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  - 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 . .

Balać, M., Tanasković, J., Kastratović, G.,& Mirkov, N.. (2023). Kočioni mehanizam kolica za za zemaljsko opsluživanje vazduhoplova. in www.mas.bg.ac.rs.
https://hdl.handle.net/21.15107/rcub_machinery_7394

Balać M, Tanasković J, Kastratović G, Mirkov N. Kočioni mehanizam kolica za za zemaljsko opsluživanje vazduhoplova. in www.mas.bg.ac.rs. 2023;.
https://hdl.handle.net/21.15107/rcub_machinery_7394 .

Balać, Martina, Tanasković, Jovan, Kastratović, Gordana, Mirkov, Nikola, "Kočioni mehanizam kolica za za zemaljsko opsluživanje vazduhoplova" in www.mas.bg.ac.rs (2023),
https://hdl.handle.net/21.15107/rcub_machinery_7394 .

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  - 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  - 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, 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  - Kastratović, Gordana
AU  - Grbović, Aleksandar
AU  - Sedmak, Aleksandar
AU  - Bozić, Z.
AU  - Sedmak, Simon
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3598
AB  - In this paper determination of mechanical properties of composite material using experimental and numerical approach is presented. The mechanical properties of a laminate obtained in the experiment are used for verification of numerically obtained values, as well as estimation of the load-carrying capacities of composite engine cover of light aircraft. Composite specimens, consisting of epoxy matrix and glass fibers with orientation angles 0 degrees, 45 degrees, and 90 degrees, have been made according to standards, and the mechanical properties were investigated in tensile and three-point bending tests. The tensile strength, bending strength, elasticity modulus, strain, and force at laminate failure have been evaluated and then compared to values obtained in numerical simulations with the aim of verifying the FE model used for failure prediction of structural laminates. Good agreement of experimental and numerical values provides a solid foundation for further improvements of the numerical model.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - 4th Int Conf Struct Integrity & Durability (ICSID 2020)
T1  - Composite material selection for aircraft structures based on experimental and numerical evaluation of mechanical properties
EP  - 133
SP  - 127
VL  - 31
DO  - 10.1016/j.prostr.2021.03.021
ER  - 

@conference{
author = "Kastratović, Gordana and Grbović, Aleksandar and Sedmak, Aleksandar and Bozić, Z. and Sedmak, Simon",
year = "2021",
abstract = "In this paper determination of mechanical properties of composite material using experimental and numerical approach is presented. The mechanical properties of a laminate obtained in the experiment are used for verification of numerically obtained values, as well as estimation of the load-carrying capacities of composite engine cover of light aircraft. Composite specimens, consisting of epoxy matrix and glass fibers with orientation angles 0 degrees, 45 degrees, and 90 degrees, have been made according to standards, and the mechanical properties were investigated in tensile and three-point bending tests. The tensile strength, bending strength, elasticity modulus, strain, and force at laminate failure have been evaluated and then compared to values obtained in numerical simulations with the aim of verifying the FE model used for failure prediction of structural laminates. Good agreement of experimental and numerical values provides a solid foundation for further improvements of the numerical model.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - 4th Int Conf Struct Integrity & Durability (ICSID 2020)",
title = "Composite material selection for aircraft structures based on experimental and numerical evaluation of mechanical properties",
pages = "133-127",
volume = "31",
doi = "10.1016/j.prostr.2021.03.021"
}

Kastratović, G., Grbović, A., Sedmak, A., Bozić, Z.,& Sedmak, S.. (2021). Composite material selection for aircraft structures based on experimental and numerical evaluation of mechanical properties. in Procedia Structural Integrity - 4th Int Conf Struct Integrity & Durability (ICSID 2020)
Elsevier Science Bv, Amsterdam., 31, 127-133.
https://doi.org/10.1016/j.prostr.2021.03.021

Kastratović G, Grbović A, Sedmak A, Bozić Z, Sedmak S. Composite material selection for aircraft structures based on experimental and numerical evaluation of mechanical properties. in Procedia Structural Integrity - 4th Int Conf Struct Integrity & Durability (ICSID 2020). 2021;31:127-133.
doi:10.1016/j.prostr.2021.03.021 .

Kastratović, Gordana, Grbović, Aleksandar, Sedmak, Aleksandar, Bozić, Z., Sedmak, Simon, "Composite material selection for aircraft structures based on experimental and numerical evaluation of mechanical properties" in Procedia Structural Integrity - 4th Int Conf Struct Integrity & Durability (ICSID 2020), 31 (2021):127-133,
https://doi.org/10.1016/j.prostr.2021.03.021 . .

TY  - JOUR
AU  - Elayeb, Abdelnaser Abdusalam
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Valenta, Tomas
AU  - Ivanović, Ivana
AU  - Sedmak, Aleksandar
PY  - 2021
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3512
AB  - The exhaust nozzle, made of titanium, is the part of a jet engine where the final expansion of the hot gas from the turbine occurs and where the speed of the exhaust gas is further increased to create thrust. During the work, it is exposed to elevated temperatures and compressive and hoop stresses, which makes the cracks' occurrence in the exhaust nozzle's inner sleeve unavoidable, making repairs during maintenance necessary. In this study, crack growth in the repaired inner sleeve was analyzed. The aim of the study was to evaluate the fatigue life of the damaged inner sleeve when a new method of repair is applied and to compare obtained number of cycles with the number observed in the maintenance workshop after the old method of repair was used. Developing the numerical model and conducting simulations using the extended finite element method (XFEM) and finite element method (FEM), it was concluded that a new type of repair should be used to provide longer fatigue life of the damaged exhaust nozzle.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Fatigue crack growth in a structure exposed to high temperature
VL  - 127
DO  - 10.1016/j.engfailanal.2021.105493
ER  - 

@article{
author = "Elayeb, Abdelnaser Abdusalam and Grbović, Aleksandar and Kastratović, Gordana and Vidanović, Nenad and Valenta, Tomas and Ivanović, Ivana and Sedmak, Aleksandar",
year = "2021",
abstract = "The exhaust nozzle, made of titanium, is the part of a jet engine where the final expansion of the hot gas from the turbine occurs and where the speed of the exhaust gas is further increased to create thrust. During the work, it is exposed to elevated temperatures and compressive and hoop stresses, which makes the cracks' occurrence in the exhaust nozzle's inner sleeve unavoidable, making repairs during maintenance necessary. In this study, crack growth in the repaired inner sleeve was analyzed. The aim of the study was to evaluate the fatigue life of the damaged inner sleeve when a new method of repair is applied and to compare obtained number of cycles with the number observed in the maintenance workshop after the old method of repair was used. Developing the numerical model and conducting simulations using the extended finite element method (XFEM) and finite element method (FEM), it was concluded that a new type of repair should be used to provide longer fatigue life of the damaged exhaust nozzle.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Fatigue crack growth in a structure exposed to high temperature",
volume = "127",
doi = "10.1016/j.engfailanal.2021.105493"
}

Elayeb, A. A., Grbović, A., Kastratović, G., Vidanović, N., Valenta, T., Ivanović, I.,& Sedmak, A.. (2021). Fatigue crack growth in a structure exposed to high temperature. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 127.
https://doi.org/10.1016/j.engfailanal.2021.105493

Elayeb AA, Grbović A, Kastratović G, Vidanović N, Valenta T, Ivanović I, Sedmak A. Fatigue crack growth in a structure exposed to high temperature. in Engineering Failure Analysis. 2021;127.
doi:10.1016/j.engfailanal.2021.105493 .

Elayeb, Abdelnaser Abdusalam, Grbović, Aleksandar, Kastratović, Gordana, Vidanović, Nenad, Valenta, Tomas, Ivanović, Ivana, Sedmak, Aleksandar, "Fatigue crack growth in a structure exposed to high temperature" in Engineering Failure Analysis, 127 (2021),
https://doi.org/10.1016/j.engfailanal.2021.105493 . .

