to fatigue life assessment of optimized printed 3D parts based on numerical simulations of both crack growth and AM process.
PB  - Elsevier
T2  - International Journal of Fatigue
T1  - Fatigue life prediction of topologically optimized torque link adjusted for additive manufacturing
SP  - 107907
VL  - 176
DO  - 10.1016/j.ijfatigue.2023.107907
ER  - 

@article{
author = "Raičević, Nikola and Grbović, Aleksandar and Kastratović, Gordana and Vidanović, Nenad and Sedmak, Aleksandar",
year = "2023",
abstract = "The torque link is part of the nose landing gear of aircraft. It prevents the piston from turning inside the cylinder of the shock absorber, enabling its up and down motion during the landing and take-off. As such, its structural integrity and life are crucial for aircraft safe operation, but because of complex geometry and variable loading conditions, its fatigue life estimation represents a real challenge. In this paper, fatigue lives of two different designs of the torque links of the light aircraft are evaluated by a numerical approach based on the improved FEM. Firstly, the fatigue life of the damaged torque link was assessed for actual load conditions. Then, improved torque links, obtained through topological optimization, were analyzed and their fatigue life was calculated. Finally, the numerical simulations of the additive manufacturing (AM) process of optimized torque links were carried out, and the fatigue life of these torque links, including residual stresses from AM, were estimated too. The obtained numbers of cycles in all cases were compared and discussed for all torque links cases. This is an advanced approach to fatigue life assessment of optimized printed 3D parts based on numerical simulations of both crack growth and AM process.",
publisher = "Elsevier",
journal = "International Journal of Fatigue",
title = "Fatigue life prediction of topologically optimized torque link adjusted for additive manufacturing",
pages = "107907",
volume = "176",
doi = "10.1016/j.ijfatigue.2023.107907"
}

Raičević, N., Grbović, A., Kastratović, G., Vidanović, N.,& Sedmak, A.. (2023). Fatigue life prediction of topologically optimized torque link adjusted for additive manufacturing. in International Journal of Fatigue
Elsevier., 176, 107907.
https://doi.org/10.1016/j.ijfatigue.2023.107907

Raičević N, Grbović A, Kastratović G, Vidanović N, Sedmak A. Fatigue life prediction of topologically optimized torque link adjusted for additive manufacturing. in International Journal of Fatigue. 2023;176:107907.
doi:10.1016/j.ijfatigue.2023.107907 .

Raičević, Nikola, Grbović, Aleksandar, Kastratović, Gordana, Vidanović, Nenad, Sedmak, Aleksandar, "Fatigue life prediction of topologically optimized torque link adjusted for additive manufacturing" in International Journal of Fatigue, 176 (2023):107907,
https://doi.org/10.1016/j.ijfatigue.2023.107907 . .

Karakoc, H., Kostić, I., Grbović, A., Svorcan, J., Dalkiran, A., Ercan, A. H.,& Peković, O.. (2023). Novel Techniques in Maintenance, Repair, and Overhaul. in Proceedings of the International Symposium on Aviation Technology, MRO, and Operations 2022
Springer, Cham...
https://doi.org/10.1007/978-3-031-42041-2

Karakoc H, Kostić I, Grbović A, Svorcan J, Dalkiran A, Ercan AH, Peković O. Novel Techniques in Maintenance, Repair, and Overhaul. in Proceedings of the International Symposium on Aviation Technology, MRO, and Operations 2022. 2023;.
doi:10.1007/978-3-031-42041-2 .

Karakoc, Hikmet, Kostić, Ivan, Grbović, Aleksandar, Svorcan, Jelena, Dalkiran, Alper, Ercan, Ali Haydar, Peković, Ognjen, "Novel Techniques in Maintenance, Repair, and Overhaul" in Proceedings of the International Symposium on Aviation Technology, MRO, and Operations 2022 (2023),
https://doi.org/10.1007/978-3-031-42041-2 . .

TY  - CONF
AU  - Balać, Martina
AU  - Grbović, Aleksandar
AU  - Sarvaš, Lajoš
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7229
AB  - Numerical analysis of protective bellows attached to aluminum frames of pivoting joints is presented in this
research. Five aluminum frames connected by protective bellows are attached to the circular rod and have
been extracted from the original geometry of passenger bridge used on ocean cruisers. It was assumed that
the circular rod was fixed since the main emphasis in the analysis was on the displacements and stresses of
aluminium frames, not rods. The main load considered in the analysis was a force of 2,500 N (simulating the
mass of 250 kg) acting perpendicularly to three middle frames. Three frames were loaded since it had been
estimated that an average person can apply pressure (with his/her body) on a maximum of three frames at
once. The mass of 250 kg was used in calculations to ensure the value of safety factor =2.5. Since no data
were available about the type of contact between the rod and ends of frames, two approaches were used in
the analysis: firstly, contact was considered to be sliding without friction, and secondly contact was considered
to be sliding with friction with the value of friction coefficient =0.2. Values of displacements and stresses
obtained using finite element analyses (FEA) for both approaches and both positions of frames (firm 0 and
max. angle45) are shown and discussed.
PB  - University of Belgrade - Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2023 PROGRAMME AND THE BOOK OF ABSTRACTS
T1  - ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT
SP  - 10
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7229
ER  - 

@conference{
author = "Balać, Martina and Grbović, Aleksandar and Sarvaš, Lajoš",
year = "2023",
abstract = "Numerical analysis of protective bellows attached to aluminum frames of pivoting joints is presented in this
research. Five aluminum frames connected by protective bellows are attached to the circular rod and have
been extracted from the original geometry of passenger bridge used on ocean cruisers. It was assumed that
the circular rod was fixed since the main emphasis in the analysis was on the displacements and stresses of
aluminium frames, not rods. The main load considered in the analysis was a force of 2,500 N (simulating the
mass of 250 kg) acting perpendicularly to three middle frames. Three frames were loaded since it had been
estimated that an average person can apply pressure (with his/her body) on a maximum of three frames at
once. The mass of 250 kg was used in calculations to ensure the value of safety factor =2.5. Since no data
were available about the type of contact between the rod and ends of frames, two approaches were used in
the analysis: firstly, contact was considered to be sliding without friction, and secondly contact was considered
to be sliding with friction with the value of friction coefficient =0.2. Values of displacements and stresses
obtained using finite element analyses (FEA) for both approaches and both positions of frames (firm 0 and
max. angle45) are shown and discussed.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2023 PROGRAMME AND THE BOOK OF ABSTRACTS",
title = "ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT",
pages = "10",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7229"
}

Balać, M., Grbović, A.,& Sarvaš, L.. (2023). ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2023 PROGRAMME AND THE BOOK OF ABSTRACTS
University of Belgrade - Faculty of Mechanical Engineering., 10.
https://hdl.handle.net/21.15107/rcub_machinery_7229

Balać M, Grbović A, Sarvaš L. ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2023 PROGRAMME AND THE BOOK OF ABSTRACTS. 2023;:10.
https://hdl.handle.net/21.15107/rcub_machinery_7229 .

Balać, Martina, Grbović, Aleksandar, Sarvaš, Lajoš, "ANALYSIS OF THE CONTRIBUTION OF PROTECTIVE BELLOWS ON THE STABILITY OF ALUMINUM FRAMES USED IN PIVOTING JOINT" in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2023 PROGRAMME AND THE BOOK OF ABSTRACTS (2023):10,
https://hdl.handle.net/21.15107/rcub_machinery_7229 .

TY  - JOUR
AU  - Šalinić, Slaviša
AU  - Obradović, Aleksandar
AU  - Tomović, Aleksandar
AU  - Trifković, Dragan
AU  - Grbović, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6802
AB  - The coupled axial-bending vibration of an axially functionally graded Timoshenko cantilever beam
of non-uniform cross-section is considered. The coupling phenomenon appears due to the presence of the transverse eccentricity of the mass centre of a rigid body attached to the beam free end. To study the coupled phenomenon, an approach based on the symbolic-numeric method of initial parameters is proposed. The influence of the transverse eccentricity on the cantilever beam natural frequencies and mode shapes is examined. The approach has the potential to be also applied to vibration problems of the systems composed of rigid bodies interconnected by non-uniform non-homogeneous beams.
PB  - Springer
T2  - Meccanica
T1  - Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6802
ER  - 

@article{
author = "Šalinić, Slaviša and Obradović, Aleksandar and Tomović, Aleksandar and Trifković, Dragan and Grbović, Aleksandar",
year = "2023",
abstract = "The coupled axial-bending vibration of an axially functionally graded Timoshenko cantilever beam
of non-uniform cross-section is considered. The coupling phenomenon appears due to the presence of the transverse eccentricity of the mass centre of a rigid body attached to the beam free end. To study the coupled phenomenon, an approach based on the symbolic-numeric method of initial parameters is proposed. The influence of the transverse eccentricity on the cantilever beam natural frequencies and mode shapes is examined. The approach has the potential to be also applied to vibration problems of the systems composed of rigid bodies interconnected by non-uniform non-homogeneous beams.",
publisher = "Springer",
journal = "Meccanica",
title = "Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6802"
}

Šalinić, S., Obradović, A., Tomović, A., Trifković, D.,& Grbović, A.. (2023). Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body. in Meccanica
Springer..
https://hdl.handle.net/21.15107/rcub_machinery_6802

Šalinić S, Obradović A, Tomović A, Trifković D, Grbović A. Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body. in Meccanica. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_6802 .

