Nebojša Hristov

University of Defence

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Co-Authors

Damir Jerković

University of Defence

Slobodan Savić

University of Kragujevac

Abdellah Ferfouri

University of Defence

Toufik Allouche

University of Defence

Aleksandar Kari

Military Technical Institute

Milan Vučković

Military Technical Institute

SŽ

Saša Živković

Military Technical Institute

Abdeselem Benmeddah

University of Defence

AŽ

Aleksandra Živković

Military Technical Institute

Marko Karić

Military Technical Institute

Cooperative Institutions

University of Defence

Carol I National Defence University

Military Technical Institute

University of Kragujevac

University of Belgrade

ORCID

Faculty (United Kingdom)

Military Medical Academy

Sportska Akademija Beograd

Texas A&M University at Qatar

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Stress analysis of integrated 12.7 mm machine gun mount

Scientific Technical Review (2016)

Aleksandar Kari D. Jovanović Damir Jerković Nebojša Hristov

The paper describes the problem of integration 12.7 millimeters machine gun on the mobile platform. Based on the dimensions of the machine gun modeling of machine guns mount with cradle is done. The completed model is fully functional and realistic. Using optimized internal ballistic parameters the calculations of recoil forces and loading of mount and rotating bearing are executed. The loading calculation of bearing was made in two ways. In the first case finite element method is applied and software package FEMAP was used. The second method is based on calculating the resistance components of bearing from the equilibrium condition. At the end the comparative analysis of data obtained from these two methods was done.

Mount

Recoil

10.5937/str1604047k

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Citations (3)

Measurement analysis of physical quantities for ballistic tests using different sensors

Scientific Technical Review (2023)

Toufik Allouche Abdellah Ferfouri Nebojša Hristov Damir Jerković Marijana Stalević

Measurements of recoil and counter-recoil movement in weapons are essential in order to optimize ballistic performances, to ensure safety during firing, to improve the accuracy and the effectiveness of the weapon during its life cycle and to guide design and development work. From this, the present work focuses on contact-based measurements of the counter-recoil movement of the D30J 122 mm howitzer using two inductive sensors, namely, displacement sensor and acceleration sensor. The measurements from the displacement sensor were used to calculate the velocity and acceleration of the counter-recoil by derivation and those of the acceleration sensors were used to calculate the velocity and displacement of the counter-recoil by integration. The comparison between the measured and calculated results obtained from the two sensors shows a very good similarity in form of variation and in values, which validates the applied experimental approach in this work and confirms the accuracy of both measurement methods.

10.5937/str2301042a

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Determination of the gun barrel walls temperature distribution and its experimental validation during multiple-shots firing process

International Journal of Thermal Sciences (2022)

Walid Boukera Abaci Nebojša Hristov Nabil Ziane Ahmed Damir Jerković Momir Drakulić

Light-gas gun

10.1016/j.ijthermalsci.2022.107667

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Citations (11)

Simulation and Measurements of Small Arms Blast Wave Overpressure in the Process of Designing a Silencer

Measurement Science Review (2015)

Nebojša Hristov Aleksandar Kari Damir Jerković Slobodan Savić Radoslav Sirovatka

Abstract Simulation and measurements of muzzle blast overpressure and its physical manifestations are studied in this paper. The use of a silencer can have a great influence on the overpressure intensity. A silencer is regarded as an acoustic transducer and a waveguide. Wave equations for an acoustic dotted source of directed effect are used for physical interpretation of overpressure as an acoustic phenomenon. Decomposition approach has proven to be suitable to describe the formation of the output wave of the wave transducer. Electroacoustic analogies are used for simulations. A measurement chain was used to compare the simulation results with the experimental ones.

Overpressure

Silencer

Blast wave

10.1515/msr-2015-0005

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Citations (12)

The application of the ballistic pendulum for the bullets velocity measurements

IOP Conference Series Materials Science and Engineering (2019)

J M Milutinovic Nebojša Hristov Damir Jerković Strahinja Marković Aleksandra Živković

Abstract The accurate values of the initial velocity of bullets are significant for the quality and precision of small arms. The application of the simple measurement methods, during the tests of the weapon and ammunition, enables the determination of the velocity values from the group of shoots. The accuracy of bullet trajectory, appropriate trajectory correction parameters and terminal ballistics parameters are depended of the quality of initial conditions as initial velocity. The ballistic pendulum, as simple and old-design device, enhanced with optoelectronic encoder sensor and computer acquisition system, can be one of the good start-up device platform for measurement of velocity and observation of the terminal ballistics effects. The function principle of the considered device is based on the energy conservation. Initial data are mass of bullet, mass and dimension of pendulum, and result is velocity, according to the values of time and angle of pendulum. The output signals of measured angle in time are captured, and as required values for calculation the velocity on the microprocessor platform, for each shoot in the test group. The microprocessor platform saves measured and calculated values in memory and generates statistic report of results. The presented method can improve weapon and ammunition tests, by decreasing the time of measurement acquisition and increasing the quality and speed of results without errors. The method and system is simple and low-cost, and enables the design of small arms ammunition database of testing results.