TY  - CONF
AU  - Grbović, Aleksandar
AU  - Bozić, Z.
AU  - Kirin, Snežana
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
AU  - Vidanović, Nenad
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3427
AB  - The exhaust nozzle represents a part of a jet engine which is crucial to its overall performance, since it accelerates the flow of hot gases out of the engine and creates a thrust. During its long service, it is exposed to elevated temperatures and high compressive and hoop stresses, which makes the cracks' occurrence in the exhaust nozzle's inner sleeve almost unavoidable. The aim of this paper is to analyze and numerically estimate the fatigue life of inner sleeve in the presence of widespread damage. When damage is detected, two repair methods are employed: welding of single cracks (manual TIG welding) and the use of welded patches. Using numerical simulations based on extended finite element method (XFEM) and finite element method (FEM), fatigue life of repaired inner sleeves were estimated. Based on the comparison of the results obtained in simulations, it was shown that the repair method with welded patches provides longer fatigue life of widespread damaged nozzle than the other with welding of cracks.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - 1st Medit Conf Fracture & Structural Integrity (Medfract1)
T1  - Fatigue life assessment of the structure with widespread damage exposed to high temperature
EP  - 408
SP  - 402
VL  - 26
DO  - 10.1016/j.prostr.2020.06.051
ER  - 

@conference{
author = "Grbović, Aleksandar and Bozić, Z. and Kirin, Snežana and Kastratović, Gordana and Sedmak, Aleksandar and Vidanović, Nenad",
year = "2020",
abstract = "The exhaust nozzle represents a part of a jet engine which is crucial to its overall performance, since it accelerates the flow of hot gases out of the engine and creates a thrust. During its long service, it is exposed to elevated temperatures and high compressive and hoop stresses, which makes the cracks' occurrence in the exhaust nozzle's inner sleeve almost unavoidable. The aim of this paper is to analyze and numerically estimate the fatigue life of inner sleeve in the presence of widespread damage. When damage is detected, two repair methods are employed: welding of single cracks (manual TIG welding) and the use of welded patches. Using numerical simulations based on extended finite element method (XFEM) and finite element method (FEM), fatigue life of repaired inner sleeves were estimated. Based on the comparison of the results obtained in simulations, it was shown that the repair method with welded patches provides longer fatigue life of widespread damaged nozzle than the other with welding of cracks.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - 1st Medit Conf Fracture & Structural Integrity (Medfract1)",
title = "Fatigue life assessment of the structure with widespread damage exposed to high temperature",
pages = "408-402",
volume = "26",
doi = "10.1016/j.prostr.2020.06.051"
}

Grbović, A., Bozić, Z., Kirin, S., Kastratović, G., Sedmak, A.,& Vidanović, N.. (2020). Fatigue life assessment of the structure with widespread damage exposed to high temperature. in Procedia Structural Integrity - 1st Medit Conf Fracture & Structural Integrity (Medfract1)
Elsevier Science Bv, Amsterdam., 26, 402-408.
https://doi.org/10.1016/j.prostr.2020.06.051

Grbović A, Bozić Z, Kirin S, Kastratović G, Sedmak A, Vidanović N. Fatigue life assessment of the structure with widespread damage exposed to high temperature. in Procedia Structural Integrity - 1st Medit Conf Fracture & Structural Integrity (Medfract1). 2020;26:402-408.
doi:10.1016/j.prostr.2020.06.051 .

Grbović, Aleksandar, Bozić, Z., Kirin, Snežana, Kastratović, Gordana, Sedmak, Aleksandar, Vidanović, Nenad, "Fatigue life assessment of the structure with widespread damage exposed to high temperature" in Procedia Structural Integrity - 1st Medit Conf Fracture & Structural Integrity (Medfract1), 26 (2020):402-408,
https://doi.org/10.1016/j.prostr.2020.06.051 . .

TY  - JOUR
AU  - Đukić, Daniela
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Sedmak, Aleksandar
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3327
AB  - In the face of enormous costs of developing new aircraft, high fuel prices, increasingly demanding environmental standards, harsh economic race and the fight against competing manufacturers, today's aviation is adapting not by producing brand new, more advanced aircraft, but through modifying existing ones by incorporating new more energy efficient engines, in accordance with today's leading criterion that requires minimal fuel consumption, enabling at the same time the longest possible range. The structure of these "new" aircraft is metallic and almost identical as it has been for decades, but now with the new requirement that its service life has to be extended, as long as it is economically justified. In such environment, it is clear that one of the leading tasks is to have the best possible assessment of the negative impact of the mechanism of Multiple Site Damage (MSD), which represents an introduction to the phenomenon of Widespread Fatigue Damage (WFD), the most insidious degradation mechanism of a metallic structure, whose significance was supposed to be diminished in recent decades with accelerated growth in the application of the composite structures. In line with the aforementioned trends, this paper aims to evaluate to what extent today's numerical methods are capable to contribute to the assessment of behavior of such phenomena and which of the proposed approaches could be used for investigating of the fracture problems, both accurately and efficiently. This assignment was conducted through numerical computations of stress intensity factors (SIFs) for two penny shaped cracks in elastic solid estimated by the methods that the authors of this paper consider to be the most relevant in the last few years.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Stress intensity factors numerical calculations for two penny shaped cracks in the elastic solid
VL  - 112
DO  - 10.1016/j.engfailanal.2020.104507
ER  - 

@article{
author = "Đukić, Daniela and Grbović, Aleksandar and Kastratović, Gordana and Vidanović, Nenad and Sedmak, Aleksandar",
year = "2020",
abstract = "In the face of enormous costs of developing new aircraft, high fuel prices, increasingly demanding environmental standards, harsh economic race and the fight against competing manufacturers, today's aviation is adapting not by producing brand new, more advanced aircraft, but through modifying existing ones by incorporating new more energy efficient engines, in accordance with today's leading criterion that requires minimal fuel consumption, enabling at the same time the longest possible range. The structure of these "new" aircraft is metallic and almost identical as it has been for decades, but now with the new requirement that its service life has to be extended, as long as it is economically justified. In such environment, it is clear that one of the leading tasks is to have the best possible assessment of the negative impact of the mechanism of Multiple Site Damage (MSD), which represents an introduction to the phenomenon of Widespread Fatigue Damage (WFD), the most insidious degradation mechanism of a metallic structure, whose significance was supposed to be diminished in recent decades with accelerated growth in the application of the composite structures. In line with the aforementioned trends, this paper aims to evaluate to what extent today's numerical methods are capable to contribute to the assessment of behavior of such phenomena and which of the proposed approaches could be used for investigating of the fracture problems, both accurately and efficiently. This assignment was conducted through numerical computations of stress intensity factors (SIFs) for two penny shaped cracks in elastic solid estimated by the methods that the authors of this paper consider to be the most relevant in the last few years.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Stress intensity factors numerical calculations for two penny shaped cracks in the elastic solid",
volume = "112",
doi = "10.1016/j.engfailanal.2020.104507"
}

Đukić, D., Grbović, A., Kastratović, G., Vidanović, N.,& Sedmak, A.. (2020). Stress intensity factors numerical calculations for two penny shaped cracks in the elastic solid. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 112.
https://doi.org/10.1016/j.engfailanal.2020.104507

Đukić D, Grbović A, Kastratović G, Vidanović N, Sedmak A. Stress intensity factors numerical calculations for two penny shaped cracks in the elastic solid. in Engineering Failure Analysis. 2020;112.
doi:10.1016/j.engfailanal.2020.104507 .

Đukić, Daniela, Grbović, Aleksandar, Kastratović, Gordana, Vidanović, Nenad, Sedmak, Aleksandar, "Stress intensity factors numerical calculations for two penny shaped cracks in the elastic solid" in Engineering Failure Analysis, 112 (2020),
https://doi.org/10.1016/j.engfailanal.2020.104507 . .