Šalinić, Slaviša, Obradović, Aleksandar, Tomović, Aleksandar, Trifković, Dragan, Grbović, Aleksandar, "Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body" in Meccanica (2023),
https://hdl.handle.net/21.15107/rcub_machinery_6802 .

TY  - JOUR
AU  - Mitić, Saša
AU  - Popović, Vladimir
AU  - Blagojević, Ivan
AU  - Grbović, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5918
AB  - Bus rollover is one of the most analyzed cases of accidents, having in mind the number of potential large number of injuries and fatalities. Therefore, this type of
traffic accident became the object of numerous national and international standards and regulations. The aim of this paper is to investigate the possibilities of experimental
verification of presented simplified model of the bus body section. For that purpose, completely new multifunctional test bench was presented. The methodology applied for
the experimental part was explained. The results provided by the numerical simulation and by the experiment were presented, and appropriate analyses were performed.
The key parameters needed for the experimental verification were specified. According to the result analysis, a comparative results review was presented, confirming that
the experimental verification of the numerical model was fully acceptable. Also, all of the requirements prescribed by the applied methodology for the achieved results
acceptance were fulfilled, providing that numerical simulation, with constant improvements, could be a powerful tool for quick and reliable bus structure analysis in design
process.
PB  - Strojarski fakultet u Slavonskom Brodu
T2  - Technical Gazzete
T1  - Verification of the numerical model of optimized bus body structure according to UN regulation no. 66
EP  - 92
IS  - 1
SP  - 87
VL  - 30
DO  - 10.17559/TV-20220304215649
ER  - 

@article{
author = "Mitić, Saša and Popović, Vladimir and Blagojević, Ivan and Grbović, Aleksandar",
year = "2023",
abstract = "Bus rollover is one of the most analyzed cases of accidents, having in mind the number of potential large number of injuries and fatalities. Therefore, this type of
traffic accident became the object of numerous national and international standards and regulations. The aim of this paper is to investigate the possibilities of experimental
verification of presented simplified model of the bus body section. For that purpose, completely new multifunctional test bench was presented. The methodology applied for
the experimental part was explained. The results provided by the numerical simulation and by the experiment were presented, and appropriate analyses were performed.
The key parameters needed for the experimental verification were specified. According to the result analysis, a comparative results review was presented, confirming that
the experimental verification of the numerical model was fully acceptable. Also, all of the requirements prescribed by the applied methodology for the achieved results
acceptance were fulfilled, providing that numerical simulation, with constant improvements, could be a powerful tool for quick and reliable bus structure analysis in design
process.",
publisher = "Strojarski fakultet u Slavonskom Brodu",
journal = "Technical Gazzete",
title = "Verification of the numerical model of optimized bus body structure according to UN regulation no. 66",
pages = "92-87",
number = "1",
volume = "30",
doi = "10.17559/TV-20220304215649"
}

Mitić, S., Popović, V., Blagojević, I.,& Grbović, A.. (2023). Verification of the numerical model of optimized bus body structure according to UN regulation no. 66. in Technical Gazzete
Strojarski fakultet u Slavonskom Brodu., 30(1), 87-92.
https://doi.org/10.17559/TV-20220304215649

Mitić S, Popović V, Blagojević I, Grbović A. Verification of the numerical model of optimized bus body structure according to UN regulation no. 66. in Technical Gazzete. 2023;30(1):87-92.
doi:10.17559/TV-20220304215649 .

Mitić, Saša, Popović, Vladimir, Blagojević, Ivan, Grbović, Aleksandar, "Verification of the numerical model of optimized bus body structure according to UN regulation no. 66" in Technical Gazzete, 30, no. 1 (2023):87-92,
https://doi.org/10.17559/TV-20220304215649 . .

TY  - CONF
AU  - Raičević, Nikola
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Sedmak, Aleksandar
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6804
AB  - This paper deals with the damage growth in High-Pressure Turbine (HPT) cooling holes of the case assembly made of Inconel 718. Several marks (cuts) were made on cooling holes into parent material during the service due to the non-skilled use of Electrical Discharge Machining (EDM) in the workshop. After a certain time, the case assembly returned to the workshop with all EDM marks cracked. Since HPT case assembly is not repairable and the only method for fixing this issue is its replacement with the new or used one (which might be pretty expensive), it was decided to use numerical analysis to estimate Paris coefficients for used Inconel 718, since the number of cycles and crack growth from the initial position were known, based on data obtained from the workshop. Firstly, finite element method (FEM) based numerical analysis was conducted in order to simulate crack propagation to match the one observed in the workshop, and then a multi-objective genetic algorithm – implemented thru response surface optimization – was used to obtain required Paris coefficients. The objectives of this optimization were the crack length and the corresponding number of cycles of crack growth. Obtained Paris coefficients were then used to estimate the residual life of HPT case assembly.
PB  - Belgrade : Društvo za Integritet i Vek Konstrukcija “Prof dr Stojan Sedmak”
C3  - 2nd International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023)
T1  - Residual life estimation of damaged structures exposed to high pressures and temperatures
SP  - 96
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6804
ER  - 

@conference{
author = "Raičević, Nikola and Grbović, Aleksandar and Kastratović, Gordana and Vidanović, Nenad and Sedmak, Aleksandar",
year = "2023",
abstract = "This paper deals with the damage growth in High-Pressure Turbine (HPT) cooling holes of the case assembly made of Inconel 718. Several marks (cuts) were made on cooling holes into parent material during the service due to the non-skilled use of Electrical Discharge Machining (EDM) in the workshop. After a certain time, the case assembly returned to the workshop with all EDM marks cracked. Since HPT case assembly is not repairable and the only method for fixing this issue is its replacement with the new or used one (which might be pretty expensive), it was decided to use numerical analysis to estimate Paris coefficients for used Inconel 718, since the number of cycles and crack growth from the initial position were known, based on data obtained from the workshop. Firstly, finite element method (FEM) based numerical analysis was conducted in order to simulate crack propagation to match the one observed in the workshop, and then a multi-objective genetic algorithm – implemented thru response surface optimization – was used to obtain required Paris coefficients. The objectives of this optimization were the crack length and the corresponding number of cycles of crack growth. Obtained Paris coefficients were then used to estimate the residual life of HPT case assembly.",
publisher = "Belgrade : Društvo za Integritet i Vek Konstrukcija “Prof dr Stojan Sedmak”",
journal = "2nd International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023)",
title = "Residual life estimation of damaged structures exposed to high pressures and temperatures",
pages = "96",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6804"
}

Raičević, N., Grbović, A., Kastratović, G., Vidanović, N.,& Sedmak, A.. (2023). Residual life estimation of damaged structures exposed to high pressures and temperatures. in 2nd International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023)
Belgrade : Društvo za Integritet i Vek Konstrukcija “Prof dr Stojan Sedmak”., 96.
https://hdl.handle.net/21.15107/rcub_machinery_6804

Raičević N, Grbović A, Kastratović G, Vidanović N, Sedmak A. Residual life estimation of damaged structures exposed to high pressures and temperatures. in 2nd International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023). 2023;:96.
https://hdl.handle.net/21.15107/rcub_machinery_6804 .

Raičević, Nikola, Grbović, Aleksandar, Kastratović, Gordana, Vidanović, Nenad, Sedmak, Aleksandar, "Residual life estimation of damaged structures exposed to high pressures and temperatures" in 2nd International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) (2023):96,
https://hdl.handle.net/21.15107/rcub_machinery_6804 .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Vučetić, Filip
AU  - Čolić, Katarina
AU  - Grbović, Aleksandar
AU  - Sedmak, Simon
AU  - Kirin, Snežana
AU  - Berto, Filippo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3710
AB  - This study is aimed to analyse fatigue life of orthopedic plates due to cracks initiated in the stress concentration areas. Material used for this analysis was typical orthopedic alloy, Ti-6Al-4V, strong but not very ductile, meaning also sensivite to cracking, as indicated by its mechanical properties, such as tensile strength, impact toughness and fracture toughness, as well as by high fatigue crack rate, all of them tested and analysed here. Extended finite element method (XFEM) in ANSYS software was used for simulating the fatigue crack growth in 5 orthopedic plates with different geometries. Results for crack length and stress intensity factor vs. number of cycles are given, indicating plate D as the best option regarding residual life. Crack paths are analysed in all 5 plates to explain such a behaviour, indicating benefits of initial crack growth into length, followed by growth into depth. Also, the effect of geometry of plates is considered to explain differences in life predictions for 5 different plates.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Fatigue life assessment of orthopedic plates made of Ti6Al4V
VL  - 137
DO  - 10.1016/j.engfailanal.2022.106259
ER  - 

