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This paper follows on research on published in the Journal of the Academy of Business & Economics [1] (authors Hron and Macak) and complements previous research on the area of design of experiments using a factorial design. Further results are compared between Fuzzy Logic and Design of experiment approaches.The main purpose of this paper is to compare the results between the mathematical model of optimization of CNC turning and the optimization using the fuzzy-logic method for multi-criteria optimization of cutting conditions. The comparison in this paper verifies these two approaches. In the case of an inconsistency, the objective of this paper would be to suggest a new approach where the incorporation of the mathematical model (as an approximation form) and the optimization of fuzzy-logic would be consistent.

An important aspect of rail vehicle dynamic analysis is a ride comfort analysis and a prediction when passengers and cargo can experience adverse conditions. The computational software utilisation helps to determine forces and accelerations in various positions through the body of the rail vehicle in order to predict ride properties or evaluate ideas for ride comfort in advance. This paper is aimed to the dynamic simulation of the rail vehicle running on a real track. The rail vehicle model creation, computations performance and determination of accelerations badly needed for the ride comfort evaluation is performed by SIMPACK package. Parameters of passenger rail vehicle model correspond to the four-axle two-bogie BR481 rail vehicle. The track model on that the vehicle has been run corresponds to the real track section in Slovakia.

This work summarizes recent results in the field of intermetallics achieved during the research in our department. The research was focused on high temperature materials, shape memory alloys and hydrogen storage materials. In the case of high-temperature intermetallics, the development of TiAl-Ti5Si3 and NiAl-Al2O3 composites and Fe-Al-Si based alloys is described. During this research, powder metallurgy using reactive sintering has been established as an innovative and promising method for easy preparation of these materials. This method is also currently being tested and optimized for NiTi shape memory alloy. Another important property of several intermetallics (as LaNi5 or Mg2Ni) is the ability to store hydrogen reversibly.

The main parameters of the hot forming machines are production capacity and the fatigue life of the used tools. The life of a tool depends on its shape and load. The load depends on the structural design and speed of forming. The goal of our paper is to present the structural optimization and technological parameters design with respect to tool life. This process is applied in the case of the hot forming machine analysis.

Aim of this paper is to explain capability of ANSYS to model induction heating of inner rolling bearing ring. This physical problem requires simulation of the interaction of three physical fields. First field is harmonic low-frequency electromagnetic, second transient thermal and third static structural analysis. The skin effect requires the fine mesh in areas near boundary of modeled ring in the vicinity of inductor. MFS concept is used to couple these three physical fields. Main result of this analysis is the thermal field history in inner ring. This analysis is used to obtain sensitivity data for appropriate shape and size of inductor to austenitize required domains of inner ring.

The paper describes specific phenomena of semi-solid casting process, especially rheo-casting method SEED, which uses mechanical swirling for reaching proper structure in semi-solid state. The eutectic segregation during processing of semi-solid slurry can cause specific casting defects. Heat treated alloy AlSi7Mg0.3 was applied for producing castings. For observing structure, metallographic observation by light and SEM microscopy was used as well as spectral analysis.

Aluminium and silicon alloys are widely used in practice currently, e.g. in car industry, aircraft industry or in civil engineering. Hence there is increasingly more emphasis placed on research and development of silumins. The aim of this paper is to analyse aluminium alloy, namely the alloy AlSi7Mg0.3. This paper is focused on the effect of particular modifiers and heat treatment on the selected properties of the alloy, especially on structural transformations caused by various modifiers, hardness measurement (Brinell method) and microhardness testing (Vickers method). Four variants of castings (unmodified alloy and alloy modified by chemical elements - strontium, calcium and antimony) were tested. All alloys were compared to the cast of pure aluminium (Al 99.8%). There were moulded four castings from each variant and two castings of pure aluminium. It was casted using a gravity-die casting into a metal mold with a thermal insulation - except of pure aluminium (without thermal insulation).

