TY  - CONF
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Jevtić, Dejan
AU  - Đurović, Radovan
PY  - 2024
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7802
AB  - Shaped charge effect have been successfully used in various fields, including defense (anti-armor projectiles and warheads) and non-military (explosive demolitions, oil and natural gas industry) applications. The shaped charge mechanism relies on conversion of explosive charge detonation energy into kinetic energy of a hypervelocity metal penetrator, known as a jet [1]. The focus of the present research is on the jet interaction with the target material and consequent target penetration. 
Two approaches to the jet penetration depth determination are considered. The first is the well-known analytical model based on the virtual origin concept [2, 3]. The second approach is the numerical modeling of the penetration process. The commercial FEM based software Abaqus/Explicit has been used for simulations and the model formulation is described in detail. The complete process of the shaped charge jet formation and penetration is successfully simulated using the pure Eulerian approach with appropriate material models [4].
Comprehensive comparison between results obtained using various theoretical models (analytical and numerical) and experimental data has been made. The following process parameters are considered: jet tip velocity, jet diameter, target cavity diameter, penetration time and penetration depth (Fig. 1). The jet velocity gradient and jet evolution are carefully analyzed in order to provide evaluation of the position of the virtual origin in time-space coordinates (Fig. 2). Comparison of analytical and numerical model results in terms of the jet tip velocity, penetration velocity and penetration depth has been performed. In contrast to the theoretically constant ratio of penetration velocity to jet tip velocity, the simulation results show that this ratio is actually variable. Analytically determined penetration depth is about 10% higher than numerical evaluation. Generally, an acceptable correlation between analytical and numerical model results has been found, which nevertheless shows that an improvement of analytical models is needed.
PB  - Fraunhofer Institute for High Speed Dynamics, Ernst-Mach-Institut, EMI, Germany
C3  - Proceedings of the 4th International Conference on Impact Loading of Structures and Materials
T1  - Numerical and analytical modeling of a shaped charge penetration depth
EP  - 89
SP  - 88
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7802
ER  - 

@conference{
author = "Elek, Predrag and Marković, Miloš and Jevtić, Dejan and Đurović, Radovan",
year = "2024",
abstract = "Shaped charge effect have been successfully used in various fields, including defense (anti-armor projectiles and warheads) and non-military (explosive demolitions, oil and natural gas industry) applications. The shaped charge mechanism relies on conversion of explosive charge detonation energy into kinetic energy of a hypervelocity metal penetrator, known as a jet [1]. The focus of the present research is on the jet interaction with the target material and consequent target penetration. 
Two approaches to the jet penetration depth determination are considered. The first is the well-known analytical model based on the virtual origin concept [2, 3]. The second approach is the numerical modeling of the penetration process. The commercial FEM based software Abaqus/Explicit has been used for simulations and the model formulation is described in detail. The complete process of the shaped charge jet formation and penetration is successfully simulated using the pure Eulerian approach with appropriate material models [4].
Comprehensive comparison between results obtained using various theoretical models (analytical and numerical) and experimental data has been made. The following process parameters are considered: jet tip velocity, jet diameter, target cavity diameter, penetration time and penetration depth (Fig. 1). The jet velocity gradient and jet evolution are carefully analyzed in order to provide evaluation of the position of the virtual origin in time-space coordinates (Fig. 2). Comparison of analytical and numerical model results in terms of the jet tip velocity, penetration velocity and penetration depth has been performed. In contrast to the theoretically constant ratio of penetration velocity to jet tip velocity, the simulation results show that this ratio is actually variable. Analytically determined penetration depth is about 10% higher than numerical evaluation. Generally, an acceptable correlation between analytical and numerical model results has been found, which nevertheless shows that an improvement of analytical models is needed.",
publisher = "Fraunhofer Institute for High Speed Dynamics, Ernst-Mach-Institut, EMI, Germany",
journal = "Proceedings of the 4th International Conference on Impact Loading of Structures and Materials",
title = "Numerical and analytical modeling of a shaped charge penetration depth",
pages = "89-88",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7802"
}

Elek, P., Marković, M., Jevtić, D.,& Đurović, R.. (2024). Numerical and analytical modeling of a shaped charge penetration depth. in Proceedings of the 4th International Conference on Impact Loading of Structures and Materials
Fraunhofer Institute for High Speed Dynamics, Ernst-Mach-Institut, EMI, Germany., 88-89.
https://hdl.handle.net/21.15107/rcub_machinery_7802

Elek P, Marković M, Jevtić D, Đurović R. Numerical and analytical modeling of a shaped charge penetration depth. in Proceedings of the 4th International Conference on Impact Loading of Structures and Materials. 2024;:88-89.
https://hdl.handle.net/21.15107/rcub_machinery_7802 .

Elek, Predrag, Marković, Miloš, Jevtić, Dejan, Đurović, Radovan, "Numerical and analytical modeling of a shaped charge penetration depth" in Proceedings of the 4th International Conference on Impact Loading of Structures and Materials (2024):88-89,
https://hdl.handle.net/21.15107/rcub_machinery_7802 .

TY  - CONF
AU  - Elek, Predrag
AU  - Đorđević, Miroslav
AU  - Marković, Miloš
AU  - Jevtić, Dejan
AU  - Đurović, Radovan
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/7075
AB  - Characterization of behind armor debris (BAD) is of utmost importance from the aspect of evaluation of an armor piercing projectile efficiency, as well as from the point of target vulnerability. The focus of the study is on the size, shape, total number, mass and velocity of fragments generated from the target plate. The experimental results of perforation of 6.35 mm thick steel plates by 12.7 mm armor-piercing projectile have been reported. Projectile impact and residual velocity were measured by the muzzle velocity radar system and make-up screens, respectively. The mass and shape distribution of a generated BAD cloud and its energetic properties were determined using the calibrated witness pack. The proposed analytical model of the problem is based on the energy conservation, fracture mechanics and fragmentation theory. A good agreement is observed between calculated results and experimental data in terms of the shape, characteristic size, mass and velocity distribution of generated fragments.
PB  - DESTech Publications, Inc.
C3  - 33rd International Symposium on Ballistics, Bruges, Belgium, 16-20 October 2023
T1  - Experimental and analytical study of behind armor debris after perforation of a steel plate by an AP projectile
SP  - pp. 1726-1737
UR  - https://hdl.handle.net/21.15107/rcub_machinery_7075
ER  - 

@conference{
author = "Elek, Predrag and Đorđević, Miroslav and Marković, Miloš and Jevtić, Dejan and Đurović, Radovan",
year = "2023",
abstract = "Characterization of behind armor debris (BAD) is of utmost importance from the aspect of evaluation of an armor piercing projectile efficiency, as well as from the point of target vulnerability. The focus of the study is on the size, shape, total number, mass and velocity of fragments generated from the target plate. The experimental results of perforation of 6.35 mm thick steel plates by 12.7 mm armor-piercing projectile have been reported. Projectile impact and residual velocity were measured by the muzzle velocity radar system and make-up screens, respectively. The mass and shape distribution of a generated BAD cloud and its energetic properties were determined using the calibrated witness pack. The proposed analytical model of the problem is based on the energy conservation, fracture mechanics and fragmentation theory. A good agreement is observed between calculated results and experimental data in terms of the shape, characteristic size, mass and velocity distribution of generated fragments.",
publisher = "DESTech Publications, Inc.",
journal = "33rd International Symposium on Ballistics, Bruges, Belgium, 16-20 October 2023",
title = "Experimental and analytical study of behind armor debris after perforation of a steel plate by an AP projectile",
pages = "pp. 1726-1737",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7075"
}

Elek, P., Đorđević, M., Marković, M., Jevtić, D.,& Đurović, R.. (2023). Experimental and analytical study of behind armor debris after perforation of a steel plate by an AP projectile. in 33rd International Symposium on Ballistics, Bruges, Belgium, 16-20 October 2023
DESTech Publications, Inc.., pp. 1726-1737.
https://hdl.handle.net/21.15107/rcub_machinery_7075

Elek P, Đorđević M, Marković M, Jevtić D, Đurović R. Experimental and analytical study of behind armor debris after perforation of a steel plate by an AP projectile. in 33rd International Symposium on Ballistics, Bruges, Belgium, 16-20 October 2023. 2023;:pp. 1726-1737.
https://hdl.handle.net/21.15107/rcub_machinery_7075 .

Elek, Predrag, Đorđević, Miroslav, Marković, Miloš, Jevtić, Dejan, Đurović, Radovan, "Experimental and analytical study of behind armor debris after perforation of a steel plate by an AP projectile" in 33rd International Symposium on Ballistics, Bruges, Belgium, 16-20 October 2023 (2023):pp. 1726-1737,
https://hdl.handle.net/21.15107/rcub_machinery_7075 .

TY  - CONF
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Jevtić, Dejan
AU  - Đurović, Radovan
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6910
AB  - The shaped charge effect is currently the most powerful target penetration mechanism. It relies on conversion of explosive charge detonation energy into kinetic energy of a hypervelocity metal penetrator, known as a jet. The first stage of the shaped charge mechanism is formation of the jet through processes of detonation wave propagation and interaction with a metal liner which accelerates and collapses towards the symmetry axis creating the slug and the jet. Our focus in the present research is on the second stage of the process: the jet interaction with the target material and consequent target penetration/perforation. 
There are many approaches to the modeling of shaped charge jet penetration depth into target material. Two major analytical models are: the simple density law and the model with variable jet velocity. However, the most accurate is the approach based on numerical simulations using so called hydrocodes. Modeling and simulation in Abaqus/Explicit software is presented in detail. The complete process of jet formation and penetration is simulated using the Eulerian approach.
Comprehensive comparison between results obtained using various theoretical models (analytical and numerical) and experimental data has been performed providing useful insights and conclusions.
PB  - Belgrade : Serbian Society of Mechanics
C3  - 9th Congress of the Serbian Society of Mechanics, July 5-7, 2023, Vrnjačka Banja, Serbia
T1  - Modeling of penetration depth of a shaped charge jet
EP  - 1
SP  - 1
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6910
ER  - 

@conference{
author = "Elek, Predrag and Marković, Miloš and Jevtić, Dejan and Đurović, Radovan",
year = "2023",
abstract = "The shaped charge effect is currently the most powerful target penetration mechanism. It relies on conversion of explosive charge detonation energy into kinetic energy of a hypervelocity metal penetrator, known as a jet. The first stage of the shaped charge mechanism is formation of the jet through processes of detonation wave propagation and interaction with a metal liner which accelerates and collapses towards the symmetry axis creating the slug and the jet. Our focus in the present research is on the second stage of the process: the jet interaction with the target material and consequent target penetration/perforation. 
There are many approaches to the modeling of shaped charge jet penetration depth into target material. Two major analytical models are: the simple density law and the model with variable jet velocity. However, the most accurate is the approach based on numerical simulations using so called hydrocodes. Modeling and simulation in Abaqus/Explicit software is presented in detail. The complete process of jet formation and penetration is simulated using the Eulerian approach.
Comprehensive comparison between results obtained using various theoretical models (analytical and numerical) and experimental data has been performed providing useful insights and conclusions.",
publisher = "Belgrade : Serbian Society of Mechanics",
journal = "9th Congress of the Serbian Society of Mechanics, July 5-7, 2023, Vrnjačka Banja, Serbia",
title = "Modeling of penetration depth of a shaped charge jet",
pages = "1-1",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6910"
}

Elek, P., Marković, M., Jevtić, D.,& Đurović, R.. (2023). Modeling of penetration depth of a shaped charge jet. in 9th Congress of the Serbian Society of Mechanics, July 5-7, 2023, Vrnjačka Banja, Serbia
Belgrade : Serbian Society of Mechanics., 1-1.
https://hdl.handle.net/21.15107/rcub_machinery_6910

Elek P, Marković M, Jevtić D, Đurović R. Modeling of penetration depth of a shaped charge jet. in 9th Congress of the Serbian Society of Mechanics, July 5-7, 2023, Vrnjačka Banja, Serbia. 2023;:1-1.
https://hdl.handle.net/21.15107/rcub_machinery_6910 .

