Zeitschriften und Ausgaben

Volumen 26 (2019): Heft 4 (December 2019)

Volumen 26 (2019): Heft 3 (September 2019)

Volumen 26 (2019): Heft 2 (June 2019)

Volumen 26 (2019): Heft 1 (March 2019)

Volumen 25 (2018): Heft 4 (December 2018)

Volumen 25 (2018): Heft 3 (September 2018)

Volumen 25 (2018): Heft 2 (June 2018)

Volumen 25 (2018): Heft 1 (March 2018)

Volumen 24 (2017): Heft 4 (December 2017)

Volumen 24 (2017): Heft 3 (September 2017)

Volumen 24 (2017): Heft 2 (June 2017)

Volumen 24 (2017): Heft 1 (March 2017)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

Volumen 24 (2017): Heft 2 (June 2017)

Zeitschriftendaten
Format
Zeitschrift
eISSN
2354-0133
Erstveröffentlichung
20 Dec 2019
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch

Suche

40 Artikel
Uneingeschränkter Zugang

Systemic Approach and Model of the Polish Tactical Air Force

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 7 - 16

Zusammenfassung

Abstract

The main purpose of this article is to present the structure of a tactical air force, on the example of the Polish Tactical Air Force, in a form of a technical system. This kind of technical system presents the technical point of view and organizationally bonds currently existing systems, objects (facilities) and components that are included into the Polish Tactical Air Force. The authors consider the Polish Tactical Air Force as the main analyses domain of this article. The model of presented system is mainly focused on operators’ organization and operation system of military aircraft, which are considered as technical objects (facilities) in a tactical air force. At the beginning of this article, the Polish Tactical Air Force is placed in more complex systemic structures. Then, the authors use the systems methodology, systems engineering, technical object-oriented (facility-oriented) approach and the matrix of the Model of Generalized Technical System to describe the Tactical Air Force System and present it via the model of such a system. The following model is based on a tree-shaped scheme divided into five levels of decomposition. The Model of Tactical Air Force System (as the “final product” of authors’ considerations over the selected analyses domain) has a considerable contribution to systems’ development in the Polish Armed Forces. The above-mentioned systems’ development could lead to greater progress in the Polish military as well as in systemic ideas. The implementation of the systems methodology in the design process of a new system, performed in a tactical air force, is an example of technical object systems engineering.

Schlüsselwörter

  • tactical air force
  • Tactical Air Force System
  • Model of Tactical Air Force System
  • Model of Generalized Technical System
  • technical object systems engineering
Uneingeschränkter Zugang

Detection of Damages in Hybrid Composite Plates with the Use of Elastic Waves Generated by PZT Active Sensors

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 17 - 24

Zusammenfassung

Abstract

The presented article is devoted to the problem of detection and localization of damages occurring in components of structures, which are made of hybrid composite materials. The subject of the work is a square plate consisting of a single layer made of aluminum alloy and several layers made of glass fibres (glass fabric) and epoxy resin. On the surface, which is made of composite, 12 piezoelectric elements are installed. These elements sequentially, one by one, generates a signal that is further recorded by the remaining piezoelectric elements. Picked up signal for the selected pair of activator – sensor is compared with the reference signal. The reference signal corresponds to the intact structure. This kind of approach is known as the pitch – catch configuration. In situations when the signal obtained for interrogated structure and reference one differs significantly, this may indicate that a damage exists between the activator and the sensor. Next, taking into account the information obtained from the other sensors, it is possible not only to detect but also to determine the approximate location of the flaw and to estimate its size. In order to visualize the obtained results, an especially dedicated software is developed according to the algorithms available in the literature – probability ellipse. Several computer simulations of wave propagation are performed using the finite element method. The proposed procedure is also tested experimentally. The presented approach makes it possible to detect both single and multiple damages.

Schlüsselwörter

  • elastic waves
  • hybrid composite plates
  • piezoelectric active sensors
  • low velocity impacts
  • damages
  • FEM
Uneingeschränkter Zugang

Engine Fuel Characterisation Based on Excitation-Emission Spectra

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 25 - 30

Zusammenfassung

Abstract

Considering that correctly functioning of diesel ship engine depends on the composition of applied fuel, it is necessary to easy characterise fuels in terms of quality. Therefore taking into account above mentioned, appropriate analyses have been undertaken and the intention of this article is to inform that characterisation of fuel used in marine transport can be described by the specific parameter based on fluorescence excitation-emission spectroscopy. Therefore, for this study fuel typically used in ship engine – Diesel fuel – is considered. For analysis, Diesel fuel dissolved in n-hexane was used and several oil samples for various oil concentration were prepared. Spectrofluorometer Aqualog Horiba was used to record the excitation-emission spectra (EEMs). EEM spectra determined for each of oil concentration were described by two specific peaks for this kind of oil. Based on registered EEMs, the specific indicator - the wavelength-independent fluorescence maximum – coded in two specific wavelengths – excitation and emission, respectively, described as Exmax/Emmax was determined for considered oil concentration. Obtained results indicate the independence from oil concentration only for one detected peak described by Exmax/Emmax = 240/332. Taking into account obtained results, we can conclude that the wavelength-independent fluorescence maximum detected for excitation wavelength at 240 nm corresponds to the emission wavelength at 332 nm due to the independence from the oil concentration, could be a good indicator to characterise this kind of oil – Diesel fuel. We can conclude that the changes in the composition of fuel could be detected in EEM spectra by the change of detected peaks position.

Schlüsselwörter

  • fuel
  • diesel
  • engine
  • excitation-emission spectra
  • fluorescence
Uneingeschränkter Zugang

The Issue of Selection: Shape and Volume of Briquettes Agglomerated in a Roller Press

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 31 - 38

Zusammenfassung

Abstract

A volume and a shape of the briquettes agglomerated in a roller press depend largely on the material properties, the design features of a roller press, and it is a complicated issue. Correctly, selected geometric parameters of the briquettes determine the proper strength of the consolidated product. The paper presents the laboratory and simulation experiments conducted to obtain knowledge about volume and shape of the roller press briquettes.

The main elements of the roller press compacting unit are the forming rollers. They are located horizontally in some roller presses of low efficiency they can be placed vertically. The shape of working surface, the volume of the melding cavities and the characteristics of the briquetted material have an important role in terms of the effects of the briquetting process especially the cost of operating of the roller press. The paper presents the description of the basic shapes of forming surfaces used in the roller presses and it systematises the knowledge of the shape and volume of briquettes produced in the roller presses on the basis of own laboratory and simulation researches.

The information contained in the article can be very useful for designers of roller presses and their users. Further work should be continued to verify the results of tests on other materials and laboratory conditions.

Schlüsselwörter

  • roller press
  • briquettes
  • simulation
  • volume of briquettes
Uneingeschränkter Zugang

Urban Transport Safety Improvement Based on Centralized Traffic Control System, Colombian Case Study

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 39 - 46

Zusammenfassung

Abstract

In a modern urban organization, mobility is an important issue for society. Traffic congestion of urban roads undermines mobility is a real problem in major cities This article shows the development and implementation of a centralized traffic control system in the city of Cali Valle (Colombia) applied to control traffic lights located to the east of the city (Simon Bolivar and Ciudad de Cali highways), allowing the central operators directly influence the traffic flow, know and display the status of the lights and generate statistics about the events of the online equipment. Particular real benefits of proposed new system of traffic lights are reflected in green times at each intersection allocated in accordance with the present traffic volumes on the road network at any time of day and in every sector of the city in particular, which of course increases the efficiency of each light installed at each intersection. As demonstrated in this article case study, the congestion scheme has been improved, and the project has opened up vast opportunities for innovative network management strategies for the optimization of network performance. Many of these strategies are developed to give a coordinated high-level control across different traffic control platforms based on real time traffic condition and performance on site.

Schlüsselwörter

  • traffic control
  • centralized control
  • software development
  • wireless communication controller
Uneingeschränkter Zugang

Numerical Prediction of GTD-350 Turboshaft Engine Combustor Deterioration

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 47 - 58

Zusammenfassung

Abstract

The aim of this article is to describe the use of Computational Fluid Dynamics (CFD) model for turboshaft combustor chamber deterioration analysis. To show advantages of the proposed approach the test bench of GTD-350 turboshaft engine operating at the Institute of Heat Engineering, Warsaw University of Technology was used as an example. The CFD modelling of the reactive flow inside 40º sector of GTD-350 engine section was developed. Proposed modelling technique provides good correlations with experimental data and shows that the combustor front wall soot accumulation is clearly related to the fuel droplets residence time and the oxygen mass fraction. The temperature distribution inside the combustion chamber allows concluding on possible hot distress areas on the combustion chamber liner walls. Engine borescope inspection (BSI) of the compressor, combustion chamber, compressor turbine and power turbine is used to correlate model predictions with a real GTD-350 engine deterioration. Very good correlation of the engine BSI observations with the numerical predictions proves usefulness of the developed model. Finally, advantages and future applications of the developed model are discussed.

Schlüsselwörter

  • turboshaft engine
  • engine health monitoring
  • digital analytics
  • engine deterioration
  • CFD modelling
Uneingeschränkter Zugang

The Influence of Treating Welded Joints Edges on the Strength and Fatigue of S640Q Steel

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 59 - 64

Zusammenfassung

Abstract

Weldable steels of high strength were discussed. The factors influencing the achievement of low grain structure that ensures high strength of these steels was explained. Traditional and modern methods of producing high strength steel were shown. The scheme of production line was shown, the line which is used to manufacture steel of high strength in thermomechanical way. The methods of achieving strength to fatigue used for welded joints were presented. The factors influencing the increase of strength to fatigue of welded joints were elaborated. The thermally hardened steel sheets of high strength weldable S640Q steel underwent research. Basic mechanical properties of this steel were indicated. The results of static tensile test and technological bend test were given. Then the sheets were welded by semiautomatic MAG method. The examinations of welds quality were conducted and their usefulness for further tests was stated. Mechanical properties of welded joints were determined. The mechanical properties of native material and welded joints were compared. The microstructure of welded joints in the weld axis, in heat influence zone as well as in native material was examined. Fatigue tests in a non-symmetrical cycle of lengthening – compressing for the welded joints were carried out. The computational strength to fatigue was determined and compared with fatigue strength of welded joints. Tests results were elaborated by the statistical analysis of linear regression. After conducting fatigue tests, the Wöhler diagrams were made. Afterwards, the joints welded with TIG method, were penetrated without adding filler metal. The results were presented for the fatigue tests as well as the Wohler graph for welded joints after penetration of the joints edges with TIG method without adding filler metal. The results were compared.

Schlüsselwörter

  • weldability
  • high strength weldable steels
  • thermomechanical treatment
  • increasing fatigue strength
  • fatigue strength
Uneingeschränkter Zugang

CFD Analysis of Effect of Misalignment Plane Position on Hydrodynamic Lubrication of Slide Conical Bearing

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 65 - 72

Zusammenfassung

Abstract

The numerical calculations of the hydrodynamic lubrication of slide bearings can be carried out by modelling the oil flow for a given value of height of bearing lubrication gap. On the basis of the assumed height of the lubrication gap, the values of hydrodynamic pressures, load carrying capacities, friction forces, temperatures, can be determined. The bearing lubrication gap height can be influenced by many effects, e.g. misalignment between the shaft axis and the axis of the sleeve, vibrations, varying load, change in the viscosity value of lubricating oil caused by changes in temperature, pressure, shear rate or by oil ageing, wear of journal and sleeve surfaces. This article presents the results of numerical simulations concerning the influence of the misalignment between the axis of shaft and the axis of sleeve of the sliding conical bearing on its hydrodynamic lubrication, by taking into account the position of the plane in which the misalignment occurs. In this study, there was defined an angle between the plane in which the misalignment occurs and the plane in which lies the line of centres of corresponding bearing without misalignment. In this research, to investigate the impact of the position of the plane in which the misalignment occurs, the CFD software, designed to solve general flow phenomena, was used. It was assumed, that the bearings operate in a steady state conditions, the flow in the bearing lubrication gap is laminar and non-isothermal. A lubricating oil has shear properties as the Ostwald-de Waele fluid.

Schlüsselwörter

  • slide bearing
  • hydrodynamic lubrication
  • conical bearing
  • misalignment
  • CFD
  • pressure distribution
Uneingeschränkter Zugang

Modern Methods of Identification Design Conditions for Single Stage Micro Scale Centrifugal Compressor

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 73 - 84

Zusammenfassung

Abstract

Micro scale gas turbine engines are low cost engines. They share their compressor impeller with automotive turbochargers. An identified design condition for the selected impeller is a critical stage of the design process. This process is had difficulties due the large number of manufacturers that provide OEM parts. It is common practice that one OEM part number provides the same impeller at different design revision. In general, parts are interchangeable but in detail, they differ slightly in terms of dimensions and performance. To avoid under predict or over predict inputs data, it is important to check the design parameters with as many methods as possible. In practice, the designer could rely on analytical methods, which are straightforward limited to the applied design. When shared its (compressor operation) it is recommended additional information be provided by computational fluid dynamics that produces a three-dimensional look into the predesign. That allows avoidance of future design failure and reduces both design time and prototype manufacturing costs.