TY  - CONF
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Grbović, Aleksandar
AU  - Mirkov, Nikola
AU  - Rašuo, Boško
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3323
AB  - This paper discusses certain aspects of numerical simulation of crack propagation in wire ropes subjected to axial loading, with the aim to explore and to demonstrate the capacity, performances and difficulties of crack propagation modeling by usage of numerical computational methods in such complex structures. For this purpose, the finite element method (FEM) was used, and 3D numerical analyses were performed in Ansys Workbench software. In order to validate and verify performed numerical modeling, crack growth rate based on calculated stress intensity factors (SIFs) along the crack fronts was obtained for the model for which experimental results could be found in the available literature. Finally, using the advanced modeling techniques, the parametric 3D model of seven-wire strand was analyzed. Conducted analysis showed that FEM could be a powerful tool for fatigue life predictions in order to reduce the need for experiments, which are still the only successful method for fatigue life estimation of wire ropes.
PB  - Springer International Publishing Ag, Cham
C3  - Computational and Experimental Approaches in Materials Science and Engineering, Cnntech 2019
T1  - Numerical Simulation of Crack Propagation in Seven-Wire Strand
EP  - 91
SP  - 76
VL  - 90
DO  - 10.1007/978-3-030-30853-7_5
ER  - 

@conference{
author = "Kastratović, Gordana and Vidanović, Nenad and Grbović, Aleksandar and Mirkov, Nikola and Rašuo, Boško",
year = "2020",
abstract = "This paper discusses certain aspects of numerical simulation of crack propagation in wire ropes subjected to axial loading, with the aim to explore and to demonstrate the capacity, performances and difficulties of crack propagation modeling by usage of numerical computational methods in such complex structures. For this purpose, the finite element method (FEM) was used, and 3D numerical analyses were performed in Ansys Workbench software. In order to validate and verify performed numerical modeling, crack growth rate based on calculated stress intensity factors (SIFs) along the crack fronts was obtained for the model for which experimental results could be found in the available literature. Finally, using the advanced modeling techniques, the parametric 3D model of seven-wire strand was analyzed. Conducted analysis showed that FEM could be a powerful tool for fatigue life predictions in order to reduce the need for experiments, which are still the only successful method for fatigue life estimation of wire ropes.",
publisher = "Springer International Publishing Ag, Cham",
journal = "Computational and Experimental Approaches in Materials Science and Engineering, Cnntech 2019",
title = "Numerical Simulation of Crack Propagation in Seven-Wire Strand",
pages = "91-76",
volume = "90",
doi = "10.1007/978-3-030-30853-7_5"
}

Kastratović, G., Vidanović, N., Grbović, A., Mirkov, N.,& Rašuo, B.. (2020). Numerical Simulation of Crack Propagation in Seven-Wire Strand. in Computational and Experimental Approaches in Materials Science and Engineering, Cnntech 2019
Springer International Publishing Ag, Cham., 90, 76-91.
https://doi.org/10.1007/978-3-030-30853-7_5

Kastratović G, Vidanović N, Grbović A, Mirkov N, Rašuo B. Numerical Simulation of Crack Propagation in Seven-Wire Strand. in Computational and Experimental Approaches in Materials Science and Engineering, Cnntech 2019. 2020;90:76-91.
doi:10.1007/978-3-030-30853-7_5 .

Kastratović, Gordana, Vidanović, Nenad, Grbović, Aleksandar, Mirkov, Nikola, Rašuo, Boško, "Numerical Simulation of Crack Propagation in Seven-Wire Strand" in Computational and Experimental Approaches in Materials Science and Engineering, Cnntech 2019, 90 (2020):76-91,
https://doi.org/10.1007/978-3-030-30853-7_5 . .

TY  - JOUR
AU  - Vidanović, Nenad
AU  - Rašuo, Boško
AU  - Kastratović, Gordana
AU  - Grbović, Aleksandar
AU  - Puharić, Mirjana
AU  - Maksimović, Katarina
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3380
AB  - The main goal of this paper is to expand previously conducted study and consequently to upgrade the proposed multimodular numerical framework developed for fluid-structure interaction simulation (FSI) and multidisciplinary design optimization (MDO) purposes, in a manner that thermal-structure interaction is observed and implemented into the established numerical framework. The upgraded and considerably improved algorithm was used for MDO of the short-range ballistic missile (SRBM) model. Because of its high-speed regimes, this aircraft model was selected for the purpose of numerical modeling and optimization of aerodynamically heated structure. The present study is concerned with a broader observation of critical multipoint flight conditions and represents a more realistic scenario, which indicates this study as one contribution more in a scope of fluid-thermal-structure interaction (FTSI) numerical modeling and optimization. With respect to predefined objectives and constraints, multidisciplinary shape optimization of the fin structure resulted in overall improvement of the missile initial performances. Also, aerothermally induced critical responses of the fin structure were prevented. Numerical modeling of FSI/FTSI and MDO within an industry-accepted design tool resulted in powerful monolithic environment, which, with adopted multipoint regimes and multicriteria settings, was used for aerodynamic-thermal/structural optimization. The obtained results were compared with the results from the previous study conducted without thermal effects.
PB  - Amer Inst Aeronautics  Astronautics, Reston
T2  - Journal of Spacecraft and Rockets
T1  - Multidisciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating
EP  - 527
IS  - 3
SP  - 510
VL  - 57
DO  - 10.2514/1.A34575
ER  - 

@article{
author = "Vidanović, Nenad and Rašuo, Boško and Kastratović, Gordana and Grbović, Aleksandar and Puharić, Mirjana and Maksimović, Katarina",
year = "2020",
abstract = "The main goal of this paper is to expand previously conducted study and consequently to upgrade the proposed multimodular numerical framework developed for fluid-structure interaction simulation (FSI) and multidisciplinary design optimization (MDO) purposes, in a manner that thermal-structure interaction is observed and implemented into the established numerical framework. The upgraded and considerably improved algorithm was used for MDO of the short-range ballistic missile (SRBM) model. Because of its high-speed regimes, this aircraft model was selected for the purpose of numerical modeling and optimization of aerodynamically heated structure. The present study is concerned with a broader observation of critical multipoint flight conditions and represents a more realistic scenario, which indicates this study as one contribution more in a scope of fluid-thermal-structure interaction (FTSI) numerical modeling and optimization. With respect to predefined objectives and constraints, multidisciplinary shape optimization of the fin structure resulted in overall improvement of the missile initial performances. Also, aerothermally induced critical responses of the fin structure were prevented. Numerical modeling of FSI/FTSI and MDO within an industry-accepted design tool resulted in powerful monolithic environment, which, with adopted multipoint regimes and multicriteria settings, was used for aerodynamic-thermal/structural optimization. The obtained results were compared with the results from the previous study conducted without thermal effects.",
publisher = "Amer Inst Aeronautics  Astronautics, Reston",
journal = "Journal of Spacecraft and Rockets",
title = "Multidisciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating",
pages = "527-510",
number = "3",
volume = "57",
doi = "10.2514/1.A34575"
}

Vidanović, N., Rašuo, B., Kastratović, G., Grbović, A., Puharić, M.,& Maksimović, K.. (2020). Multidisciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating. in Journal of Spacecraft and Rockets
Amer Inst Aeronautics  Astronautics, Reston., 57(3), 510-527.
https://doi.org/10.2514/1.A34575

Vidanović N, Rašuo B, Kastratović G, Grbović A, Puharić M, Maksimović K. Multidisciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating. in Journal of Spacecraft and Rockets. 2020;57(3):510-527.
doi:10.2514/1.A34575 .