Elek, Predrag, Marković, Miloš, Jevtić, Dejan, Đurović, Radovan, "Modeling of penetration depth of a shaped charge jet" in 9th Congress of the Serbian Society of Mechanics, July 5-7, 2023, Vrnjačka Banja, Serbia (2023):1-1,
https://hdl.handle.net/21.15107/rcub_machinery_6910 .

TY  - JOUR
AU  - Marković, Miloš
AU  - Elek, Predrag
AU  - Jaramaz, Dragana
AU  - Jevtić, Dejan
AU  - Đurović, Radovan
AU  - Jaramaz, Lana
AU  - Micković, Dušan
PY  - 2023
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6064
AB  - The purpose of a gun bore evacuator on the turret-mounted gun barrel is to prevent the entry of the gaseous products of gun propellant combustion into the turret compartment of the vehicle after the breech block opening. The mathematical
model which takes into account all of the main parameters influencing the pressure
change inside the cylinder of the evacuator was developed. Differential equations
that describe the flow field through the nozzle in the barrel wall and in the cylinder
of the evacuator were solved numerically. Furthermore, the numerical simulations
were performed using the ANSYS FLUENT in order to analyze the phenomena
occuring in the evacuator during the charge and discharge cycles which are difficult to be taken into account with the analytical model. Aforementioned simulations were performed with the 3-D model of the evacuator and with the initial and
boundary conditions obtained from the interior ballistic calculations. In order to
find the change of the static pressure in the cylinder of the gun bore evacuator, the
experimental research was performed. The comprehensive comparison between
the numerical results and the experimental data has shown good agreement. Based
upon this analysis, the influence of the evacuator’s main design parameters on the
pressure distribution and the temperatures in the critical zones was determined.
The influence of the propellant’s initial temperature on the pressure and wall temperatures in the evacuator was also analyzed, due to the wide range of gun operating temperatures and the possibility of erosion occurrence
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Analysis of parameters influencing the pressure and temperature distribution in the gun bore evacuator
EP  - 738
IS  - 1B
SP  - 727
VL  - 27
DO  - 10.2298/TSCI220409102M
ER  - 

@article{
author = "Marković, Miloš and Elek, Predrag and Jaramaz, Dragana and Jevtić, Dejan and Đurović, Radovan and Jaramaz, Lana and Micković, Dušan",
year = "2023",
abstract = "The purpose of a gun bore evacuator on the turret-mounted gun barrel is to prevent the entry of the gaseous products of gun propellant combustion into the turret compartment of the vehicle after the breech block opening. The mathematical
model which takes into account all of the main parameters influencing the pressure
change inside the cylinder of the evacuator was developed. Differential equations
that describe the flow field through the nozzle in the barrel wall and in the cylinder
of the evacuator were solved numerically. Furthermore, the numerical simulations
were performed using the ANSYS FLUENT in order to analyze the phenomena
occuring in the evacuator during the charge and discharge cycles which are difficult to be taken into account with the analytical model. Aforementioned simulations were performed with the 3-D model of the evacuator and with the initial and
boundary conditions obtained from the interior ballistic calculations. In order to
find the change of the static pressure in the cylinder of the gun bore evacuator, the
experimental research was performed. The comprehensive comparison between
the numerical results and the experimental data has shown good agreement. Based
upon this analysis, the influence of the evacuator’s main design parameters on the
pressure distribution and the temperatures in the critical zones was determined.
The influence of the propellant’s initial temperature on the pressure and wall temperatures in the evacuator was also analyzed, due to the wide range of gun operating temperatures and the possibility of erosion occurrence",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Analysis of parameters influencing the pressure and temperature distribution in the gun bore evacuator",
pages = "738-727",
number = "1B",
volume = "27",
doi = "10.2298/TSCI220409102M"
}

Marković, M., Elek, P., Jaramaz, D., Jevtić, D., Đurović, R., Jaramaz, L.,& Micković, D.. (2023). Analysis of parameters influencing the pressure and temperature distribution in the gun bore evacuator. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 27(1B), 727-738.
https://doi.org/10.2298/TSCI220409102M

Marković M, Elek P, Jaramaz D, Jevtić D, Đurović R, Jaramaz L, Micković D. Analysis of parameters influencing the pressure and temperature distribution in the gun bore evacuator. in Thermal Science. 2023;27(1B):727-738.
doi:10.2298/TSCI220409102M .

Marković, Miloš, Elek, Predrag, Jaramaz, Dragana, Jevtić, Dejan, Đurović, Radovan, Jaramaz, Lana, Micković, Dušan, "Analysis of parameters influencing the pressure and temperature distribution in the gun bore evacuator" in Thermal Science, 27, no. 1B (2023):727-738,
https://doi.org/10.2298/TSCI220409102M . .

TY  - CONF
AU  - Al Ameri, Omar
AU  - Elek, Predrag
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4871
AB  - The efficiency of the weapon system has been usually studied by altering the guidance and control or aerodynamics of the missile. This research investigated methods of enhancing the efficiency of the weapon system against soft targets based on the fragmentation warhead design. Different warhead geometric configurations, initiation points, as well as premade fragment material and shapes have been studied to enhance overall weapon efficiency against soft target. The study considered the static fragment distribution and velocity as the base for the analysis. A new vulnerability code has been developed based on the mean area of effectiveness to prove the study using both simulations and field tests. There were significant improvements on the weapon efficiency by altering the warhead parameters. The simulated results showed good correspondence with the test results. The newly developed vulnerability code can be
considered as an additional system engineering analysis tool for the calculations of weapon efficiency.
PB  - Belgrade : Military Technical Institute
C3  - 10th Scientific Conference on Defensive Technologies OTEH 2022
T1  - Efficiency analysis of a fragmentation warhead against soft targets
EP  - 79
SP  - 72
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4871
ER  - 

@conference{
author = "Al Ameri, Omar and Elek, Predrag",
year = "2022",
abstract = "The efficiency of the weapon system has been usually studied by altering the guidance and control or aerodynamics of the missile. This research investigated methods of enhancing the efficiency of the weapon system against soft targets based on the fragmentation warhead design. Different warhead geometric configurations, initiation points, as well as premade fragment material and shapes have been studied to enhance overall weapon efficiency against soft target. The study considered the static fragment distribution and velocity as the base for the analysis. A new vulnerability code has been developed based on the mean area of effectiveness to prove the study using both simulations and field tests. There were significant improvements on the weapon efficiency by altering the warhead parameters. The simulated results showed good correspondence with the test results. The newly developed vulnerability code can be
considered as an additional system engineering analysis tool for the calculations of weapon efficiency.",
publisher = "Belgrade : Military Technical Institute",
journal = "10th Scientific Conference on Defensive Technologies OTEH 2022",
title = "Efficiency analysis of a fragmentation warhead against soft targets",
pages = "79-72",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4871"
}

Al Ameri, O.,& Elek, P.. (2022). Efficiency analysis of a fragmentation warhead against soft targets. in 10th Scientific Conference on Defensive Technologies OTEH 2022
Belgrade : Military Technical Institute., 72-79.
https://hdl.handle.net/21.15107/rcub_machinery_4871

Al Ameri O, Elek P. Efficiency analysis of a fragmentation warhead against soft targets. in 10th Scientific Conference on Defensive Technologies OTEH 2022. 2022;:72-79.
https://hdl.handle.net/21.15107/rcub_machinery_4871 .

Al Ameri, Omar, Elek, Predrag, "Efficiency analysis of a fragmentation warhead against soft targets" in 10th Scientific Conference on Defensive Technologies OTEH 2022 (2022):72-79,
https://hdl.handle.net/21.15107/rcub_machinery_4871 .

TY  - CONF
AU  - Elek, Predrag
AU  - Đurović, Radovan
AU  - Hristov, Nebojša
AU  - Jerković, Damir
AU  - Aničić, Aleksa
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4541
AB  - In the present study, penetration of a 6 mm thick ARMOX 500T high-hardness steel plate by a 7.62x39 mm armor-piercing incendiary bullet with a hard steel core was experimentally investigated. Projectile’s impact velocity has been varied in order to determine its influence on the interaction between the penetrator and the target during the penetration process. The initial velocity was measured by the optical measurement system while the residual velocity was measured using the contact screens. Analytical model for the impact velocity calculation was experimentally verified. Based on the obtained ballistic test results, ballistic limit velocity of the target plate was determined and the residual versus impact velocity curve was formed. Furthermore, categorization of the performed firings was conducted in accordance with the observed penetration process outcomes. Finally, target material failure mechanism and its change due to the increase in the projectile’s impact velocity was investigated.
PB  - Belgrade : The Military Technical Institute
C3  - 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade
T1  - Experimental investigation on the perforation of high-hardness steel plate by an API projectile
EP  - 149
SP  - 144
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4541
ER  - 

@conference{
author = "Elek, Predrag and Đurović, Radovan and Hristov, Nebojša and Jerković, Damir and Aničić, Aleksa",
year = "2022",
abstract = "In the present study, penetration of a 6 mm thick ARMOX 500T high-hardness steel plate by a 7.62x39 mm armor-piercing incendiary bullet with a hard steel core was experimentally investigated. Projectile’s impact velocity has been varied in order to determine its influence on the interaction between the penetrator and the target during the penetration process. The initial velocity was measured by the optical measurement system while the residual velocity was measured using the contact screens. Analytical model for the impact velocity calculation was experimentally verified. Based on the obtained ballistic test results, ballistic limit velocity of the target plate was determined and the residual versus impact velocity curve was formed. Furthermore, categorization of the performed firings was conducted in accordance with the observed penetration process outcomes. Finally, target material failure mechanism and its change due to the increase in the projectile’s impact velocity was investigated.",
publisher = "Belgrade : The Military Technical Institute",
journal = "10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade",
title = "Experimental investigation on the perforation of high-hardness steel plate by an API projectile",
pages = "149-144",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4541"
}

Elek, P., Đurović, R., Hristov, N., Jerković, D.,& Aničić, A.. (2022). Experimental investigation on the perforation of high-hardness steel plate by an API projectile. in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade
Belgrade : The Military Technical Institute., 144-149.
https://hdl.handle.net/21.15107/rcub_machinery_4541

Elek P, Đurović R, Hristov N, Jerković D, Aničić A. Experimental investigation on the perforation of high-hardness steel plate by an API projectile. in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade. 2022;:144-149.
https://hdl.handle.net/21.15107/rcub_machinery_4541 .