Schlüsselwörter

  • jet engine
  • gas turbine
  • design
  • off design
  • trend prediction
  • centrifugal compressor
Uneingeschränkter Zugang

The Application of Friction Stir Welding (FSW) of Aluminium Alloys in Shipbuilding and Railway Industry

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 85 - 90

Zusammenfassung

Abstract

The article describes possibilities of application of friction stir welding (FSW) in shipbuilding and railway industry. Actually, in these sectors of industry more and more often modern construction materials are used. The biggest restriction of implementing new materials is technological possibility of joining them. One of construction materials used in the shipbuilding is aluminum, mainly its alloy of 5xxx-aluminium-magnesium series. Its application is justified by good corrosion resistance in seawater and good mechanical attributes. Thanks to susceptibility to plastic treatment, one gains good mechanical attributes with thrice-smaller density than a density of steel, what causes triple reduction of weight of aluminum construction relative to steel one. Alloys of 5xxx series are well weldable. It is generally known that welding is not a good way to joint metals, especially the aluminum. The application of FSW with mixing allows one to change approach to production of aluminum constructions. Using aluminum plates prefabricated with FSW method allows one to reduce time needed for installation of construction and considerably decreases the production costs. The article describes technology and directions of development of friction welding of aluminum alloys of 5xxx series using FSW method. There is also shown analysis of its usefulness in ship and railway industry and comparison of mechanical attributes of weld made with electric arc using MIG (135), TIG (141) method and FSW method.

Schlüsselwörter

  • Friction Stir Welding (FSW)
  • aluminium alloys
  • welding
  • shipbuilding industry
  • mechanical properties
Uneingeschränkter Zugang

Remarks on Utilization of Marine Trent 30 Gas Turbine as Prime Mover on Vessels

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 91 - 97

Zusammenfassung

Abstract

Utilization of gas turbines on vessels is a reality. It was presented the examples of utilization on ships of United States Navy and the Rolls-Royce suggestion for sharing on merchant shipping. It was mentioned the advantages of gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It was stated the characteristics of specific fuel consumption, the shaft power rating, the MT30 operating envelope with propeller characteristics as a power receiver. It was given propositions of vessel types for MT30 utilization. It was discussed the remarks on maintenance requirements and needed systems for upkeep the turbine in good technical state for the possibility of full nominal power independent on ambient temperature. It was discussed the requirements of emissions from exhaust gasses to the atmosphere in comparison gas turbines to diesel engines as a one of important problems for utilization engines as prime movers on vessels in merchant shipping. In the end, some final remarks with Rolls-Royce statements are presented.

Schlüsselwörter

  • marine prime mover
  • gas turbine
  • propulsion
  • gas-electric plant
  • gas turbine utilization
Uneingeschränkter Zugang

Progress in the Construction of Passenger Cars as a Result of CO2 Emission Limitation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 99 - 106

Zusammenfassung

Abstract

Global warming is a scientifically proven fact. Much of the temperature rise on the surface of the globe has been caused by human activity. That is why several years’ efforts are aimed at reducing of CO2 emissions, related to the human activities. Major sources of CO2 emissions include electricity production from fossil fuels, transport sector and intensive agriculture. Cutting down forests also contributes climate changes. In the field of transport, decisions are made at the level of the European Commission, and also by the wider audiences of introducing limits for CO2 emissions entire fleet of new passenger cars for year 2015, 2021 and later. The actions taken by car manufacturers are diverse. Cheaper and simpler solutions are focused on the concept of micro-hybrid based on a system of 48 V. More advanced solutions are a wide range of hybrid vehicles, including PHEV, and pure electric vehicles. The use of lighter materials, improved aerodynamics and rolling resistance, more efficient internal combustion engines and gearboxes also have an impact on energy demand and, consequently, CO2 emissions. An important problem to solve in many countries is the dissemination of renewable energy sources rather than fossil fuels. This article presents an outline of the issues related to eco-friendly solutions, including requirements for batteries intended for this type of vehicles. It also presents an overview of European standards in this area and progress in advanced energy sources.

Schlüsselwörter

  • Hybrid Electric Vehicles
  • Electric Vehicles
  • battery
  • capacity
Uneingeschränkter Zugang

Initial Numerical Analysis of a Small Electric Vehicle

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 107 - 116

Zusammenfassung

Abstract

This article presents a concept of a two-seat urban electric vehicle, whose model was developed in the FEM Nastran-in-Cad software. The performed simulations formed an optimization tool applied for the purpose of a study involving the distribution of the vehicle mass and its impact on the strength parameters of the body. The study focuses on the impact of the vertical road characteristics on the stress transferred through the vehicle’s body throughout drive conditions. In addition, a quasi-static analysis was performed with regard to the deformation of the load-bearing elements resulting from external impact forces with various magnitude and contact angle.

In the article, the authors focused on the study of the impact of vertical road characteristics on the stress that is transferred through the vehicle body, as it occurs in driving conditions. The simulations presented in the article focus on the procedures applied during the analytical and numerical analysis with the purpose of developing an environment to test the structural components of the vehicle in terms of its response to vertical road roughness. The analysed system examined the impact of the road surface on the occurrence of stress and displacement in the structure of the body of the designed vehicle.

Schlüsselwörter

  • vibrations
  • car chassis
  • finite element method
  • dynamic modelling
  • suspension
Uneingeschränkter Zugang

Residual Stresses Assessment in the Marine Diesel Engine Crankshaft 12V38 Type

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 117 - 123

Zusammenfassung

Abstract

In the paper, the measurement of the marine diesel engine crankshaft residual stresses is presented. The hole drilling strain gauge was chosen because of its simplicity and low cost. Moreover, deflection calculation was made for the load corresponding to its weight and the concentrated force in the chosen bearing conditions. Deflection of the journal and bending rigidity under the concentrated force was calculated as well. In that case, the crankshaft was supported in the neighbouring crank journals. The reduced stresses were calculated according to the Huber – Mises hypothesis. The residual stresses were measured in the marine diesel engine crankshaft type 12V38 after the finishing, with the hole-drilling method. It was found that the residual stresses reach the maximal value of 86 MPa, but for 50% of measuring points, the residual stresses did not exceed the value of 20 MPa. The squeezing stresses were found to be dominant. The measurement results provided important data for further consideration, especially for the correction of the bending deformation of the produced crankshaft.

Schlüsselwörter

  • diesel engine
  • crankshaft
  • simulation
  • residual stress
Uneingeschränkter Zugang

Propeller Optimization for Small Unmanned Aerial Vehicles

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 125 - 132

Zusammenfassung

Abstract

Small-unmanned aerial vehicle propellers usually have a low figure of merit due to operating in the low Reynold’s number region due to their size and velocity. The airflow on the airfoil becomes increasingly laminar in this region thus increasing the profile drag and consequently reducing the figure of merit of the rotor. In the article, the airfoil geometries are parameterized using the Class/Shape function transformation. Particle swarm optimization is used to design an airfoil, operating in a Reynolds number of 100,000, which has a high lift to drag ratio. To avoid exceeding geometric constraints of the airfoil, a deterministic box constraint is added to the algorithm. The optimized airfoil is then used for a preliminary design of a rotor; given some design, constraints on the tip chord the rotor radius and the blade root chord, with parameters that achieve the highest theoretical figure of merit. The rotor parameters are obtained using a combination of momentum theory and blade element theory. The figure of merit of an optimal propeller with the same geometric parameters is then compared using the optimized airfoil and the Clark Y airfoil. The optimization is done in MATLAB while the aerodynamic coefficients are obtained from XFOIL. The results of the numerical simulation are presented in the article.

Schlüsselwörter

  • unmanned aerial vehicles
  • particle swarm optimization
  • airfoil modelling
Uneingeschränkter Zugang

Determination of the Material Constants of Composite Materials on the Example of Modified Wood

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 133 - 140

Zusammenfassung

Abstract

Homogenization is the transition from the level of microscopic heterogeneity to a homogeneous macroscopic level. The analysis of the value of equivalent parameters and their variability requires prior determination of the influence of microstructure on the values of these parameters [15]. Wood is a composite material and has a layered structure in the form of alternate layers of soft and hard wood. One of the main issues was the determination of constants materials of individual layers of natural wood and modified and then equivalent material constants of natural and modified wood. The material constants of single layers and the material constants of composite were determined on the basis of experimental studies. For this purpose, a homogenization method has been used to determine equivalent material constants on the basis of material constants of single layers of soft and hard wood [1, 2, 14]. A representative cell consisting of a softwood and hardwood layer has been isolated from the sample-measuring portion. On the basis of this cell have been developed mathematical model of equivalent material constants. A sample consisting of two layers was subjected to an even stretch in the direction of the axes x1, x2, x3. The equivalent material constants have been defined by using equilibrium conditions, geometric conditions, and Hooke’s generalized law. Each wood component on the micro-level is homogeneous, continuous with its constitutive equation, conservation laws, and boundary conditions at the boundary of the separation of components. The equivalent material constants of natural and modified wood have been determined using the homogenization method [12, 13]. The results obtained from the research and the results obtained from the calculations are very similar.

Schlüsselwörter

  • modified wood
  • polymethylmethacrylate
  • homogenization
  • equivalent material constants
Uneingeschränkter Zugang

Binary Valves in Analog Control

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 141 - 146

Zusammenfassung

Abstract

Continuous control systems are built with standard transducer measured signal, the controller and actuator. The actuator is responsible for the direct setting of the size of the control object. The actuator is connected to the control valve and the actuator position change signal into the flow rate of the working medium. Since the operating element is required the linear characteristics in the standard signal range to work. The other hand, the control valve provides flow characteristics linear or equal percentage. This flow control principle is used in various control systems. The actuator of the control valve is always equipped with a positioner, which corrects errors in the position of the valve relative to the input signal. The presented design of the control valve is an analogue system. Using the technique of converting multiple digital signal causes, the system is susceptible to damage. Remove the intermediate elements can improve the quality control and safety system. Such benefits give a design of the operating element based on direct digital processing unit and control program. The examples of control present article.

Schlüsselwörter

  • control
  • digital signal
  • actuator
  • control valve
  • transducer
  • positioner
Uneingeschränkter Zugang

Influence of Lapping Plate Temperature on Roughness Parameters of Specimens

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 147 - 152

Zusammenfassung

Abstract

Lapping is used in the production of components of the highest quality in terms of form finish accuracy and surface integrity. A number of precision manufacturing applications use lapping process as a critical technology to achieve thickness tolerance and surface quality specification. Because of required parts accuracy tool flatness is the key to the successful machining. To avoid its excessive thermal expansion, plate temperature research was taken. This article goal was to check the influence of lapping wheel temperature on workpiece roughness after lapping process. In earlier work, authors investigated the dependence between time and the temperature of executory system elements. Tests showed that after five hours of machine working temperature stabilizes and slightly fluctuated around a certain value. Thus, this work concerns lapping results in this elevated temperature. Research was proceed during Al2O3 elements lapping. It was realised with use of ABRALAP 380 lapping machine. The lapping machine executory system consisted of three working conditioning rings. Executory system elements temperature was measured remotely by infrared camera Thermo Gear G100. Elements machining was started after 10, 140, and 270 minutes of machine working time. Studies showed that machine executory system elements temperature affected only the ΔRa parameter, which is higher for surfaces, which were processed starting from 270th minute of machine working time.

Schlüsselwörter

  • lapping
  • infrared measurement
  • lapping plate temperature
  • lapped surface quality
Uneingeschränkter Zugang

Developing Innovation Through Data Collection and Analysis

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 153 - 158

Zusammenfassung

Abstract

This paper is part of the study, for the creation of maintenance engineering culture and a system capable to control the input and output of vehicles operation and maintenance in developing countries. The focus of this paper will be the use of digital technologies to change business models, basing on the analyses of the data collected to develop innovation in transport system by creation of a system that works according to the local needs. This work has, as case of study, the transport system in Cape Verde (Praia city); a bus company, operating in the city for more than 40 years, will provide the data for analyses. The study of the exploitation efficiency of the transport system will focus in the analyses of the data collected, after the definition of the data for collection, is defined how the data will be analysed and used in order to create the desired solution. In this paper is also defined the platform used for data collection. The definition and selection of the vehicle systems/components for data collection has been supported by engineers and mechanics with long experience and knowledge of the local situation as well as vehicles operation and maintenance. The information that, if collected and analysed correctly, can help transform the vehicle operation and maintenance, data collection can empower us to direct resources toward the modules that are in most pressing need of technical refinement. With this knowledge base, we will be able to use predictive analysis to identify what, how and where to improve the services and manage the vehicle maintenance and operation.