Vidanović, Nenad, Rašuo, Boško, Kastratović, Gordana, Grbović, Aleksandar, Puharić, Mirjana, Maksimović, Katarina, "Multidisciplinary Shape Optimization of Missile Fin Configuration Subject to Aerodynamic Heating" in Journal of Spacecraft and Rockets, 57, no. 3 (2020):510-527,
https://doi.org/10.2514/1.A34575 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
AU  - Eldwaib, Khalid
AU  - Kirin, Snežana
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3107
AB  - Shape optimisation is a nowadays-standard requirement in the design of lightweight structural components. In this paper, optimisation of I-beam cross-section of integral aluminium 2024-T3 wing spar is presented, taking the maximum fatigue life as the criterion. Toward this aim, the extended finite element method (XFEM) was used to simulate crack growth in complex I-beam geometry. The computations were carried out using Morfeo/Crack add-on based on XFEM implementation in Abaqus software. Fatigue lives of wing spars with different sizes of cross section but constant area were compared. Conducted analysis has shown that XFEM seems to be efficient tool for complex three-dimensional configurations optimisation.
PB  - Elsevier Sci Ltd, Oxford
T2  - International Journal of Fatigue
T1  - Determination of optimum wing spar cross section for maximum fatigue life
EP  - 311
SP  - 305
VL  - 127
DO  - 10.1016/j.ijfatigue.2019.06.019
ER  - 

@article{
author = "Grbović, Aleksandar and Kastratović, Gordana and Sedmak, Aleksandar and Eldwaib, Khalid and Kirin, Snežana",
year = "2019",
abstract = "Shape optimisation is a nowadays-standard requirement in the design of lightweight structural components. In this paper, optimisation of I-beam cross-section of integral aluminium 2024-T3 wing spar is presented, taking the maximum fatigue life as the criterion. Toward this aim, the extended finite element method (XFEM) was used to simulate crack growth in complex I-beam geometry. The computations were carried out using Morfeo/Crack add-on based on XFEM implementation in Abaqus software. Fatigue lives of wing spars with different sizes of cross section but constant area were compared. Conducted analysis has shown that XFEM seems to be efficient tool for complex three-dimensional configurations optimisation.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "International Journal of Fatigue",
title = "Determination of optimum wing spar cross section for maximum fatigue life",
pages = "311-305",
volume = "127",
doi = "10.1016/j.ijfatigue.2019.06.019"
}

Grbović, A., Kastratović, G., Sedmak, A., Eldwaib, K.,& Kirin, S.. (2019). Determination of optimum wing spar cross section for maximum fatigue life. in International Journal of Fatigue
Elsevier Sci Ltd, Oxford., 127, 305-311.
https://doi.org/10.1016/j.ijfatigue.2019.06.019

Grbović A, Kastratović G, Sedmak A, Eldwaib K, Kirin S. Determination of optimum wing spar cross section for maximum fatigue life. in International Journal of Fatigue. 2019;127:305-311.
doi:10.1016/j.ijfatigue.2019.06.019 .

Grbović, Aleksandar, Kastratović, Gordana, Sedmak, Aleksandar, Eldwaib, Khalid, Kirin, Snežana, "Determination of optimum wing spar cross section for maximum fatigue life" in International Journal of Fatigue, 127 (2019):305-311,
https://doi.org/10.1016/j.ijfatigue.2019.06.019 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
AU  - Balać, Igor
AU  - Popović, Mihajlo
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3104
AB  - Different cracks paths in three different wing spar designs are analysed (differential, integral and optimized integral) to explore how those cracks paths affect fatigue life estimation. First, numerical analysis was carried out and verified, using the experimental data for differential wing spar, followed by numerical analysis of both optimized integral wing spars. The optimized integral spar was obtained by analysing three different cross sections regarding fatigue life. Crack propagation simulation and fatigue life estimation were carried out by the extended finite element method, using Morfeo/Crack for Abaqus. Results provided better understanding and prediction of multiple cracks propagation in 3D structures.
PB  - Elsevier Sci Ltd, Oxford
T2  - International Journal of Fatigue
T1  - Fatigue crack paths in light aircraft wing spars
EP  - 104
SP  - 96
VL  - 123
DO  - 10.1016/j.ijfatigue.2019.02.013
ER  - 

@article{
author = "Grbović, Aleksandar and Kastratović, Gordana and Sedmak, Aleksandar and Balać, Igor and Popović, Mihajlo",
year = "2019",
abstract = "Different cracks paths in three different wing spar designs are analysed (differential, integral and optimized integral) to explore how those cracks paths affect fatigue life estimation. First, numerical analysis was carried out and verified, using the experimental data for differential wing spar, followed by numerical analysis of both optimized integral wing spars. The optimized integral spar was obtained by analysing three different cross sections regarding fatigue life. Crack propagation simulation and fatigue life estimation were carried out by the extended finite element method, using Morfeo/Crack for Abaqus. Results provided better understanding and prediction of multiple cracks propagation in 3D structures.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "International Journal of Fatigue",
title = "Fatigue crack paths in light aircraft wing spars",
pages = "104-96",
volume = "123",
doi = "10.1016/j.ijfatigue.2019.02.013"
}

Grbović, A., Kastratović, G., Sedmak, A., Balać, I.,& Popović, M.. (2019). Fatigue crack paths in light aircraft wing spars. in International Journal of Fatigue
Elsevier Sci Ltd, Oxford., 123, 96-104.
https://doi.org/10.1016/j.ijfatigue.2019.02.013

Grbović A, Kastratović G, Sedmak A, Balać I, Popović M. Fatigue crack paths in light aircraft wing spars. in International Journal of Fatigue. 2019;123:96-104.
doi:10.1016/j.ijfatigue.2019.02.013 .

Grbović, Aleksandar, Kastratović, Gordana, Sedmak, Aleksandar, Balać, Igor, Popović, Mihajlo, "Fatigue crack paths in light aircraft wing spars" in International Journal of Fatigue, 123 (2019):96-104,
https://doi.org/10.1016/j.ijfatigue.2019.02.013 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3165
AB  - Three different wing spar designs (differential, equivalent integral, and optimized integral) are analysed, in order to establish the optimum one. Numerical analysis was carried out by extended finite element method (XFEM) and verified using the experimental data for differential wing spar, followed by the analysis of both equivalent and optimized integral wing spar. The optimized spar design regarding fatigue life was obtained by analysing three different cross sections of integral wing spar.
PB  - John Wiley and Sons Inc
T2  - Material Design and Processing Communications
T1  - Design aspects of light aircraft wing spar—Differential and integral approach
IS  - 6
VL  - 1
DO  - 10.1002/mdp2.105
ER  - 

@article{
author = "Grbović, Aleksandar and Kastratović, Gordana and Sedmak, Aleksandar",
year = "2019",
abstract = "Three different wing spar designs (differential, equivalent integral, and optimized integral) are analysed, in order to establish the optimum one. Numerical analysis was carried out by extended finite element method (XFEM) and verified using the experimental data for differential wing spar, followed by the analysis of both equivalent and optimized integral wing spar. The optimized spar design regarding fatigue life was obtained by analysing three different cross sections of integral wing spar.",
publisher = "John Wiley and Sons Inc",
journal = "Material Design and Processing Communications",
title = "Design aspects of light aircraft wing spar—Differential and integral approach",
number = "6",
volume = "1",
doi = "10.1002/mdp2.105"
}

Grbović, A., Kastratović, G.,& Sedmak, A.. (2019). Design aspects of light aircraft wing spar—Differential and integral approach. in Material Design and Processing Communications
John Wiley and Sons Inc., 1(6).
https://doi.org/10.1002/mdp2.105

Grbović A, Kastratović G, Sedmak A. Design aspects of light aircraft wing spar—Differential and integral approach. in Material Design and Processing Communications. 2019;1(6).
doi:10.1002/mdp2.105 .