@article{
author = "Sedmak, Aleksandar and Vučetić, Filip and Čolić, Katarina and Grbović, Aleksandar and Sedmak, Simon and Kirin, Snežana and Berto, Filippo",
year = "2022",
abstract = "This study is aimed to analyse fatigue life of orthopedic plates due to cracks initiated in the stress concentration areas. Material used for this analysis was typical orthopedic alloy, Ti-6Al-4V, strong but not very ductile, meaning also sensivite to cracking, as indicated by its mechanical properties, such as tensile strength, impact toughness and fracture toughness, as well as by high fatigue crack rate, all of them tested and analysed here. Extended finite element method (XFEM) in ANSYS software was used for simulating the fatigue crack growth in 5 orthopedic plates with different geometries. Results for crack length and stress intensity factor vs. number of cycles are given, indicating plate D as the best option regarding residual life. Crack paths are analysed in all 5 plates to explain such a behaviour, indicating benefits of initial crack growth into length, followed by growth into depth. Also, the effect of geometry of plates is considered to explain differences in life predictions for 5 different plates.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Fatigue life assessment of orthopedic plates made of Ti6Al4V",
volume = "137",
doi = "10.1016/j.engfailanal.2022.106259"
}

Sedmak, A., Vučetić, F., Čolić, K., Grbović, A., Sedmak, S., Kirin, S.,& Berto, F.. (2022). Fatigue life assessment of orthopedic plates made of Ti6Al4V. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 137.
https://doi.org/10.1016/j.engfailanal.2022.106259

Sedmak A, Vučetić F, Čolić K, Grbović A, Sedmak S, Kirin S, Berto F. Fatigue life assessment of orthopedic plates made of Ti6Al4V. in Engineering Failure Analysis. 2022;137.
doi:10.1016/j.engfailanal.2022.106259 .

Sedmak, Aleksandar, Vučetić, Filip, Čolić, Katarina, Grbović, Aleksandar, Sedmak, Simon, Kirin, Snežana, Berto, Filippo, "Fatigue life assessment of orthopedic plates made of Ti6Al4V" in Engineering Failure Analysis, 137 (2022),
https://doi.org/10.1016/j.engfailanal.2022.106259 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Bozić, Željko
AU  - Božić, Ivan
AU  - Obradović, Aleksandar
AU  - Sedmak, Aleksandar
AU  - Sedmak, Simon
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3709
AB  - The aircraft industry is a leading industry in terms of the implementation of new materials and technologies. In the development of a light aircraft several different materials were considered for the engine cover design and the final decision was to select a composite material. Part of the research performed on the cover design is presented in this paper. The composite test specimens were produced and mechanical properties were investigated in the tensile and three-point flexural tests according to the required standards. The comparison of experimentally and numerically obtained mechanical properties showed good agreement, which led to the design, verification and manufacturing of the complex-shaped engine cover without costly and demanding tests. It was considered that numerical simulations of the engine cover performance under different loading conditions yielded realistic results, therefore experimental verification was excluded. The flight tests proved the predicted behavior, thus verifying the design methodology presented in this paper.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Experimental and numerical evaluation of fracture characteristics of composite material used in the aircraft engine cover manufacturing
VL  - 137
DO  - 10.1016/j.engfailanal.2022.106286
ER  - 

@article{
author = "Grbović, Aleksandar and Kastratović, Gordana and Bozić, Željko and Božić, Ivan and Obradović, Aleksandar and Sedmak, Aleksandar and Sedmak, Simon",
year = "2022",
abstract = "The aircraft industry is a leading industry in terms of the implementation of new materials and technologies. In the development of a light aircraft several different materials were considered for the engine cover design and the final decision was to select a composite material. Part of the research performed on the cover design is presented in this paper. The composite test specimens were produced and mechanical properties were investigated in the tensile and three-point flexural tests according to the required standards. The comparison of experimentally and numerically obtained mechanical properties showed good agreement, which led to the design, verification and manufacturing of the complex-shaped engine cover without costly and demanding tests. It was considered that numerical simulations of the engine cover performance under different loading conditions yielded realistic results, therefore experimental verification was excluded. The flight tests proved the predicted behavior, thus verifying the design methodology presented in this paper.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Experimental and numerical evaluation of fracture characteristics of composite material used in the aircraft engine cover manufacturing",
volume = "137",
doi = "10.1016/j.engfailanal.2022.106286"
}

Grbović, A., Kastratović, G., Bozić, Ž., Božić, I., Obradović, A., Sedmak, A.,& Sedmak, S.. (2022). Experimental and numerical evaluation of fracture characteristics of composite material used in the aircraft engine cover manufacturing. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 137.
https://doi.org/10.1016/j.engfailanal.2022.106286

Grbović A, Kastratović G, Bozić Ž, Božić I, Obradović A, Sedmak A, Sedmak S. Experimental and numerical evaluation of fracture characteristics of composite material used in the aircraft engine cover manufacturing. in Engineering Failure Analysis. 2022;137.
doi:10.1016/j.engfailanal.2022.106286 .

Grbović, Aleksandar, Kastratović, Gordana, Bozić, Željko, Božić, Ivan, Obradović, Aleksandar, Sedmak, Aleksandar, Sedmak, Simon, "Experimental and numerical evaluation of fracture characteristics of composite material used in the aircraft engine cover manufacturing" in Engineering Failure Analysis, 137 (2022),
https://doi.org/10.1016/j.engfailanal.2022.106286 . .

TY  - CONF
AU  - Milovanović, Nikola
AU  - Đorđević, Branislav
AU  - Sedmak, Simon
AU  - Grbović, Aleksandar
AU  - Martić, Igor
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6275
AB  - One of the major problems in numerical simulation of fatigue loading represents the generation of a finite element mesh, since the model with crack cannot use combinations of different types of mesh elements (such as HEX or TET). This paper presents the problem of the generated FE mesh during fatigue simulation of the Kaplan Turbine Shaft model in ABAQUS and Morfeo Crack software packages. The model contains an initial crack of 37 mm. Simulation was performed in order of assessing the integrity of shaft with crack. During the first attempt, a fined mesh in the vicinity of the crack was used, which did not prove to be effective in obtaining satisfactory results. FE whose size was similar or the same as the FE around the fatigue crack growth domain were used in the second attempt. After remeshing, the numerical simulation proved to be successful and gave more realistic results.
C3  - Procedia Structural Integrity 23 European Conference on Fracture
T1  - Some problems of xFEM modelling of surface crack growth in a turbine shaft
EP  - 367
SP  - 362
VL  - 42
DO  - 10.1016/j.prostr.2022.12.045
ER  - 

@conference{
author = "Milovanović, Nikola and Đorđević, Branislav and Sedmak, Simon and Grbović, Aleksandar and Martić, Igor",
year = "2022",
abstract = "One of the major problems in numerical simulation of fatigue loading represents the generation of a finite element mesh, since the model with crack cannot use combinations of different types of mesh elements (such as HEX or TET). This paper presents the problem of the generated FE mesh during fatigue simulation of the Kaplan Turbine Shaft model in ABAQUS and Morfeo Crack software packages. The model contains an initial crack of 37 mm. Simulation was performed in order of assessing the integrity of shaft with crack. During the first attempt, a fined mesh in the vicinity of the crack was used, which did not prove to be effective in obtaining satisfactory results. FE whose size was similar or the same as the FE around the fatigue crack growth domain were used in the second attempt. After remeshing, the numerical simulation proved to be successful and gave more realistic results.",
journal = "Procedia Structural Integrity 23 European Conference on Fracture",
title = "Some problems of xFEM modelling of surface crack growth in a turbine shaft",
pages = "367-362",
volume = "42",
doi = "10.1016/j.prostr.2022.12.045"
}

Milovanović, N., Đorđević, B., Sedmak, S., Grbović, A.,& Martić, I.. (2022). Some problems of xFEM modelling of surface crack growth in a turbine shaft. in Procedia Structural Integrity 23 European Conference on Fracture, 42, 362-367.
https://doi.org/10.1016/j.prostr.2022.12.045

Milovanović N, Đorđević B, Sedmak S, Grbović A, Martić I. Some problems of xFEM modelling of surface crack growth in a turbine shaft. in Procedia Structural Integrity 23 European Conference on Fracture. 2022;42:362-367.
doi:10.1016/j.prostr.2022.12.045 .