Schlüsselwörter

  • vehicle maintenance
  • digitalization
  • data analyses
Uneingeschränkter Zugang

Interval-Valued Intuitionistic Fuzzy Failure Modes and Effect Analysis of the System Failure Risk Estimation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

Among the risk assessment methods, failure modes and effects analysis (FMEA) is a popular, widely used engineering technique in many areas. It can be used to identify and eliminate known or potential failure modes to enhance reliability and safety of complex systems. In practice, risk estimations encounter difficulties connected with shortage of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, the decision makers might be unable to assign the exact values to the evaluation judgments due to his/her limited knowledge. In other words, there is a certain degree of hesitancy in human cognition and his/her judgment, who may have insufficient knowledge of the problem domain or uncertainty in assigning the evaluation values to the objects considered. In order to deal with ambiguity and uncertainty in the imperfect information, there have been recently proposed many various such theories as fuzzy sets, interval-valued fuzzy sets, type-2 fuzzy sets, hesitant sets, grey sets, rough sets and intuitionistic fuzzy sets. They have drawn more and more attention of scholars and been adopted in many applications This article addresses the Atanassov’s interval-valued intuitionistic fuzzy sets and FMEA methods in the risk estimation of the system failures based on the expert judgments.

Schlüsselwörter

  • interval-valued intuitionistic fuzzy sets
  • failure modes and effects analysis
  • system failure risk estimation
  • expert judgment
Uneingeschränkter Zugang

Possibilities of Research Electromagnetic Fuel Injectors

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 167 - 175

Zusammenfassung

Abstract

Article discusses issues concerning researching electromagnetic fuel injectors. These fuel system is using in automobiles all the time. Bosch Company declined piezoelectric fuel injectors and reverted to electromagnetic. There are known Denso, Delphi and Bosch electromagnetic fuel injectors. Article describes how to diagnose and repair it. Denso and Bosch fuel injectors have almost the same construction. These objects have very similar repair technology. Despite Denso fuel injectors has not manufacturer official repair technology it is possibility to regenerate it because there are tools and many spare parts available on the market. Article discusses construction and operation presented fuel injectors. There has been shown diagnostic parameters and how to analysis it. Researches have been made in laboratory handle; to research and repair Diesel injection systems. Article describes construction, operating testing and repairing of electromagnetic fuel injectors. The aim of the article is to present the possibilities of researching and repairing electromagnetic fuel injectors. The fuel unit injector testing and repair process is carried out. The tests were conducted in a specialist laboratory where fuel injectors, fuel unit injectors and fuel injection pumps are being regenerated. The setting of the opening pressure of fuel unit injector is a very important stage because it affects the volume of injection doses. The opening pressure of fuel unit injector should amount to 28 MPa. F

Schlüsselwörter

  • fuel injector
  • CI – engine
  • diagnosing procedure
  • Common Rail system
Uneingeschränkter Zugang

The Effect of Measurement Method for Assessing Stereometric Structure of Surface

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 177 - 182

Zusammenfassung

Abstract

The article presents the influence of measuring methods of surfaces topography evaluation. Surface topography was measured using a mechanical, contact method by Hommel Tester T-8000-R60 profilometer (Gdynia Maritime University) and using the contactless, optical method by Olympus Lext OLS4100 Confocal Laser Scanning Microscope (Gdynia Maritime University). A pattern of roughness grade 4 sample was studied (standards PN-58/M-02425 (Ra=10 µm, Rz=40 µm)). Seven measurements were made on each of devices, resulting in a more accurate stereometric image of the sample surface. The area of the test was 1.5×1.5 mm. The radius of the edge of the blade imaging the surface used in the contact method was 2 µm. In the case of the optical method, the test sample surface was subjected to a laser light 405 nm long. This article describes the principle of used measuring instrument operation and their advantages and disadvantages. The results and descriptive statistics (Mann–Whitney U test, Kolmogorov–Smirnov test) of surface altitude parameters, such as Sa, Sp, Sq, Sv, Sz. There were statistically significant differences in topography values between measurements by T-8000 profilometer and Confocal Laser Scanning Microscope. It was noted that the values of the parameters Sa, Sq are higher with the T-8000 profilometer as a measuring device. The parameters Sp, Sv, Sz have a higher value, when measured on a Confocal Laser Scanning Microscope.

Schlüsselwörter

  • top layer
  • roughness
  • contact profilometer
  • confocal laser microscope
  • surface topography
Uneingeschränkter Zugang

Ground Effect Influence on the Aerodynamic Characteristics of Ultralight High-Wing Aircraft – Wind Tunnel Tests

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 183 - 190

Zusammenfassung

Abstract

The ground proximity may significantly improve the performance of the aircraft, but in some conditions, it affects its stability. The gain of lift which and reduction of drag during low altitude flight is known as the wing in ground effect (WIG effect). It may concern aircrafts or WIG-crafts (ground effect vehicles). In the article experimental results of the wind tunnel test of an aircraft in ground effect has been presented. The main aim of the test was to investigate the ground effect influence on aerodynamic characteristic of the of the ultralight high-wing aircraft model during early take off, taxiing or final landing stage. Investigation was carried out in the 1.5 m diameter low speed T-1 wind tunnel in the Institute of Aviation in Warsaw. The velocity was 32 m/s and Reynolds number related to the aerodynamic chord was equal about 0.37·106. Tests were performed for chosen angles of attack in range 0-10°. During investigation, the strain gauge balance measurements and Particle Image Velocimetry (PIV) flow visualization technique were applied. Tested model position was relatively close to the ground. It was found, that the ground proximity has significant influence on the pitching moment. The normal force was increased and the axial force is decreased due to the WIG effect, which is compatible with the theory. It has significant meaning for control aircraft issue and safety.

Schlüsselwörter

  • ground effect
  • aerodynamic characteristics
  • high-wing ultralight aircraft
  • wind tunnel research
Uneingeschränkter Zugang

Detection of Defects of Multilayer Aramid Composites after Fragment-Proof Test by Ultrasonic IR Thermography

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 191 - 195

Zusammenfassung

Abstract

Modern soft ballistic armour is composed of high-strength fibres often used as packages of loose fabrics or laminates. These fibres include carbon, glass fibres, polymer fibres including aramid fibres and polyethylene fibres. Soft armour is applied to provide ballistic protection typically against the impact of small arms projectiles and fragments. In order to determine the level of ballistic protection for ballistic armour, fragment-simulating projectiles (FSP) are used which simulate the properties of fragments created during the explosion of various types of grenades and projectiles. The above-mentioned composites can include a variety of defects such as manufacturing defects, moisture ingress, projectiles impact and other defects. Infrared thermography is a method, which can be used to non-destructive testing and detecting defects of this type of material. However, ultrasonic stimulation is one of method of thermal stimulation used for detection defects in composite. The article presents the results of experimental research of multilayer aramid composite after fragment-proof tests by ultrasonic IR thermography method.

Schlüsselwörter

  • ultrasonic IR thermography
  • composite material
  • aramid fabrics
  • ballistic protection
Uneingeschränkter Zugang

Development of an on-Line Damage Detection, Discrimination and Tracking System for the Spin Rig Facility

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 197 - 209

Zusammenfassung

Abstract

The main goal of the work reported here was to expand the capability of the NRC-Aerospace spin rig by adding an on-line damage detection, discrimination and tracking system, and to develop necessary expertise that will allow for optimizing the NDE inspection periods of gas turbine engine components in this facility and minimizing undetected crack nucleation and growth and possibility of catastrophic failures. Passive eddy-current sensors and a data acquisition system able to simultaneously measure blade deflection and tip clearance were selected to monitor health of rotating components. Before application of the system in the spin rig, the system was tested with a rotor rig to check sensor responses to deliberately induced changes in blade tip positions in both radial and circumferential directions. The monitored disc had 12 bolts simulating aerofoils that could be turned into threaded holes to extend or shorten the protruding parts of the bolts. On the other hand, bolt vibration was not excited and analysed during the experiment. Lessons learned on the rotor rig are used to prepare and plan spin tests in vacuum chamber.

Schlüsselwörter

  • disc crack
  • disc health monitoring
  • vacuum spin testing
  • tip timing
  • tip clearance
  • low cycle fatigue
Uneingeschränkter Zugang

Flaps Influence on Wing in Ground Effect Lift Coefficient

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 211 - 216

Zusammenfassung

Abstract

The main purpose of this article was to study flaps application influence on airfoil, which flies in the wing in ground effect with lift, and drag coefficients changes. Wing in ground effect occurs in the direct proximity of ground, it makes lift coefficient higher than in free stream flight, also decreases drag coefficient. WIG effect craft can be an alternative for traditional aircraft, but also for marine transportation. The article presents wing in ground effect creation mechanism description with height coefficient explanation, also presents experimental analysis of lift coefficient with reference to height coefficient. Airfoil with flaps simulation and for free stream flight. Application of flaps makes the wing in ground effect more efficient by lift coefficient rise, what provides also to drag coefficient rise. Flaps provide to absolute pressure rise under the airfoil. It allows to fly slower without lift force change or to make aircraft start shorter without risk of stall. The article shows also conditions and results of Ansys Fluent software simulation for NACA M8 airfoil for angles of attack equal to: 0°, 6°, 10° for three different cases: free stream flight, wing in ground flight with the clear wing, wing in ground flight with flaps, and conditions of analysis convergence.

Schlüsselwörter

  • transport
  • ground effect vehicle
  • numerical analysis
  • wing in ground effect
  • flaps
Uneingeschränkter Zugang

Characteristics of Loss Power in Compared Hydraulic Systems

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 217 - 223

Zusammenfassung

Abstract

In this article, two hydrostatic systems with a throttling steering fed by a constant capacity pump were compared. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of a speed and a load of hydraulic cylinder, which were different due to structure and ability of an energy saving, were presented and were compared. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide the required unchanged usable pump-driven hydraulic cylinder. Presents the impact on the output (useful) power of the power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. Instantaneous useful power of the cylinder, which is determined by the product of force and speed of the cylinder rod, is independent of all losses. There are mechanical loss power occurs in the cylinder, the loss power in the conduits, the structural volume and pressure loss power that are associated with the throttling control and loss power in the pump: pressure, volumetric and mechanical which have to be added to the useful power. As a result, the sum of the effective useful power and the loss power of all system is the instantaneous value of the power consumed by the pump from the electric motor that drives it.

Schlüsselwörter

  • power
  • energy losses
  • hydraulic system
  • pump
  • throttling valve
  • cylinder
Uneingeschränkter Zugang

Laboratory Investigations on Landing Gear Ground Reactions (Load) Measurement

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 225 - 230

Zusammenfassung

Abstract

Ground reaction measurement in landing gear laboratory tests is used in order to gain knowledge about loads transferred to the aircraft structure. Ground reaction level is defined during aircraft design phase and it is required not to exceed limit value in real construction. Load from landing affect directly strength of aircraft structure especially mounting points what translates both strength of aircraft structure especially mounting points what translates both on safety and weight of the final design. Meeting the safety requirements is crucial in aviation regulations conformity. Landing gear ground reactions evaluation is performed during laboratory tests in order to meet the compliance with the ground load requirements assumed in design phase. Proper test method is crucial to prove the actual load. One of the methods is landing gear dynamic drop test where landing forces are measured. Force measurement is made in several ways according to test stand construction and test object specifics. In this article, three methods are described due to author’s experience in landing gear tests. Proposed techniques cover two direct and one indirect force measurements. Direct approach is based on strain gauge measurement principle. One is a strain gauge plate fixed to the ground while the second one is based on strain gauges attached to landing gear mounting nodes. Indirect approach is based on the acceleration of the tested object, which by definition is correlated with the force applied to the structure. Obtained test results allow determining the kinetic energy absorbed by landing gear during drop test. In this article author also presented numerical integration of the time history data and compared them with simulation results in order to show equivalence of all three of the test methods and to prove correctness of the test initial conditions determination.

Schlüsselwörter

  • laboratory-testing
  • landing gear
  • load measurement
  • direct measurement
  • indirect measurement
Uneingeschränkter Zugang

Robust Predictive Control of an overhead Crane

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 231 - 238

Zusammenfassung

Abstract

The predictive control scheme is developed for an overhead crane using the generalized predictive procedure applied for the discrete time linear parameter-varying model of a crane dynamic. The robust control technique is developed with respect to the constraints of sway angle of a payload and control input signal. The two predictive strategies are presented and compared experimentally. In the first predictive control scheme, the online estimation of the parameters of a crane dynamic model is performed using the recursive least square algorithm. The second approach is a sensorless anti-sway control strategy. The sway angle feedback signal is estimated by a linear parameter-varying model of an unactuated pendulum system with the parameters interpolated using a quasi-linear fuzzy model designed through utilizing the P1-TS fuzzy theory. The fuzzy interpolator is applied to approximate the parameters of a crane discrete-time dynamic model within the range of scheduling variables changes: the rope length and mass of a payload. The experiments carried out on a laboratory scaled overhead crane confirmed effectiveness and feasibility of the proposed solutions. The implementation of control systems was performed using the PAC system with RX3i controller. The series of experiments carried out for different operating points proved robustness of the control approaches presented in the article.