Grbović, Aleksandar, Kastratović, Gordana, Sedmak, Aleksandar, "Design aspects of light aircraft wing spar—Differential and integral approach" in Material Design and Processing Communications, 1, no. 6 (2019),
https://doi.org/10.1002/mdp2.105 . .

TY  - JOUR
AU  - Grbović, Aleksandar
AU  - Sedmak, Aleksandar
AU  - Kastratović, Gordana
AU  - Petrašinović, Danilo
AU  - Vidanović, Nenad
AU  - Sghayer, Abulgasem
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3135
AB  - In this paper, numerical analyses of fatigue crack growth in integral skin-stringer panel produced by means of laser beam welding (LBW) are presented along with fatigue results verified by previously conducted experiments. Skin-stringer panel is fail-safe structure widely used in aircraft industry, which requires a good estimate of fatigue life after crack initiation. In the past, experimental work was the only successful method for fatigue life estimation of complex damaged structure, but nowadays researches have powerful numerical tools, such as extended finite element method (XFEM), for three-dimensional crack growth analysis. In research presented here, XFEM was initially used for crack growth simulation in simple flat plate made of aluminium 6156 T6 and 6156 T4 for the purpose of procedure verification, since fatigue life for simple plate was known from experiment. Then, XFEM was used to simulate fatigue crack growth in the panel reinforced with four stringers. Fatigue life obtained on the basis of calculated stress intensity factors (SIFS) along the crack fronts on LBW skin-stringer panels was, as expected, significantly longer than experimentally measured life of simple flat plate. Finally, several numerical simulations were performed in order to analyse the influence of mesh size on accuracy of estimated fatigue life of damaged LBW skin panels. For that purpose, average element sizes of 1, 2 and 4 mm were used.
PB  - Pergamon-Elsevier Science Ltd, Oxford
T2  - Engineering Failure Analysis
T1  - Effect of laser beam welded reinforcement on integral skin panel fatigue life
EP  - 393
SP  - 383
VL  - 101
DO  - 10.1016/j.engfailanal.2019.03.029
ER  - 

@article{
author = "Grbović, Aleksandar and Sedmak, Aleksandar and Kastratović, Gordana and Petrašinović, Danilo and Vidanović, Nenad and Sghayer, Abulgasem",
year = "2019",
abstract = "In this paper, numerical analyses of fatigue crack growth in integral skin-stringer panel produced by means of laser beam welding (LBW) are presented along with fatigue results verified by previously conducted experiments. Skin-stringer panel is fail-safe structure widely used in aircraft industry, which requires a good estimate of fatigue life after crack initiation. In the past, experimental work was the only successful method for fatigue life estimation of complex damaged structure, but nowadays researches have powerful numerical tools, such as extended finite element method (XFEM), for three-dimensional crack growth analysis. In research presented here, XFEM was initially used for crack growth simulation in simple flat plate made of aluminium 6156 T6 and 6156 T4 for the purpose of procedure verification, since fatigue life for simple plate was known from experiment. Then, XFEM was used to simulate fatigue crack growth in the panel reinforced with four stringers. Fatigue life obtained on the basis of calculated stress intensity factors (SIFS) along the crack fronts on LBW skin-stringer panels was, as expected, significantly longer than experimentally measured life of simple flat plate. Finally, several numerical simulations were performed in order to analyse the influence of mesh size on accuracy of estimated fatigue life of damaged LBW skin panels. For that purpose, average element sizes of 1, 2 and 4 mm were used.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Engineering Failure Analysis",
title = "Effect of laser beam welded reinforcement on integral skin panel fatigue life",
pages = "393-383",
volume = "101",
doi = "10.1016/j.engfailanal.2019.03.029"
}

Grbović, A., Sedmak, A., Kastratović, G., Petrašinović, D., Vidanović, N.,& Sghayer, A.. (2019). Effect of laser beam welded reinforcement on integral skin panel fatigue life. in Engineering Failure Analysis
Pergamon-Elsevier Science Ltd, Oxford., 101, 383-393.
https://doi.org/10.1016/j.engfailanal.2019.03.029

Grbović A, Sedmak A, Kastratović G, Petrašinović D, Vidanović N, Sghayer A. Effect of laser beam welded reinforcement on integral skin panel fatigue life. in Engineering Failure Analysis. 2019;101:383-393.
doi:10.1016/j.engfailanal.2019.03.029 .

Grbović, Aleksandar, Sedmak, Aleksandar, Kastratović, Gordana, Petrašinović, Danilo, Vidanović, Nenad, Sghayer, Abulgasem, "Effect of laser beam welded reinforcement on integral skin panel fatigue life" in Engineering Failure Analysis, 101 (2019):383-393,
https://doi.org/10.1016/j.engfailanal.2019.03.029 . .

TY  - CONF
AU  - Eldwaib, Khalid
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Aldarwish, Mustafa
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2814
AB  - Aircraft structure is the most obvious example where functional requirements demand light weight and strong structures. Shape and sizing optimization are being increasingly used nowadays for designing lightweight structural components. The aim of this paper is to present optimization of I-section integral wing spar made of aluminum 2024-T3. The efficient design, based on optimum fatigue life, was achieved using Extended Finite Element Method (XFEM) and its ability to simulate crack growth in complex geometry. The computations were carried out in Morfeo/Crack for Abaqus software which relies on the implementation of XFEM. Shape optimization of the aircraft wing spar beam was conducted by comparing the fatigue crack growth lives for different cross section shapes, but constant cross section area of the spar. The analysis revealed that XFEM is efficient tool for complex three-dimensional configurations optimization where extended fatigue life is one of the most important objectives.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
T1  - Design of Wing Spar Cross Section for Optimum Fatigue Life
EP  - 449
SP  - 444
VL  - 13
DO  - 10.1016/j.prostr.2018.12.074
ER  - 

@conference{
author = "Eldwaib, Khalid and Grbović, Aleksandar and Kastratović, Gordana and Aldarwish, Mustafa",
year = "2018",
abstract = "Aircraft structure is the most obvious example where functional requirements demand light weight and strong structures. Shape and sizing optimization are being increasingly used nowadays for designing lightweight structural components. The aim of this paper is to present optimization of I-section integral wing spar made of aluminum 2024-T3. The efficient design, based on optimum fatigue life, was achieved using Extended Finite Element Method (XFEM) and its ability to simulate crack growth in complex geometry. The computations were carried out in Morfeo/Crack for Abaqus software which relies on the implementation of XFEM. Shape optimization of the aircraft wing spar beam was conducted by comparing the fatigue crack growth lives for different cross section shapes, but constant cross section area of the spar. The analysis revealed that XFEM is efficient tool for complex three-dimensional configurations optimization where extended fatigue life is one of the most important objectives.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity",
title = "Design of Wing Spar Cross Section for Optimum Fatigue Life",
pages = "449-444",
volume = "13",
doi = "10.1016/j.prostr.2018.12.074"
}

Eldwaib, K., Grbović, A., Kastratović, G.,& Aldarwish, M.. (2018). Design of Wing Spar Cross Section for Optimum Fatigue Life. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
Elsevier Science Bv, Amsterdam., 13, 444-449.
https://doi.org/10.1016/j.prostr.2018.12.074

Eldwaib K, Grbović A, Kastratović G, Aldarwish M. Design of Wing Spar Cross Section for Optimum Fatigue Life. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity. 2018;13:444-449.
doi:10.1016/j.prostr.2018.12.074 .

Eldwaib, Khalid, Grbović, Aleksandar, Kastratović, Gordana, Aldarwish, Mustafa, "Design of Wing Spar Cross Section for Optimum Fatigue Life" in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity, 13 (2018):444-449,
https://doi.org/10.1016/j.prostr.2018.12.074 . .