The article deals with the analysis of the chemical pre-treatment influence based on nanotechnology on the roughness and morphology of the Al sheet surface. Experimental material is Al-Mg sheet on which were applied two variants of surface chemical pre-treatment. The first chemical pre-treatment variant is based on the application of zirconium passivating product intended for creating of nanomolecular coatings on the surface of metallic material. The second chemical pre-treatment variant consists in application of fluid single-component product for protection of the aluminium surface after previous application of zirconium nanopassivation. Within the experiment are prepared experimental samples, which are as the next included to the surface rougness measurement on the confocal laser microscope. Experimantal samples are further examined in the terms of morphology of the surface thus according to the form of exluded layers of the chemical products on the basic material surface on the laser confocal microscope and on the electron microscope.

An article deals with a realization and a statistical evaluation of a pressure test using a hydraulic testing machine ZD 40 in order to determine a strength of a designed implant prototype of a femoral component, more precisely a maximal force F that breaks a material and creates a crack. It is needed to make real testing samples of the new implant prototype of the femoral component for this purpose. Four pieces of testing samples are made in cooperation with the company in Velka Bites. Because of a price and availability in a range of offered cast materials testing samples are made of a bio tolerated cobalt alloy Co-Cr-Mo that is frequently implanted to a live organism. The implant prototype of the femoral component is designed from evaluated CT data of a patient's affected knee-joint (a femur distal part, a proximal tibia part). An individual 3D model of the implant prototype of the femoral component is created on the basis of editing of gained data in software CATIA.
The created 3D model is converted to *.stl format with a high resolution. Subsequently, the shell implant of the femoral component (a master model) is made using an additive method FDM (Fused Deposition Modelling). The next production method follows - production of a ceramic mould and casting of the real implant prototype of the femoral component from the bio tolerated cobalt alloy Co-Cr-Mo.

The article deals with the problem of vertical vibration of vehicle model driving a horizontal curve of radius R = 100 m. A brief theoretical work on the topic is presented in the introduction part. Where a descriptions of the forces acting on the vehicle while passing through the curve are discussed. In the second part of this work, a detailed description of the vehicle model is given. The equations of motion of the vehicle model are then derived for vertical dynamic response of the mechanical system considered herein. Analysis of the effect of asymmetry is then performed when the vehicle is driving the curve at a constant speed v = 30 km/h, excitated by general kinematic excitations. Firstly, the asymmetrical model is considered and the results are then compared to a fully symmetrical model.

Alloys based on the intermetallic phases are presently considered to be very promising materials for demanding technological applications in a wide range of industries. The biggest disadvantage of intermetallics is their low toughness at room temperature. One of the way how to increase their plasticity and eliminate susceptibility to low temperature brittleness is preparing intermetallic phases with ultrafine grain structure. The paper describes the preparation of ultra-fine grained alloys based on intermetallic phases by mechanical alloying and subsequent compaction by the "Spark Plasma Sintering" (SPS). Influence of the individual alloy components on the preparation and mechanical properties of intermetallics alloys were studied. The basic mechanical properties at room and elevated temperatures, resistance to high temperature oxidation and thermal stability of alloys were measured.

The trend towards using turbochargers in various engines continues. In some applications, including engines of light duty trucks, city buses and even tractors and harvesters, the warranty of long life is demanded because turbochargers are subject to high cyclic loading and on consequence the turbochargers can determine the lifetime of the whole engine. The replacement of the aluminium compressor wheel for a titanium one significantly improves the turbocharger lifetime, but since a titanium alloy has about 60 % higher density than an aluminium alloy, the mass and the moments of inertia of the wheel increases, which further leads to changes in natural frequencies, rotor stability and power losses in bearings assuming the same bearing system as for the rotor with the aluminium wheel is employed. In this article the influence of the increased mass properties are discussed. AVL EXCITE and in-house developed model are used for the construction of Campbell diagrams and stability maps and for the obtaining of detailed information about the behaviour of the oil films in floating bearings.

This article is deals of noise and vibration measurement of rollers for belt conveyor. In the first part of article a stand measuring is described and individual rollers types which were measured. There are five types of rollers for measurement. The first type are the Transroll rollers which were measured with the rubber pads. The second type are the Transroll rollers again. The third type are the Sandvik rollers and the fourth type are "Italian" rollers. Process of noise and vibration measurement of the individual rollers types is given. In conclusion of this article is noise and vibration measurement evaluation. Compared of the Transroll roller with pad and without pads is given. Three the highest acceleration values in depending on the frequency of vibration in individual directions (x, y, z) are given.

