Actual number: 4/2020

ISSN 1339-5017 (Online)

Archive:


No. 3

EXTERNAL FINISHING OF TURNED SURFACES BY TECHNOLOGY OF BURNISHING

Author: Igor BARÉNYI, Jozef MAJERÍK, Jozef ŠANDORA

Abstract: The paper is the scientific study of the burnishing technology which is finishing operation of turned surfaces. The topic of experiments is the comparison of surface qualitative parameters between turned only and burnished surfaces on cylindrical experimental samples. The burnishing of turned surface is a cold forming method with using of fulcrum cylindrical rollers. This method bring better surface quality, dimensional accuracy or surface hardness increase. Therefore the burnishing technology could replace surface finishing by grinding or polishing. First chapter describes the ways of turning. Second chapter deals with turned and then burnished surfaces and used burnish tools. Chapters three and four are core of the paper and they are targeted to experiment realization. Conclusion summarizes the advantages of burnishing process and its good influence on the utility parameters of industrial components.

Keywords: burnishing, turned surface, surface quality, microgeometry, cutting parameters.

Vol. 7, 2013, No. 3, p. 2-7

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TRENDS OF DEVELOPMENT IN UNMANNED MILITARY MOTOR VEHICLES

Author: Jozef ELIÁŠ, Danka RAKÚSOVÁ

Abstract: Based on an executed analysis of a current state the contents of the paper should point at trends of development in unmanned military motor vehicles of a special assignment.

Keywords: unmanned motor vehicles, combat activity, mobility, manoeuvrability, supporting means, IEDs

Vol. 7, 2013, No. 3, p. 8-14

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3D SIMULATION ANALYSIS OF AIRCRAFT PROTECTION MATERIAL IMPACTING BY 7.62 MM AMMUNITION

Author: Juraj HUB, Pavel KNEYS

Abstract: The article presents 3D numerical model of the penetration of 7.62 × 54R bullet into three kinds of armour material using explicit hydrocode Ansys Autodyn. Add-on armour materials are used also in transport aircraft cockpit in order to protect personnel on board. Analysed are following materials: steel HARDOX 450, aluminium alloy 7039 and titanium alloy Ti-6Al-4V. The analysis estimates the ballistic limit thickness to avoid complete penetration of the target. Another evaluating parameter is weight of protection system in order to find the material of minimum area density to save aircraft performance. Using the titanium alloy reduces the weight of protective system approximately twice when comparing to steel and aluminium alloy materials. The results obtained can be useful in the analysis of the airframe structures facing ballistic threat during war operations or terrorist attacks.

Keywords: Projectile 7.62 × 54R, penetration, ballistic limit, aircraft protection system, Finite Element Method

Vol. 7, 2013, No. 3, p. 15-19

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MECHANICAL TESTING OF NATURAL FIBER COMPOSITES FOR AUTOMOTIVE INDUSTRY

Author: Zuzana JAMRICHOVÁ, Eva AKOVÁ

Abstract: In the recent past, considerable investigations have been made in natural fibers as a reinforcement in polymer matrix. Manufacturing companies are in constant search of new materials to lower costs and profit margins. Natural fibers are low-cost fibers with high specific properties and low density. Performance characteristics that predestine polymer use in automotive applications include corrosion resistance, low density, good impact toughness and chemical resistance.

The contribution deals with composites from corn, sunflower and hop fibers, their testing and potentional use in the automotive industry.

Keywords: composites, natural fibers, tensile test, automotive industry

Vol. 7, 2013, No. 3, p. 20-25

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POSSIBILITIES USAGE OF THE AREA POSSIBLE ASSAULT AT OVERFLOW AIR TARGETS

Author: Miroslav JANOŠEK

Abstract: The article analyzes maneuvering capabilities of fighter aircraft in order to determine proper maneuvers with regard to full utilization of their tactical and technical capabilities during air target interception. Initial presumptions for mathematical model build-up are mentioned, as well as development diagram and results with graphical outputs, which show the possibilities of a successful engagement under given conditions.

Keywords: Aircraft, dogfight, performance, subsonic, air missile.

Vol. 7, 2013, No. 3, p. 26-31

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TESTING OF RIGID POLYURETHANE FOAM REINFORCED NATURAL FIBERS PROPERTIES AND POSSIBILITY OF USING THIS MATERIALS IN AUTOMOTIVE INDUSTRY

Author: Zuzana Jamrichová, Marcela Hejduková

Abstract: The contribution provides an overview of composite materials, their distribution and use in the automotive industry. Further this contribution provides an overview of the properties of composite foam specimens. Selected natural fibers (hop, corn, sunflower and chestnut) were used as reinforcement in polyurethane (PUR) foam in order to increase the properties of foam. The polyurethane foam specimens reinforced by 4wt% and 6wt% of individual fibers were produced to investigate two mechanical tests - three point bending test and fatigue test.