TY  - JOUR
AU  - Eldwaib, Khalid
AU  - Grbović, Aleksandar
AU  - Sedmak, Aleksandar
AU  - Kastratović, Gordana
AU  - Petrašinović, Danilo
AU  - Sedmak, Simon
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2897
AB  - This paper presents the application of the extended finite element method (XFEM) in crack propagation simulation on the integral wing spar that should replace existing differential spar of the light aircraft UTVA 75. Numerical model of integral spar was developed in software Abaqus. Stress intensity factors (SIFs) were calculated using add-in Morfeo/Crack for Abaqus and obtained number of cycles that would propagate crack to certain length was compared to the experimentally obtained number of cycles for differential spar. Numerical analysis showed that integral spar with the same dimensions as differential spar has significant increase in fatigue life. Analysis that was carried out showed that XFEM could be efficient and cost beneficial tool for simulation of crack propagation in the 3D structures (such as wing spar) and that it should be used in the future for fatigue analysis of newly designed structures in all phases of development and production.
PB  - Univ Osijek, Tech Fac, Slavonski Brod
T2  - Tehnički vjesnik
T1  - Fatigue Life Estimation of Damaged Integral Wing Spar Using XFEM
EP  - 1842
IS  - 6
SP  - 1837
VL  - 25
DO  - 10.17559/TV-20171007105350
ER  - 

@article{
author = "Eldwaib, Khalid and Grbović, Aleksandar and Sedmak, Aleksandar and Kastratović, Gordana and Petrašinović, Danilo and Sedmak, Simon",
year = "2018",
abstract = "This paper presents the application of the extended finite element method (XFEM) in crack propagation simulation on the integral wing spar that should replace existing differential spar of the light aircraft UTVA 75. Numerical model of integral spar was developed in software Abaqus. Stress intensity factors (SIFs) were calculated using add-in Morfeo/Crack for Abaqus and obtained number of cycles that would propagate crack to certain length was compared to the experimentally obtained number of cycles for differential spar. Numerical analysis showed that integral spar with the same dimensions as differential spar has significant increase in fatigue life. Analysis that was carried out showed that XFEM could be efficient and cost beneficial tool for simulation of crack propagation in the 3D structures (such as wing spar) and that it should be used in the future for fatigue analysis of newly designed structures in all phases of development and production.",
publisher = "Univ Osijek, Tech Fac, Slavonski Brod",
journal = "Tehnički vjesnik",
title = "Fatigue Life Estimation of Damaged Integral Wing Spar Using XFEM",
pages = "1842-1837",
number = "6",
volume = "25",
doi = "10.17559/TV-20171007105350"
}

Eldwaib, K., Grbović, A., Sedmak, A., Kastratović, G., Petrašinović, D.,& Sedmak, S.. (2018). Fatigue Life Estimation of Damaged Integral Wing Spar Using XFEM. in Tehnički vjesnik
Univ Osijek, Tech Fac, Slavonski Brod., 25(6), 1837-1842.
https://doi.org/10.17559/TV-20171007105350

Eldwaib K, Grbović A, Sedmak A, Kastratović G, Petrašinović D, Sedmak S. Fatigue Life Estimation of Damaged Integral Wing Spar Using XFEM. in Tehnički vjesnik. 2018;25(6):1837-1842.
doi:10.17559/TV-20171007105350 .

Eldwaib, Khalid, Grbović, Aleksandar, Sedmak, Aleksandar, Kastratović, Gordana, Petrašinović, Danilo, Sedmak, Simon, "Fatigue Life Estimation of Damaged Integral Wing Spar Using XFEM" in Tehnički vjesnik, 25, no. 6 (2018):1837-1842,
https://doi.org/10.17559/TV-20171007105350 . .

TY  - CONF
AU  - Kastratović, Gordana
AU  - Aldarwish, Mustafa
AU  - Grbović, Aleksandar
AU  - Vidanović, Nenad
AU  - Eldwaib, Khalid
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2824
AB  - The aim of this paper is to explore and to demonstrate the capacity, performances and difficulties of stress intensity factors (SIFs) calculations in a case of multiple cracks on curved panels analyzed by means of different computational methods. So-called bulging effect, which is occurring in cracked curved panels, increases the effective stress-intensity factor, making the SIFs assessment in case of multiple cracks more challenging. Here, the stress intensity factors are considered by using two different computational methods: extended finite element method (XFEM) and the approximate method based on superposition, which has been adjusted for curved panel application. The SIFs determination was carried out for aircraft fuselage model: unstiffened panel with three cracked fastener holes, for four different curvature diameters, subjected to uniform internal pressurization. The comparison of the results showed that conducted analyses delivered the data which can be useful in evaluation of crack-growth rate, residual strength and fatigue life of curved aircraft structures with multi-site damage.
PB  - Elsevier Science Bv, Amsterdam
C3  - Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
T1  - Stress intensity factor for multiple cracks on curved panels
EP  - 474
SP  - 469
VL  - 13
DO  - 10.1016/j.prostr.2018.12.078
ER  - 

@conference{
author = "Kastratović, Gordana and Aldarwish, Mustafa and Grbović, Aleksandar and Vidanović, Nenad and Eldwaib, Khalid",
year = "2018",
abstract = "The aim of this paper is to explore and to demonstrate the capacity, performances and difficulties of stress intensity factors (SIFs) calculations in a case of multiple cracks on curved panels analyzed by means of different computational methods. So-called bulging effect, which is occurring in cracked curved panels, increases the effective stress-intensity factor, making the SIFs assessment in case of multiple cracks more challenging. Here, the stress intensity factors are considered by using two different computational methods: extended finite element method (XFEM) and the approximate method based on superposition, which has been adjusted for curved panel application. The SIFs determination was carried out for aircraft fuselage model: unstiffened panel with three cracked fastener holes, for four different curvature diameters, subjected to uniform internal pressurization. The comparison of the results showed that conducted analyses delivered the data which can be useful in evaluation of crack-growth rate, residual strength and fatigue life of curved aircraft structures with multi-site damage.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity",
title = "Stress intensity factor for multiple cracks on curved panels",
pages = "474-469",
volume = "13",
doi = "10.1016/j.prostr.2018.12.078"
}

Kastratović, G., Aldarwish, M., Grbović, A., Vidanović, N.,& Eldwaib, K.. (2018). Stress intensity factor for multiple cracks on curved panels. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity
Elsevier Science Bv, Amsterdam., 13, 469-474.
https://doi.org/10.1016/j.prostr.2018.12.078

Kastratović G, Aldarwish M, Grbović A, Vidanović N, Eldwaib K. Stress intensity factor for multiple cracks on curved panels. in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity. 2018;13:469-474.
doi:10.1016/j.prostr.2018.12.078 .

Kastratović, Gordana, Aldarwish, Mustafa, Grbović, Aleksandar, Vidanović, Nenad, Eldwaib, Khalid, "Stress intensity factor for multiple cracks on curved panels" in Procedia Structural Integrity - ECF22 - Loading and environmental effects on structural integrity, 13 (2018):469-474,
https://doi.org/10.1016/j.prostr.2018.12.078 . .