Article deals with the detection of reduced stress in a braked railway wheel based on thermal transient analysis on virtual models, because they influence the characteristics of the railway wheels. Structural analysis was performed by means of the ANSYS Multiphysics program system package. Thermal transient analysis deals with the detection of temperature fields which are result of braking by brake block. The applied heat flux represents the heat generated by friction of brake block. It is applied to the quarter model because of the acceleration calculation. This analysis simulates two braking with subsequent by cooling. Distribution of the equivalent stress was detected in the cross section railway wheel, at selected points. The input parameters were used from the thermal transient analysis. These equivalent stresses result due to thermal load.

In most cases, construction materials are selected so as to attain the optimal technological properties at the lowest possible weight and cost. Studies on the improvement of the properties of casting alloys have been continuously conducted over the recent years. Both the microstructure and properties of alloys may be altered via modification with chemical components, optimization of the crystallization process, heat treatment or a combination of these methods. While searching for alternative methods of improving the engineering surface properties of hypo- and hypereutectic Al-Si alloy, an attempt was made to modify its microstructure with the use one of a heat sources. This paper presents the results of an experiment investigating the microstructure and the hardness of the Al-9%SiMg and Al-20%SiMg alloys processed by TIG welding method.

Cutting tool wear monitoring is one of key problems in automation of machining processes. Apart from the cutting tool wear monitoring for the cutting tool change and cutting tool failure, cutting tool wear monitoring may be one of the components for the adaptive control of a machining process. This paper is focused on the design of turning cutting tool wear sensors of the system flap - jet principal with increased extend. On the geometric principles in cutting with a turning cutting tool, the relations among the output of jet mouth, clearance angle and cutting tool wear were expressed. Two variants of turning cutting tool sensors were designed and experimentally verified. The results of experiments have proved the possibility to apply cutting tool wear sensor of the system flap - jet principal with increased extend in practical use.

In modern analysis of structures it is not only important to study structures subjected to static loading but also to study the effects of dynamic loading. One of the results of impact loading is the dynamic response of structures. This can cause far more damage than the effects of static loading. Composite materials are more and more used in engineering praxis. This allows the creation materials of high strength at low weight which are more durable then the same construction made of homogenous materials. This paper presents a study of dynamic response of carbon fiber reinforced polymer composite plates in the form of modal analysis and transient response (subjected to unit pulse point load in the center of the plate). The plate consists of layered uniaxial carbon fiber fabric and the layers are layered symmetrically at different angles for various variants. The response in the form of displacement magnitude is measured. At the end a comparison study is presented for each analysis.

The article presents the measurement results of the relaxation of long-term loaded compression springs manufactured out of non-alloy steel. The goal was to determine the differences between the interrupted and uninterrupted tests. During the relaxation test that lasted 5000 hr in a laboratory with a temperature of 22ºC, initial shear stress set at a value of 30% of the ultimate tensile strength of the material, decreased the strength of the springs with a wire diameter of 1 mm by 3.6%, springs with a wire diameter of 3.15 mm by 2.5%, and springs with a wire diameter of 5 mm by 1.3%. The difference in the results was found in tests 16 times and 4 times interrupted to measure the current relaxation. The results of intermittent tests cannot be considered as relaxation values for statically loaded springs. Conversely, when determining the maximum tension of quasi-statically loaded springs with respect to the relaxation, the uninterrupted relaxation tests cannot be used.