Milovanović, Nikola, Đorđević, Branislav, Sedmak, Simon, Grbović, Aleksandar, Martić, Igor, "Some problems of xFEM modelling of surface crack growth in a turbine shaft" in Procedia Structural Integrity 23 European Conference on Fracture, 42 (2022):362-367,
https://doi.org/10.1016/j.prostr.2022.12.045 . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Vučetić, Filip
AU  - Čolić, Katarina
AU  - Grbović, Aleksandar
AU  - Bozić, Željko
AU  - Sedmak, Simon
AU  - Lozanović Šajić, Jasmina
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3716
AB  - Fatigue crack growth in orthopaedic locking compression plates (LCP), under four-point bending, has been simulated by the extended finite element method (xFEM) to assess LCP optimal geometry in respect to remaining life. Loads corresponded to those occurring in human tibia during gait cycle for different body weights (60, 90 and 120 kg). Experimental investigation consisted of tensile testing and fatigue crack growth rate testing of Ti6Al-4 V alloy, as used for LCP, by standard testing using tensile testing machine and Fractomat, respectively. Results showed that the remaining life of LCPs strongly depend on plate geometry and patient body weight (load).
PB  - Elsevier Sci Ltd, Oxford
T2  - International Journal of Fatigue
T1  - Fatigue crack growth in locking compression plates
VL  - 157
DO  - 10.1016/j.ijfatigue.2022.106727
ER  - 

@article{
author = "Sedmak, Aleksandar and Vučetić, Filip and Čolić, Katarina and Grbović, Aleksandar and Bozić, Željko and Sedmak, Simon and Lozanović Šajić, Jasmina",
year = "2022",
abstract = "Fatigue crack growth in orthopaedic locking compression plates (LCP), under four-point bending, has been simulated by the extended finite element method (xFEM) to assess LCP optimal geometry in respect to remaining life. Loads corresponded to those occurring in human tibia during gait cycle for different body weights (60, 90 and 120 kg). Experimental investigation consisted of tensile testing and fatigue crack growth rate testing of Ti6Al-4 V alloy, as used for LCP, by standard testing using tensile testing machine and Fractomat, respectively. Results showed that the remaining life of LCPs strongly depend on plate geometry and patient body weight (load).",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "International Journal of Fatigue",
title = "Fatigue crack growth in locking compression plates",
volume = "157",
doi = "10.1016/j.ijfatigue.2022.106727"
}

Sedmak, A., Vučetić, F., Čolić, K., Grbović, A., Bozić, Ž., Sedmak, S.,& Lozanović Šajić, J.. (2022). Fatigue crack growth in locking compression plates. in International Journal of Fatigue
Elsevier Sci Ltd, Oxford., 157.
https://doi.org/10.1016/j.ijfatigue.2022.106727

Sedmak A, Vučetić F, Čolić K, Grbović A, Bozić Ž, Sedmak S, Lozanović Šajić J. Fatigue crack growth in locking compression plates. in International Journal of Fatigue. 2022;157.
doi:10.1016/j.ijfatigue.2022.106727 .

Sedmak, Aleksandar, Vučetić, Filip, Čolić, Katarina, Grbović, Aleksandar, Bozić, Željko, Sedmak, Simon, Lozanović Šajić, Jasmina, "Fatigue crack growth in locking compression plates" in International Journal of Fatigue, 157 (2022),
https://doi.org/10.1016/j.ijfatigue.2022.106727 . .

TY  - JOUR
AU  - Sedmak, Aleksandar
AU  - Grbović, Aleksandar
AU  - Petrovski, Blagoj
AU  - Sghayer, Abulgasem
AU  - Sedmak, Simon
AU  - Berto, Filippo
AU  - Đurđević, A.
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3813
AB  - Fatigue crack growth in different panels, made of AA6156 T6, was investigated experimentally and numerically. Three different types of panels were used, simple one, so-called base metal (BM), panel with 4 welded stringers and panel with 4 welded stringers and 3 welded clips. Experimental investigation indicated benefits of stringers, especially in respect to residual life, since the number of cycles were more than doubled (420 Kcyc vs 195 Kcyc for initial crack length 14 mm), but that was not the case for panels with clips (220 Kcyc). Experimental investigation was also performed on panels with longer cracks (75 mm) to check the effect of initial crack length in the case of BM and panels with 4 stringers, showing practically the same effect of stringers on residual life (95 Kcyc vs 50 Kcyc). Then, fatigue crack growth in panels was simulated numerically using xFEM. Numerical simulation indicated the same trend and effectiveness of stringers, with sufficient agreement with experimental results for BM and panels with stringers only. Anyhow in the case of clips panels with 4 stringers and 3 clips, number of cycles for panel with additional 3-clips was higher than for panel with just 4-stringer, (278 Kcyc vs 265 Kcyc), improving fatigue life for cca 5 %, contrary to experimental results.
PB  - Elsevier Ltd
T2  - International Journal of Fatigue
T1  - The effects of welded clips on fatigue crack growth in AA6156 T6 panels
VL  - 165
DO  - 10.1016/j.ijfatigue.2022.107162
ER  - 

@article{
author = "Sedmak, Aleksandar and Grbović, Aleksandar and Petrovski, Blagoj and Sghayer, Abulgasem and Sedmak, Simon and Berto, Filippo and Đurđević, A.",
year = "2022",
abstract = "Fatigue crack growth in different panels, made of AA6156 T6, was investigated experimentally and numerically. Three different types of panels were used, simple one, so-called base metal (BM), panel with 4 welded stringers and panel with 4 welded stringers and 3 welded clips. Experimental investigation indicated benefits of stringers, especially in respect to residual life, since the number of cycles were more than doubled (420 Kcyc vs 195 Kcyc for initial crack length 14 mm), but that was not the case for panels with clips (220 Kcyc). Experimental investigation was also performed on panels with longer cracks (75 mm) to check the effect of initial crack length in the case of BM and panels with 4 stringers, showing practically the same effect of stringers on residual life (95 Kcyc vs 50 Kcyc). Then, fatigue crack growth in panels was simulated numerically using xFEM. Numerical simulation indicated the same trend and effectiveness of stringers, with sufficient agreement with experimental results for BM and panels with stringers only. Anyhow in the case of clips panels with 4 stringers and 3 clips, number of cycles for panel with additional 3-clips was higher than for panel with just 4-stringer, (278 Kcyc vs 265 Kcyc), improving fatigue life for cca 5 %, contrary to experimental results.",
publisher = "Elsevier Ltd",
journal = "International Journal of Fatigue",
title = "The effects of welded clips on fatigue crack growth in AA6156 T6 panels",
volume = "165",
doi = "10.1016/j.ijfatigue.2022.107162"
}

Sedmak, A., Grbović, A., Petrovski, B., Sghayer, A., Sedmak, S., Berto, F.,& Đurđević, A.. (2022). The effects of welded clips on fatigue crack growth in AA6156 T6 panels. in International Journal of Fatigue
Elsevier Ltd., 165.
https://doi.org/10.1016/j.ijfatigue.2022.107162

Sedmak A, Grbović A, Petrovski B, Sghayer A, Sedmak S, Berto F, Đurđević A. The effects of welded clips on fatigue crack growth in AA6156 T6 panels. in International Journal of Fatigue. 2022;165.
doi:10.1016/j.ijfatigue.2022.107162 .

Sedmak, Aleksandar, Grbović, Aleksandar, Petrovski, Blagoj, Sghayer, Abulgasem, Sedmak, Simon, Berto, Filippo, Đurđević, A., "The effects of welded clips on fatigue crack growth in AA6156 T6 panels" in International Journal of Fatigue, 165 (2022),
https://doi.org/10.1016/j.ijfatigue.2022.107162 . .

TY  - JOUR
AU  - Raičević, Nikola
AU  - Petrašinović, Danilo
AU  - Grbović, Aleksandar
AU  - Petrašinović, Miloš
AU  - Balać, Martina
AU  - Petrović, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6045
AB  - Wind turbines are structures that transform wind energy into other types of energy. In the modern age, wind turbines are closely related to the production of electricity and are considered starters of the green industry. Designing this type of construction is a complex and demanding process. Wind turbine
blades are the most important part of the construction and are usually made of
composite materials that meet the requirements of strength as well as aerodynamic requirements. Due to the high cost of composite materials, numerical modeling programs are very important because they allow the structure to be inspected before production, as well as to identify possible errors and weaknesses. In this way, additional manufacturing costs are avoided and a fully optimized structure is obtained. The finite element method (FEM) is a reliable method that allows the structure to be tested for the occurrence of normal and shear stresses that can lead to unwanted values of deformations on the blade. In this paper, the procedure of static analysis of a wind turbine blade is presented and the results that are important for optimizing the blade structure are analyzed. The purpose of FEM analysis is to find critical sections of the blade and to predict where maximum values of stresses may occur. In this way, it can be concluded whether the chosen material is appropriate and how the structure can be further optimized.
PB  - Springer Cham
T2  - Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022.
T1  - The wind speed impact on stress and deformation of composite wind turbine blade
EP  - 120
SP  - 114
DO  - 10.1007/978-3-031-19499-3_6
ER  - 

@article{
author = "Raičević, Nikola and Petrašinović, Danilo and Grbović, Aleksandar and Petrašinović, Miloš and Balać, Martina and Petrović, Mihailo",
year = "2022",
abstract = "Wind turbines are structures that transform wind energy into other types of energy. In the modern age, wind turbines are closely related to the production of electricity and are considered starters of the green industry. Designing this type of construction is a complex and demanding process. Wind turbine
blades are the most important part of the construction and are usually made of
composite materials that meet the requirements of strength as well as aerodynamic requirements. Due to the high cost of composite materials, numerical modeling programs are very important because they allow the structure to be inspected before production, as well as to identify possible errors and weaknesses. In this way, additional manufacturing costs are avoided and a fully optimized structure is obtained. The finite element method (FEM) is a reliable method that allows the structure to be tested for the occurrence of normal and shear stresses that can lead to unwanted values of deformations on the blade. In this paper, the procedure of static analysis of a wind turbine blade is presented and the results that are important for optimizing the blade structure are analyzed. The purpose of FEM analysis is to find critical sections of the blade and to predict where maximum values of stresses may occur. In this way, it can be concluded whether the chosen material is appropriate and how the structure can be further optimized.",
publisher = "Springer Cham",
journal = "Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022.",
title = "The wind speed impact on stress and deformation of composite wind turbine blade",
pages = "120-114",
doi = "10.1007/978-3-031-19499-3_6"
}

Raičević, N., Petrašinović, D., Grbović, A., Petrašinović, M., Balać, M.,& Petrović, M.. (2022). The wind speed impact on stress and deformation of composite wind turbine blade. in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022.
Springer Cham., 114-120.
https://doi.org/10.1007/978-3-031-19499-3_6

Raičević N, Petrašinović D, Grbović A, Petrašinović M, Balać M, Petrović M. The wind speed impact on stress and deformation of composite wind turbine blade. in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022.. 2022;:114-120.
doi:10.1007/978-3-031-19499-3_6 .