Elek, Predrag, Đurović, Radovan, Hristov, Nebojša, Jerković, Damir, Aničić, Aleksa, "Experimental investigation on the perforation of high-hardness steel plate by an API projectile" in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade (2022):144-149,
https://hdl.handle.net/21.15107/rcub_machinery_4541 .

TY  - CONF
AU  - Đurović, Radovan
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Jevtić, Dejan
AU  - Erčević, Mihailo
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4997
AB  - In the present study, penetration of a 6.5 mm Grendel armor-piercing projectile with a front tungsten carbidecobalt core and rear lead-antimony core into the 8.5 mm PROTAC 500 high hardness armor steel plate was analyzed both experimentally and numerically. Ballistic tests were performed in which the projectile’s initial velocity had the value of 740 m/s. Experimental results have shown that the partial perforation with the projectile embedment was the most frequent outcome. Two-dimensional axisymmetric non-linear numerical model corresponding to the performed tests was developed in ANSYS AUTODYN software using the mesh based Lagrangian technique. Johnson-Cook strength and failure models were employed for the characterization of the material behavior. Developed numerical model was verified against the experimental results and the influence of the projectile’s impact velocity on the parameters of the penetration was investigated. Rear lead alloy core was found to be able to provide significant enhancement of the projectile’s efficiency.
PB  - Belgrade : Military Technical Institute
C3  - 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade
T1  - Numerical analysis of the tungsten carbide-cobalt cored bullet penetrating the high-hardness steel plate
SP  - 161/61
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4997
ER  - 

@conference{
author = "Đurović, Radovan and Elek, Predrag and Marković, Miloš and Jevtić, Dejan and Erčević, Mihailo",
year = "2022",
abstract = "In the present study, penetration of a 6.5 mm Grendel armor-piercing projectile with a front tungsten carbidecobalt core and rear lead-antimony core into the 8.5 mm PROTAC 500 high hardness armor steel plate was analyzed both experimentally and numerically. Ballistic tests were performed in which the projectile’s initial velocity had the value of 740 m/s. Experimental results have shown that the partial perforation with the projectile embedment was the most frequent outcome. Two-dimensional axisymmetric non-linear numerical model corresponding to the performed tests was developed in ANSYS AUTODYN software using the mesh based Lagrangian technique. Johnson-Cook strength and failure models were employed for the characterization of the material behavior. Developed numerical model was verified against the experimental results and the influence of the projectile’s impact velocity on the parameters of the penetration was investigated. Rear lead alloy core was found to be able to provide significant enhancement of the projectile’s efficiency.",
publisher = "Belgrade : Military Technical Institute",
journal = "10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade",
title = "Numerical analysis of the tungsten carbide-cobalt cored bullet penetrating the high-hardness steel plate",
pages = "161/61",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4997"
}

Đurović, R., Elek, P., Marković, M., Jevtić, D.,& Erčević, M.. (2022). Numerical analysis of the tungsten carbide-cobalt cored bullet penetrating the high-hardness steel plate. in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade
Belgrade : Military Technical Institute., 161/61.
https://hdl.handle.net/21.15107/rcub_machinery_4997

Đurović R, Elek P, Marković M, Jevtić D, Erčević M. Numerical analysis of the tungsten carbide-cobalt cored bullet penetrating the high-hardness steel plate. in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade. 2022;:161/61.
https://hdl.handle.net/21.15107/rcub_machinery_4997 .

Đurović, Radovan, Elek, Predrag, Marković, Miloš, Jevtić, Dejan, Erčević, Mihailo, "Numerical analysis of the tungsten carbide-cobalt cored bullet penetrating the high-hardness steel plate" in 10th International Scientific Conference on Defensive Technologies – OTEH 2022, Belgrade (2022):161/61,
https://hdl.handle.net/21.15107/rcub_machinery_4997 .

TY  - CONF
AU  - Marković, Miloš
AU  - Elek, Predrag
AU  - Jevtić, Dejan
AU  - Đurović, Radovan
AU  - Todić, Ivana
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6050
AB  - Purpose of the precursor shaped charge warhead is to initiate the Explosive Reactive Armor (ERA) and thus
provide an unobstructed path to the jet of the main shaped charge. The precursor warhead is most commonly placed in
the front of the missile where it is surrounded by other subsystems. All of the subsystems which lay on the path of the
precursor warhead’s shaped charge jet represent the obstacle that will decrease its efficiency. The goal of this paper is
to analyze the precursor warhead’s performance in a case where the inhomogeneous obstacle is placed in front of it.
The numerical analysis of the obstructed formation process was performed in order to determine the properties of the
formed jet using ANSYS AUTODYN 2D software. For the existing missile configuration, jet formation process and
precursor warhead's performance against ERA were analyzed numerically. Significant differences in formed jet's
properties were observed for the simulations with and without the inhomogeneous obstacles. In the case of
inhomogeneous obstacle it is present decreasing of jet tip velocity for around 23%, decreasing of jet tip dimaeter for
around 50% and jet time are delayed in contact with ERA front panel for around 10 µs. Obtained results indicate that
in the observed cases, formed jet has enough energy to initiate the explosive reactive armor.
PB  - Belgrade : Military Technical Institute
C3  - 10th International Scientific Conference – OTEH 2022, Belgrade, 13-14 October 2022
T1  - Numerical analysis of the inhomogeneous obstacle influence on the precursor shaped charge warhead performance
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6050
ER  - 

@conference{
author = "Marković, Miloš and Elek, Predrag and Jevtić, Dejan and Đurović, Radovan and Todić, Ivana",
year = "2022",
abstract = "Purpose of the precursor shaped charge warhead is to initiate the Explosive Reactive Armor (ERA) and thus
provide an unobstructed path to the jet of the main shaped charge. The precursor warhead is most commonly placed in
the front of the missile where it is surrounded by other subsystems. All of the subsystems which lay on the path of the
precursor warhead’s shaped charge jet represent the obstacle that will decrease its efficiency. The goal of this paper is
to analyze the precursor warhead’s performance in a case where the inhomogeneous obstacle is placed in front of it.
The numerical analysis of the obstructed formation process was performed in order to determine the properties of the
formed jet using ANSYS AUTODYN 2D software. For the existing missile configuration, jet formation process and
precursor warhead's performance against ERA were analyzed numerically. Significant differences in formed jet's
properties were observed for the simulations with and without the inhomogeneous obstacles. In the case of
inhomogeneous obstacle it is present decreasing of jet tip velocity for around 23%, decreasing of jet tip dimaeter for
around 50% and jet time are delayed in contact with ERA front panel for around 10 µs. Obtained results indicate that
in the observed cases, formed jet has enough energy to initiate the explosive reactive armor.",
publisher = "Belgrade : Military Technical Institute",
journal = "10th International Scientific Conference – OTEH 2022, Belgrade, 13-14 October 2022",
title = "Numerical analysis of the inhomogeneous obstacle influence on the precursor shaped charge warhead performance",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6050"
}

Marković, M., Elek, P., Jevtić, D., Đurović, R.,& Todić, I.. (2022). Numerical analysis of the inhomogeneous obstacle influence on the precursor shaped charge warhead performance. in 10th International Scientific Conference – OTEH 2022, Belgrade, 13-14 October 2022
Belgrade : Military Technical Institute..
https://hdl.handle.net/21.15107/rcub_machinery_6050

Marković M, Elek P, Jevtić D, Đurović R, Todić I. Numerical analysis of the inhomogeneous obstacle influence on the precursor shaped charge warhead performance. in 10th International Scientific Conference – OTEH 2022, Belgrade, 13-14 October 2022. 2022;.
https://hdl.handle.net/21.15107/rcub_machinery_6050 .

Marković, Miloš, Elek, Predrag, Jevtić, Dejan, Đurović, Radovan, Todić, Ivana, "Numerical analysis of the inhomogeneous obstacle influence on the precursor shaped charge warhead performance" in 10th International Scientific Conference – OTEH 2022, Belgrade, 13-14 October 2022 (2022),
https://hdl.handle.net/21.15107/rcub_machinery_6050 .

TY  - JOUR
AU  - Tomić, Stefan
AU  - Elek, Predrag
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4571
AB  - The importance of investigation of main explosive charge initiation using booster charge stems directly from the objective to optimize the mass of booster charge needed to ensure steady state detonation of main explosive charge in order to achieve maximum projectile efficiency. Considered configuration consists of two explosives and three metal parts which represent
elements of fuze and projectile. The main objective of this paper is to develop a numerical model of initiation of main explosive charge of an insensitive artillery ammunition. Through this research two variants of detonation point location were analyzed, ideal and stochastic one. The effects of the detonation transfer are analyzed using the Jones-Wilkins-Lee and Ignition and Growth equation of state models for explosives, applying the Coupled Eulerian-Lagrangian approach in the Abaqus/Explicit software. Analytical computation is introduced in this paper with a purpose to present P-u interaction between configuration elements and for comparison with results obtained by numerical method. The results of analytical and numerical approach are presented and discussed in detail. It is shown that suggested numerical model enables simulation and optimization of explosive train in fuzes of HE projectiles.
PB  - Belgrade : Military Technical Institute
T2  - Scientific Technical Review
T1  - Numerical Analysis of Initiation of Main Explosive Charge in an Artillery Projectile
EP  - 54
IS  - 1
SP  - 48
VL  - 72
DO  - 10.5937/str2201048T
ER  - 

@article{
author = "Tomić, Stefan and Elek, Predrag",
year = "2022",
abstract = "The importance of investigation of main explosive charge initiation using booster charge stems directly from the objective to optimize the mass of booster charge needed to ensure steady state detonation of main explosive charge in order to achieve maximum projectile efficiency. Considered configuration consists of two explosives and three metal parts which represent
elements of fuze and projectile. The main objective of this paper is to develop a numerical model of initiation of main explosive charge of an insensitive artillery ammunition. Through this research two variants of detonation point location were analyzed, ideal and stochastic one. The effects of the detonation transfer are analyzed using the Jones-Wilkins-Lee and Ignition and Growth equation of state models for explosives, applying the Coupled Eulerian-Lagrangian approach in the Abaqus/Explicit software. Analytical computation is introduced in this paper with a purpose to present P-u interaction between configuration elements and for comparison with results obtained by numerical method. The results of analytical and numerical approach are presented and discussed in detail. It is shown that suggested numerical model enables simulation and optimization of explosive train in fuzes of HE projectiles.",
publisher = "Belgrade : Military Technical Institute",
journal = "Scientific Technical Review",
title = "Numerical Analysis of Initiation of Main Explosive Charge in an Artillery Projectile",
pages = "54-48",
number = "1",
volume = "72",
doi = "10.5937/str2201048T"
}

Tomić, S.,& Elek, P.. (2022). Numerical Analysis of Initiation of Main Explosive Charge in an Artillery Projectile. in Scientific Technical Review
Belgrade : Military Technical Institute., 72(1), 48-54.
https://doi.org/10.5937/str2201048T

Tomić S, Elek P. Numerical Analysis of Initiation of Main Explosive Charge in an Artillery Projectile. in Scientific Technical Review. 2022;72(1):48-54.
doi:10.5937/str2201048T .