Schlüsselwörter

  • overhead crane
  • predictive control
  • linear parameter varying model
  • recursive estimation
  • fuzzy interpolation
Uneingeschränkter Zugang

Simulation Investigation of Rotor Loads and Blade Deformations in Steady States and at Boundaries of Helicopter Flight Envelope

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 239 - 246

Zusammenfassung

Abstract

Results of calculation of the helicopter main rotor loads and deformations of rotor blades are presented. The simulations concern level flight states and cases of boundary flight envelope such as wind gust, dive recovery and pull-up manoeuvre. The calculations were performed for data of the three-bladed articulated rotor of light helicopter. The method of analysis assumes modelling the rotor blades as elastic axes with sets of lumped masses of blade segments distributed along radius of blade. The model of deformable blade allows flap, lead-lag and pitch motion of blade including effects of out-of-plane bending, in-plane bending and torsion due to aerodynamic and inertial forces and moments acting on the blade. Equations of motion of rotor blades are solved applying Runge-Kutta method. Parameters of blade motion, according to Galerkin method, are considered as a combination of assumed torsion and bending eigen modes of the rotor blade. The rotor loads, in all considered cases of flight states, are calculated for quasi-steady conditions assuming the constant value of the following parameters: rotor rotational speed, position of the main rotor axis in air and position of swashplate due to rotor axis which defines the collective and cyclic control pitch angle of blades. The results of calculations of rotor loads and blade deflections are presented in form of time-runs and as distributions on rotor disk due to blade elements radial and azimuthal positions. The simulation investigation may help to collect data for prediction the fatigue strength of blade applying results for steady flight states and for definition the extreme loads for boundaries of helicopter flight envelope.

Schlüsselwörter

  • helicopter
  • rotor loads
  • blade deformation
Uneingeschränkter Zugang

Safety and Intelligent Control System for Plasmatron Application

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 247 - 252

Zusammenfassung

Abstract

This article presents safety and intelligent control systems essential for safe and reliable operation of DC arc plasmatron. Presented methods and techniques are also applicable to other types of plasmatrons and devices. Author presents and describes subsystems of DC arc plasmatrons including its: start up and operation algorithms, detection of malfunction’s, control parameters and techniques for plasmatron operation. Moreover, issues and requirements identified in field operation are presented in case of plasmatron operation on site, communication and supervisory system for flexible integration of independent device in complex SCADA systems. Presented material covers also safety techniques, procedures and subsystems necessary for safe and reliable plasmatron operation, with examples of experience in plasmatrons applications.

Presented in this article plasmatrons control and safety systems with theirs functions together with operation algorithms were applied and validated in constructed and operated plasmatrons. Plasmatrons were tested in different environments. For example in the plasmatron plasma reactor where three 20 kW plasmatrons were used and installed directly in high temperature refractory that consisted of plasma incineration and smelting of metals chamber.

Schlüsselwörter

  • safety
  • intelligent control
  • systems
  • automation
  • plasmatron
  • arc
  • control
  • plasma
Uneingeschränkter Zugang

Water Tunnel Visualisation and Numerical Analysis of Flow Around TS-11 Iskra Wing with Flow Control Surfaces

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 253 - 261

Zusammenfassung

Abstract

The article presents investigation of flow around wing of TS-11 Iskra airplane. The flow visualization around 3D printed model of wing with flow control surfaces was performed in a water tunnel. Two configurations were investigated: first with a flap and second with an aileron. The flow visualisation was performed with a use of a dye. The geometry of model was prepared with use Computer Aided Design (CAD) software basing on scans of real object and technical documentation. The model was built with use of additive manufacturing technology. Movement of the flow control surfaces was remotely controlled with servomechanisms incorporated in channels inside the model. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The article presents visualisation results of flow around wing section of TS-11 Iskra airplane and water tunnel model preparation. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The goal of the research was to investigate the complex flow field in the vicinity of flow control surfaces and provide aerodynamic characteristics at various deployment angles via numerical simulations. The results can be used for verification of water tunnel testing procedures and training.

Schlüsselwörter

  • flow visualisation
  • TS-11 Iskra aircraft
  • aileron
  • flap
Uneingeschränkter Zugang

Quality Assessment of Welded Joints using the Mean Value Distribution of Amplitude Spectrums Calculated by the Time Window Method

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 263 - 270

Zusammenfassung

Abstract

In continuous monitoring systems of welded joints of thin-walled structures, a vibrodiagnostic method is the most promising. Its most important advantage is that it is effective and offers the greatest real-time research capabilities. It is used in classic NDT techniques as well as in structural health monitoring during exploitation. This work presents a measurement method of dynamic characteristics of the structure with the use of piezoelectric sensors. The article presents the assumptions concerning the evaluation of welded joints using the analysis of the mean value distribution of the amplitude spectrums calculated by the time window method. The statistical measure used in the form of the mean value is a proposed parameter. The parameter’s analysis for a given welded joint may enable an unambiguous assessment of its quality. Attention was paid to the elements important for the study. A calculation algorithm as well as and the exemplary results from the proposed method used for some selected samples with different welds is included in the article. The work contains the description of the scientific apparatus to register dynamic characteristics in case of welded joints. The results of the tests show that the analysis of the distribution of mean value for amplitude spectrums calculated by the time window method indicates that they differ markedly depending on the welds, indicating their quality and defects that are associated with them.

Schlüsselwörter

  • diagnostics
  • welded joints
  • non-destructive testing
  • NDT
  • SHM
  • vibration
  • spectrum analysis
  • time window
  • mean value
Uneingeschränkter Zugang

Determination of Ice Deposit Shape and Ice Accretion Rate on Airfoil in Atmospheric Icing Conditions and its Effects on Airfoil Characteristics

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 271 - 278

Zusammenfassung

Abstract

Simulations of ice accretion on airfoil in icing conditions were conducted using ice accretion model implemented by authors in ANSYS FLUENT CFD solver. The computational model includes several sub-models intended for simulations of two-phase flow, determination of zones of water droplets impinging on the investigated surface, flow of water in a thin film on airfoil surface and heat balance in air-water-ice contact zone. The method operates in an iterative loop, which enables determination of effects of gradual deformation of aircraft surface on airflow over the surface, which has impact on distribution of collected water, flow of water film over the surface and local freezing rates. The implementation of the method in CFD solver made it necessary to complement the mathematical model of determination of local rates of deformation of aircraft surface with modification of computational mesh around the surface, which must conform, to the deformed surface. Results of simulated ice accretion on NACA 0012 airfoil were compared with results of experiment conducted in icing wind tunnel for a 420 s long process of ice accretion in steady-flow, steady angle-of-attack conditions. Close agreement of values and location of maximum ice thickness obtained in experiment and in the flow, simulations can be observed. For the airfoil deformed with ice, contour determination of its aerodynamic characteristics at several other angles of attack was conducted proving dramatic degradation of its aerodynamic characteristics due to ice deformation.

Schlüsselwörter

  • aerodynamics
  • two-phase flow
  • simulations of ice accretion
  • Aircraft Engineering
  • Transport
  • Vehicles
Uneingeschränkter Zugang

Magnetic Field Impact on the Temperature and Pressure Distribution in Slide Journal Bearing

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 279 - 286

Zusammenfassung

Abstract

The topic of the presented article aims to demonstrate a new principle of hydrodynamic lubrication in mechanical, non-isothermal and electro-magnetic fields. In this article is presented hydrodynamic slide journal bearing in electromagnetic field. The aim of this article is a new general analytical and numerical solution determined the influence of the electro-magnetic field on the temperature distribution in the internal surfaces of the slide-bearing sleeve and pressure distribution in bearing gap. To the research methods and materials used in this article realization belong: the Mathcad 15 Professional Program and new semi-analytical methods applied for theory of hydrodynamic lubrication extended to the curvilinear orthogonal surface and coordinates. Particular solutions are introduced to the cylindrical coordinates. To the obtained results of lubrication of movable sleeve surface belong the increments of the bearing load carrying capacity during the presence and absence magnetic induction field in the case if non-Newtonian lubricant features and constant temperature are taken into account. Simultaneously are observed the increments of the bearing load carrying capacity during the presence magnetic field and Newtonian lubricant. Temperature increments (decrements) without and with magnetic field lead to the hydrodynamic pressure decrements (increments). Moreover are assumed simultaneously the temperature T and oil dynamic viscosity variations in length, width and bearing gap-height directions. From this assumption follows, that the energy equation must be solved simultaneously with the equations of motion i.e. consequently with pressure equation where viscosity depends on temperature and temperature depends on the coordinate in gap height direction.

Schlüsselwörter

  • slide journal bearing
  • magnetic induction field
  • non-Newtonian lubricant
  • conjugated fields
  • new general method
  • load carrying capacity
  • pressure decrements
  • pressure increments
Uneingeschränkter Zugang

The Correct Selection of Diagnostic Parameters of Marine Diesel Engine and their Minimization of as a Necessary Action in the Formation of Diagnostic Algorithm

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 287 - 292

Zusammenfassung

Abstract

This article describes the methodology of creating algorithms and diagnostic programs. Still in the construction of such algorithms and diagnostic creating programs mostly is used classical approach, the methodological basis can be reduced to the several basic tasks. One of them is the proper selection and minimization of diagnostic parameters. The article shows the importance of proper selection and minimization of diagnostic parameters on the example of the diagnostics of the injection system of a marine diesel engine. It was indicated to practical usefulness for this purpose calculated the values sensitivity of a given parameter. The stronger the diagnostic parameter responds to a change in the structural parameter, the greater its diagnostic sensitivity is and thus the early development of a given fault can be detected based on deviation analysis of this parameter from its reference value. Based on experimental data, FIS (Fault Isolation System) matrix was built after selecting and minimizing diagnostic parameters. Triple-valued evaluation of residues (–1, 0, +1) was used. The research was carried out on a real object – a four-stroke, medium-speed marine engine from Sulzer. The impact of selected fault in the injection system on the diagnostic parameters was researched and a FIS (Fault Isolation System) matrix was built on this basis.

Schlüsselwörter

  • ship diesel engine
  • diagnostic parameters
  • diagnostics programs
  • experimental data
  • Fault Isolation System
Uneingeschränkter Zugang

Strength Analysis of the Magnesium Alloy Control System Lever of the ILX-27 Unmanned Helicopter

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 293 - 300

Zusammenfassung

Abstract

The article presents the potential use of magnesium alloys in the aerospace industry. In this project the static strength analysis of magnesium alloy AZ31 of the control – system lever of the ILX-27 unmanned helicopter was carried out. Control-system levers are located between the swash plate and an actuator. The aim of the tests was to confirm the strength properties of the magnesium alloy control-system lever for their implementation on the ILX-27 unmanned helicopter. Strain gauge sensor was used during the tests. Strain gauges installation on easily corrodes surface requires special method. The laboratory tests were proceeded by the lever static strength calculations in the computing environment ANSYS Inc. Additionally, a geometry measurement of the control-system lever at CMM equipped with a laser scanner head was made to compare with the lever CAD model to assess the quality and method of conformance. Unmanned helicopter ILX-27 is being developed through the introduction new materials and technologies. Tests of control system lever have shown if it is possible to use lighter materials than aluminum alloy to provide sufficient strength properties while reducing the mass of the object. Analysis of the available materials used in aerospace engineering allowed selecting the best of magnesium alloy.

Schlüsselwörter

  • magnesium alloys
  • FEM
  • strain gauges
  • geometry verification
  • strength test
Uneingeschränkter Zugang

Analysis of the Impact of the Technological Parameters Pad Welding Steel C45E Wire CASTOMAG 4554S on Geometry Padding Weld Method Taguchi

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 301 - 306

Zusammenfassung

Abstract

Using the pad welding technique it is possible to regenerate machine parts or improve surface properties such as abrasion, corrosion and aging resistance. The regeneration process with the use of pad welding can be performed using the same equipment, which we use for welding. Metals and their alloys with required properties in the form of wire, rod or powder are selected for the additional material. To ensure optimum processing conditions and economic efforts should be made, while providing a high deposition efficiency for the small amount of metal in the pad weld substrate. The pad welding process for the test subject should be carried out by preheating to evaporate the moisture and reduce the porosity of the weld. This treatment is required depending on the carbon equivalent. This article is an introduction to a series of investigations that will allow you to choose the best parameters of pad welding GMA (gas metal arc) method, steel C45E with wire CASTOMAG 4554S. Steel samples were prepared and preheated to 300°C. Using the orthogonal experiment plan, the influence of selected parameters on the geometry and depth of fusion was determined. The analysis was based on current and wire feed speed. The test was carried out for three current values: 60, 75, 90 A and wire feed rate of 1.5, 2, 2.5 m/min. The purpose of the analysis was to select appropriate technological parameters. Obtaining the smallest share of the base material in the weld pad and impact assessment parameters for welding seam geometries. For the analysis of the results of multiple regression was used.

Schlüsselwörter

  • pad welding
  • regression
  • analysis
  • GMA
  • padding weld
Uneingeschränkter Zugang

Investigation of Friction Loss in Internal Combustion Engine of Experimental Microgeometry Piston Bearing Surface

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 307 - 313

Zusammenfassung

Abstract

The piston is the most mechanically and thermally loaded engine component. The energy required to overcome the mechanical losses in the combustion engine is approx. 10% of the energy supplied to the engine in a fuel. The main node piston-pin-piston rings are most responsible for the formation of mechanical losses. It is advisable to reduce friction losses in the piston-cylinder group lead to an increase in the overall efficiency of the engine and thus reduce the fuel consumption. The way of achieving these objectives is modification of microgeometry of the piston-bearing surface, which cooperates with the cylinder wall. The geometry of the gap between the piston skirt and the cylinder liner greatly affects the friction loss inside combustion engine. A way to reduce the area covered by the oil film is the application of a stepped profile of the piston skirt. The stepwise profile can be obtained covering the cylindrical or tapered piston-bearing surface with a thin layer graphite. Covering the piston bearing surface with a thin layer of graphite one can get an extremely advantageous tribological properties of the piston assembly which means the expected parameters of oil film and reduction friction loss. In this article, the results of research on experimental pistons on friction loss in combustion engine are presented.