This article deals with the influence of the alloy temper during heat treatment on mechanical and corrosion properties of aluminium alloys 2024 (Al-Cu-Mg) and 6064 (Al-Mg-Si). For the experiment initial alloy tempers 2024-T351 and 6064-T8 were heat treated to three conditions - underaged, peak aged (T6) and overaged - to simulate the circumstances during the manufacturing process. Structure of all conditions and tempers was observed. The mechanical properties - hardness, yield strength, ultimate strength and elongation - and corrosion properties - maximum depth of corrosion attack peneration and corrosion rate in Audi immersion test for automotive industry (internal standard PV 11 13) - were measured. Structures of investigated alloy show evidence of intermediate phases arrangement in the direction of plastic deformation and they do not change during heat treatment. The lowest hardness, yield strength and ultimate strength have the underaged samples, the highest hardness, yield strength and ultimate strength have peak aged (2024) or initial samples (6064). Elongation decreases with ageing time or ageing temperature. In case of alloy 2024 corrosion rate and maximum depth of corrosion attack penetration increase with ageing time or temperature, in case of alloy 6064 corrosion rate increases with increasing ageing time or temperature while maximum depth of corrosion attack penetration decreases. Both alloys are attacked by intergranular corrosion with initiating surface pits.

Ammunition projectiles disposal armored facilities used hard core as the main effect. The hard core has a smaller diameter than the calibre of gun. The core of the projectile is made of tungsten carbide, titanium, molybdenum or depleted uranium with a hardness of 80 to 120 measures by the Rockwell hardness test. The core must be not only hard but also tough and have a high bending strength. Knowledge of the hard core chemical composition, which the attacker uses, is important in relation to provide ballistic protection, minimization of radioactive risk and optimization of conditions for disposing of old ammunition. The basic tool for detection of the necessary data is material analysis. This analysis provides information about the weight, chemical composition and material microstructure of the hard core.

The key topic of this article is a study of the oil flow and pressure distribution on the surface gearing investigated using numerical simulations. Particularly, this paper is focused on a simulation of the single flow of oil, which is governed by the gearing motion. Results of the unsteady flow between two rotating gearing could help to identify reasons of damages of gearings. The destruction of surface is identified after several hours on the helical gearing which is used in a heavy industry. In the case of moving and rotating gearing, it was necessary to use dynamic mesh and procedure of remeshing based on the parameters of quality cells. The simulation provides the complete information of pressure distribution on the surface of gearings. By the analysis of numerical results the areas with the high frequencies of low pressure were identified.

The article deals with the design of a process recirculation air cooler for cooling natural gas when the latter is processed. The cooler is intended for extreme climatic conditions, and due to this reason, it is necessary when designing and fabricating the cooler to comply with the specific requirements for both the calculation and materials to be used on constructing it. In the winter period when the ambient temperature drops even below the solidification point of the medium the cooler works with reduced rpm of the fan, and when necessary, even in the recirculation mode, partial or full (depending on the ambient temperature). In this case, the inlet and outlet louvers are closed, and the recirculation louvers are opened. This system allows, using the control of the temperature of the inlet cooling air, to maintain the temperature of the cooled medium at the desired level.

The research into root causes of defects in cylinder head castings are described in the paper. Chemical composition of castings, evaluation of casting microstructure before and after the heat treatment and final inspection of casting quality from various points of view are parts of the research. The list of the most common defects in case of using five selected products is the result of the experiment. The objective of the research was to identify causes of defects in the process of cylinder head casting as well as to identify root causes of discrepancy using the quality management tool.

Biodegradation properties of magnesium and its alloys that can be used for implants are not satisfactory and cause serious problems. These problems can be solved by biodegradable surface coatings. Evaluation of biodegradation process of Mg-RE-Zr alloy surfaces after grinding and grinding followed by potential controlled electrodeposition of octacalcium phosphate (OCP) was investigated by electrochemical impedance spectroscopy measurements in this study. The potentiostatic electrodeposition treatment process was performed in water solution of 0.167 M CaCl2 and 0.1 M NH4H2PO4. The corrosion process on treated and nontreated samples after various exposure times was evaluated in 0.9% NaCl solution simulating body fluid environment at 37 °C. The significant increase of polarization resistance and time resistance against corrosion were found after electrochemical surface treatment.

The translation in this article analyses the technology of laser cutting, describes properties of laser cutting equipment the oxidation process of melting and sublimation laser cutting. In the article chemical composition of cutted material in the interaction with the quality of cutting edges from cut-outs is analysed. The measurement was performed on experimental samples made from steel grade S355 however the composition of chemical elements in each sample varied. On these experimental samples the cutting edges was examined for the purpose to find out the influence of chemical purity of material on the quality of components which were cut by using laser technology.