Tomić, Stefan, Elek, Predrag, "Numerical Analysis of Initiation of Main Explosive Charge in an Artillery Projectile" in Scientific Technical Review, 72, no. 1 (2022):48-54,
https://doi.org/10.5937/str2201048T . .

TY  - JOUR
AU  - Al Ameri, Omar
AU  - Elek, Predrag
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4567
AB  - The efficiency of the weapon system has been usually studied by altering the guidance and control or aerodynamics of the missile. This research investigated methods of enhancing the efficiency of the weapon system against soft targets based on the fragmentation warhead design. Different warhead geometric configurations, initiation points, as well as premade fragment
material and shapes have been studied to enhance overall weapon efficiency against soft target. The study considered the static fragment distribution and velocity as the base for the analysis. A new vulnerability code has been developed based on the mean area of effectiveness to prove the study using both simulations and field tests. There were significant improvements
on the weapon efficiency by altering the warhead parameters. The simulated results showed good correspondence with the test results. The newly developed vulnerability code can be considered as an additional system engineering analysis tool for the calculations of weapon efficiency
PB  - Belgrade : Military Technical Institute
T2  - Scientific Technical Review
T1  - Efficiency Analysis of a Fragmentation Warhead Against Soft Targets
EP  - 26
IS  - 2
SP  - 19
VL  - 72
DO  - doi: 10.5937/str2202019A
ER  - 

@article{
author = "Al Ameri, Omar and Elek, Predrag",
year = "2022",
abstract = "The efficiency of the weapon system has been usually studied by altering the guidance and control or aerodynamics of the missile. This research investigated methods of enhancing the efficiency of the weapon system against soft targets based on the fragmentation warhead design. Different warhead geometric configurations, initiation points, as well as premade fragment
material and shapes have been studied to enhance overall weapon efficiency against soft target. The study considered the static fragment distribution and velocity as the base for the analysis. A new vulnerability code has been developed based on the mean area of effectiveness to prove the study using both simulations and field tests. There were significant improvements
on the weapon efficiency by altering the warhead parameters. The simulated results showed good correspondence with the test results. The newly developed vulnerability code can be considered as an additional system engineering analysis tool for the calculations of weapon efficiency",
publisher = "Belgrade : Military Technical Institute",
journal = "Scientific Technical Review",
title = "Efficiency Analysis of a Fragmentation Warhead Against Soft Targets",
pages = "26-19",
number = "2",
volume = "72",
doi = "doi: 10.5937/str2202019A"
}

Al Ameri, O.,& Elek, P.. (2022). Efficiency Analysis of a Fragmentation Warhead Against Soft Targets. in Scientific Technical Review
Belgrade : Military Technical Institute., 72(2), 19-26.
https://doi.org/doi: 10.5937/str2202019A

Al Ameri O, Elek P. Efficiency Analysis of a Fragmentation Warhead Against Soft Targets. in Scientific Technical Review. 2022;72(2):19-26.
doi:doi: 10.5937/str2202019A .

Al Ameri, Omar, Elek, Predrag, "Efficiency Analysis of a Fragmentation Warhead Against Soft Targets" in Scientific Technical Review, 72, no. 2 (2022):19-26,
https://doi.org/doi: 10.5937/str2202019A . .

TY  - JOUR
AU  - Alazeezi, Mohammed
AU  - Popović, Nikola P.
AU  - Elek, Predrag
PY  - 2022
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3788
AB  - The paper considers utilization of rocket motor propellant grains that consist of two propellants. The idea is to achieve approximately neutral burning using an outer surface inhibited cylindrical shape and complex contact surface between propellants. An existing propellant grain with complex geometry has been analytically modeled in terms of determination of evolution of corresponding burning surface areas. The analytical and experimental results' diagrams of this grain have been found to have a saw-tooth shape because of the segments that separate the two propellants, causing potential problems in the burning process during the relatively short active phase, showing an obvious need for further optimization. This has created an opportunity for development of improved propellant grain geometry and corresponding mathematical model for determination of main interior ballistic parameters. Comparison between calculation results based on both models and experimentally determined chamber pressure data shows very good agreement. Therefore, two-component propellant grains have significant application possibilities using the suggested modeling approaches.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Two-component propellant grain for rocket motor combustion analysis and geometric optimization
EP  - 1578
IS  - 2
SP  - 1567
VL  - 26
DO  - 10.2298/TSCI210604290A
ER  - 

@article{
author = "Alazeezi, Mohammed and Popović, Nikola P. and Elek, Predrag",
year = "2022",
abstract = "The paper considers utilization of rocket motor propellant grains that consist of two propellants. The idea is to achieve approximately neutral burning using an outer surface inhibited cylindrical shape and complex contact surface between propellants. An existing propellant grain with complex geometry has been analytically modeled in terms of determination of evolution of corresponding burning surface areas. The analytical and experimental results' diagrams of this grain have been found to have a saw-tooth shape because of the segments that separate the two propellants, causing potential problems in the burning process during the relatively short active phase, showing an obvious need for further optimization. This has created an opportunity for development of improved propellant grain geometry and corresponding mathematical model for determination of main interior ballistic parameters. Comparison between calculation results based on both models and experimentally determined chamber pressure data shows very good agreement. Therefore, two-component propellant grains have significant application possibilities using the suggested modeling approaches.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Two-component propellant grain for rocket motor combustion analysis and geometric optimization",
pages = "1578-1567",
number = "2",
volume = "26",
doi = "10.2298/TSCI210604290A"
}

Alazeezi, M., Popović, N. P.,& Elek, P.. (2022). Two-component propellant grain for rocket motor combustion analysis and geometric optimization. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 26(2), 1567-1578.
https://doi.org/10.2298/TSCI210604290A

Alazeezi M, Popović NP, Elek P. Two-component propellant grain for rocket motor combustion analysis and geometric optimization. in Thermal Science. 2022;26(2):1567-1578.
doi:10.2298/TSCI210604290A .

Alazeezi, Mohammed, Popović, Nikola P., Elek, Predrag, "Two-component propellant grain for rocket motor combustion analysis and geometric optimization" in Thermal Science, 26, no. 2 (2022):1567-1578,
https://doi.org/10.2298/TSCI210604290A . .

TY  - CONF
AU  - Alazeezi, Mohammed
AU  - Elek, Predrag
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3376
AB  - Optimizing the nozzle of a solid propellant rocket motor plays an essential rule in the overall performance of the motor. In this paper, the investigation of an optimization model of dual thrust propellant rocket motors will be presented. Due to having two phases of thrust in this type of rocket motors, determination of the rocket nozzle expansion ratio is a non-trivial problem. The idea is to use a simple, fixed length and expansion ratio, convergent-divergent nozzle, which provides the highest total impulse of the motor. Usual assumptions for an ideal rocket motor have been used. The optimization model was developed in MATLAB and calculations has been performed using previously obtained interior ballistic and other relevant data for a dual thrust solid propellant rocket motor.
PB  - Springer International Publishing Ag, Cham
C3  - New Technologies, Development and Application Ii
T1  - Nozzle Optimization of Dual Thrust Rocket Motors
EP  - 477
SP  - 468
VL  - 76
DO  - 10.1007/978-3-030-18072-0_54
ER  - 

@conference{
author = "Alazeezi, Mohammed and Elek, Predrag",
year = "2020",
abstract = "Optimizing the nozzle of a solid propellant rocket motor plays an essential rule in the overall performance of the motor. In this paper, the investigation of an optimization model of dual thrust propellant rocket motors will be presented. Due to having two phases of thrust in this type of rocket motors, determination of the rocket nozzle expansion ratio is a non-trivial problem. The idea is to use a simple, fixed length and expansion ratio, convergent-divergent nozzle, which provides the highest total impulse of the motor. Usual assumptions for an ideal rocket motor have been used. The optimization model was developed in MATLAB and calculations has been performed using previously obtained interior ballistic and other relevant data for a dual thrust solid propellant rocket motor.",
publisher = "Springer International Publishing Ag, Cham",
journal = "New Technologies, Development and Application Ii",
title = "Nozzle Optimization of Dual Thrust Rocket Motors",
pages = "477-468",
volume = "76",
doi = "10.1007/978-3-030-18072-0_54"
}

Alazeezi, M.,& Elek, P.. (2020). Nozzle Optimization of Dual Thrust Rocket Motors. in New Technologies, Development and Application Ii
Springer International Publishing Ag, Cham., 76, 468-477.
https://doi.org/10.1007/978-3-030-18072-0_54

Alazeezi M, Elek P. Nozzle Optimization of Dual Thrust Rocket Motors. in New Technologies, Development and Application Ii. 2020;76:468-477.
doi:10.1007/978-3-030-18072-0_54 .

Alazeezi, Mohammed, Elek, Predrag, "Nozzle Optimization of Dual Thrust Rocket Motors" in New Technologies, Development and Application Ii, 76 (2020):468-477,
https://doi.org/10.1007/978-3-030-18072-0_54 . .