Ballistics

Ammunition

Microprocessor

Pendulum

Internal ballistics

10.1088/1757-899x/659/1/012016

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Citations (1)

Weapons barrel life cycle determination

Vojnotehnicki glasnik (2013)

Nebojša Hristov Gordana R. Jovičić

This article describes the dynamic processes within the gun barrel during the firing process in exploitation. It generally defines the basic principles of constructing tube elements, and shows the distortion of the basic geometry of the tube interior due to wear as well as the impact it causes during exploitation. The article also defines basic empirical models as well as a model based on fracture mechanics for the calculation of a use-life of the barrel, and other elements essential for the safe use of the barrel as the basic weapon element. Erosion causes are analyzed in order to control and reduce wear and prolong the lifetime of the gun barrel. It gives directions for the reparation of barrels with wasted resources. In conclusion, the most influential elements of tube wear are given as well as possible modifications of existing systems, primarily propellant charges, with a purpose of prolonging lifetime of gun barrels. The guidelines for a proper determination of the lifetime based on the barrel condition assessment are given as well.

Internal ballistics

Distortion (music)

10.5937/vojtehg61-2062

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Design of mortar barrel 82 mm on basis of analysis of internal ballistics parameters

Marija Milovanović N.S. Radovanovic Nebojša Hristov Lazar Arsić Aleksandra Živković

The aim of this work was to obtain mortar with a higher initial velocity and lower pressure of powder gases. Aanalysis of the Internal ballistics (IB) parameters in the design phase of the 82 mm M69 mortar was perforormed using mathematical model of the Serebryakov method. In order to see the influence of certain parameters on the pressure of the gunpowder gases in the barrel and the initial velocity were first calculated with unchanged IB parameters, and then the influential parameters were varied in a certain range. A comparative method of calculating IB parameters is presented in a tabular way. By optimally varying IB parameters in the range of ± 5%, the maximum pressure was reduced while the initial velocity was increased, which was the aim of this work.

Internal ballistics

Ballistics

Basis (linear algebra)

10.5937/oteh24021m

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Analysis of thermal and gas-dynamic characteristics of different types of propellant in small weapons

Thermal Science (2021)

Abaci Boukera Nebojša Hristov Ahmed Ziane Damir Jerković Slobodan Savić

This paper presents a numerical and an analytical approach for calculation of internal ballistics parameters through determination of thermal and gasdynamic characteristics. The calculated parameters are validated through experimental tests on a real weapon system. The internal ballistic calculations are provided for two types of propellants using an analytical and a numerical model. Calculations and tests are performed for an anti-material rifle 12.7 mm. Weapon and ammunition testing is carried out according to the permanent international commission standard. Theoretical and experimental results for the gunpowder gases pressure and the muzzle velocity are compared. The good agreements between the calculated and the measured pressures and velocities increase the reliability of the estimated gunpowder gas temperatures in the barrel. The obtained results enable analysis and comparison of the output internal ballistics parameters for different types of propellant applications.

Internal ballistics

Ballistics

Muzzle velocity

Ammunition

Muzzle

Rocket (weapon)

Rifle

10.2298/tsci200814138b

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Citations (5)

Application of a CFD Model in Determination of the Muzzle Blast Overpressure in Small Arms and Its Validation by Measurement

Tehnicki vjesnik - Technical Gazette (2018)

Nebojša Hristov Aleksandar Kari Damir Jerković Slobodan Savić

The main subject of this paper is application of a Computational Fluid Dynamics (CFD) model in determination of the muzzle blast overpressure and its physical manifestations, as well as its validation through measurements of primary parameters.Unsteady Reynolds-averaged Navier-Stokes equations (URANS) with a corresponding turbulence model were applied for numerical simulation of complex gas-dynamic process of propellant gases release from the barrel after firing.The unstructured adaptive mesh for spatial discretization was applied, as suitable model for numerical calculation and physical interpretation of these intensive dynamic processes.The provided experimental results were compared with the results of numerical simulations, which were thus validated, according to adopted minor simplifications.

Overpressure

Muzzle

Blast wave

10.17559/tv-20180321135212

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Citations (6)

Numerical modeling of explosively formed projectiles formation

Andjela Mitrović Saša Savić Milan Vučković Nebojša Hristov Damir Jerković

Within this study, the process of forming explosively formed projectiles is analyzed. This type of warhead is used for military purposes due to its excellent impact performance. The projectile is shaped like a metal disc which, during the action of the explosive, forms into a high-speed projectile. Such formed projectiles act on the target. The performance of the projectile is influenced by a large number of parameters, such as structural characteristics and material properties. Using a numerical program on the EFP model, various parameters influencing the final shape of the projectile and thus its performance on the target can be analyzed. The parameters considered within this study are the type of explosive filling and the thickness of the copper disc. The analyzed disc thickness was 1-4% of the explosive filling diameter. It was observed that reducing the thickness of the projectile results in higher values of projectile stable velocity. Specifically, reducing the initial thickness of the projectile can replace the use of more explosive explosives, thereby reducing the overall mass of the construction.

10.5937/oteh24042m

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