Schlüsselwörter

  • combustion engine
  • friction
  • lubrication
  • piston
  • microgeometry bearing surface
Uneingeschränkter Zugang

Advanced Communication System: for the Survey of Rail Tracks to Improve Safety of Rail Transportation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 315 - 322

Zusammenfassung

Abstract

Railway transportation is a backbone of any country for transporting people and cargo. At present Indian railway is the largest network in Asia. So that safety is always big concern. Here in this article low cost railway track surveillance and monitoring system is proposed which will identify drastic and minor changes into the railway track. It consist a high-resolution CMOS camera mounted on robot. It is designed like: it can easily roll on railway track. In case of any obstacle or train coming on track, robot folds itself and provides a path to pass the train. It is controlled by wireless control system, which can be operated from remote location or station. For accurate results, a live video streaming is done to the remote station for future references and comparison of results. On the assembly of robot, a GPS (Global Positioning System) is mounted to know the location of robot on the rail track. An obstacle detector sensor is also mounted on the front of the robot to detect any coming obstacle. In this article ultrasonic method (Non-Destructive Method) is also explained to detects presence of cracks on rail track in real time. Overall, power utilization of this system will be very low by operating this system by solar power. Signal processing and wireless communication system is used as technology, which cuts off the overall cost. By implementing this surveillance system, we can improve the safety parameters of Indian railway by minimizing the errors and reducing the time and cost.

Schlüsselwörter

  • rail transport
  • smart communication
  • video streaming
  • crack detection
40 Artikel
Uneingeschränkter Zugang

Systemic Approach and Model of the Polish Tactical Air Force

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 7 - 16

Zusammenfassung

Abstract

The main purpose of this article is to present the structure of a tactical air force, on the example of the Polish Tactical Air Force, in a form of a technical system. This kind of technical system presents the technical point of view and organizationally bonds currently existing systems, objects (facilities) and components that are included into the Polish Tactical Air Force. The authors consider the Polish Tactical Air Force as the main analyses domain of this article. The model of presented system is mainly focused on operators’ organization and operation system of military aircraft, which are considered as technical objects (facilities) in a tactical air force. At the beginning of this article, the Polish Tactical Air Force is placed in more complex systemic structures. Then, the authors use the systems methodology, systems engineering, technical object-oriented (facility-oriented) approach and the matrix of the Model of Generalized Technical System to describe the Tactical Air Force System and present it via the model of such a system. The following model is based on a tree-shaped scheme divided into five levels of decomposition. The Model of Tactical Air Force System (as the “final product” of authors’ considerations over the selected analyses domain) has a considerable contribution to systems’ development in the Polish Armed Forces. The above-mentioned systems’ development could lead to greater progress in the Polish military as well as in systemic ideas. The implementation of the systems methodology in the design process of a new system, performed in a tactical air force, is an example of technical object systems engineering.

Schlüsselwörter

  • tactical air force
  • Tactical Air Force System
  • Model of Tactical Air Force System
  • Model of Generalized Technical System
  • technical object systems engineering
Uneingeschränkter Zugang

Detection of Damages in Hybrid Composite Plates with the Use of Elastic Waves Generated by PZT Active Sensors

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 17 - 24

Zusammenfassung

Abstract

The presented article is devoted to the problem of detection and localization of damages occurring in components of structures, which are made of hybrid composite materials. The subject of the work is a square plate consisting of a single layer made of aluminum alloy and several layers made of glass fibres (glass fabric) and epoxy resin. On the surface, which is made of composite, 12 piezoelectric elements are installed. These elements sequentially, one by one, generates a signal that is further recorded by the remaining piezoelectric elements. Picked up signal for the selected pair of activator – sensor is compared with the reference signal. The reference signal corresponds to the intact structure. This kind of approach is known as the pitch – catch configuration. In situations when the signal obtained for interrogated structure and reference one differs significantly, this may indicate that a damage exists between the activator and the sensor. Next, taking into account the information obtained from the other sensors, it is possible not only to detect but also to determine the approximate location of the flaw and to estimate its size. In order to visualize the obtained results, an especially dedicated software is developed according to the algorithms available in the literature – probability ellipse. Several computer simulations of wave propagation are performed using the finite element method. The proposed procedure is also tested experimentally. The presented approach makes it possible to detect both single and multiple damages.

Schlüsselwörter

  • elastic waves
  • hybrid composite plates
  • piezoelectric active sensors
  • low velocity impacts
  • damages
  • FEM
Uneingeschränkter Zugang

Engine Fuel Characterisation Based on Excitation-Emission Spectra

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 25 - 30

Zusammenfassung

Abstract

Considering that correctly functioning of diesel ship engine depends on the composition of applied fuel, it is necessary to easy characterise fuels in terms of quality. Therefore taking into account above mentioned, appropriate analyses have been undertaken and the intention of this article is to inform that characterisation of fuel used in marine transport can be described by the specific parameter based on fluorescence excitation-emission spectroscopy. Therefore, for this study fuel typically used in ship engine – Diesel fuel – is considered. For analysis, Diesel fuel dissolved in n-hexane was used and several oil samples for various oil concentration were prepared. Spectrofluorometer Aqualog Horiba was used to record the excitation-emission spectra (EEMs). EEM spectra determined for each of oil concentration were described by two specific peaks for this kind of oil. Based on registered EEMs, the specific indicator - the wavelength-independent fluorescence maximum – coded in two specific wavelengths – excitation and emission, respectively, described as Exmax/Emmax was determined for considered oil concentration. Obtained results indicate the independence from oil concentration only for one detected peak described by Exmax/Emmax = 240/332. Taking into account obtained results, we can conclude that the wavelength-independent fluorescence maximum detected for excitation wavelength at 240 nm corresponds to the emission wavelength at 332 nm due to the independence from the oil concentration, could be a good indicator to characterise this kind of oil – Diesel fuel. We can conclude that the changes in the composition of fuel could be detected in EEM spectra by the change of detected peaks position.

Schlüsselwörter

  • fuel
  • diesel
  • engine
  • excitation-emission spectra
  • fluorescence
Uneingeschränkter Zugang

The Issue of Selection: Shape and Volume of Briquettes Agglomerated in a Roller Press

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 31 - 38

Zusammenfassung

Abstract

A volume and a shape of the briquettes agglomerated in a roller press depend largely on the material properties, the design features of a roller press, and it is a complicated issue. Correctly, selected geometric parameters of the briquettes determine the proper strength of the consolidated product. The paper presents the laboratory and simulation experiments conducted to obtain knowledge about volume and shape of the roller press briquettes.

The main elements of the roller press compacting unit are the forming rollers. They are located horizontally in some roller presses of low efficiency they can be placed vertically. The shape of working surface, the volume of the melding cavities and the characteristics of the briquetted material have an important role in terms of the effects of the briquetting process especially the cost of operating of the roller press. The paper presents the description of the basic shapes of forming surfaces used in the roller presses and it systematises the knowledge of the shape and volume of briquettes produced in the roller presses on the basis of own laboratory and simulation researches.

The information contained in the article can be very useful for designers of roller presses and their users. Further work should be continued to verify the results of tests on other materials and laboratory conditions.

Schlüsselwörter

  • roller press
  • briquettes
  • simulation
  • volume of briquettes
Uneingeschränkter Zugang

Urban Transport Safety Improvement Based on Centralized Traffic Control System, Colombian Case Study

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 39 - 46

Zusammenfassung

Abstract

In a modern urban organization, mobility is an important issue for society. Traffic congestion of urban roads undermines mobility is a real problem in major cities This article shows the development and implementation of a centralized traffic control system in the city of Cali Valle (Colombia) applied to control traffic lights located to the east of the city (Simon Bolivar and Ciudad de Cali highways), allowing the central operators directly influence the traffic flow, know and display the status of the lights and generate statistics about the events of the online equipment. Particular real benefits of proposed new system of traffic lights are reflected in green times at each intersection allocated in accordance with the present traffic volumes on the road network at any time of day and in every sector of the city in particular, which of course increases the efficiency of each light installed at each intersection. As demonstrated in this article case study, the congestion scheme has been improved, and the project has opened up vast opportunities for innovative network management strategies for the optimization of network performance. Many of these strategies are developed to give a coordinated high-level control across different traffic control platforms based on real time traffic condition and performance on site.

Schlüsselwörter

  • traffic control
  • centralized control
  • software development
  • wireless communication controller
Uneingeschränkter Zugang

Numerical Prediction of GTD-350 Turboshaft Engine Combustor Deterioration

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 47 - 58

Zusammenfassung

Abstract

The aim of this article is to describe the use of Computational Fluid Dynamics (CFD) model for turboshaft combustor chamber deterioration analysis. To show advantages of the proposed approach the test bench of GTD-350 turboshaft engine operating at the Institute of Heat Engineering, Warsaw University of Technology was used as an example. The CFD modelling of the reactive flow inside 40º sector of GTD-350 engine section was developed. Proposed modelling technique provides good correlations with experimental data and shows that the combustor front wall soot accumulation is clearly related to the fuel droplets residence time and the oxygen mass fraction. The temperature distribution inside the combustion chamber allows concluding on possible hot distress areas on the combustion chamber liner walls. Engine borescope inspection (BSI) of the compressor, combustion chamber, compressor turbine and power turbine is used to correlate model predictions with a real GTD-350 engine deterioration. Very good correlation of the engine BSI observations with the numerical predictions proves usefulness of the developed model. Finally, advantages and future applications of the developed model are discussed.

Schlüsselwörter

  • turboshaft engine
  • engine health monitoring
  • digital analytics
  • engine deterioration
  • CFD modelling
Uneingeschränkter Zugang

The Influence of Treating Welded Joints Edges on the Strength and Fatigue of S640Q Steel

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 59 - 64

Zusammenfassung

Abstract

Weldable steels of high strength were discussed. The factors influencing the achievement of low grain structure that ensures high strength of these steels was explained. Traditional and modern methods of producing high strength steel were shown. The scheme of production line was shown, the line which is used to manufacture steel of high strength in thermomechanical way. The methods of achieving strength to fatigue used for welded joints were presented. The factors influencing the increase of strength to fatigue of welded joints were elaborated. The thermally hardened steel sheets of high strength weldable S640Q steel underwent research. Basic mechanical properties of this steel were indicated. The results of static tensile test and technological bend test were given. Then the sheets were welded by semiautomatic MAG method. The examinations of welds quality were conducted and their usefulness for further tests was stated. Mechanical properties of welded joints were determined. The mechanical properties of native material and welded joints were compared. The microstructure of welded joints in the weld axis, in heat influence zone as well as in native material was examined. Fatigue tests in a non-symmetrical cycle of lengthening – compressing for the welded joints were carried out. The computational strength to fatigue was determined and compared with fatigue strength of welded joints. Tests results were elaborated by the statistical analysis of linear regression. After conducting fatigue tests, the Wöhler diagrams were made. Afterwards, the joints welded with TIG method, were penetrated without adding filler metal. The results were presented for the fatigue tests as well as the Wohler graph for welded joints after penetration of the joints edges with TIG method without adding filler metal. The results were compared.

Schlüsselwörter

  • weldability
  • high strength weldable steels
  • thermomechanical treatment
  • increasing fatigue strength
  • fatigue strength
Uneingeschränkter Zugang

CFD Analysis of Effect of Misalignment Plane Position on Hydrodynamic Lubrication of Slide Conical Bearing

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 65 - 72

Zusammenfassung

Abstract

The numerical calculations of the hydrodynamic lubrication of slide bearings can be carried out by modelling the oil flow for a given value of height of bearing lubrication gap. On the basis of the assumed height of the lubrication gap, the values of hydrodynamic pressures, load carrying capacities, friction forces, temperatures, can be determined. The bearing lubrication gap height can be influenced by many effects, e.g. misalignment between the shaft axis and the axis of the sleeve, vibrations, varying load, change in the viscosity value of lubricating oil caused by changes in temperature, pressure, shear rate or by oil ageing, wear of journal and sleeve surfaces. This article presents the results of numerical simulations concerning the influence of the misalignment between the axis of shaft and the axis of sleeve of the sliding conical bearing on its hydrodynamic lubrication, by taking into account the position of the plane in which the misalignment occurs. In this study, there was defined an angle between the plane in which the misalignment occurs and the plane in which lies the line of centres of corresponding bearing without misalignment. In this research, to investigate the impact of the position of the plane in which the misalignment occurs, the CFD software, designed to solve general flow phenomena, was used. It was assumed, that the bearings operate in a steady state conditions, the flow in the bearing lubrication gap is laminar and non-isothermal. A lubricating oil has shear properties as the Ostwald-de Waele fluid.