TY  - JOUR
AU  - Kastratović, Gordana
AU  - Vidanović, Nenad
AU  - Grbović, Aleksandar
AU  - Rašuo, Boško
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2799
AB  - U ovom radu korišćena je jednostavna aproksimativna metoda za procenu faktora intenziteta napona za mod I tip opterećenja, i to u slučaju višestrukih površinskih prslina u trodimenzionalnom elastičnom telu, koje je podvrgnuto udaljenom jednoosnom opterećenju. Navedena metoda koristi poznata rešenja za 2D ili 3D konfiguracije koje sadrže samo jednu prslinu i uzima u obzir efekat interakcije između istih. Ova metoda, inače zasnovana na principu super-pozicije, konkretno je primenjena na konfiguraciji sa tri koplanarne polueliptične prsline koje su umetnute u trodimenzionalno elastično telo, a koje je podvrgnuto udaljenom jednoosnom naponu na zatezanje. Sve prsline se nalaze u istoj ravni na istim rastojanjima, u sredini tela, a primenjeni napon je upravan na ravan u kojoj prsline leže. Za potrebe verifikacije, faktori intenziteta napona su određenii pomoću kompjuterskog programa baziranog na metodi konačnih elemenata. Sprovedena analiza pokazala je da je aproksimativna metoda pre svega brz i efikasan alat za procenu faktora intenziteta napona čak i u slučaju 3D konfiguracija sa višestrukim prslinama. Poređenje rezultata pokazalo je i značaj preciznog izračunavanja faktora intenziteta napona, kako bi se omogućilo bolje razumevanje i predviđanje širenja 3D prslina.
AB  - In this paper a versatile and easy to use approximate procedure was used for the estimation of mode I stress intensity factors in case of multiple surface cracks in a three dimensional elastic body, subjected to remote uniaxial tensile loading. The mentioned method uses known solutions for either 2D or 3D configurations containing only one crack, and takes into consideration the interaction effect between cracks. This procedure, which is based on the principle of superposition, was applied on a configuration with three coplanar semi-elliptical cracks embedded in three dimensional elastic body, subjected to remote uniaxial tensile loading. All cracks are located in the same plane at the same distances, in the middle of the body and the applied stress is perpendicular to the cracks plane. For the verification purposes, the stress intensity factors solutions were obtained by using finite element method based computer program. The conducted analysis showed that approximate method is, above all, fast and efficient tool for stress intensity factors assessment even in the case of 3D configurations with multiple site damage. The comparison between results also showed the significance of accurate calculation of stress intensity factors, in order to provide a better understanding and prediction of 3D multiple cracks propagation.
PB  - Univerzitet u Beogradu - Mašinski fakultet, Beograd
T2  - FME Transactions
T1  - Aproksimativno određivanje faktora intenziteta napona za slučaj višestrukih površinskih prslina
T1  - Approximate determination of stress intensity factor for multiple surface cracks
EP  - 45
IS  - 1
SP  - 39
VL  - 46
DO  - 10.5937/fmet1801039K
ER  - 

@article{
author = "Kastratović, Gordana and Vidanović, Nenad and Grbović, Aleksandar and Rašuo, Boško",
year = "2018",
abstract = "U ovom radu korišćena je jednostavna aproksimativna metoda za procenu faktora intenziteta napona za mod I tip opterećenja, i to u slučaju višestrukih površinskih prslina u trodimenzionalnom elastičnom telu, koje je podvrgnuto udaljenom jednoosnom opterećenju. Navedena metoda koristi poznata rešenja za 2D ili 3D konfiguracije koje sadrže samo jednu prslinu i uzima u obzir efekat interakcije između istih. Ova metoda, inače zasnovana na principu super-pozicije, konkretno je primenjena na konfiguraciji sa tri koplanarne polueliptične prsline koje su umetnute u trodimenzionalno elastično telo, a koje je podvrgnuto udaljenom jednoosnom naponu na zatezanje. Sve prsline se nalaze u istoj ravni na istim rastojanjima, u sredini tela, a primenjeni napon je upravan na ravan u kojoj prsline leže. Za potrebe verifikacije, faktori intenziteta napona su određenii pomoću kompjuterskog programa baziranog na metodi konačnih elemenata. Sprovedena analiza pokazala je da je aproksimativna metoda pre svega brz i efikasan alat za procenu faktora intenziteta napona čak i u slučaju 3D konfiguracija sa višestrukim prslinama. Poređenje rezultata pokazalo je i značaj preciznog izračunavanja faktora intenziteta napona, kako bi se omogućilo bolje razumevanje i predviđanje širenja 3D prslina., In this paper a versatile and easy to use approximate procedure was used for the estimation of mode I stress intensity factors in case of multiple surface cracks in a three dimensional elastic body, subjected to remote uniaxial tensile loading. The mentioned method uses known solutions for either 2D or 3D configurations containing only one crack, and takes into consideration the interaction effect between cracks. This procedure, which is based on the principle of superposition, was applied on a configuration with three coplanar semi-elliptical cracks embedded in three dimensional elastic body, subjected to remote uniaxial tensile loading. All cracks are located in the same plane at the same distances, in the middle of the body and the applied stress is perpendicular to the cracks plane. For the verification purposes, the stress intensity factors solutions were obtained by using finite element method based computer program. The conducted analysis showed that approximate method is, above all, fast and efficient tool for stress intensity factors assessment even in the case of 3D configurations with multiple site damage. The comparison between results also showed the significance of accurate calculation of stress intensity factors, in order to provide a better understanding and prediction of 3D multiple cracks propagation.",
publisher = "Univerzitet u Beogradu - Mašinski fakultet, Beograd",
journal = "FME Transactions",
title = "Aproksimativno određivanje faktora intenziteta napona za slučaj višestrukih površinskih prslina, Approximate determination of stress intensity factor for multiple surface cracks",
pages = "45-39",
number = "1",
volume = "46",
doi = "10.5937/fmet1801039K"
}

Kastratović, G., Vidanović, N., Grbović, A.,& Rašuo, B.. (2018). Aproksimativno određivanje faktora intenziteta napona za slučaj višestrukih površinskih prslina. in FME Transactions
Univerzitet u Beogradu - Mašinski fakultet, Beograd., 46(1), 39-45.
https://doi.org/10.5937/fmet1801039K

Kastratović G, Vidanović N, Grbović A, Rašuo B. Aproksimativno određivanje faktora intenziteta napona za slučaj višestrukih površinskih prslina. in FME Transactions. 2018;46(1):39-45.
doi:10.5937/fmet1801039K .

Kastratović, Gordana, Vidanović, Nenad, Grbović, Aleksandar, Rašuo, Boško, "Aproksimativno određivanje faktora intenziteta napona za slučaj višestrukih površinskih prslina" in FME Transactions, 46, no. 1 (2018):39-45,
https://doi.org/10.5937/fmet1801039K . .

TY  - JOUR
AU  - Aldarwish, Mustafa
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
AU  - Lazić, Mirjana M.
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2905
AB  - The aim of this paper was to establish and demonstrate significant capacity and performances of extended finite element method (XFEM) to calculate stress intensity factors (SIFs) histories versus crack length for problems involving multiple, interacting cracks resulting from multiple site damage (MSD). A typical aero structural configuration was analysed: unstiffened flat panel made of aluminium Al 2024-T3, containing 11 holes, each of which is a site for crack growth. Analysed model makes a unique 3D configuration with 22 cracks, propagating at the same time. Short theoretical background information is provided on the XFEM, as well as representation of cracks and SIFs computation. The computations were carried out in Morfeo/Crack for Abaqus software which relies on the implementation of XFEM. The accuracy of these computations was verified through FRANC2D/L software and superposition based approximate method. The conducted analysis showed that XFEM is efficient tool for the simulation of crack propagation even in the case of 3D configurations with MSD, and that the obtained solutions can be used for the prediction of SIFs in analysed MSD configuration with acceptable accuracy.
PB  - Univ Osijek, Tech Fac, Slavonski Brod
T2  - Tehnički vjesnik
T1  - Stress Intensity Factors Evaluation at Tips of Multi-Site Cracks in Unstiffened 2024-T3 Aluminium Panel Using XFEM
EP  - 1622
IS  - 6
SP  - 1616
VL  - 25
DO  - 10.17559/TV-20170309133824
ER  - 