TY  - CONF
AU  - Jevtić, Dejan
AU  - Micković, Dejan
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Jaramaz, Lana
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6057
AB  - The muzzle brake is an important part of the artillery system because of its efficiency
depends reliable work of the recoil system. To estimate the efficiency of the muzzle brake, it is
important to determine the time-dependent pressure and velocity field inside the muzzle brake,
which depends on the geometry of the brake, pressure and velocity of the gases at the gun muzzle,
energy loses in the flow field along the muzzle brake etc. Also, the analysis of the flow field
parameters of the gunpowder combustion products in the muzzle brake provides stress and
temperature field in the brake, which affects the design parameters, material type and surface
protection of the muzzle brake. The numerical simulation was performed using CFD software
ANSYS Fluent to analyze phenomena inside the muzzle brake during the emptying of the gun
barrel. Numerical simulation was performed in 2D geometry which was created based on the mass
flow in 3D geometry. Experimental results were obtained measuring static pressure of the
gunpowder combustion products at three places along the axis of the brake. A comprehensive
comparison between numerical and experimental results shows good agreement. Based on this
analysis, it was determined how geometry parameters of the muzzle brake and flow parameters on
the gun muzzle affects its efficiency. This allows finding the optimal design parameters of the
muzzle brake, taking into account the possibility of production. The analysis of the flow field
parameters in the muzzle brake is not important only because of the determination of its efficiency,
but it allows further analysis of the blast pressure around the gun and its effect on the gun crew
members.
PB  - University Politehnica Timișoara,  University of Banja Luka
C3  - International Conference on Applied Sciences – ICAS 2020, Maz 20-22, 2020, Romania
T1  - Numerical simulation of gas flow field in a muzzle brake
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6057
ER  - 

@conference{
author = "Jevtić, Dejan and Micković, Dejan and Elek, Predrag and Marković, Miloš and Jaramaz, Lana",
year = "2020",
abstract = "The muzzle brake is an important part of the artillery system because of its efficiency
depends reliable work of the recoil system. To estimate the efficiency of the muzzle brake, it is
important to determine the time-dependent pressure and velocity field inside the muzzle brake,
which depends on the geometry of the brake, pressure and velocity of the gases at the gun muzzle,
energy loses in the flow field along the muzzle brake etc. Also, the analysis of the flow field
parameters of the gunpowder combustion products in the muzzle brake provides stress and
temperature field in the brake, which affects the design parameters, material type and surface
protection of the muzzle brake. The numerical simulation was performed using CFD software
ANSYS Fluent to analyze phenomena inside the muzzle brake during the emptying of the gun
barrel. Numerical simulation was performed in 2D geometry which was created based on the mass
flow in 3D geometry. Experimental results were obtained measuring static pressure of the
gunpowder combustion products at three places along the axis of the brake. A comprehensive
comparison between numerical and experimental results shows good agreement. Based on this
analysis, it was determined how geometry parameters of the muzzle brake and flow parameters on
the gun muzzle affects its efficiency. This allows finding the optimal design parameters of the
muzzle brake, taking into account the possibility of production. The analysis of the flow field
parameters in the muzzle brake is not important only because of the determination of its efficiency,
but it allows further analysis of the blast pressure around the gun and its effect on the gun crew
members.",
publisher = "University Politehnica Timișoara,  University of Banja Luka",
journal = "International Conference on Applied Sciences – ICAS 2020, Maz 20-22, 2020, Romania",
title = "Numerical simulation of gas flow field in a muzzle brake",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6057"
}

Jevtić, D., Micković, D., Elek, P., Marković, M.,& Jaramaz, L.. (2020). Numerical simulation of gas flow field in a muzzle brake. in International Conference on Applied Sciences – ICAS 2020, Maz 20-22, 2020, Romania
University Politehnica Timișoara,  University of Banja Luka..
https://hdl.handle.net/21.15107/rcub_machinery_6057

Jevtić D, Micković D, Elek P, Marković M, Jaramaz L. Numerical simulation of gas flow field in a muzzle brake. in International Conference on Applied Sciences – ICAS 2020, Maz 20-22, 2020, Romania. 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_6057 .

Jevtić, Dejan, Micković, Dejan, Elek, Predrag, Marković, Miloš, Jaramaz, Lana, "Numerical simulation of gas flow field in a muzzle brake" in International Conference on Applied Sciences – ICAS 2020, Maz 20-22, 2020, Romania (2020),
https://hdl.handle.net/21.15107/rcub_machinery_6057 .

TY  - CONF
AU  - Jevtić, Dejan
AU  - Micković, Dejan
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Jaramaz, Lana
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6053
AB  - The pressure change in time in the hydraulic brake of the automatic cannon depends on many factors such as
the geometry of the brake, the velocity of the piston, the amount of the hydraulic oil in the brake, elevation angle of the
cannon, etc. The analysis was made at the extreme values of the temperature interval of the cannon usage as well as the
normal temperature since the temperature affects the properties of the hydraulic oil. The numerical simulation of the flow
field in the hydraulic brake during recoil was performed in CFD software ANSYS Fluent. The simulation was made in a
2D numerical domain based on the flow geometry in 3D space. Due to the flow field boundaries movement during the
process, the dynamic mesh was employed. The dynamics of the hydraulic brake piston was determined using the solver
in which the forces that act on the gun are defined by the User Defined Function file. The experiment was performed by
firing from the 20mm M55 gun mounted on the stand. Experimental results contain pressure change in time inside the
brake which was measured by the piezoelectric pressure sensor. The dynamic behavior of the cannon was recorded by
the high-speed camera. The numerical results of the pressure change and position of the gun deviate within acceptable
limits with respect to experimental results. Based on that, further analysis of the influence parameters on the hydraulic
brake force can be done by numerical simulation.
PB  - Belgrade : Military Technical Institute
C3  - 9th International Scientific Conference – OTEH 2020, Belgrade, 8-9 October 2020
T1  - Analysis of the influence parameters on the pressure field in the hydraulic brake
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6053
ER  - 

@conference{
author = "Jevtić, Dejan and Micković, Dejan and Elek, Predrag and Marković, Miloš and Jaramaz, Lana",
year = "2020",
abstract = "The pressure change in time in the hydraulic brake of the automatic cannon depends on many factors such as
the geometry of the brake, the velocity of the piston, the amount of the hydraulic oil in the brake, elevation angle of the
cannon, etc. The analysis was made at the extreme values of the temperature interval of the cannon usage as well as the
normal temperature since the temperature affects the properties of the hydraulic oil. The numerical simulation of the flow
field in the hydraulic brake during recoil was performed in CFD software ANSYS Fluent. The simulation was made in a
2D numerical domain based on the flow geometry in 3D space. Due to the flow field boundaries movement during the
process, the dynamic mesh was employed. The dynamics of the hydraulic brake piston was determined using the solver
in which the forces that act on the gun are defined by the User Defined Function file. The experiment was performed by
firing from the 20mm M55 gun mounted on the stand. Experimental results contain pressure change in time inside the
brake which was measured by the piezoelectric pressure sensor. The dynamic behavior of the cannon was recorded by
the high-speed camera. The numerical results of the pressure change and position of the gun deviate within acceptable
limits with respect to experimental results. Based on that, further analysis of the influence parameters on the hydraulic
brake force can be done by numerical simulation.",
publisher = "Belgrade : Military Technical Institute",
journal = "9th International Scientific Conference – OTEH 2020, Belgrade, 8-9 October 2020",
title = "Analysis of the influence parameters on the pressure field in the hydraulic brake",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6053"
}

Jevtić, D., Micković, D., Elek, P., Marković, M.,& Jaramaz, L.. (2020). Analysis of the influence parameters on the pressure field in the hydraulic brake. in 9th International Scientific Conference – OTEH 2020, Belgrade, 8-9 October 2020
Belgrade : Military Technical Institute..
https://hdl.handle.net/21.15107/rcub_machinery_6053

Jevtić D, Micković D, Elek P, Marković M, Jaramaz L. Analysis of the influence parameters on the pressure field in the hydraulic brake. in 9th International Scientific Conference – OTEH 2020, Belgrade, 8-9 October 2020. 2020;.
https://hdl.handle.net/21.15107/rcub_machinery_6053 .

Jevtić, Dejan, Micković, Dejan, Elek, Predrag, Marković, Miloš, Jaramaz, Lana, "Analysis of the influence parameters on the pressure field in the hydraulic brake" in 9th International Scientific Conference – OTEH 2020, Belgrade, 8-9 October 2020 (2020),
https://hdl.handle.net/21.15107/rcub_machinery_6053 .

TY  - JOUR
AU  - Jevtić, Dejan
AU  - Micković, Dejan
AU  - Jaramaz, Slobodan
AU  - Elek, Predrag
AU  - Marković, Miloš
AU  - Živković, Saša
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3309
AB  - The change of gas parameters in the cylinder of the automatic gun has a great influence on the dynamics of the gun. Many factors have an influence on the gas parameters in the gas cylinder such as the diameter and position of the gas port, the initial volume of the gas cylinder, the gap between the piston and the cylinder, initial temperature of the cylinder parts, etc. The analytical model was made to analyze the parameters on which depends gas piston dynamics. The numerical simulation with CFD software ANSYS Fluent was performed to analyze the change of the thermodynamic properties of the gases in the cylinder, temperature change of the cylinder parts and dynamics of the gas piston. The experiment was performed to provide pressures in the barrel and the gas cylinder and velocity of the gas piston. The comprehensive comparisons between results obtained by the analytical model, the numerical simulation and experiments have been performed and good agreements were observed.
PB  - Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd
T2  - Thermal Science
T1  - Modeling of gas parameters in the cylinder of the automatic gun during firing
EP  - 4145
IS  - 6
SP  - 4135
VL  - 24
DO  - 10.2298/TSCI200118152J
ER  - 

@article{
author = "Jevtić, Dejan and Micković, Dejan and Jaramaz, Slobodan and Elek, Predrag and Marković, Miloš and Živković, Saša",
year = "2020",
abstract = "The change of gas parameters in the cylinder of the automatic gun has a great influence on the dynamics of the gun. Many factors have an influence on the gas parameters in the gas cylinder such as the diameter and position of the gas port, the initial volume of the gas cylinder, the gap between the piston and the cylinder, initial temperature of the cylinder parts, etc. The analytical model was made to analyze the parameters on which depends gas piston dynamics. The numerical simulation with CFD software ANSYS Fluent was performed to analyze the change of the thermodynamic properties of the gases in the cylinder, temperature change of the cylinder parts and dynamics of the gas piston. The experiment was performed to provide pressures in the barrel and the gas cylinder and velocity of the gas piston. The comprehensive comparisons between results obtained by the analytical model, the numerical simulation and experiments have been performed and good agreements were observed.",
publisher = "Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd",
journal = "Thermal Science",
title = "Modeling of gas parameters in the cylinder of the automatic gun during firing",
pages = "4145-4135",
number = "6",
volume = "24",
doi = "10.2298/TSCI200118152J"
}

Jevtić, D., Micković, D., Jaramaz, S., Elek, P., Marković, M.,& Živković, S.. (2020). Modeling of gas parameters in the cylinder of the automatic gun during firing. in Thermal Science
Univerzitet u Beogradu - Institut za nuklearne nauke Vinča, Beograd., 24(6), 4135-4145.
https://doi.org/10.2298/TSCI200118152J

Jevtić D, Micković D, Jaramaz S, Elek P, Marković M, Živković S. Modeling of gas parameters in the cylinder of the automatic gun during firing. in Thermal Science. 2020;24(6):4135-4145.
doi:10.2298/TSCI200118152J .

Jevtić, Dejan, Micković, Dejan, Jaramaz, Slobodan, Elek, Predrag, Marković, Miloš, Živković, Saša, "Modeling of gas parameters in the cylinder of the automatic gun during firing" in Thermal Science, 24, no. 6 (2020):4135-4145,
https://doi.org/10.2298/TSCI200118152J . .