The fiber reinforced plastic (CFRP) are widely used in stacks with metallic materials. The parts are usually bolted together during assembling procedure. That is why drilling is one of the most widely used operations for machining of CFRP/metal and metal/CFRP stacks. That allows to obtain components, which combine high strength and low weight. This paper presents tool wear study based on the drilling experiment of CFRP/ steel stack. The most common problems of CFRP/metal stacks machining are CFRP delamination, fiber pull - out, thermal degradation and intensive tool wear. Last decade such parameters of CFRP/metal stacks drilling as axial force and torque are in the focus of researches. However, the cutting temperature in the drilling process of CFRP/metal stack and its influence on drill bit wear is still not fully gained at the present time. The purpose of current study is to investigate the effect of cutting temperature on the tool life of carbide drill. The temperature was measured with K type thermocouple which was embedded on the flank surface of the drill. Axial force was measured with dynamometer. Data of cutting temperature and axial force was digitalized with analog - digital converter (ACD) and visualized on personal computer (PC). The dominating tool wear mode when drilling CFRP/steel - was flank wear which was measured with optical microscope. The experimental study of cutting temperature effect on the tool wear of carbide drill was established. It was found that the most unfavourable combination of stack materials in the conditions of drill wear is CFRP/metal.

Authors define general dependability characteristics (reliability, maintainability, supportability and availability) and their measures. Further there is introduced method of data collection which shall be planned taking into account appropriate targets. Dependability data analysis needs clear understanding of an object, its operation, environment and physical attributes to be obtained required dependability measures which are described. These measures can be used as indicators for measuring maintenance impacts on reliability and maintainability. Data collection and its evaluation help to monitor the impact of maintenance on these indicators. Dependency between non-fulfillment of preventive maintenance and failure intensity including maintenance costs are also evaluated.

An adhesive bonding technology is a method of a connecting which is used at a construction of coach-works, agricultural machines etc. This method is suitable for workings with a serial production. Many research projects dealt with a preparation of adhesive bonds, degradation aspects etc. An area, which has not been properly investigated at present, is an influence of a loading speed on strength of the adhesive bond and a destruction time of the adhesive bond. Adhesive bonds are loaded by a different intensity and a speed at a practice.
The research focused on an evaluation of the influence of the loading speed at a temperature 22 ± 2 °C on the shear tensile strength, the time needed for the destruction and a failure area. Second part of the research was focused on the influence of a bending moment. This bending moment can be minimalized by using so-called underlaying sheet of metal. The underlaying sheet of metal was of a thickness corresponding to a thickness of the adhesive bonded material. Also a behaviour of the adhesive bonded material was observed within the research.

This article describes the effect of selected parameters of plasma nitriding on the change of dynamic parameters of steel DIN 1654/4. Plasma nitriding is currently used in a wide range of technical applications such as a final operation to improve the mechanical properties of components. This experimental investigation is devoted to the analysis of the influence of plasma nitriding on the notch toughness of structural steel DIN 1654/4 (CSN 41 2042.4). The test of the dynamic fracture behaviour of structural steel was carried out using by instrumental Charpy hammer on the plasma nitrided specimens with V and U notch, manufactured according to standard CSN ISO 148-1. The plasma nitriding was implemented at 500 (°C), process duration t = 10 and 20 (h) and variable gas mixture ratio of 24H2: 8N2 (l/h) and 8H2: 24N2 (l/h). The test results showed that nitrided steel has become more brittle. However, it was found that for different gas composition, the notch toughness has behaved quite diversely. The values of notch toughness of steel in case of gas ratio 8H2: 24N2 (l/h) were decreased but for gas ratio 24H2: 8N2 (l/h), with extension of time, the notch toughness was slightly increased.

This paper deals with evaluation of the controlling processes service reliability of degradation processes leading to embrittlement, fracture at elevated temperatures, fatigue and fatigue fracture with the possible effect of corrosion and with interaction of all the previously mentioned processes.