Raičević, Nikola, Petrašinović, Danilo, Grbović, Aleksandar, Petrašinović, Miloš, Balać, Martina, Petrović, Mihailo, "The wind speed impact on stress and deformation of composite wind turbine blade" in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. (2022):114-120,
https://doi.org/10.1007/978-3-031-19499-3_6 . .

TY  - CHAP
AU  - Raičević, Nikola
AU  - Petrašinović, Danilo
AU  - Grbović, Aleksandar
AU  - Petrašinović, Miloš
AU  - Balać, Martina
AU  - Petrović, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5554
AB  - Wind turbines are structures that transform wind energy into other types of energy. In the modern age, wind turbines are closely related to the production of electricity and are considered starters of the green industry. Designing this type of construction is a complex and demanding process. Wind turbine blades are the most important part of the construction and are usually made of composite materials that meet the requirements of strength as well as aerodynamic requirements. Due to the high cost of composite materials, numerical modeling programs are very important because they allow the structure to be inspected before production, as well as to identify possible errors and weaknesses. In this way, additional manufacturing costs are avoided and a fully optimized structure is obtained. The finite element method (FEM) is a reliable method that allows the structure to be tested for the occurrence of normal and shear stresses that can lead to unwanted values of deformations on the blade. In this paper, the procedure of static analysis of a wind turbine blade is presented and the results that are important for optimizing the blade structure are analyzed. The purpose of FEM analysis is to find critical sections of the blade and to predict where maximum values of stresses may occur. In this way, it can be concluded whether the chosen material is appropriate and how the structure can be further optimized.
PB  - Springer Nature Switzerland AG
T2  - Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. Lecture Notes in Networks and Systems
T1  - The Wind Speed Impact on Stress and Deformation of Composite Wind Turbine Blade
EP  - 130
SP  - 114
VL  - 564
DO  - 10.1007/978-3-031-19499-3_6
ER  - 

@inbook{
author = "Raičević, Nikola and Petrašinović, Danilo and Grbović, Aleksandar and Petrašinović, Miloš and Balać, Martina and Petrović, Mihailo",
year = "2022",
abstract = "Wind turbines are structures that transform wind energy into other types of energy. In the modern age, wind turbines are closely related to the production of electricity and are considered starters of the green industry. Designing this type of construction is a complex and demanding process. Wind turbine blades are the most important part of the construction and are usually made of composite materials that meet the requirements of strength as well as aerodynamic requirements. Due to the high cost of composite materials, numerical modeling programs are very important because they allow the structure to be inspected before production, as well as to identify possible errors and weaknesses. In this way, additional manufacturing costs are avoided and a fully optimized structure is obtained. The finite element method (FEM) is a reliable method that allows the structure to be tested for the occurrence of normal and shear stresses that can lead to unwanted values of deformations on the blade. In this paper, the procedure of static analysis of a wind turbine blade is presented and the results that are important for optimizing the blade structure are analyzed. The purpose of FEM analysis is to find critical sections of the blade and to predict where maximum values of stresses may occur. In this way, it can be concluded whether the chosen material is appropriate and how the structure can be further optimized.",
publisher = "Springer Nature Switzerland AG",
journal = "Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. Lecture Notes in Networks and Systems",
booktitle = "The Wind Speed Impact on Stress and Deformation of Composite Wind Turbine Blade",
pages = "130-114",
volume = "564",
doi = "10.1007/978-3-031-19499-3_6"
}

Raičević, N., Petrašinović, D., Grbović, A., Petrašinović, M., Balać, M.,& Petrović, M.. (2022). The Wind Speed Impact on Stress and Deformation of Composite Wind Turbine Blade. in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. Lecture Notes in Networks and Systems
Springer Nature Switzerland AG., 564, 114-130.
https://doi.org/10.1007/978-3-031-19499-3_6

Raičević N, Petrašinović D, Grbović A, Petrašinović M, Balać M, Petrović M. The Wind Speed Impact on Stress and Deformation of Composite Wind Turbine Blade. in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. Lecture Notes in Networks and Systems. 2022;564:114-130.
doi:10.1007/978-3-031-19499-3_6 .

Raičević, Nikola, Petrašinović, Danilo, Grbović, Aleksandar, Petrašinović, Miloš, Balać, Martina, Petrović, Mihailo, "The Wind Speed Impact on Stress and Deformation of Composite Wind Turbine Blade" in Experimental Research and Numerical Simulation in Applied Sciences. CNNTech 2022. Lecture Notes in Networks and Systems, 564 (2022):114-130,
https://doi.org/10.1007/978-3-031-19499-3_6 . .

TY  - CONF
AU  - Balać, Martina
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Petrović, A.
AU  - Sarvas, L.
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3797
AB  - Bridge constructions are developing rapidly as they are necessity in the transport network. The Passenger Boarding Bridge (PBB) provides passengers with means to embark and disembark a ship through weather protected tunnels. It is obvious that the endurance and safety of such structures are of paramount importance. It has been shown that forces and moments at three-tunnel boarding bridge supports were high in the critical cases, as well as stresses in pins and lugs. The aim of this research is to analyze crack propagation in the damaged supporting part of the PBB. After determination of critical components to demonstrate how dangerous the appearance of the crack could be and to evaluate the fatigue life of the damaged supporting part, numerical simulations based on the improved finite element method (FEM) were carried out. To do this, the determination of actual loads was conducted with special consideration. The predicted number of cycles to complete failure was low, indicating the fact that special attention has to be paid on the design of PBB’s critical supporting components.
PB  - Springer Science and Business Media Deutschland GmbH
C3  - Lecture Notes in Networks and Systems
T1  - Fatigue Life Evaluation of the Damaged Passenger Boarding Bridge Supports
EP  - 318
SP  - 299
VL  - 323
DO  - 10.1007/978-3-030-86009-7_16
ER  - 

@conference{
author = "Balać, Martina and Grbović, Aleksandar and Kastratović, Gordana and Petrović, A. and Sarvas, L.",
year = "2022",
abstract = "Bridge constructions are developing rapidly as they are necessity in the transport network. The Passenger Boarding Bridge (PBB) provides passengers with means to embark and disembark a ship through weather protected tunnels. It is obvious that the endurance and safety of such structures are of paramount importance. It has been shown that forces and moments at three-tunnel boarding bridge supports were high in the critical cases, as well as stresses in pins and lugs. The aim of this research is to analyze crack propagation in the damaged supporting part of the PBB. After determination of critical components to demonstrate how dangerous the appearance of the crack could be and to evaluate the fatigue life of the damaged supporting part, numerical simulations based on the improved finite element method (FEM) were carried out. To do this, the determination of actual loads was conducted with special consideration. The predicted number of cycles to complete failure was low, indicating the fact that special attention has to be paid on the design of PBB’s critical supporting components.",
publisher = "Springer Science and Business Media Deutschland GmbH",
journal = "Lecture Notes in Networks and Systems",
title = "Fatigue Life Evaluation of the Damaged Passenger Boarding Bridge Supports",
pages = "318-299",
volume = "323",
doi = "10.1007/978-3-030-86009-7_16"
}

Balać, M., Grbović, A., Kastratović, G., Petrović, A.,& Sarvas, L.. (2022). Fatigue Life Evaluation of the Damaged Passenger Boarding Bridge Supports. in Lecture Notes in Networks and Systems
Springer Science and Business Media Deutschland GmbH., 323, 299-318.
https://doi.org/10.1007/978-3-030-86009-7_16

Balać M, Grbović A, Kastratović G, Petrović A, Sarvas L. Fatigue Life Evaluation of the Damaged Passenger Boarding Bridge Supports. in Lecture Notes in Networks and Systems. 2022;323:299-318.
doi:10.1007/978-3-030-86009-7_16 .