Schlüsselwörter

  • slide bearing
  • hydrodynamic lubrication
  • conical bearing
  • misalignment
  • CFD
  • pressure distribution
Uneingeschränkter Zugang

Modern Methods of Identification Design Conditions for Single Stage Micro Scale Centrifugal Compressor

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 73 - 84

Zusammenfassung

Abstract

Micro scale gas turbine engines are low cost engines. They share their compressor impeller with automotive turbochargers. An identified design condition for the selected impeller is a critical stage of the design process. This process is had difficulties due the large number of manufacturers that provide OEM parts. It is common practice that one OEM part number provides the same impeller at different design revision. In general, parts are interchangeable but in detail, they differ slightly in terms of dimensions and performance. To avoid under predict or over predict inputs data, it is important to check the design parameters with as many methods as possible. In practice, the designer could rely on analytical methods, which are straightforward limited to the applied design. When shared its (compressor operation) it is recommended additional information be provided by computational fluid dynamics that produces a three-dimensional look into the predesign. That allows avoidance of future design failure and reduces both design time and prototype manufacturing costs.

Schlüsselwörter

  • jet engine
  • gas turbine
  • design
  • off design
  • trend prediction
  • centrifugal compressor
Uneingeschränkter Zugang

The Application of Friction Stir Welding (FSW) of Aluminium Alloys in Shipbuilding and Railway Industry

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 85 - 90

Zusammenfassung

Abstract

The article describes possibilities of application of friction stir welding (FSW) in shipbuilding and railway industry. Actually, in these sectors of industry more and more often modern construction materials are used. The biggest restriction of implementing new materials is technological possibility of joining them. One of construction materials used in the shipbuilding is aluminum, mainly its alloy of 5xxx-aluminium-magnesium series. Its application is justified by good corrosion resistance in seawater and good mechanical attributes. Thanks to susceptibility to plastic treatment, one gains good mechanical attributes with thrice-smaller density than a density of steel, what causes triple reduction of weight of aluminum construction relative to steel one. Alloys of 5xxx series are well weldable. It is generally known that welding is not a good way to joint metals, especially the aluminum. The application of FSW with mixing allows one to change approach to production of aluminum constructions. Using aluminum plates prefabricated with FSW method allows one to reduce time needed for installation of construction and considerably decreases the production costs. The article describes technology and directions of development of friction welding of aluminum alloys of 5xxx series using FSW method. There is also shown analysis of its usefulness in ship and railway industry and comparison of mechanical attributes of weld made with electric arc using MIG (135), TIG (141) method and FSW method.

Schlüsselwörter

  • Friction Stir Welding (FSW)
  • aluminium alloys
  • welding
  • shipbuilding industry
  • mechanical properties
Uneingeschränkter Zugang

Remarks on Utilization of Marine Trent 30 Gas Turbine as Prime Mover on Vessels

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 91 - 97

Zusammenfassung

Abstract

Utilization of gas turbines on vessels is a reality. It was presented the examples of utilization on ships of United States Navy and the Rolls-Royce suggestion for sharing on merchant shipping. It was mentioned the advantages of gas turbine MT30 with nominal power 36 MW or 40 MW prepared for marine utilization. It was stated the characteristics of specific fuel consumption, the shaft power rating, the MT30 operating envelope with propeller characteristics as a power receiver. It was given propositions of vessel types for MT30 utilization. It was discussed the remarks on maintenance requirements and needed systems for upkeep the turbine in good technical state for the possibility of full nominal power independent on ambient temperature. It was discussed the requirements of emissions from exhaust gasses to the atmosphere in comparison gas turbines to diesel engines as a one of important problems for utilization engines as prime movers on vessels in merchant shipping. In the end, some final remarks with Rolls-Royce statements are presented.

Schlüsselwörter

  • marine prime mover
  • gas turbine
  • propulsion
  • gas-electric plant
  • gas turbine utilization
Uneingeschränkter Zugang

Progress in the Construction of Passenger Cars as a Result of CO2 Emission Limitation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 99 - 106

Zusammenfassung

Abstract

Global warming is a scientifically proven fact. Much of the temperature rise on the surface of the globe has been caused by human activity. That is why several years’ efforts are aimed at reducing of CO2 emissions, related to the human activities. Major sources of CO2 emissions include electricity production from fossil fuels, transport sector and intensive agriculture. Cutting down forests also contributes climate changes. In the field of transport, decisions are made at the level of the European Commission, and also by the wider audiences of introducing limits for CO2 emissions entire fleet of new passenger cars for year 2015, 2021 and later. The actions taken by car manufacturers are diverse. Cheaper and simpler solutions are focused on the concept of micro-hybrid based on a system of 48 V. More advanced solutions are a wide range of hybrid vehicles, including PHEV, and pure electric vehicles. The use of lighter materials, improved aerodynamics and rolling resistance, more efficient internal combustion engines and gearboxes also have an impact on energy demand and, consequently, CO2 emissions. An important problem to solve in many countries is the dissemination of renewable energy sources rather than fossil fuels. This article presents an outline of the issues related to eco-friendly solutions, including requirements for batteries intended for this type of vehicles. It also presents an overview of European standards in this area and progress in advanced energy sources.

Schlüsselwörter

  • Hybrid Electric Vehicles
  • Electric Vehicles
  • battery
  • capacity
Uneingeschränkter Zugang

Initial Numerical Analysis of a Small Electric Vehicle

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 107 - 116

Zusammenfassung

Abstract

This article presents a concept of a two-seat urban electric vehicle, whose model was developed in the FEM Nastran-in-Cad software. The performed simulations formed an optimization tool applied for the purpose of a study involving the distribution of the vehicle mass and its impact on the strength parameters of the body. The study focuses on the impact of the vertical road characteristics on the stress transferred through the vehicle’s body throughout drive conditions. In addition, a quasi-static analysis was performed with regard to the deformation of the load-bearing elements resulting from external impact forces with various magnitude and contact angle.

In the article, the authors focused on the study of the impact of vertical road characteristics on the stress that is transferred through the vehicle body, as it occurs in driving conditions. The simulations presented in the article focus on the procedures applied during the analytical and numerical analysis with the purpose of developing an environment to test the structural components of the vehicle in terms of its response to vertical road roughness. The analysed system examined the impact of the road surface on the occurrence of stress and displacement in the structure of the body of the designed vehicle.

Schlüsselwörter

  • vibrations
  • car chassis
  • finite element method
  • dynamic modelling
  • suspension
Uneingeschränkter Zugang

Residual Stresses Assessment in the Marine Diesel Engine Crankshaft 12V38 Type

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 117 - 123

Zusammenfassung

Abstract

In the paper, the measurement of the marine diesel engine crankshaft residual stresses is presented. The hole drilling strain gauge was chosen because of its simplicity and low cost. Moreover, deflection calculation was made for the load corresponding to its weight and the concentrated force in the chosen bearing conditions. Deflection of the journal and bending rigidity under the concentrated force was calculated as well. In that case, the crankshaft was supported in the neighbouring crank journals. The reduced stresses were calculated according to the Huber – Mises hypothesis. The residual stresses were measured in the marine diesel engine crankshaft type 12V38 after the finishing, with the hole-drilling method. It was found that the residual stresses reach the maximal value of 86 MPa, but for 50% of measuring points, the residual stresses did not exceed the value of 20 MPa. The squeezing stresses were found to be dominant. The measurement results provided important data for further consideration, especially for the correction of the bending deformation of the produced crankshaft.

Schlüsselwörter

  • diesel engine
  • crankshaft
  • simulation
  • residual stress
Uneingeschränkter Zugang

Propeller Optimization for Small Unmanned Aerial Vehicles

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 125 - 132

Zusammenfassung

Abstract

Small-unmanned aerial vehicle propellers usually have a low figure of merit due to operating in the low Reynold’s number region due to their size and velocity. The airflow on the airfoil becomes increasingly laminar in this region thus increasing the profile drag and consequently reducing the figure of merit of the rotor. In the article, the airfoil geometries are parameterized using the Class/Shape function transformation. Particle swarm optimization is used to design an airfoil, operating in a Reynolds number of 100,000, which has a high lift to drag ratio. To avoid exceeding geometric constraints of the airfoil, a deterministic box constraint is added to the algorithm. The optimized airfoil is then used for a preliminary design of a rotor; given some design, constraints on the tip chord the rotor radius and the blade root chord, with parameters that achieve the highest theoretical figure of merit. The rotor parameters are obtained using a combination of momentum theory and blade element theory. The figure of merit of an optimal propeller with the same geometric parameters is then compared using the optimized airfoil and the Clark Y airfoil. The optimization is done in MATLAB while the aerodynamic coefficients are obtained from XFOIL. The results of the numerical simulation are presented in the article.

Schlüsselwörter

  • unmanned aerial vehicles
  • particle swarm optimization
  • airfoil modelling
Uneingeschränkter Zugang

Determination of the Material Constants of Composite Materials on the Example of Modified Wood

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 133 - 140

Zusammenfassung

Abstract

Homogenization is the transition from the level of microscopic heterogeneity to a homogeneous macroscopic level. The analysis of the value of equivalent parameters and their variability requires prior determination of the influence of microstructure on the values of these parameters [15]. Wood is a composite material and has a layered structure in the form of alternate layers of soft and hard wood. One of the main issues was the determination of constants materials of individual layers of natural wood and modified and then equivalent material constants of natural and modified wood. The material constants of single layers and the material constants of composite were determined on the basis of experimental studies. For this purpose, a homogenization method has been used to determine equivalent material constants on the basis of material constants of single layers of soft and hard wood [1, 2, 14]. A representative cell consisting of a softwood and hardwood layer has been isolated from the sample-measuring portion. On the basis of this cell have been developed mathematical model of equivalent material constants. A sample consisting of two layers was subjected to an even stretch in the direction of the axes x1, x2, x3. The equivalent material constants have been defined by using equilibrium conditions, geometric conditions, and Hooke’s generalized law. Each wood component on the micro-level is homogeneous, continuous with its constitutive equation, conservation laws, and boundary conditions at the boundary of the separation of components. The equivalent material constants of natural and modified wood have been determined using the homogenization method [12, 13]. The results obtained from the research and the results obtained from the calculations are very similar.

Schlüsselwörter

  • modified wood
  • polymethylmethacrylate
  • homogenization
  • equivalent material constants
Uneingeschränkter Zugang

Binary Valves in Analog Control

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 141 - 146

Zusammenfassung

Abstract

Continuous control systems are built with standard transducer measured signal, the controller and actuator. The actuator is responsible for the direct setting of the size of the control object. The actuator is connected to the control valve and the actuator position change signal into the flow rate of the working medium. Since the operating element is required the linear characteristics in the standard signal range to work. The other hand, the control valve provides flow characteristics linear or equal percentage. This flow control principle is used in various control systems. The actuator of the control valve is always equipped with a positioner, which corrects errors in the position of the valve relative to the input signal. The presented design of the control valve is an analogue system. Using the technique of converting multiple digital signal causes, the system is susceptible to damage. Remove the intermediate elements can improve the quality control and safety system. Such benefits give a design of the operating element based on direct digital processing unit and control program. The examples of control present article.

Schlüsselwörter

  • control
  • digital signal
  • actuator
  • control valve
  • transducer
  • positioner
Uneingeschränkter Zugang

Influence of Lapping Plate Temperature on Roughness Parameters of Specimens

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 147 - 152

Zusammenfassung

Abstract

Lapping is used in the production of components of the highest quality in terms of form finish accuracy and surface integrity. A number of precision manufacturing applications use lapping process as a critical technology to achieve thickness tolerance and surface quality specification. Because of required parts accuracy tool flatness is the key to the successful machining. To avoid its excessive thermal expansion, plate temperature research was taken. This article goal was to check the influence of lapping wheel temperature on workpiece roughness after lapping process. In earlier work, authors investigated the dependence between time and the temperature of executory system elements. Tests showed that after five hours of machine working temperature stabilizes and slightly fluctuated around a certain value. Thus, this work concerns lapping results in this elevated temperature. Research was proceed during Al2O3 elements lapping. It was realised with use of ABRALAP 380 lapping machine. The lapping machine executory system consisted of three working conditioning rings. Executory system elements temperature was measured remotely by infrared camera Thermo Gear G100. Elements machining was started after 10, 140, and 270 minutes of machine working time. Studies showed that machine executory system elements temperature affected only the ΔRa parameter, which is higher for surfaces, which were processed starting from 270th minute of machine working time.