@article{
author = "Aldarwish, Mustafa and Grbović, Aleksandar and Kastratović, Gordana and Sedmak, Aleksandar and Lazić, Mirjana M.",
year = "2018",
abstract = "The aim of this paper was to establish and demonstrate significant capacity and performances of extended finite element method (XFEM) to calculate stress intensity factors (SIFs) histories versus crack length for problems involving multiple, interacting cracks resulting from multiple site damage (MSD). A typical aero structural configuration was analysed: unstiffened flat panel made of aluminium Al 2024-T3, containing 11 holes, each of which is a site for crack growth. Analysed model makes a unique 3D configuration with 22 cracks, propagating at the same time. Short theoretical background information is provided on the XFEM, as well as representation of cracks and SIFs computation. The computations were carried out in Morfeo/Crack for Abaqus software which relies on the implementation of XFEM. The accuracy of these computations was verified through FRANC2D/L software and superposition based approximate method. The conducted analysis showed that XFEM is efficient tool for the simulation of crack propagation even in the case of 3D configurations with MSD, and that the obtained solutions can be used for the prediction of SIFs in analysed MSD configuration with acceptable accuracy.",
publisher = "Univ Osijek, Tech Fac, Slavonski Brod",
journal = "Tehnički vjesnik",
title = "Stress Intensity Factors Evaluation at Tips of Multi-Site Cracks in Unstiffened 2024-T3 Aluminium Panel Using XFEM",
pages = "1622-1616",
number = "6",
volume = "25",
doi = "10.17559/TV-20170309133824"
}

Aldarwish, M., Grbović, A., Kastratović, G., Sedmak, A.,& Lazić, M. M.. (2018). Stress Intensity Factors Evaluation at Tips of Multi-Site Cracks in Unstiffened 2024-T3 Aluminium Panel Using XFEM. in Tehnički vjesnik
Univ Osijek, Tech Fac, Slavonski Brod., 25(6), 1616-1622.
https://doi.org/10.17559/TV-20170309133824

Aldarwish M, Grbović A, Kastratović G, Sedmak A, Lazić MM. Stress Intensity Factors Evaluation at Tips of Multi-Site Cracks in Unstiffened 2024-T3 Aluminium Panel Using XFEM. in Tehnički vjesnik. 2018;25(6):1616-1622.
doi:10.17559/TV-20170309133824 .

Aldarwish, Mustafa, Grbović, Aleksandar, Kastratović, Gordana, Sedmak, Aleksandar, Lazić, Mirjana M., "Stress Intensity Factors Evaluation at Tips of Multi-Site Cracks in Unstiffened 2024-T3 Aluminium Panel Using XFEM" in Tehnički vjesnik, 25, no. 6 (2018):1616-1622,
https://doi.org/10.17559/TV-20170309133824 . .

TY  - JOUR
AU  - Eldwaib, Khalid
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Radu, Dorin
AU  - Sedmak, Simon
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2728
AB  - In this study a central crack tension (CCT) specimen is chosen for analysis to demonstrate the capability and reliability of the extended finite element method (XFEM) in predicting the crack propagation trajectory and evaluating stress intensity factors (SIFs). This specimen is frequently used in fatigue tests for studying various effects on fatigue crack propagation and for obtaining crack growth properties of a material. The XFEM obtained SIFs solutions are compared with several well-known solutions from literature. Evaluation of fatigue life of the CCT specimen is also carried out and compared with the obtained by NASGRO.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Fatigue life estimation of cct specimen using xfem
EP  - 156
IS  - 2
SP  - 151
VL  - 17
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2728
ER  - 

@article{
author = "Eldwaib, Khalid and Grbović, Aleksandar and Kastratović, Gordana and Radu, Dorin and Sedmak, Simon",
year = "2017",
abstract = "In this study a central crack tension (CCT) specimen is chosen for analysis to demonstrate the capability and reliability of the extended finite element method (XFEM) in predicting the crack propagation trajectory and evaluating stress intensity factors (SIFs). This specimen is frequently used in fatigue tests for studying various effects on fatigue crack propagation and for obtaining crack growth properties of a material. The XFEM obtained SIFs solutions are compared with several well-known solutions from literature. Evaluation of fatigue life of the CCT specimen is also carried out and compared with the obtained by NASGRO.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Fatigue life estimation of cct specimen using xfem",
pages = "156-151",
number = "2",
volume = "17",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2728"
}

Eldwaib, K., Grbović, A., Kastratović, G., Radu, D.,& Sedmak, S.. (2017). Fatigue life estimation of cct specimen using xfem. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 17(2), 151-156.
https://hdl.handle.net/21.15107/rcub_machinery_2728

Eldwaib K, Grbović A, Kastratović G, Radu D, Sedmak S. Fatigue life estimation of cct specimen using xfem. in Structural Integrity and Life. 2017;17(2):151-156.
https://hdl.handle.net/21.15107/rcub_machinery_2728 .

Eldwaib, Khalid, Grbović, Aleksandar, Kastratović, Gordana, Radu, Dorin, Sedmak, Simon, "Fatigue life estimation of cct specimen using xfem" in Structural Integrity and Life, 17, no. 2 (2017):151-156,
https://hdl.handle.net/21.15107/rcub_machinery_2728 .

TY  - JOUR
AU  - Aldarwish, Mustafa
AU  - Grbović, Aleksandar
AU  - Kastratović, Gordana
AU  - Sedmak, Aleksandar
AU  - Vidanović, Nenad
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2739
AB  - The aim of this paper is to establish and demonstrate diverse capacity and performances of different numerical methods for calculating stress intensity factors' (SIFs) histories versus crack length for problems involving multiple, interacting cracks resulting from multiple site damage (MSD). A typical aero structural configuration is analysed: unstiffened flat panel made of aluminium Al 2024-T3, containing 11 holes, each of which is a site for crack growth. Analysed model makes a complex configuration with 22 cracks, propagating at the same time. The computations are carried out in FRANC2D software which is FEM based and with superposition based approximate method. The comparison of the results has shown that obtained solutions can be used for SIF predictions with acceptable accuracy.
PB  - Institut za ispitivanje materijala, Beograd
T2  - Structural Integrity and Life
T1  - Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel
EP  - 14
IS  - 1
SP  - 11
VL  - 17
UR  - https://hdl.handle.net/21.15107/rcub_machinery_2739
ER  - 

@article{
author = "Aldarwish, Mustafa and Grbović, Aleksandar and Kastratović, Gordana and Sedmak, Aleksandar and Vidanović, Nenad",
year = "2017",
abstract = "The aim of this paper is to establish and demonstrate diverse capacity and performances of different numerical methods for calculating stress intensity factors' (SIFs) histories versus crack length for problems involving multiple, interacting cracks resulting from multiple site damage (MSD). A typical aero structural configuration is analysed: unstiffened flat panel made of aluminium Al 2024-T3, containing 11 holes, each of which is a site for crack growth. Analysed model makes a complex configuration with 22 cracks, propagating at the same time. The computations are carried out in FRANC2D software which is FEM based and with superposition based approximate method. The comparison of the results has shown that obtained solutions can be used for SIF predictions with acceptable accuracy.",
publisher = "Institut za ispitivanje materijala, Beograd",
journal = "Structural Integrity and Life",
title = "Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel",
pages = "14-11",
number = "1",
volume = "17",
url = "https://hdl.handle.net/21.15107/rcub_machinery_2739"
}

Aldarwish, M., Grbović, A., Kastratović, G., Sedmak, A.,& Vidanović, N.. (2017). Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel. in Structural Integrity and Life
Institut za ispitivanje materijala, Beograd., 17(1), 11-14.
https://hdl.handle.net/21.15107/rcub_machinery_2739

Aldarwish M, Grbović A, Kastratović G, Sedmak A, Vidanović N. Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel. in Structural Integrity and Life. 2017;17(1):11-14.
https://hdl.handle.net/21.15107/rcub_machinery_2739 .

Aldarwish, Mustafa, Grbović, Aleksandar, Kastratović, Gordana, Sedmak, Aleksandar, Vidanović, Nenad, "Numerical assessment of stress intensity factors at tips of multi-site cracks in unstiffened panel" in Structural Integrity and Life, 17, no. 1 (2017):11-14,
https://hdl.handle.net/21.15107/rcub_machinery_2739 .