AiMT Volume 14 (2019), Issue 2

TECHNICAL INFORMATION
Analysis of Engine Surges in Military Jet Aircraft in Czechoslovakia and the Czech Republic

O. Zavila and M. Hocko

The article deals with the statistics, causes and consequences of aviation accidents and preconditions for aviation accidents linked causally to jet engine surge events in military jet fighter, fighter-trainer and trainer aircraft in the service of Czechoslovakia and the Czech Republic from 1960 until the end of 2016. It presents a complete list of such aviation emergencies on a timeline, as well as technical contexts and facts of interest (for example, hazardous flight stages, hazardous aircraft types prone to engine surges or possibilities and developments in anti-surge systems). The role of human, technical and environmental factors in the occurrence of these air emergency events is also analyzed.

The study is complemented by an overview of information sources on the subject that are currently still accessible.

Keywords: aviation accident, cause, fire, jet aircraft, jet engine surge, precondition for aviation accident, statistics.

Pages: 171–187  [References]   [Download Citation]

Optimization of Production Process of Frangible Bullets Based on Bismuth Powder

V. Minh Do, X. Son Bui, J. Komenda, R. Vítek and P. Skalický

The article deals with the pressing process of the samples from bismuth powder, which were used in place of the bullet in order to optimize the frangible bullets manufacturing process. Cylindrical samples with a diameter of 9 mm were compacted by cold pressing in a cylindrical rigid die without sintering. Various pressing conditions (the changing of pressing force, pressing velocity and dwell time) were applied for compacting the samples. After compaction, the axial strength of the samples was tested to determine the optimal manufacturing process of the frangible bullet based on the bismuth powders.

Keywords: bismuth, frangible bullet, green strength, green density, powder metallurgy, pressing force, pressing velocity.

Pages: 189–196  [References]   [Download Citation]

Hydration Bags Construction Materials Resistance to Chemical Warfare Agents and their Comparison

J. Kiszka and S. Florus

When working in a contaminated area while wearing individual protective equipment, there is a high risk of overheating and dehydration. In accordance with the valid documents of the Army of the Czech Republic, a person using protective equipment has to be provided with an adequate fluid intake. To perform the work, it is necessary to equip the soldier with a hydration device that is resistant to chemical warfare agents and is structured in a way that allows its use when means of personal protection or other equipment is used. The aim of the experimental work was to verify resistance of the construction materials of hydration devices and to compare them. For this purpose, devices designed to provide resistance to chemical warfare agents and those that did not provide it were tested. To determine breakthrough times of selected materials, the MIKROTEST and the MINITEST methods were used.

Keywords: breakthrough time, chemical warfare agents, hydration device, mustard gas, organism dehydration.

Pages: 197–212  [References]   [Download Citation]

Target Programming with Multicriterial Restrictions Application to the Defense Budget Optimization

O.V. Barabash, P.V. Open’ko, O.V. Kopiika, H.V. Shevchenko and N.B. Dakhno

The analysis of the main factors of decision-making on media planning, methods of automation the advertising targeting and existing models and algorithms discovered, the contradictions between the possibilities of traditional methods and classical models of advertising budget distribution. The requirements to automate decision-making support in managing the advertising process became important when organizing and conducting public Purchases for the needs of the Armed Forces of Ukraine. In order to increase the efficiency of defense resources management for rational advertising budget distribution between different types of advertising platforms, an advanced mathematical model for making decisions on the application of targeting informational technology to advertising has been developed.

Keywords: method of leading priorities, target function, utility function, targeting informational technology, weighting factors.