Schlüsselwörter

  • lapping
  • infrared measurement
  • lapping plate temperature
  • lapped surface quality
Uneingeschränkter Zugang

Developing Innovation Through Data Collection and Analysis

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 153 - 158

Zusammenfassung

Abstract

This paper is part of the study, for the creation of maintenance engineering culture and a system capable to control the input and output of vehicles operation and maintenance in developing countries. The focus of this paper will be the use of digital technologies to change business models, basing on the analyses of the data collected to develop innovation in transport system by creation of a system that works according to the local needs. This work has, as case of study, the transport system in Cape Verde (Praia city); a bus company, operating in the city for more than 40 years, will provide the data for analyses. The study of the exploitation efficiency of the transport system will focus in the analyses of the data collected, after the definition of the data for collection, is defined how the data will be analysed and used in order to create the desired solution. In this paper is also defined the platform used for data collection. The definition and selection of the vehicle systems/components for data collection has been supported by engineers and mechanics with long experience and knowledge of the local situation as well as vehicles operation and maintenance. The information that, if collected and analysed correctly, can help transform the vehicle operation and maintenance, data collection can empower us to direct resources toward the modules that are in most pressing need of technical refinement. With this knowledge base, we will be able to use predictive analysis to identify what, how and where to improve the services and manage the vehicle maintenance and operation.

Schlüsselwörter

  • vehicle maintenance
  • digitalization
  • data analyses
Uneingeschränkter Zugang

Interval-Valued Intuitionistic Fuzzy Failure Modes and Effect Analysis of the System Failure Risk Estimation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 159 - 166

Zusammenfassung

Abstract

Among the risk assessment methods, failure modes and effects analysis (FMEA) is a popular, widely used engineering technique in many areas. It can be used to identify and eliminate known or potential failure modes to enhance reliability and safety of complex systems. In practice, risk estimations encounter difficulties connected with shortage of data. In such cases, we have to rely on subjective estimations made by persons with practical knowledge in the field of interest, i.e. experts. However, in some realistic situations, the decision makers might be unable to assign the exact values to the evaluation judgments due to his/her limited knowledge. In other words, there is a certain degree of hesitancy in human cognition and his/her judgment, who may have insufficient knowledge of the problem domain or uncertainty in assigning the evaluation values to the objects considered. In order to deal with ambiguity and uncertainty in the imperfect information, there have been recently proposed many various such theories as fuzzy sets, interval-valued fuzzy sets, type-2 fuzzy sets, hesitant sets, grey sets, rough sets and intuitionistic fuzzy sets. They have drawn more and more attention of scholars and been adopted in many applications This article addresses the Atanassov’s interval-valued intuitionistic fuzzy sets and FMEA methods in the risk estimation of the system failures based on the expert judgments.

Schlüsselwörter

  • interval-valued intuitionistic fuzzy sets
  • failure modes and effects analysis
  • system failure risk estimation
  • expert judgment
Uneingeschränkter Zugang

Possibilities of Research Electromagnetic Fuel Injectors

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 167 - 175

Zusammenfassung

Abstract

Article discusses issues concerning researching electromagnetic fuel injectors. These fuel system is using in automobiles all the time. Bosch Company declined piezoelectric fuel injectors and reverted to electromagnetic. There are known Denso, Delphi and Bosch electromagnetic fuel injectors. Article describes how to diagnose and repair it. Denso and Bosch fuel injectors have almost the same construction. These objects have very similar repair technology. Despite Denso fuel injectors has not manufacturer official repair technology it is possibility to regenerate it because there are tools and many spare parts available on the market. Article discusses construction and operation presented fuel injectors. There has been shown diagnostic parameters and how to analysis it. Researches have been made in laboratory handle; to research and repair Diesel injection systems. Article describes construction, operating testing and repairing of electromagnetic fuel injectors. The aim of the article is to present the possibilities of researching and repairing electromagnetic fuel injectors. The fuel unit injector testing and repair process is carried out. The tests were conducted in a specialist laboratory where fuel injectors, fuel unit injectors and fuel injection pumps are being regenerated. The setting of the opening pressure of fuel unit injector is a very important stage because it affects the volume of injection doses. The opening pressure of fuel unit injector should amount to 28 MPa. F

Schlüsselwörter

  • fuel injector
  • CI – engine
  • diagnosing procedure
  • Common Rail system
Uneingeschränkter Zugang

The Effect of Measurement Method for Assessing Stereometric Structure of Surface

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 177 - 182

Zusammenfassung

Abstract

The article presents the influence of measuring methods of surfaces topography evaluation. Surface topography was measured using a mechanical, contact method by Hommel Tester T-8000-R60 profilometer (Gdynia Maritime University) and using the contactless, optical method by Olympus Lext OLS4100 Confocal Laser Scanning Microscope (Gdynia Maritime University). A pattern of roughness grade 4 sample was studied (standards PN-58/M-02425 (Ra=10 µm, Rz=40 µm)). Seven measurements were made on each of devices, resulting in a more accurate stereometric image of the sample surface. The area of the test was 1.5×1.5 mm. The radius of the edge of the blade imaging the surface used in the contact method was 2 µm. In the case of the optical method, the test sample surface was subjected to a laser light 405 nm long. This article describes the principle of used measuring instrument operation and their advantages and disadvantages. The results and descriptive statistics (Mann–Whitney U test, Kolmogorov–Smirnov test) of surface altitude parameters, such as Sa, Sp, Sq, Sv, Sz. There were statistically significant differences in topography values between measurements by T-8000 profilometer and Confocal Laser Scanning Microscope. It was noted that the values of the parameters Sa, Sq are higher with the T-8000 profilometer as a measuring device. The parameters Sp, Sv, Sz have a higher value, when measured on a Confocal Laser Scanning Microscope.

Schlüsselwörter

  • top layer
  • roughness
  • contact profilometer
  • confocal laser microscope
  • surface topography
Uneingeschränkter Zugang

Ground Effect Influence on the Aerodynamic Characteristics of Ultralight High-Wing Aircraft – Wind Tunnel Tests

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 183 - 190

Zusammenfassung

Abstract

The ground proximity may significantly improve the performance of the aircraft, but in some conditions, it affects its stability. The gain of lift which and reduction of drag during low altitude flight is known as the wing in ground effect (WIG effect). It may concern aircrafts or WIG-crafts (ground effect vehicles). In the article experimental results of the wind tunnel test of an aircraft in ground effect has been presented. The main aim of the test was to investigate the ground effect influence on aerodynamic characteristic of the of the ultralight high-wing aircraft model during early take off, taxiing or final landing stage. Investigation was carried out in the 1.5 m diameter low speed T-1 wind tunnel in the Institute of Aviation in Warsaw. The velocity was 32 m/s and Reynolds number related to the aerodynamic chord was equal about 0.37·106. Tests were performed for chosen angles of attack in range 0-10°. During investigation, the strain gauge balance measurements and Particle Image Velocimetry (PIV) flow visualization technique were applied. Tested model position was relatively close to the ground. It was found, that the ground proximity has significant influence on the pitching moment. The normal force was increased and the axial force is decreased due to the WIG effect, which is compatible with the theory. It has significant meaning for control aircraft issue and safety.

Schlüsselwörter

  • ground effect
  • aerodynamic characteristics
  • high-wing ultralight aircraft
  • wind tunnel research
Uneingeschränkter Zugang

Detection of Defects of Multilayer Aramid Composites after Fragment-Proof Test by Ultrasonic IR Thermography

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 191 - 195

Zusammenfassung

Abstract

Modern soft ballistic armour is composed of high-strength fibres often used as packages of loose fabrics or laminates. These fibres include carbon, glass fibres, polymer fibres including aramid fibres and polyethylene fibres. Soft armour is applied to provide ballistic protection typically against the impact of small arms projectiles and fragments. In order to determine the level of ballistic protection for ballistic armour, fragment-simulating projectiles (FSP) are used which simulate the properties of fragments created during the explosion of various types of grenades and projectiles. The above-mentioned composites can include a variety of defects such as manufacturing defects, moisture ingress, projectiles impact and other defects. Infrared thermography is a method, which can be used to non-destructive testing and detecting defects of this type of material. However, ultrasonic stimulation is one of method of thermal stimulation used for detection defects in composite. The article presents the results of experimental research of multilayer aramid composite after fragment-proof tests by ultrasonic IR thermography method.

Schlüsselwörter

  • ultrasonic IR thermography
  • composite material
  • aramid fabrics
  • ballistic protection
Uneingeschränkter Zugang

Development of an on-Line Damage Detection, Discrimination and Tracking System for the Spin Rig Facility

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 197 - 209

Zusammenfassung

Abstract

The main goal of the work reported here was to expand the capability of the NRC-Aerospace spin rig by adding an on-line damage detection, discrimination and tracking system, and to develop necessary expertise that will allow for optimizing the NDE inspection periods of gas turbine engine components in this facility and minimizing undetected crack nucleation and growth and possibility of catastrophic failures. Passive eddy-current sensors and a data acquisition system able to simultaneously measure blade deflection and tip clearance were selected to monitor health of rotating components. Before application of the system in the spin rig, the system was tested with a rotor rig to check sensor responses to deliberately induced changes in blade tip positions in both radial and circumferential directions. The monitored disc had 12 bolts simulating aerofoils that could be turned into threaded holes to extend or shorten the protruding parts of the bolts. On the other hand, bolt vibration was not excited and analysed during the experiment. Lessons learned on the rotor rig are used to prepare and plan spin tests in vacuum chamber.

Schlüsselwörter

  • disc crack
  • disc health monitoring
  • vacuum spin testing
  • tip timing
  • tip clearance
  • low cycle fatigue
Uneingeschränkter Zugang

Flaps Influence on Wing in Ground Effect Lift Coefficient

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 211 - 216

Zusammenfassung

Abstract

The main purpose of this article was to study flaps application influence on airfoil, which flies in the wing in ground effect with lift, and drag coefficients changes. Wing in ground effect occurs in the direct proximity of ground, it makes lift coefficient higher than in free stream flight, also decreases drag coefficient. WIG effect craft can be an alternative for traditional aircraft, but also for marine transportation. The article presents wing in ground effect creation mechanism description with height coefficient explanation, also presents experimental analysis of lift coefficient with reference to height coefficient. Airfoil with flaps simulation and for free stream flight. Application of flaps makes the wing in ground effect more efficient by lift coefficient rise, what provides also to drag coefficient rise. Flaps provide to absolute pressure rise under the airfoil. It allows to fly slower without lift force change or to make aircraft start shorter without risk of stall. The article shows also conditions and results of Ansys Fluent software simulation for NACA M8 airfoil for angles of attack equal to: 0°, 6°, 10° for three different cases: free stream flight, wing in ground flight with the clear wing, wing in ground flight with flaps, and conditions of analysis convergence.

Schlüsselwörter

  • transport
  • ground effect vehicle
  • numerical analysis
  • wing in ground effect
  • flaps
Uneingeschränkter Zugang

Characteristics of Loss Power in Compared Hydraulic Systems

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 217 - 223

Zusammenfassung

Abstract

In this article, two hydrostatic systems with a throttling steering fed by a constant capacity pump were compared. It also includes a subject matter connected with an energy loss power of hydrostatic systems with hydraulic cylinder controlled by proportional directional control valve. Diagrams of loss power of two hydraulic systems worked at the same parameters of a speed and a load of hydraulic cylinder, which were different due to structure and ability of an energy saving, were presented and were compared. There are possibilities to reduce energy losses in proportional control systems (in the pump, in the throttle control unit, especially in the cylinder), and thus to improve the energy efficiency of the throttling manifold. The considerations allow for comparison of the loss power resulting from the applied hydraulic control structure of the hydraulic cylinder and the power consumed by the pump from the electric motor that drives it, the power necessary to provide the required unchanged usable pump-driven hydraulic cylinder. Presents the impact on the output (useful) power of the power consumed in the considered systems, and the impact on the power consumed of the loss power in the individual elements. Instantaneous useful power of the cylinder, which is determined by the product of force and speed of the cylinder rod, is independent of all losses. There are mechanical loss power occurs in the cylinder, the loss power in the conduits, the structural volume and pressure loss power that are associated with the throttling control and loss power in the pump: pressure, volumetric and mechanical which have to be added to the useful power. As a result, the sum of the effective useful power and the loss power of all system is the instantaneous value of the power consumed by the pump from the electric motor that drives it.

Schlüsselwörter

  • power
  • energy losses
  • hydraulic system
  • pump
  • throttling valve
  • cylinder
Uneingeschränkter Zugang

Laboratory Investigations on Landing Gear Ground Reactions (Load) Measurement

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 225 - 230

Zusammenfassung

Abstract

Ground reaction measurement in landing gear laboratory tests is used in order to gain knowledge about loads transferred to the aircraft structure. Ground reaction level is defined during aircraft design phase and it is required not to exceed limit value in real construction. Load from landing affect directly strength of aircraft structure especially mounting points what translates both strength of aircraft structure especially mounting points what translates both on safety and weight of the final design. Meeting the safety requirements is crucial in aviation regulations conformity. Landing gear ground reactions evaluation is performed during laboratory tests in order to meet the compliance with the ground load requirements assumed in design phase. Proper test method is crucial to prove the actual load. One of the methods is landing gear dynamic drop test where landing forces are measured. Force measurement is made in several ways according to test stand construction and test object specifics. In this article, three methods are described due to author’s experience in landing gear tests. Proposed techniques cover two direct and one indirect force measurements. Direct approach is based on strain gauge measurement principle. One is a strain gauge plate fixed to the ground while the second one is based on strain gauges attached to landing gear mounting nodes. Indirect approach is based on the acceleration of the tested object, which by definition is correlated with the force applied to the structure. Obtained test results allow determining the kinetic energy absorbed by landing gear during drop test. In this article author also presented numerical integration of the time history data and compared them with simulation results in order to show equivalence of all three of the test methods and to prove correctness of the test initial conditions determination.