TY  - JOUR
AU  - Glavšić, Milica
AU  - Elek, Predrag
PY  - 2020
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/3363
AB  - Osnovni cilj ovog istraživanja je izrada numeričkog modela oštećenja vozila pod dejstvom eksplozije mine, kao i pronalaženje najpovoljnijeg slučaja geometrije V-trupa i ukazivanje na moguće rešenje za ublažavanje efekata eksplozije mina na oklopno borbeno vozilo. U obzir je uzeto sedam različitih geometrija V-trupa i izvršena je analiza oštećenja strukture za svih sedam mogućnosti. Takođe, analizirana je i promena mase za različite geometrije. Efekat eksplozije mina na ciljnu strukturu analiziran je korišćenjem funkcije natpritiska prema empirijskom modelu CONWEP, korišćenjem programa Abaqus/Explicit. Analiziran je primer eksplozije 8 kg eksplozivne materije Kompozicija B koja deluje na vozilo ukupne mase 8000 kg. Vozilo se sastoji od dva glavna dela - kabine mase 6 t i V-trupa mase 2 t. Trup u obliku slova V je u svim prikazanim primerima sačinjen od ploča debljine 10 mm izrađenih od čelika Hardox 400. Položaj eksplozivnog punjenja je za sve primere geometrije isti i nalazi se 0.6 m ispod centra vozila. Nakon analize dobijenih rezultata utvrđena je najpovoljnija geometrija V-trupa i ukazano je na mogućnosti daljeg unapređenja numeričkog modela.
AB  - The main objective of this research is to develop a numerical model of vehicle damage caused by an explosion of a mine, as well as to find the most favorable case of V-hull geometry and to point out a possible solution for mitigating the effects of mine explosion on an armored vehicle. Seven different V-hull geometries were considered and structure damage analysis was performed for all seven options. Also, the mass change for different geometries was analyzed. The effect of the mine explosion on the target structure was analyzed using the overpressure function according to the empirical CONWEP model, using Abaqus / Explicit software. An example of an explosion of 8 kg of Composition B acting on a vehicle with a total mass of 8000 kg was analyzed. The vehicle has two main parts - the cabin with mass of 6 t and a V-hull of mass of 2 t. The V-shaped hull in all the examples shown is made of 10 mm thick plates of Hardox 400 steel. The position of the explosive charge is the same for all geometry examples and is 0.6 m below the center of the vehicle. After analysis of the obtained results the most favorable V-hull geometry is determined. The guidelines for the further work and model improvement are suggested.
PB  - Vojnotehnički institut, Beograd
T2  - Scientific Technical Review
T1  - Numerička analiza uticaja eksplozije na oklopno vozilo za različite geometrije V-trupa
T1  - Numerical analysis of the mine blast action on an armored vehicle for different V-hull geometries
EP  - 35
IS  - 1
SP  - 29
VL  - 70
DO  - 10.5937/str2001029G
ER  - 

@article{
author = "Glavšić, Milica and Elek, Predrag",
year = "2020",
abstract = "Osnovni cilj ovog istraživanja je izrada numeričkog modela oštećenja vozila pod dejstvom eksplozije mine, kao i pronalaženje najpovoljnijeg slučaja geometrije V-trupa i ukazivanje na moguće rešenje za ublažavanje efekata eksplozije mina na oklopno borbeno vozilo. U obzir je uzeto sedam različitih geometrija V-trupa i izvršena je analiza oštećenja strukture za svih sedam mogućnosti. Takođe, analizirana je i promena mase za različite geometrije. Efekat eksplozije mina na ciljnu strukturu analiziran je korišćenjem funkcije natpritiska prema empirijskom modelu CONWEP, korišćenjem programa Abaqus/Explicit. Analiziran je primer eksplozije 8 kg eksplozivne materije Kompozicija B koja deluje na vozilo ukupne mase 8000 kg. Vozilo se sastoji od dva glavna dela - kabine mase 6 t i V-trupa mase 2 t. Trup u obliku slova V je u svim prikazanim primerima sačinjen od ploča debljine 10 mm izrađenih od čelika Hardox 400. Položaj eksplozivnog punjenja je za sve primere geometrije isti i nalazi se 0.6 m ispod centra vozila. Nakon analize dobijenih rezultata utvrđena je najpovoljnija geometrija V-trupa i ukazano je na mogućnosti daljeg unapređenja numeričkog modela., The main objective of this research is to develop a numerical model of vehicle damage caused by an explosion of a mine, as well as to find the most favorable case of V-hull geometry and to point out a possible solution for mitigating the effects of mine explosion on an armored vehicle. Seven different V-hull geometries were considered and structure damage analysis was performed for all seven options. Also, the mass change for different geometries was analyzed. The effect of the mine explosion on the target structure was analyzed using the overpressure function according to the empirical CONWEP model, using Abaqus / Explicit software. An example of an explosion of 8 kg of Composition B acting on a vehicle with a total mass of 8000 kg was analyzed. The vehicle has two main parts - the cabin with mass of 6 t and a V-hull of mass of 2 t. The V-shaped hull in all the examples shown is made of 10 mm thick plates of Hardox 400 steel. The position of the explosive charge is the same for all geometry examples and is 0.6 m below the center of the vehicle. After analysis of the obtained results the most favorable V-hull geometry is determined. The guidelines for the further work and model improvement are suggested.",
publisher = "Vojnotehnički institut, Beograd",
journal = "Scientific Technical Review",
title = "Numerička analiza uticaja eksplozije na oklopno vozilo za različite geometrije V-trupa, Numerical analysis of the mine blast action on an armored vehicle for different V-hull geometries",
pages = "35-29",
number = "1",
volume = "70",
doi = "10.5937/str2001029G"
}

Glavšić, M.,& Elek, P.. (2020). Numerička analiza uticaja eksplozije na oklopno vozilo za različite geometrije V-trupa. in Scientific Technical Review
Vojnotehnički institut, Beograd., 70(1), 29-35.
https://doi.org/10.5937/str2001029G

Glavšić M, Elek P. Numerička analiza uticaja eksplozije na oklopno vozilo za različite geometrije V-trupa. in Scientific Technical Review. 2020;70(1):29-35.
doi:10.5937/str2001029G .

Glavšić, Milica, Elek, Predrag, "Numerička analiza uticaja eksplozije na oklopno vozilo za različite geometrije V-trupa" in Scientific Technical Review, 70, no. 1 (2020):29-35,
https://doi.org/10.5937/str2001029G . .

TY  - CONF
AU  - Glavšić, Milica
AU  - Elek, Predrag
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4583
AB  - The main objective of the present research is development of a preliminary numerical model
of dynamics and possible damage of a vehicle under the action of blast wave generated by the
activation of a landmine. Such a model should provide a valuable insight into complex
phenomena accompanied by detonation of a mine – pressure distribution in time, vehicle motion,
damage, etc. Numerical simulation has been performed using Abaqus/Explicit, FEM-based
software suitable for nonlinear processes with high strains, strain rates and energy densities,
which is typical for explosion effects. A representative case study of an explosion of 8 kg
explosive substance Composition B was analyzed. The explosion takes place under a vehicle with
the mass of 8 tons, with specific V-shaped body consisted from 10 mm thick armor steel plates.
The numerical model based on usage of Abaqus build-in CONWEP blast relations is described.
The results obtained show the displacement, and stress-stain field in the loaded vehicle, on the
basis of which the degree of damage to the target structure can be predicted. The guidelines for
the further work and model improvement are suggested.
PB  - Serbian Society of Mechanics
C3  - Proceedings of 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, Serbia, June 24-26, 2019
T1  - Numerical analysis of mine blast action on a vehicle
SP  - I1b
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4583
ER  - 

@conference{
author = "Glavšić, Milica and Elek, Predrag",
year = "2019",
abstract = "The main objective of the present research is development of a preliminary numerical model
of dynamics and possible damage of a vehicle under the action of blast wave generated by the
activation of a landmine. Such a model should provide a valuable insight into complex
phenomena accompanied by detonation of a mine – pressure distribution in time, vehicle motion,
damage, etc. Numerical simulation has been performed using Abaqus/Explicit, FEM-based
software suitable for nonlinear processes with high strains, strain rates and energy densities,
which is typical for explosion effects. A representative case study of an explosion of 8 kg
explosive substance Composition B was analyzed. The explosion takes place under a vehicle with
the mass of 8 tons, with specific V-shaped body consisted from 10 mm thick armor steel plates.
The numerical model based on usage of Abaqus build-in CONWEP blast relations is described.
The results obtained show the displacement, and stress-stain field in the loaded vehicle, on the
basis of which the degree of damage to the target structure can be predicted. The guidelines for
the further work and model improvement are suggested.",
publisher = "Serbian Society of Mechanics",
journal = "Proceedings of 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, Serbia, June 24-26, 2019",
title = "Numerical analysis of mine blast action on a vehicle",
pages = "I1b",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4583"
}

Glavšić, M.,& Elek, P.. (2019). Numerical analysis of mine blast action on a vehicle. in Proceedings of 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, Serbia, June 24-26, 2019
Serbian Society of Mechanics., I1b.
https://hdl.handle.net/21.15107/rcub_machinery_4583

Glavšić M, Elek P. Numerical analysis of mine blast action on a vehicle. in Proceedings of 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, Serbia, June 24-26, 2019. 2019;:I1b.
https://hdl.handle.net/21.15107/rcub_machinery_4583 .

Glavšić, Milica, Elek, Predrag, "Numerical analysis of mine blast action on a vehicle" in Proceedings of 7th International Congress of Serbian Society of Mechanics, Sremski Karlovci, Serbia, June 24-26, 2019 (2019):I1b,
https://hdl.handle.net/21.15107/rcub_machinery_4583 .

TY  - CONF
AU  - Jevtić, Dejan
AU  - Micković, Dejan
AU  - Jaramaz, Slobodan
AU  - Elek, Predrag
AU  - Marković, Miloš
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/6056
AB  - Hydraulic brake is an important part of the artillery system because reliable amortization of
energy of the recoil parts depends on its functioning. Therefore, it is important to estimate time-dependent
pressure field inside the brake which depends on many factors, such as geometry of the brake parts,
velocity of recoil parts and physical characteristics of the oil that is used in the brake. During recoil and
counterrecoil process of the recoil parts of the artillery system, heating of the oil and the other parts of the
hydraulic brake occurs. In this paper the influence of the temperature change of the hydraulic brake parts
on the recoil force is analyzed. Since the hydraulic brake assembly is axisymmetric, the problem is
considered to be two-dimensional. Differential equations that describe flow field in the brake are solved
numerically using CFD software. A comprehensive comparison between numerical and experimental
results has been performed and good agreement is observed.
PB  - Society of Thermal Engineers of Serbia, Faculty of Mechanical Engineering in Niš
C3  - 19th Symposium on Thermal Science and Engineering of Serbia, Sokobanja, October 22-25, 2019
T1  - The influence of the temperature change on the force in the hydraulic brake of the artillery system
UR  - https://hdl.handle.net/21.15107/rcub_machinery_6056
ER  - 

@conference{
author = "Jevtić, Dejan and Micković, Dejan and Jaramaz, Slobodan and Elek, Predrag and Marković, Miloš",
year = "2019",
abstract = "Hydraulic brake is an important part of the artillery system because reliable amortization of
energy of the recoil parts depends on its functioning. Therefore, it is important to estimate time-dependent
pressure field inside the brake which depends on many factors, such as geometry of the brake parts,
velocity of recoil parts and physical characteristics of the oil that is used in the brake. During recoil and
counterrecoil process of the recoil parts of the artillery system, heating of the oil and the other parts of the
hydraulic brake occurs. In this paper the influence of the temperature change of the hydraulic brake parts
on the recoil force is analyzed. Since the hydraulic brake assembly is axisymmetric, the problem is
considered to be two-dimensional. Differential equations that describe flow field in the brake are solved
numerically using CFD software. A comprehensive comparison between numerical and experimental
results has been performed and good agreement is observed.",
publisher = "Society of Thermal Engineers of Serbia, Faculty of Mechanical Engineering in Niš",
journal = "19th Symposium on Thermal Science and Engineering of Serbia, Sokobanja, October 22-25, 2019",
title = "The influence of the temperature change on the force in the hydraulic brake of the artillery system",
url = "https://hdl.handle.net/21.15107/rcub_machinery_6056"
}

Jevtić, D., Micković, D., Jaramaz, S., Elek, P.,& Marković, M.. (2019). The influence of the temperature change on the force in the hydraulic brake of the artillery system. in 19th Symposium on Thermal Science and Engineering of Serbia, Sokobanja, October 22-25, 2019
Society of Thermal Engineers of Serbia, Faculty of Mechanical Engineering in Niš..
https://hdl.handle.net/21.15107/rcub_machinery_6056

Jevtić D, Micković D, Jaramaz S, Elek P, Marković M. The influence of the temperature change on the force in the hydraulic brake of the artillery system. in 19th Symposium on Thermal Science and Engineering of Serbia, Sokobanja, October 22-25, 2019. 2019;.
https://hdl.handle.net/21.15107/rcub_machinery_6056 .