Pages: 213–229  [References]   [Download Citation]

Cartridge Case Design and its Analysis by Bilinear, Kinematic Hardening Model

B.A. Parate, S. Chandel and H. Shekhar

The objective of this research paper is to design the cartridge case and to carry out its analysis by bilinear, kinematic hardening model for water disruptor applications. An attempt has been made in the paper to determine the strain of the cartridge case theoretically and experimentally by conducting tensile testing of test specimen. The maximum strain experienced by the cartridge case is calculated as 0.395×10-3 (εreturn) using bilinear kinematic hardening model. The aim of this paper is to provide theoretical calculations and technological aspects about the study of bilinear kinematic hardening model of power cartridge. After the conducting of the trials, it was ensured that smooth extractions of cartridges were observed.

Keywords: bilinear, breech module, kinematic hardening, improvised explosive devices, modulus of elasticity, obturation, power cartridge, stress, strain, water disruptor.

Pages: 231–243  [References]   [Download Citation]

Vortex Induced Aerodynamic Noise Generation from Wind Turbine Blades

V. Bhargava, S.P. Maddula and R. Samala

An important aerodynamic noise source from lifting surface occurs from trailing edge of an aerofoil as found in wind turbine blades. In this work, semi-empirical method proposed by Brookes, Pope, Marcolini is applied to evaluate trailing edge bluntness vortex shedding noise source. For low Mach number flows (0.1884) and moderate to high chord Reynolds number, 4.73 × 105 – 3.35 × 106, change in sound power level was assessed for trailing edge thicknesses in terms of 0.1%, 0.5% and 1% chord lengths at wind speeds of 8 m/s, 10 m/s. For overall change of trailing edge thickness from 0.1% to 1% chord, an increase in noise levels up to 50 dB was found at low frequencies, while a decrease up to 30 dB was found between mid-band to high frequencies of spectra.

Keywords: aerofoil, boundary layer, sound power level, wind turbine.

Pages: 245–261  [References]   [Download Citation]

TECHNICAL INFORMATION
Cyber Security Challenges in Future Military Battlefield Information Networks

M. Ďulík and M. Ďulík jr.

This paper explains the evolution of technology from obsolete military battlefield networks towards the global military battlefield information network from information and cyber security point of view. The authors focus on the threat of the communication medium which is mainly used in military battlefield information networks – the wireless channel, which is the basis of different mobile wireless systems. This paper deals with complex threats to military cyberspace, in which primarily wireless channels may be easily available by the enemy. Employed subnetworks may have different properties. A unifying extended layered model is presented in the article, which in addition to ISO/OSI model spreads cyber threat to geographic and social spheres. The article also shortly illustrates the development of electronic military warfare towards cyber military warfare.

Keywords: cybersecurity, cyberspace, cyber warfare, electronic warfare, radio networks, security.

Pages: 263–277  [References]   [Download Citation]

Quantification of Command and Control Approaches – Model Based Evaluation

J. Hodický, D. Procházka, P. Stodola and J. Drozd

The Post-Information Age brings new challenges into the military operational environment. The current approach of the extreme hierarchical command and control cannot be sustained in this complex and dynamic environment. Thus, making the search for new command and control approaches is a critical activity. The description and classification of command and control approaches is expressed in a very abstract way. The article describes a unique, quantification technique of command and control approaches. The quantification is demonstrated by Use Case with self-synchronization as the selected command and control approach. In the Use Case, the deterministic dynamic model is implemented. The results achieved from the model demonstrate a variance of a single parameter, on which the quality of the selected Command and Control approach in the given operational scenario quantifies.

Keywords: deterministic model-based evaluation, military command and control system, self-synchronization.

Pages: 279–289  [References]   [Download Citation]

TECHNICAL INFORMATION
Human Factors Approach to Cybersecurity Teamwork – The Military Perspective

C. Krasznay and B.P. Hámornik

Successful national cyber defence requires talented experts who can work together in teams. In military organizations, there has been a long history of methods defining how talents and teams can be developed. Drills and practices can serve as a unique opportunity for setting up successful groups to protect military IT systems even in the most hostile environment, however the cyberspace might be different from the physical space from the human perspective. In this paper, we introduce some ways of how cybersecurity incidents are managed in the military environment; in addition, we describe the main requirements towards humans in milCERTs and how these requirements differentiate from civilian CERTs. Further on, we highlight the institutional background of Hungary’s cybersecurity training, specifically underlining the role of National University of Public Service in it, which is responsible for the education of all public servants, including cadets. The paper also focuses on the major challenges and some suggestions from Academia how to respond to them by building successful teams for the protection of national cyberspace.