Balać, Martina, Grbović, Aleksandar, Kastratović, Gordana, Petrović, A., Sarvas, L., "Fatigue Life Evaluation of the Damaged Passenger Boarding Bridge Supports" in Lecture Notes in Networks and Systems, 323 (2022):299-318,
https://doi.org/10.1007/978-3-030-86009-7_16 . .

TY  - CONF
AU  - Raičević, Nikola
AU  - Petrašinović, Danilo
AU  - Grbović, Aleksandar
AU  - Petrašinović, Miloš
AU  - Petrović, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5629
AB  - Macro programs used in computer modeling programs have become extremely important due to the high complexity of the models as well as the opportunity to create or adapt a specific geometry as soon as possible. Due to the implementation of the Python programming language, the FreeCAD program is highly suitable for creating advanced macros. When modeling aircraft parts (wings and tail surfaces), wind turbine blades, and similar structures, the biggest problem, due to the shape of the outer contour, is drawing the cross-section of the structures. The ImportAirfoil program allows to quickly and easily import and draw the contour of the desired airfoil, as well as modify it. This paper shows the complete procedure for importing and drawing of NACA2410 airfoil.
PB  - University of Belgrade - Faculty of Mechanical Engineering
C3  - 8th International Conference on Industrial Engineering - SIE 2022, Proceedings
T1  - FreeCAD ImportAirfoil Macro - Drawing Airfoil Geometry in an Open-Source CAD Program
EP  - 108
SP  - 105
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5629
ER  - 

@conference{
author = "Raičević, Nikola and Petrašinović, Danilo and Grbović, Aleksandar and Petrašinović, Miloš and Petrović, Mihailo",
year = "2022",
abstract = "Macro programs used in computer modeling programs have become extremely important due to the high complexity of the models as well as the opportunity to create or adapt a specific geometry as soon as possible. Due to the implementation of the Python programming language, the FreeCAD program is highly suitable for creating advanced macros. When modeling aircraft parts (wings and tail surfaces), wind turbine blades, and similar structures, the biggest problem, due to the shape of the outer contour, is drawing the cross-section of the structures. The ImportAirfoil program allows to quickly and easily import and draw the contour of the desired airfoil, as well as modify it. This paper shows the complete procedure for importing and drawing of NACA2410 airfoil.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering",
journal = "8th International Conference on Industrial Engineering - SIE 2022, Proceedings",
title = "FreeCAD ImportAirfoil Macro - Drawing Airfoil Geometry in an Open-Source CAD Program",
pages = "108-105",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5629"
}

Raičević, N., Petrašinović, D., Grbović, A., Petrašinović, M.,& Petrović, M.. (2022). FreeCAD ImportAirfoil Macro - Drawing Airfoil Geometry in an Open-Source CAD Program. in 8th International Conference on Industrial Engineering - SIE 2022, Proceedings
University of Belgrade - Faculty of Mechanical Engineering., 105-108.
https://hdl.handle.net/21.15107/rcub_machinery_5629

Raičević N, Petrašinović D, Grbović A, Petrašinović M, Petrović M. FreeCAD ImportAirfoil Macro - Drawing Airfoil Geometry in an Open-Source CAD Program. in 8th International Conference on Industrial Engineering - SIE 2022, Proceedings. 2022;:105-108.
https://hdl.handle.net/21.15107/rcub_machinery_5629 .

Raičević, Nikola, Petrašinović, Danilo, Grbović, Aleksandar, Petrašinović, Miloš, Petrović, Mihailo, "FreeCAD ImportAirfoil Macro - Drawing Airfoil Geometry in an Open-Source CAD Program" in 8th International Conference on Industrial Engineering - SIE 2022, Proceedings (2022):105-108,
https://hdl.handle.net/21.15107/rcub_machinery_5629 .

TY  - CONF
AU  - Raičević, Nikola
AU  - Petrašinović, Danilo
AU  - Grbović, Aleksandar
AU  - Petrašinović, Miloš
AU  - Petrović, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5739
AB  - Wind energy is one of the most promising sources of renewable energy. The wind energy is converted into mechanical power through blades which are a major part of wind turbines. Nowadays, composite materials have been used for the fabrication of wind turbine blades to reduce blade weight. Fluid flows over the blade's structure surface and creates pressure loads resulting in the deformation of the blade. Numerical modeling methods are applied to estimate flow-induced deformation and they are required for the optimization of composite wind turbine blades. The wind turbine blade is analysed by computational fluid dynamics (CFD), finite element analysis (FEA), and the one-way and two-way system coupling of fluid-structure interaction (FSI) simulations of the composite wind turbine blade. The CFD was used to find the initial pressure load of the structure. Five types of the composite material were analysed to compare the results and define the optimum composite material based on the values of stress and deformation. The finite element analysis was used to test the tensile stiffness of the chosen composite laminate and to study the effect of micro-scale structural porosity on strength of structural materials. FSI simulations were performed for several wind speeds and then the results were analysed through the comparison of normal and shear stresses, blade deformations, force and moment reactions. The results are presented in the terms of the normal and shear stress distribution, and blade deformation with defined positions of the maximum values on the blade structure.
PB  - Innovation Center of Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
T1  - Fluid-Structural Analysis and Optimization of Composite Wind Turbine Blade
EP  - 84
SP  - 84
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5739
ER  - 

@conference{
author = "Raičević, Nikola and Petrašinović, Danilo and Grbović, Aleksandar and Petrašinović, Miloš and Petrović, Mihailo",
year = "2022",
abstract = "Wind energy is one of the most promising sources of renewable energy. The wind energy is converted into mechanical power through blades which are a major part of wind turbines. Nowadays, composite materials have been used for the fabrication of wind turbine blades to reduce blade weight. Fluid flows over the blade's structure surface and creates pressure loads resulting in the deformation of the blade. Numerical modeling methods are applied to estimate flow-induced deformation and they are required for the optimization of composite wind turbine blades. The wind turbine blade is analysed by computational fluid dynamics (CFD), finite element analysis (FEA), and the one-way and two-way system coupling of fluid-structure interaction (FSI) simulations of the composite wind turbine blade. The CFD was used to find the initial pressure load of the structure. Five types of the composite material were analysed to compare the results and define the optimum composite material based on the values of stress and deformation. The finite element analysis was used to test the tensile stiffness of the chosen composite laminate and to study the effect of micro-scale structural porosity on strength of structural materials. FSI simulations were performed for several wind speeds and then the results were analysed through the comparison of normal and shear stresses, blade deformations, force and moment reactions. The results are presented in the terms of the normal and shear stress distribution, and blade deformation with defined positions of the maximum values on the blade structure.",
publisher = "Innovation Center of Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022",
title = "Fluid-Structural Analysis and Optimization of Composite Wind Turbine Blade",
pages = "84-84",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5739"
}

Raičević, N., Petrašinović, D., Grbović, A., Petrašinović, M.,& Petrović, M.. (2022). Fluid-Structural Analysis and Optimization of Composite Wind Turbine Blade. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
Innovation Center of Faculty of Mechanical Engineering., 84-84.
https://hdl.handle.net/21.15107/rcub_machinery_5739

Raičević N, Petrašinović D, Grbović A, Petrašinović M, Petrović M. Fluid-Structural Analysis and Optimization of Composite Wind Turbine Blade. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022. 2022;:84-84.
https://hdl.handle.net/21.15107/rcub_machinery_5739 .

Raičević, Nikola, Petrašinović, Danilo, Grbović, Aleksandar, Petrašinović, Miloš, Petrović, Mihailo, "Fluid-Structural Analysis and Optimization of Composite Wind Turbine Blade" in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022 (2022):84-84,
https://hdl.handle.net/21.15107/rcub_machinery_5739 .

TY  - CONF
AU  - Petrašinović, Miloš
AU  - Petrašinović, Danilo
AU  - Grbović, Aleksandar
AU  - Petrović, Veljko M.
AU  - Petrović, Mihailo
AU  - Raičević, Nikola
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5738
AB  - The constant advance in the usage of unmanned aerial vehicles (UAVs) of all types, including electric multicopters (rotary-wing drones), requests further advancement on all project levels in order to create a competitive final product. With the usage of composite materials, mainly carbon fiber in epoxy resin, it is possible to have a very lightweight structure that is strong enough to sustain all anticipated loads. Arms are a crucial part of multicopter structures that are often made entirely of composite materials. Each multicopter arm has at least one electric motor and propeller on one and a connection with the body on the other end. A static load test stand for various sizes of arms is designed and developed in order to test prototypes within the design process and to be able to test the mechanical characteristics of each produced final part that will be later assembled with other parts. The test stand consists of a robust steel frame, part mounting clamps, a movable low-speed hydraulic cylinder with an appropriate hydraulic power pack powered by an electric motor which is controlled by a variable frequency drive, a load cell for force measurement, and a linear displacement transducer for displacement. A custom digital electronic circuit with a microcontroller is developed in order to control the actuator and obtain data from sensors. Also, custom user-friendly software with a graphical user interface is designed to control experiments and process measurements.
PB  - Innovation Center of Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
T1  - Design and Development of Static Load Test Stand for Various Sizes of Multicopter Arms
EP  - 44
SP  - 44
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5738
ER  - 