Jevtić, Dejan, Micković, Dejan, Jaramaz, Slobodan, Elek, Predrag, Marković, Miloš, "The influence of the temperature change on the force in the hydraulic brake of the artillery system" in 19th Symposium on Thermal Science and Engineering of Serbia, Sokobanja, October 22-25, 2019 (2019),
https://hdl.handle.net/21.15107/rcub_machinery_6056 .

TY  - CONF
AU  - Alazeezi, Mohammed
AU  - Elek, Predrag
PY  - 2019
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4911
AB  - Optimizing the nozzle of a solid propellant rocket motor plays an essential rule in the overall performance of the motor. In this paper, the investigation of an optimization model of dual thrust propellant rocket motors will be presented. Due to having two phases of thrust in this type of rocket motors, determination of the rocket nozzle expansion ratio is a non-trivial problem. The idea is to use a simple, fixed length and expansion ratio, convergent-divergent nozzle, which provides the highest total impulse of the motor. Usual assumptions for an ideal rocket motor have been used. The optimization model was developed in MATLAB and calculations has been performed using previously obtained interior ballistic and other relevant data for a dual thrust solid propellant rocket motor.
PB  - SOCIETY FOR ROBOTICS OF BOSNIA AND HERZEGOVINA
C3  - Proceedings of 5th International Conference "New Technologies, Development, and Application NT-2019", Sarajevo, Bosnia and Hercegovina
T1  - Nozzle optimization of dual thrust rocket motor
SP  - 31
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4911
ER  - 

@conference{
author = "Alazeezi, Mohammed and Elek, Predrag",
year = "2019",
abstract = "Optimizing the nozzle of a solid propellant rocket motor plays an essential rule in the overall performance of the motor. In this paper, the investigation of an optimization model of dual thrust propellant rocket motors will be presented. Due to having two phases of thrust in this type of rocket motors, determination of the rocket nozzle expansion ratio is a non-trivial problem. The idea is to use a simple, fixed length and expansion ratio, convergent-divergent nozzle, which provides the highest total impulse of the motor. Usual assumptions for an ideal rocket motor have been used. The optimization model was developed in MATLAB and calculations has been performed using previously obtained interior ballistic and other relevant data for a dual thrust solid propellant rocket motor.",
publisher = "SOCIETY FOR ROBOTICS OF BOSNIA AND HERZEGOVINA",
journal = "Proceedings of 5th International Conference "New Technologies, Development, and Application NT-2019", Sarajevo, Bosnia and Hercegovina",
title = "Nozzle optimization of dual thrust rocket motor",
pages = "31",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4911"
}

Alazeezi, M.,& Elek, P.. (2019). Nozzle optimization of dual thrust rocket motor. in Proceedings of 5th International Conference "New Technologies, Development, and Application NT-2019", Sarajevo, Bosnia and Hercegovina
SOCIETY FOR ROBOTICS OF BOSNIA AND HERZEGOVINA., 31.
https://hdl.handle.net/21.15107/rcub_machinery_4911

Alazeezi M, Elek P. Nozzle optimization of dual thrust rocket motor. in Proceedings of 5th International Conference "New Technologies, Development, and Application NT-2019", Sarajevo, Bosnia and Hercegovina. 2019;:31.
https://hdl.handle.net/21.15107/rcub_machinery_4911 .

Alazeezi, Mohammed, Elek, Predrag, "Nozzle optimization of dual thrust rocket motor" in Proceedings of 5th International Conference "New Technologies, Development, and Application NT-2019", Sarajevo, Bosnia and Hercegovina (2019):31,
https://hdl.handle.net/21.15107/rcub_machinery_4911 .

TY  - CONF
AU  - Alazeezi, Mohammed
AU  - Elek, Predrag
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4585
AB  - Burnback analysis is a critical stage in the design of solid propellant rocket motors. This paper will focus on investigating the burnback analysis of an end burner grain with central cylindrical cavity. Analytical and numerical methods for evaluating the burning surface area have been used. The analytical geometrical equations that illustrate the burning surface area evolution were developed for the two-phase burning process. The first phase is the boost phase and the second phase is the sustaining which lasts longer. A parametric model of the grain was also created in PTC Creo to simulate the burn back numerically. The results from both methods show an agreement which approves that the numerical method could be used for complex grain shapes, for which it is difficult to obtain the analytical solution. Furthermore, a MATLAB program was developed in order to compare the numerical and analytical results and to predict some of the main interior
ballistics parameters.
PB  - Belgrade : Military Technical Institute
C3  - 8th International Scientific Conference on Defensive Technologies OTEH 2018, Belgrade 11-12 October
T1  - Analytical and numerical burnback analysis of end burner grain with cylindrical cavity
EP  - 188
SP  - 184
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4585
ER  - 

@conference{
author = "Alazeezi, Mohammed and Elek, Predrag",
year = "2018",
abstract = "Burnback analysis is a critical stage in the design of solid propellant rocket motors. This paper will focus on investigating the burnback analysis of an end burner grain with central cylindrical cavity. Analytical and numerical methods for evaluating the burning surface area have been used. The analytical geometrical equations that illustrate the burning surface area evolution were developed for the two-phase burning process. The first phase is the boost phase and the second phase is the sustaining which lasts longer. A parametric model of the grain was also created in PTC Creo to simulate the burn back numerically. The results from both methods show an agreement which approves that the numerical method could be used for complex grain shapes, for which it is difficult to obtain the analytical solution. Furthermore, a MATLAB program was developed in order to compare the numerical and analytical results and to predict some of the main interior
ballistics parameters.",
publisher = "Belgrade : Military Technical Institute",
journal = "8th International Scientific Conference on Defensive Technologies OTEH 2018, Belgrade 11-12 October",
title = "Analytical and numerical burnback analysis of end burner grain with cylindrical cavity",
pages = "188-184",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4585"
}

Alazeezi, M.,& Elek, P.. (2018). Analytical and numerical burnback analysis of end burner grain with cylindrical cavity. in 8th International Scientific Conference on Defensive Technologies OTEH 2018, Belgrade 11-12 October
Belgrade : Military Technical Institute., 184-188.
https://hdl.handle.net/21.15107/rcub_machinery_4585

Alazeezi M, Elek P. Analytical and numerical burnback analysis of end burner grain with cylindrical cavity. in 8th International Scientific Conference on Defensive Technologies OTEH 2018, Belgrade 11-12 October. 2018;:184-188.
https://hdl.handle.net/21.15107/rcub_machinery_4585 .

Alazeezi, Mohammed, Elek, Predrag, "Analytical and numerical burnback analysis of end burner grain with cylindrical cavity" in 8th International Scientific Conference on Defensive Technologies OTEH 2018, Belgrade 11-12 October (2018):184-188,
https://hdl.handle.net/21.15107/rcub_machinery_4585 .

TY  - GEN
AU  - Elek, Predrag
PY  - 2018
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4594
PB  - Univerzitet u Beogradu - Mašinski fakultet
T1  - Balistika na cilju
EP  - 217
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4594
ER  - 

@misc{
author = "Elek, Predrag",
year = "2018",
publisher = "Univerzitet u Beogradu - Mašinski fakultet",
title = "Balistika na cilju",
pages = "217",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4594"
}

Elek, P.. (2018). Balistika na cilju. 
Univerzitet u Beogradu - Mašinski fakultet..
https://hdl.handle.net/21.15107/rcub_machinery_4594

Elek P. Balistika na cilju. 2018;:null-217.
https://hdl.handle.net/21.15107/rcub_machinery_4594 .

Elek, Predrag, "Balistika na cilju" (2018),
https://hdl.handle.net/21.15107/rcub_machinery_4594 .

TY  - CONF
AU  - Elek, Predrag
AU  - Jaramaz, Slobodan
AU  - Micković, Dejan
AU  - Todić, Ivana
PY  - 2017
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4488
AB  - The paper considers the ballistic perforation of ductile metal plates by rigid projectiles in plug formation regime. Analytical modelling of the penetration process is based on the application of momentum and energy conservation laws for the penetrator/plug system. After outlining of the well-known Recht-Ipson model, the new analytical model has been formulated. The model considers the plug compression and shear – two most important resistance forces acting on the
projectile. The final result of the model is the ballistic curve – a simple relation between the projectile and plug residual velocity and the projectile impact velocity. The important parameters in the relation are the ballistic limit velocity and the relative mass of the plug. For low values of the relative plug mass, the ballistic curves of the proposed model and the Recht-Ipson model are very close to each other, but for higher values of this parameter the results of two models significantly deviates. Comparison with available experimental data indicates good agreement between measured velocities and model predictions. However, further experiments are needed for validation of the model, especially in the case of high values of relative plug thickness.
C3  - Proceedings of 6th International Congress of Serbian Society of Mechanics, Mountain Tara, Serbia, June 19-21
T1  - Analytical modelling of ballistic perforation in plug formation mode
EP  - 8
SP  - 1
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4488
ER  - 

@conference{
author = "Elek, Predrag and Jaramaz, Slobodan and Micković, Dejan and Todić, Ivana",
year = "2017",
abstract = "The paper considers the ballistic perforation of ductile metal plates by rigid projectiles in plug formation regime. Analytical modelling of the penetration process is based on the application of momentum and energy conservation laws for the penetrator/plug system. After outlining of the well-known Recht-Ipson model, the new analytical model has been formulated. The model considers the plug compression and shear – two most important resistance forces acting on the
projectile. The final result of the model is the ballistic curve – a simple relation between the projectile and plug residual velocity and the projectile impact velocity. The important parameters in the relation are the ballistic limit velocity and the relative mass of the plug. For low values of the relative plug mass, the ballistic curves of the proposed model and the Recht-Ipson model are very close to each other, but for higher values of this parameter the results of two models significantly deviates. Comparison with available experimental data indicates good agreement between measured velocities and model predictions. However, further experiments are needed for validation of the model, especially in the case of high values of relative plug thickness.",
journal = "Proceedings of 6th International Congress of Serbian Society of Mechanics, Mountain Tara, Serbia, June 19-21",
title = "Analytical modelling of ballistic perforation in plug formation mode",
pages = "8-1",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4488"
}

Elek, P., Jaramaz, S., Micković, D.,& Todić, I.. (2017). Analytical modelling of ballistic perforation in plug formation mode. in Proceedings of 6th International Congress of Serbian Society of Mechanics, Mountain Tara, Serbia, June 19-21, 1-8.
https://hdl.handle.net/21.15107/rcub_machinery_4488

Elek P, Jaramaz S, Micković D, Todić I. Analytical modelling of ballistic perforation in plug formation mode. in Proceedings of 6th International Congress of Serbian Society of Mechanics, Mountain Tara, Serbia, June 19-21. 2017;:1-8.
https://hdl.handle.net/21.15107/rcub_machinery_4488 .