Keywords: capacity building, CERT, CSIRT, cyber command, cybersecurity, cyber training, incident management.

Pages: 291–305  [References]   [Download Citation]

TECHNICAL INFORMATION
System of Systems Architecture for Generic Torpedo Defence System for Surface Ships

G. Jomon, J.V. Jojish and T. Santhanakrishnan

Protecting war ships from torpedo attack is considered as the most challenging task in Anti-Submarine Warfare. Torpedo Defence System (TDS) is an essential fitment on modern high value platforms. Timely detection and identification of a torpedo attack is the primary function of a TDS. Localisation and countermeasures against the weapon are the next stage in torpedo defence. Detection of modern torpedoes with long endurance can only be achieved using an underwater sensor suit with wide frequency coverage. Tactical use of multiple counter measures is essential for evading an attacking torpedo with intelligent homing mechanism. Individual sensors and counter measures are no longer considered as a solution; they are rather considered as components of a large network of systems to protect the platform from torpedo attack. A System of Systems (SOS) architecture with multiple sensors, processing techniques, countermeasures and tactics are presented in this paper for achieving fail-safe torpedo defence capability.

Keywords: systems engineering, system of systems, requirement analysis, torpedo defence system.

Pages: 307–319  [References]   [Download Citation]

Improved Production Sequence for a Ballistic Test Barrel

V. Nezval, S. Procházka and E. Svoboda

Based on experimental verification, technology consisting of copper plating blank bores before the barrels are forged is implemented in the manufacturing process of ballistic test barrels. This technology helps to optimize the process of plastic deformation during the forging process. A barrel hammered using this technology has better roughness parameters in the rifling, which is reflected in shooting tests by improved bullet accuracy. Comparative tests revealed that barrels forged using this technology can successfully compete with button rifled barrels in terms of target shooting accuracy.

Keywords: accuracy, ballistic test barrel, cold forging, hammering, steel 1.7765.

Pages: 321–330  [References]   [Download Citation]

TECHNICAL INFORMATION
Sleeping Encryption Unit in the Integrated Air Defence Systems

O.A. Dawood, H. Almulla and S. Khan

This research introduces a new military crypto-cipher authentication model developed for an Integrated Air Defence System (IADS). This study focused on the encryption aspect that is built as a hidden cryptographic of a sleeping encryption unit (SEU) in an IADS. SEU is utilised as a sleeping unit under the control of manufacturer countries during wartime. SEU permits high access to manufacturer countries to remotely deactivate an IADS. This hidden unit identifies and verifies targets before targeting them, thereby preventing their destruction at a critical time. Algorithms and protocols assigned to this unit are often confidential, highly secret and undisclosed.

Keywords: crisis management, integrated air defence system (IADS), military mobility, Patriot PAC-3 usa, S-400 & S-500.

Pages: 331–346  [References]   [Download Citation]

Magnetohydrodynamic Model of Electric Arc during Contact Opening

M. Mačák, P. Vyroubal and J. Maxa

A numerical model of an electric arc based on Magnetohydrodynamics Theory was investigated, adjusted and implemented as a user-defined model into ANSYS FLUENT. The goal of this model was to simultaneously calculate electric and magnetic fields, which is not possible with built-in ANSYS MHD model. This custom model was then applied on a problem which described opening of contacts between which an electric arc was created. The development of the arc was investigated by its temperature field. A comparison of built-in and presented model was carried out.

Keywords: ANSYS FLUENT, CFD, magnetohydrodynamics, plasma.

Pages: 307–319  [References]   [Download Citation]

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