@conference{
author = "Petrašinović, Miloš and Petrašinović, Danilo and Grbović, Aleksandar and Petrović, Veljko M. and Petrović, Mihailo and Raičević, Nikola",
year = "2022",
abstract = "The constant advance in the usage of unmanned aerial vehicles (UAVs) of all types, including electric multicopters (rotary-wing drones), requests further advancement on all project levels in order to create a competitive final product. With the usage of composite materials, mainly carbon fiber in epoxy resin, it is possible to have a very lightweight structure that is strong enough to sustain all anticipated loads. Arms are a crucial part of multicopter structures that are often made entirely of composite materials. Each multicopter arm has at least one electric motor and propeller on one and a connection with the body on the other end. A static load test stand for various sizes of arms is designed and developed in order to test prototypes within the design process and to be able to test the mechanical characteristics of each produced final part that will be later assembled with other parts. The test stand consists of a robust steel frame, part mounting clamps, a movable low-speed hydraulic cylinder with an appropriate hydraulic power pack powered by an electric motor which is controlled by a variable frequency drive, a load cell for force measurement, and a linear displacement transducer for displacement. A custom digital electronic circuit with a microcontroller is developed in order to control the actuator and obtain data from sensors. Also, custom user-friendly software with a graphical user interface is designed to control experiments and process measurements.",
publisher = "Innovation Center of Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022",
title = "Design and Development of Static Load Test Stand for Various Sizes of Multicopter Arms",
pages = "44-44",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5738"
}

Petrašinović, M., Petrašinović, D., Grbović, A., Petrović, V. M., Petrović, M.,& Raičević, N.. (2022). Design and Development of Static Load Test Stand for Various Sizes of Multicopter Arms. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
Innovation Center of Faculty of Mechanical Engineering., 44-44.
https://hdl.handle.net/21.15107/rcub_machinery_5738

Petrašinović M, Petrašinović D, Grbović A, Petrović VM, Petrović M, Raičević N. Design and Development of Static Load Test Stand for Various Sizes of Multicopter Arms. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022. 2022;:44-44.
https://hdl.handle.net/21.15107/rcub_machinery_5738 .

Petrašinović, Miloš, Petrašinović, Danilo, Grbović, Aleksandar, Petrović, Veljko M., Petrović, Mihailo, Raičević, Nikola, "Design and Development of Static Load Test Stand for Various Sizes of Multicopter Arms" in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022 (2022):44-44,
https://hdl.handle.net/21.15107/rcub_machinery_5738 .

TY  - CONF
AU  - Raičević, Nikola
AU  - Petrašinović, Miloš
AU  - Petrašinović, Danilo
AU  - Kastratović, Gordana
AU  - Grbović, Aleksandar
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5637
AB  - To become a reliable and widely accepted production process, additive manufacturing (AM) must provide metal structures with the same or better structural integrity than those produced using traditional methods. In the AM process, multiple build attempts are often required to obtain the part of standardized quality. Another crucial issue is the fatigue behaviour of AM structures (particularly in the presence of voids) which must be assessed and predicted with satisfactory accuracy. There are several major challenges connected to this issue, including obtaining the exact material properties and assessing the life of the complex shapes produced using AM. Bearing this in mind, numerical simulations of AM processes, as well as of the fatigue crack growth in structures of complex shapes, become crucial factors in speeding up the industrial implementation of AM. The aim of this paper is to demonstrate current abilities and performances, as well as the restrictions of the numerical methods in simulating AM processes and fatigue crack growth in metallic structures of complex geometry. In this study, numerical simulations were first carried out on the standard CT specimen (Fig. 1), and then on the real shape of an UAV’s attachment used to hold the composite arm and transfer loads to the main body of the UAV (Fig. 2, 3). For this purpose, the finite element method (FEM) was used, and the results of 3D numerical analyses, performed in Ansys Workbench software, were compared to experimental findings.
PB  - University of Belgrade - Faculty of Mechanical Engineering
C3  - 3rd International Workshop on Reliability and Design of Additively Manufactured Materials - RdAMM22, Workshop Programme & Book of Abstracts
T1  - Evaluation of fatigue life of damaged UAV’s attachment produced using additive manufacturing
EP  - 39
SP  - 38
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5637
ER  - 

@conference{
author = "Raičević, Nikola and Petrašinović, Miloš and Petrašinović, Danilo and Kastratović, Gordana and Grbović, Aleksandar",
year = "2022",
abstract = "To become a reliable and widely accepted production process, additive manufacturing (AM) must provide metal structures with the same or better structural integrity than those produced using traditional methods. In the AM process, multiple build attempts are often required to obtain the part of standardized quality. Another crucial issue is the fatigue behaviour of AM structures (particularly in the presence of voids) which must be assessed and predicted with satisfactory accuracy. There are several major challenges connected to this issue, including obtaining the exact material properties and assessing the life of the complex shapes produced using AM. Bearing this in mind, numerical simulations of AM processes, as well as of the fatigue crack growth in structures of complex shapes, become crucial factors in speeding up the industrial implementation of AM. The aim of this paper is to demonstrate current abilities and performances, as well as the restrictions of the numerical methods in simulating AM processes and fatigue crack growth in metallic structures of complex geometry. In this study, numerical simulations were first carried out on the standard CT specimen (Fig. 1), and then on the real shape of an UAV’s attachment used to hold the composite arm and transfer loads to the main body of the UAV (Fig. 2, 3). For this purpose, the finite element method (FEM) was used, and the results of 3D numerical analyses, performed in Ansys Workbench software, were compared to experimental findings.",
publisher = "University of Belgrade - Faculty of Mechanical Engineering",
journal = "3rd International Workshop on Reliability and Design of Additively Manufactured Materials - RdAMM22, Workshop Programme & Book of Abstracts",
title = "Evaluation of fatigue life of damaged UAV’s attachment produced using additive manufacturing",
pages = "39-38",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5637"
}

Raičević, N., Petrašinović, M., Petrašinović, D., Kastratović, G.,& Grbović, A.. (2022). Evaluation of fatigue life of damaged UAV’s attachment produced using additive manufacturing. in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials - RdAMM22, Workshop Programme & Book of Abstracts
University of Belgrade - Faculty of Mechanical Engineering., 38-39.
https://hdl.handle.net/21.15107/rcub_machinery_5637

Raičević N, Petrašinović M, Petrašinović D, Kastratović G, Grbović A. Evaluation of fatigue life of damaged UAV’s attachment produced using additive manufacturing. in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials - RdAMM22, Workshop Programme & Book of Abstracts. 2022;:38-39.
https://hdl.handle.net/21.15107/rcub_machinery_5637 .

Raičević, Nikola, Petrašinović, Miloš, Petrašinović, Danilo, Kastratović, Gordana, Grbović, Aleksandar, "Evaluation of fatigue life of damaged UAV’s attachment produced using additive manufacturing" in 3rd International Workshop on Reliability and Design of Additively Manufactured Materials - RdAMM22, Workshop Programme & Book of Abstracts (2022):38-39,
https://hdl.handle.net/21.15107/rcub_machinery_5637 .

TY  - CONF
AU  - Petrašinović, Miloš
AU  - Grbović, Aleksandar
AU  - Petrašinović, Danilo
AU  - Raičević, Nikola
AU  - Petrović, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/5737
AB  - One of the most important characteristics of the mechanism used for flight simulation is its workspace. The workspace of any mechanism (including parallel mechanisms, which has a closed kinematic chain) is a set of positions and orientations reachable by its end-effector. In order to be able to successfully simulate flight with a motion platform, on which the pilot sits while in training, its workspace has to meet some criteria. Based on previous, it is essential to have a computationally fast and efficient but at the same time also accurate workspace determination process in order to design and optimize the geometry of the mechanism used for the flight simulator. Full flight simulators are most often with parallel mechanisms based on the Stewart platform which has six degrees of freedom inside the workspace. There is no analytical solution for the workspace of this type of mechanism that considers all constraints (such as motion limits of joints) and that can be practically used in the design process. One option is to simply test all significant positions and orientations, this includes defining the range for each axis and value change step (increment between consecutive values) and then testing all possible combinations. In order to lower the number of combinations that must be tested space is divided a few times, first with the coarser step and then with the finer one just around the boundary of the workspace. The final step is defining the boundary surface based on points that are within the workspace.
PB  - Innovation Center of Faculty of Mechanical Engineering
C3  - International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
T1  - Numerical Method for Workspace Determination of Flight Simulator with Stewart Platform Mechanism
EP  - 43
SP  - 43
UR  - https://hdl.handle.net/21.15107/rcub_machinery_5737
ER  - 