Elek, Predrag, Jaramaz, Slobodan, Micković, Dejan, Todić, Ivana, "Analytical modelling of ballistic perforation in plug formation mode" in Proceedings of 6th International Congress of Serbian Society of Mechanics, Mountain Tara, Serbia, June 19-21 (2017):1-8,
https://hdl.handle.net/21.15107/rcub_machinery_4488 .

TY  - CONF
AU  - Elek, Predrag
AU  - Jaramaz, Slobodan
AU  - Micković, Dejan
AU  - Đorđević, Miroslav
AU  - Miloradović, Nenad
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4591
AB  - Characterization of behind armor debris (BAD) is of utmost importance from the aspect of evaluation of an armor piercing projectile efficiency as well as from the point of target vulnerability. In the present study, the research focus is on the size, mass and shape distribution of fragments generated from the target plate. The experimental results of perforation of 6.35 mm thick steel plates by 12.7 mm armor-piercing projectile have been reported. Projectile impact and residual velocity were measured by the muzzle velocity radar system and make-up screens, respectively. Distribution of a generated BAD cloud and its energetic properties were determined using the calibrated witness pack. The proposed analytical model of the problem is based on the energy conservation, fracture mechanics and fragmentation theory. A good agreement is observed between calculated results and experimental data in terms of the shape, characteristic size and mass distribution of generated fragments. The further research will be focused on the spatial distribution of fragments, as well as on the distribution of their velocities.
PB  - Belgrade : Military Technical Institute
C3  - 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016
T1  - Characterization of behind armor debris after perforation of steel plates by armor piercing projectile
EP  - 277
SP  - 272
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4591
ER  - 

@conference{
author = "Elek, Predrag and Jaramaz, Slobodan and Micković, Dejan and Đorđević, Miroslav and Miloradović, Nenad",
year = "2016",
abstract = "Characterization of behind armor debris (BAD) is of utmost importance from the aspect of evaluation of an armor piercing projectile efficiency as well as from the point of target vulnerability. In the present study, the research focus is on the size, mass and shape distribution of fragments generated from the target plate. The experimental results of perforation of 6.35 mm thick steel plates by 12.7 mm armor-piercing projectile have been reported. Projectile impact and residual velocity were measured by the muzzle velocity radar system and make-up screens, respectively. Distribution of a generated BAD cloud and its energetic properties were determined using the calibrated witness pack. The proposed analytical model of the problem is based on the energy conservation, fracture mechanics and fragmentation theory. A good agreement is observed between calculated results and experimental data in terms of the shape, characteristic size and mass distribution of generated fragments. The further research will be focused on the spatial distribution of fragments, as well as on the distribution of their velocities.",
publisher = "Belgrade : Military Technical Institute",
journal = "7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016",
title = "Characterization of behind armor debris after perforation of steel plates by armor piercing projectile",
pages = "277-272",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4591"
}

Elek, P., Jaramaz, S., Micković, D., Đorđević, M.,& Miloradović, N.. (2016). Characterization of behind armor debris after perforation of steel plates by armor piercing projectile. in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016
Belgrade : Military Technical Institute., 272-277.
https://hdl.handle.net/21.15107/rcub_machinery_4591

Elek P, Jaramaz S, Micković D, Đorđević M, Miloradović N. Characterization of behind armor debris after perforation of steel plates by armor piercing projectile. in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016. 2016;:272-277.
https://hdl.handle.net/21.15107/rcub_machinery_4591 .

Elek, Predrag, Jaramaz, Slobodan, Micković, Dejan, Đorđević, Miroslav, Miloradović, Nenad, "Characterization of behind armor debris after perforation of steel plates by armor piercing projectile" in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016 (2016):272-277,
https://hdl.handle.net/21.15107/rcub_machinery_4591 .

TY  - CONF
AU  - Micković, Dejan
AU  - Jaramaz, Slobodan
AU  - Elek, Predrag
AU  - Miloradović, Nenad
AU  - Micković, Dušan
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/4909
AB  - Study of interaction of explosive reactive armor (ERA) with shaped charge jet is the basis for evaluation of the effectiveness of ERA. The physically based theoretical model of this interaction is given. It is incorporated in the NERA computer code. The influences of backward moving plate and forward moving plate thickness, explosive layer thickness, jet attack angle, and distance between ERA and main armor are investigated. Computational results of NERA code are
compared with experimental data. The computational and experimental results of penetration in the steel armor target are in good agreement. The results of NERA code calculations reveal the possibilities for an improvement of ERA efficiency.
PB  - Belgrade : Military Technical Institute
C3  - 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016
T1  - Explosive reactive armor action against shaped charge jet
SP  - 304-309
UR  - https://hdl.handle.net/21.15107/rcub_machinery_4909
ER  - 

@conference{
author = "Micković, Dejan and Jaramaz, Slobodan and Elek, Predrag and Miloradović, Nenad and Micković, Dušan",
year = "2016",
abstract = "Study of interaction of explosive reactive armor (ERA) with shaped charge jet is the basis for evaluation of the effectiveness of ERA. The physically based theoretical model of this interaction is given. It is incorporated in the NERA computer code. The influences of backward moving plate and forward moving plate thickness, explosive layer thickness, jet attack angle, and distance between ERA and main armor are investigated. Computational results of NERA code are
compared with experimental data. The computational and experimental results of penetration in the steel armor target are in good agreement. The results of NERA code calculations reveal the possibilities for an improvement of ERA efficiency.",
publisher = "Belgrade : Military Technical Institute",
journal = "7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016",
title = "Explosive reactive armor action against shaped charge jet",
pages = "304-309",
url = "https://hdl.handle.net/21.15107/rcub_machinery_4909"
}

Micković, D., Jaramaz, S., Elek, P., Miloradović, N.,& Micković, D.. (2016). Explosive reactive armor action against shaped charge jet. in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016
Belgrade : Military Technical Institute., 304-309.
https://hdl.handle.net/21.15107/rcub_machinery_4909

Micković D, Jaramaz S, Elek P, Miloradović N, Micković D. Explosive reactive armor action against shaped charge jet. in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016. 2016;:304-309.
https://hdl.handle.net/21.15107/rcub_machinery_4909 .

Micković, Dejan, Jaramaz, Slobodan, Elek, Predrag, Miloradović, Nenad, Micković, Dušan, "Explosive reactive armor action against shaped charge jet" in 7th International Conference on Defensive Technologies - OTEH 2016, Belgrade, 6-7 October 2016 (2016):304-309,
https://hdl.handle.net/21.15107/rcub_machinery_4909 .

TY  - JOUR
AU  - Elek, Predrag
AU  - Jaramaz, Slobodan
AU  - Micković, Dejan
AU  - Miloradović, Nenad
PY  - 2016
UR  - https://machinery.mas.bg.ac.rs/handle/123456789/2426
AB  - This paper considers the modeling of perforation of thin steel plates by cylindrical steel penetrators fragment simulators. A comprehensive experimental investigation was performed and relevant data about the experiment setup and measuring equipment are reported. A numerical model developed in FEM based software Abaqus is described in detail. The Johnson-Cook thermo-viscoplastic constitutive law, as well as the Johnson-Cook damage model is used in the model. It has been shown that simulations correctly reproduce the main mechanisms of penetration process - indentation, bulging and plugging. Computational results are compared with experimental data in terms of the ballistic curves - diagrams that define the dependence of penetrator residual velocity on its impact velocity. The comparison of numerically obtained and measured values of deformed penetrator's diameter, plug thickness and maximum plate deflection has been also performed. Very good overall agreement is obtained between results of simulation and experimental measurements. After the validation of the numerical model, some empirical relations between perforation process parameters are derived.
PB  - Elsevier Sci Ltd, Oxford
T2  - Thin-Walled Structures
T1  - Experimental and numerical investigation of perforation of thin steel plates by deformable steel penetrators
EP  - 67
SP  - 58
VL  - 102
DO  - 10.1016/j.tws.2016.01.022
ER  - 

@article{
author = "Elek, Predrag and Jaramaz, Slobodan and Micković, Dejan and Miloradović, Nenad",
year = "2016",
abstract = "This paper considers the modeling of perforation of thin steel plates by cylindrical steel penetrators fragment simulators. A comprehensive experimental investigation was performed and relevant data about the experiment setup and measuring equipment are reported. A numerical model developed in FEM based software Abaqus is described in detail. The Johnson-Cook thermo-viscoplastic constitutive law, as well as the Johnson-Cook damage model is used in the model. It has been shown that simulations correctly reproduce the main mechanisms of penetration process - indentation, bulging and plugging. Computational results are compared with experimental data in terms of the ballistic curves - diagrams that define the dependence of penetrator residual velocity on its impact velocity. The comparison of numerically obtained and measured values of deformed penetrator's diameter, plug thickness and maximum plate deflection has been also performed. Very good overall agreement is obtained between results of simulation and experimental measurements. After the validation of the numerical model, some empirical relations between perforation process parameters are derived.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Thin-Walled Structures",
title = "Experimental and numerical investigation of perforation of thin steel plates by deformable steel penetrators",
pages = "67-58",
volume = "102",
doi = "10.1016/j.tws.2016.01.022"
}

Elek, P., Jaramaz, S., Micković, D.,& Miloradović, N.. (2016). Experimental and numerical investigation of perforation of thin steel plates by deformable steel penetrators. in Thin-Walled Structures
Elsevier Sci Ltd, Oxford., 102, 58-67.
https://doi.org/10.1016/j.tws.2016.01.022

Elek P, Jaramaz S, Micković D, Miloradović N. Experimental and numerical investigation of perforation of thin steel plates by deformable steel penetrators. in Thin-Walled Structures. 2016;102:58-67.
doi:10.1016/j.tws.2016.01.022 .

Elek, Predrag, Jaramaz, Slobodan, Micković, Dejan, Miloradović, Nenad, "Experimental and numerical investigation of perforation of thin steel plates by deformable steel penetrators" in Thin-Walled Structures, 102 (2016):58-67,
https://doi.org/10.1016/j.tws.2016.01.022 . .