Keywords: Composite material, automotive industry, polyurethane foam, natural fiber, mechanical testing

Vol. 7, 2013, No. 3, p. 32-37

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INFORMATION SUPPORT FOR MODELLING OF THE PROCESSES IN MOBILE ROBOTICS SYSTEM

Author: Juraj MADARÁS, Martin BUGÁR, Viktor FERENCEY

Abstract: The current crisis situations required immediate action of rescue equipment during the life-threatening operation conditions. In this case, a special robotic vehicles for operations in adverse conditions, finds its application. This type of vehicles uses embedded controller systems for the controlling processes during its operations. This paper presents methodology for design and simulation of the hybrid power sources for the electric propulsion system of the robotic vehicle and its critical states and processes.

Keywords: Vehicle information system, modelling, mobile robotics system, energy storage system.

Vol. 7, 2013, No. 3, p. 38-43

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INVESTIGATE THE POSSIBILITY OF TEKCAST METHODS USED FOR CASTING POLYMERIC RESIN MATERIALS

Author: Harold Mäsiar, Mária Zichová

Abstract: Contribution gives an overview of knowledge about the method of centrifugal casting with orientate on Tekcast system. Company Tekcast Industries has developed a device for centrifugal casting, extending the area of production of castings or prototyping of metal or plastic. Materials suitable for the centrifugal casting with flexible operating parameters may include non-ferrous metal alloy based on zinc or aluminum or non-metallic materials such as polyester resins, polyurethane resins, epoxy resins, waxes and the like. The casting process is particularly suitable for a wide range of commercial castings and decorative objects.

Keywords: Silicone mold, model, vulcanization, centrifugal force, cast

Vol. 7, 2013, No. 3, p. 44-48

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CAPILLARY PLASMA GENERATOR AS THE NEW METHOD OF PROPELLANTS IGNITION IN CLOSSED VESSEL TEST

Author: Jakub MICHALSKI, Zbigniew LECIEJEWSKI

Abstract: Contemporary development of new types of ammunition is focused to improve the energetic characteristics, chemical stability and operational safety of propellants. Response to this requests are low vulnerability (LOVA) propellants. Therefore in Laboratory of Ballistics (Military University of Technology in Warsaw) began to develop a new method of low vulnerability propellants ignition and investigation - a new closed vessel equipped with the capillary plasma generator (CPG). Previous published results of closed vessel investigations indicated that classical primers (electric or percussion with black powder bedding) when used with LOVA propellants causes unstable burning, deflagration or even lack of ignition. Plasma generators, which create higher energy flux, temperature and make possible to control combustion process are possible solution of this problem. In CPG systems plasma generation is obtained by discharge of high power capacitors through low diameter conductors in polyethylene coating (mainly cooper, aluminium and tungsten wires), causing them to explode, generating metallic vapour which still conducts current. After wire explosion plasma causes burning of polyethylene, giving additional energy to plasma cloud. Plasma is vented to vessel causing high energy and heat flux through radiation and metallic vapour condensation. CPG is one of the most reliable ignition sources which make possible a reduction of temperature gradient effect and control combustion process. Comparable test of black powder and plasma ignition in closed vessel with conventional propellant were done. This paper (presented as a poster form) is mainly devoted to initial testing of free air plasma jet and black powder ignition comparable investigation but initial results of laboratory closed vessel tests are shown too.

Keywords: Plasma, Inner Ballistics, CPG, Insensitive Munition

Vol. 7, 2013, No. 3, p. 49-55

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SIMULATION TECHNOLOGIES SUPPORT IN CONSTRUCTION OF COMBAT AND SPECIAL VEHICLES

Author: Vlastimil NEUMANN

Abstract: The paper is focus on usage of simulating technologies in construction of combat and special vehicles. Simulating technologies are widely spread in all of spheres of industry. These technologies offer a lot of advantages – e.g. evaluation of various vehicle configurations, simulation of various critical states of vehicle, comparison of vehicles in the same surrounding. This manner is suitable for vehicle evaluation, too. Paper consists of introduction, mathematic model description, terrain – obstacle description and simulation.

Keywords: simulation, vehicle, evaluation, obstacle.

Vol. 7, 2013, No. 3, p. 56-61

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RESEARCH OF DETERIORATION OF SELECTED NON-METTALIC MATERIALS IN SLIDING ARRANGEMENTS OF THE VERTICAL FRAME SAW

Author: Monika Pilková, Alena Breznická

Abstract: The authors attempt to investigate and provide reasonable grounds for the application of selected non-metallic construction materials in linear slide bearing arrangement of the frame guidance of the vertical saw frame. In their experimental research, the authors verify the selected technical parameters of selected materials under laboratory and operating conditions.

Keywords: Friction coefficient, sliding pair, wear, service life.

Vol. 7, 2013, No. 3, p. 62-67

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