@conference{
author = "Petrašinović, Miloš and Grbović, Aleksandar and Petrašinović, Danilo and Raičević, Nikola and Petrović, Mihailo",
year = "2022",
abstract = "One of the most important characteristics of the mechanism used for flight simulation is its workspace. The workspace of any mechanism (including parallel mechanisms, which has a closed kinematic chain) is a set of positions and orientations reachable by its end-effector. In order to be able to successfully simulate flight with a motion platform, on which the pilot sits while in training, its workspace has to meet some criteria. Based on previous, it is essential to have a computationally fast and efficient but at the same time also accurate workspace determination process in order to design and optimize the geometry of the mechanism used for the flight simulator. Full flight simulators are most often with parallel mechanisms based on the Stewart platform which has six degrees of freedom inside the workspace. There is no analytical solution for the workspace of this type of mechanism that considers all constraints (such as motion limits of joints) and that can be practically used in the design process. One option is to simply test all significant positions and orientations, this includes defining the range for each axis and value change step (increment between consecutive values) and then testing all possible combinations. In order to lower the number of combinations that must be tested space is divided a few times, first with the coarser step and then with the finer one just around the boundary of the workspace. The final step is defining the boundary surface based on points that are within the workspace.",
publisher = "Innovation Center of Faculty of Mechanical Engineering",
journal = "International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022",
title = "Numerical Method for Workspace Determination of Flight Simulator with Stewart Platform Mechanism",
pages = "43-43",
url = "https://hdl.handle.net/21.15107/rcub_machinery_5737"
}

Petrašinović, M., Grbović, A., Petrašinović, D., Raičević, N.,& Petrović, M.. (2022). Numerical Method for Workspace Determination of Flight Simulator with Stewart Platform Mechanism. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022
Innovation Center of Faculty of Mechanical Engineering., 43-43.
https://hdl.handle.net/21.15107/rcub_machinery_5737

Petrašinović M, Grbović A, Petrašinović D, Raičević N, Petrović M. Numerical Method for Workspace Determination of Flight Simulator with Stewart Platform Mechanism. in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022. 2022;:43-43.
https://hdl.handle.net/21.15107/rcub_machinery_5737 .

Petrašinović, Miloš, Grbović, Aleksandar, Petrašinović, Danilo, Raičević, Nikola, Petrović, Mihailo, "Numerical Method for Workspace Determination of Flight Simulator with Stewart Platform Mechanism" in International Conference of Experimental and Numerical Investigations and New Technologies – CNN TECH 2022 (2022):43-43,
https://hdl.handle.net/21.15107/rcub_machinery_5737 .

TY  - JOUR
AU  - Petrašinović, Miloš
AU  - Grbović, Aleksandar
AU  - Petrašinović, Danilo
AU  - Petrović, Mihailo G.
AU  - Raičević, Nikola
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3730
AB  - Featured Application Low-cost flight simulators with electric rotary actuators and optimized geometry for flight simulation. Designing the motion platform for the flight simulator is closely coupled with the particular aircraft's flight envelope. While in training, the pilot on the motion platform has to experience the same feeling as in the aircraft. That means that flight simulators need to simulate all flight cases and forces acting upon the pilot during flight. Among many existing mechanisms, parallel mechanisms based on the Stewart platform are suitable because they have six degrees of freedom. In this paper, a real coded mixed integer genetic algorithm (RCMIGA) is applied for geometry optimization of the Stewart platform with rotary actuators (6-RUS) to design a mechanism with appropriate physical limitations of workspace and motion performances. The chosen algorithm proved that it can find the best global solution with all imposed constraints. At the same time, the obtained geometry can be manufactured because integer solutions can be mapped to available discrete values. Geometry is defined with a minimum number of parameters that fully define the mechanism with all constraints. These geometric parameters are then optimized to obtain custom-tailored geometry for aircraft flight simulation.
PB  - MDPI, Basel
T2  - Applied Sciences-Basel
T1  - Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform
IS  - 14
VL  - 12
DO  - 10.3390/app12147085
ER  - 

@article{
author = "Petrašinović, Miloš and Grbović, Aleksandar and Petrašinović, Danilo and Petrović, Mihailo G. and Raičević, Nikola",
year = "2022",
abstract = "Featured Application Low-cost flight simulators with electric rotary actuators and optimized geometry for flight simulation. Designing the motion platform for the flight simulator is closely coupled with the particular aircraft's flight envelope. While in training, the pilot on the motion platform has to experience the same feeling as in the aircraft. That means that flight simulators need to simulate all flight cases and forces acting upon the pilot during flight. Among many existing mechanisms, parallel mechanisms based on the Stewart platform are suitable because they have six degrees of freedom. In this paper, a real coded mixed integer genetic algorithm (RCMIGA) is applied for geometry optimization of the Stewart platform with rotary actuators (6-RUS) to design a mechanism with appropriate physical limitations of workspace and motion performances. The chosen algorithm proved that it can find the best global solution with all imposed constraints. At the same time, the obtained geometry can be manufactured because integer solutions can be mapped to available discrete values. Geometry is defined with a minimum number of parameters that fully define the mechanism with all constraints. These geometric parameters are then optimized to obtain custom-tailored geometry for aircraft flight simulation.",
publisher = "MDPI, Basel",
journal = "Applied Sciences-Basel",
title = "Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform",
number = "14",
volume = "12",
doi = "10.3390/app12147085"
}

Petrašinović, M., Grbović, A., Petrašinović, D., Petrović, M. G.,& Raičević, N.. (2022). Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform. in Applied Sciences-Basel
MDPI, Basel., 12(14).
https://doi.org/10.3390/app12147085

Petrašinović M, Grbović A, Petrašinović D, Petrović MG, Raičević N. Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform. in Applied Sciences-Basel. 2022;12(14).
doi:10.3390/app12147085 .

Petrašinović, Miloš, Grbović, Aleksandar, Petrašinović, Danilo, Petrović, Mihailo G., Raičević, Nikola, "Real Coded Mixed Integer Genetic Algorithm for Geometry Optimization of Flight Simulator Mechanism Based on Rotary Stewart Platform" in Applied Sciences-Basel, 12, no. 14 (2022),
https://doi.org/10.3390/app12147085 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Sedmak, Aleksandar
AU  - Sghayer, Abulgasem
AU  - Čolić, Katarina
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3756
AB  - Relevantne lokalne karakteristike zamornog opterećenja su najveći amplitudni napon i odgovrajauća srednja vrednost napona, koje treba odrediti za celu komponentu. Relevantna svojtva materijala se onda upoređuju sa dobijenim naponima, na osnovu čega je procenjen integritet i vek panela od Al legure sa zavarenim ukrućenjem. Za određivanje najvećih napona korišćena je metoda konačnih elemenata.
AB  - Relevant local characteristics of fatigue loading are the largest stress amplitudes in the related mean stress values. They should be determined for the whole components. The relevant material properties are then compared with the stresses to assess integrity and life of a panel, made of Al allow, with welded stringers. To determine the maximum stresses the Finite Element Method was used.
PB  - DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd
T2  - Zavarivanje i zavarene konstrukcije
T1  - Procena integriteta i veka zavarenog panela primenom lokalnih napona
T1  - Assessment of the integrity and life of welded panel using local stresses
EP  - 19
IS  - 1
SP  - 11
VL  - 67
DO  - 10.5937/zzk2201011G
ER  - 

@article{
author = "Grbović, Aleksandar and Sedmak, Aleksandar and Sghayer, Abulgasem and Čolić, Katarina",
year = "2022",
abstract = "Relevantne lokalne karakteristike zamornog opterećenja su najveći amplitudni napon i odgovrajauća srednja vrednost napona, koje treba odrediti za celu komponentu. Relevantna svojtva materijala se onda upoređuju sa dobijenim naponima, na osnovu čega je procenjen integritet i vek panela od Al legure sa zavarenim ukrućenjem. Za određivanje najvećih napona korišćena je metoda konačnih elemenata., Relevant local characteristics of fatigue loading are the largest stress amplitudes in the related mean stress values. They should be determined for the whole components. The relevant material properties are then compared with the stresses to assess integrity and life of a panel, made of Al allow, with welded stringers. To determine the maximum stresses the Finite Element Method was used.",
publisher = "DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd",
journal = "Zavarivanje i zavarene konstrukcije",
title = "Procena integriteta i veka zavarenog panela primenom lokalnih napona, Assessment of the integrity and life of welded panel using local stresses",
pages = "19-11",
number = "1",
volume = "67",
doi = "10.5937/zzk2201011G"
}

Grbović, A., Sedmak, A., Sghayer, A.,& Čolić, K.. (2022). Procena integriteta i veka zavarenog panela primenom lokalnih napona. in Zavarivanje i zavarene konstrukcije
DUZS - Društvo za unapređivanje zavarivanja u Srbiji, Beograd., 67(1), 11-19.
https://doi.org/10.5937/zzk2201011G

Grbović A, Sedmak A, Sghayer A, Čolić K. Procena integriteta i veka zavarenog panela primenom lokalnih napona. in Zavarivanje i zavarene konstrukcije. 2022;67(1):11-19.
doi:10.5937/zzk2201011G .

Grbović, Aleksandar, Sedmak, Aleksandar, Sghayer, Abulgasem, Čolić, Katarina, "Procena integriteta i veka zavarenog panela primenom lokalnih napona" in Zavarivanje i zavarene konstrukcije, 67, no. 1 (2022):11-19,
https://doi.org/10.5937/zzk2201011G . .