Schlüsselwörter

  • laboratory-testing
  • landing gear
  • load measurement
  • direct measurement
  • indirect measurement
Uneingeschränkter Zugang

Robust Predictive Control of an overhead Crane

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 231 - 238

Zusammenfassung

Abstract

The predictive control scheme is developed for an overhead crane using the generalized predictive procedure applied for the discrete time linear parameter-varying model of a crane dynamic. The robust control technique is developed with respect to the constraints of sway angle of a payload and control input signal. The two predictive strategies are presented and compared experimentally. In the first predictive control scheme, the online estimation of the parameters of a crane dynamic model is performed using the recursive least square algorithm. The second approach is a sensorless anti-sway control strategy. The sway angle feedback signal is estimated by a linear parameter-varying model of an unactuated pendulum system with the parameters interpolated using a quasi-linear fuzzy model designed through utilizing the P1-TS fuzzy theory. The fuzzy interpolator is applied to approximate the parameters of a crane discrete-time dynamic model within the range of scheduling variables changes: the rope length and mass of a payload. The experiments carried out on a laboratory scaled overhead crane confirmed effectiveness and feasibility of the proposed solutions. The implementation of control systems was performed using the PAC system with RX3i controller. The series of experiments carried out for different operating points proved robustness of the control approaches presented in the article.

Schlüsselwörter

  • overhead crane
  • predictive control
  • linear parameter varying model
  • recursive estimation
  • fuzzy interpolation
Uneingeschränkter Zugang

Simulation Investigation of Rotor Loads and Blade Deformations in Steady States and at Boundaries of Helicopter Flight Envelope

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 239 - 246

Zusammenfassung

Abstract

Results of calculation of the helicopter main rotor loads and deformations of rotor blades are presented. The simulations concern level flight states and cases of boundary flight envelope such as wind gust, dive recovery and pull-up manoeuvre. The calculations were performed for data of the three-bladed articulated rotor of light helicopter. The method of analysis assumes modelling the rotor blades as elastic axes with sets of lumped masses of blade segments distributed along radius of blade. The model of deformable blade allows flap, lead-lag and pitch motion of blade including effects of out-of-plane bending, in-plane bending and torsion due to aerodynamic and inertial forces and moments acting on the blade. Equations of motion of rotor blades are solved applying Runge-Kutta method. Parameters of blade motion, according to Galerkin method, are considered as a combination of assumed torsion and bending eigen modes of the rotor blade. The rotor loads, in all considered cases of flight states, are calculated for quasi-steady conditions assuming the constant value of the following parameters: rotor rotational speed, position of the main rotor axis in air and position of swashplate due to rotor axis which defines the collective and cyclic control pitch angle of blades. The results of calculations of rotor loads and blade deflections are presented in form of time-runs and as distributions on rotor disk due to blade elements radial and azimuthal positions. The simulation investigation may help to collect data for prediction the fatigue strength of blade applying results for steady flight states and for definition the extreme loads for boundaries of helicopter flight envelope.

Schlüsselwörter

  • helicopter
  • rotor loads
  • blade deformation
Uneingeschränkter Zugang

Safety and Intelligent Control System for Plasmatron Application

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 247 - 252

Zusammenfassung

Abstract

This article presents safety and intelligent control systems essential for safe and reliable operation of DC arc plasmatron. Presented methods and techniques are also applicable to other types of plasmatrons and devices. Author presents and describes subsystems of DC arc plasmatrons including its: start up and operation algorithms, detection of malfunction’s, control parameters and techniques for plasmatron operation. Moreover, issues and requirements identified in field operation are presented in case of plasmatron operation on site, communication and supervisory system for flexible integration of independent device in complex SCADA systems. Presented material covers also safety techniques, procedures and subsystems necessary for safe and reliable plasmatron operation, with examples of experience in plasmatrons applications.

Presented in this article plasmatrons control and safety systems with theirs functions together with operation algorithms were applied and validated in constructed and operated plasmatrons. Plasmatrons were tested in different environments. For example in the plasmatron plasma reactor where three 20 kW plasmatrons were used and installed directly in high temperature refractory that consisted of plasma incineration and smelting of metals chamber.

Schlüsselwörter

  • safety
  • intelligent control
  • systems
  • automation
  • plasmatron
  • arc
  • control
  • plasma
Uneingeschränkter Zugang

Water Tunnel Visualisation and Numerical Analysis of Flow Around TS-11 Iskra Wing with Flow Control Surfaces

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 253 - 261

Zusammenfassung

Abstract

The article presents investigation of flow around wing of TS-11 Iskra airplane. The flow visualization around 3D printed model of wing with flow control surfaces was performed in a water tunnel. Two configurations were investigated: first with a flap and second with an aileron. The flow visualisation was performed with a use of a dye. The geometry of model was prepared with use Computer Aided Design (CAD) software basing on scans of real object and technical documentation. The model was built with use of additive manufacturing technology. Movement of the flow control surfaces was remotely controlled with servomechanisms incorporated in channels inside the model. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The article presents visualisation results of flow around wing section of TS-11 Iskra airplane and water tunnel model preparation. In order to perform qualitative validation of the results the investigated flow was simulated with use of CFD commercial software. The goal of the research was to investigate the complex flow field in the vicinity of flow control surfaces and provide aerodynamic characteristics at various deployment angles via numerical simulations. The results can be used for verification of water tunnel testing procedures and training.

Schlüsselwörter

  • flow visualisation
  • TS-11 Iskra aircraft
  • aileron
  • flap
Uneingeschränkter Zugang

Quality Assessment of Welded Joints using the Mean Value Distribution of Amplitude Spectrums Calculated by the Time Window Method

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 263 - 270

Zusammenfassung

Abstract

In continuous monitoring systems of welded joints of thin-walled structures, a vibrodiagnostic method is the most promising. Its most important advantage is that it is effective and offers the greatest real-time research capabilities. It is used in classic NDT techniques as well as in structural health monitoring during exploitation. This work presents a measurement method of dynamic characteristics of the structure with the use of piezoelectric sensors. The article presents the assumptions concerning the evaluation of welded joints using the analysis of the mean value distribution of the amplitude spectrums calculated by the time window method. The statistical measure used in the form of the mean value is a proposed parameter. The parameter’s analysis for a given welded joint may enable an unambiguous assessment of its quality. Attention was paid to the elements important for the study. A calculation algorithm as well as and the exemplary results from the proposed method used for some selected samples with different welds is included in the article. The work contains the description of the scientific apparatus to register dynamic characteristics in case of welded joints. The results of the tests show that the analysis of the distribution of mean value for amplitude spectrums calculated by the time window method indicates that they differ markedly depending on the welds, indicating their quality and defects that are associated with them.

Schlüsselwörter

  • diagnostics
  • welded joints
  • non-destructive testing
  • NDT
  • SHM
  • vibration
  • spectrum analysis
  • time window
  • mean value
Uneingeschränkter Zugang

Determination of Ice Deposit Shape and Ice Accretion Rate on Airfoil in Atmospheric Icing Conditions and its Effects on Airfoil Characteristics

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 271 - 278

Zusammenfassung

Abstract

Simulations of ice accretion on airfoil in icing conditions were conducted using ice accretion model implemented by authors in ANSYS FLUENT CFD solver. The computational model includes several sub-models intended for simulations of two-phase flow, determination of zones of water droplets impinging on the investigated surface, flow of water in a thin film on airfoil surface and heat balance in air-water-ice contact zone. The method operates in an iterative loop, which enables determination of effects of gradual deformation of aircraft surface on airflow over the surface, which has impact on distribution of collected water, flow of water film over the surface and local freezing rates. The implementation of the method in CFD solver made it necessary to complement the mathematical model of determination of local rates of deformation of aircraft surface with modification of computational mesh around the surface, which must conform, to the deformed surface. Results of simulated ice accretion on NACA 0012 airfoil were compared with results of experiment conducted in icing wind tunnel for a 420 s long process of ice accretion in steady-flow, steady angle-of-attack conditions. Close agreement of values and location of maximum ice thickness obtained in experiment and in the flow, simulations can be observed. For the airfoil deformed with ice, contour determination of its aerodynamic characteristics at several other angles of attack was conducted proving dramatic degradation of its aerodynamic characteristics due to ice deformation.

Schlüsselwörter

  • aerodynamics
  • two-phase flow
  • simulations of ice accretion
  • Aircraft Engineering
  • Transport
  • Vehicles
Uneingeschränkter Zugang

Magnetic Field Impact on the Temperature and Pressure Distribution in Slide Journal Bearing

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 279 - 286

Zusammenfassung

Abstract

The topic of the presented article aims to demonstrate a new principle of hydrodynamic lubrication in mechanical, non-isothermal and electro-magnetic fields. In this article is presented hydrodynamic slide journal bearing in electromagnetic field. The aim of this article is a new general analytical and numerical solution determined the influence of the electro-magnetic field on the temperature distribution in the internal surfaces of the slide-bearing sleeve and pressure distribution in bearing gap. To the research methods and materials used in this article realization belong: the Mathcad 15 Professional Program and new semi-analytical methods applied for theory of hydrodynamic lubrication extended to the curvilinear orthogonal surface and coordinates. Particular solutions are introduced to the cylindrical coordinates. To the obtained results of lubrication of movable sleeve surface belong the increments of the bearing load carrying capacity during the presence and absence magnetic induction field in the case if non-Newtonian lubricant features and constant temperature are taken into account. Simultaneously are observed the increments of the bearing load carrying capacity during the presence magnetic field and Newtonian lubricant. Temperature increments (decrements) without and with magnetic field lead to the hydrodynamic pressure decrements (increments). Moreover are assumed simultaneously the temperature T and oil dynamic viscosity variations in length, width and bearing gap-height directions. From this assumption follows, that the energy equation must be solved simultaneously with the equations of motion i.e. consequently with pressure equation where viscosity depends on temperature and temperature depends on the coordinate in gap height direction.

Schlüsselwörter

  • slide journal bearing
  • magnetic induction field
  • non-Newtonian lubricant
  • conjugated fields
  • new general method
  • load carrying capacity
  • pressure decrements
  • pressure increments
Uneingeschränkter Zugang

The Correct Selection of Diagnostic Parameters of Marine Diesel Engine and their Minimization of as a Necessary Action in the Formation of Diagnostic Algorithm

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 287 - 292

Zusammenfassung

Abstract

This article describes the methodology of creating algorithms and diagnostic programs. Still in the construction of such algorithms and diagnostic creating programs mostly is used classical approach, the methodological basis can be reduced to the several basic tasks. One of them is the proper selection and minimization of diagnostic parameters. The article shows the importance of proper selection and minimization of diagnostic parameters on the example of the diagnostics of the injection system of a marine diesel engine. It was indicated to practical usefulness for this purpose calculated the values sensitivity of a given parameter. The stronger the diagnostic parameter responds to a change in the structural parameter, the greater its diagnostic sensitivity is and thus the early development of a given fault can be detected based on deviation analysis of this parameter from its reference value. Based on experimental data, FIS (Fault Isolation System) matrix was built after selecting and minimizing diagnostic parameters. Triple-valued evaluation of residues (–1, 0, +1) was used. The research was carried out on a real object – a four-stroke, medium-speed marine engine from Sulzer. The impact of selected fault in the injection system on the diagnostic parameters was researched and a FIS (Fault Isolation System) matrix was built on this basis.

Schlüsselwörter

  • ship diesel engine
  • diagnostic parameters
  • diagnostics programs
  • experimental data
  • Fault Isolation System
Uneingeschränkter Zugang

Strength Analysis of the Magnesium Alloy Control System Lever of the ILX-27 Unmanned Helicopter

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 293 - 300

Zusammenfassung

Abstract

The article presents the potential use of magnesium alloys in the aerospace industry. In this project the static strength analysis of magnesium alloy AZ31 of the control – system lever of the ILX-27 unmanned helicopter was carried out. Control-system levers are located between the swash plate and an actuator. The aim of the tests was to confirm the strength properties of the magnesium alloy control-system lever for their implementation on the ILX-27 unmanned helicopter. Strain gauge sensor was used during the tests. Strain gauges installation on easily corrodes surface requires special method. The laboratory tests were proceeded by the lever static strength calculations in the computing environment ANSYS Inc. Additionally, a geometry measurement of the control-system lever at CMM equipped with a laser scanner head was made to compare with the lever CAD model to assess the quality and method of conformance. Unmanned helicopter ILX-27 is being developed through the introduction new materials and technologies. Tests of control system lever have shown if it is possible to use lighter materials than aluminum alloy to provide sufficient strength properties while reducing the mass of the object. Analysis of the available materials used in aerospace engineering allowed selecting the best of magnesium alloy.

Schlüsselwörter

  • magnesium alloys
  • FEM
  • strain gauges
  • geometry verification
  • strength test
Uneingeschränkter Zugang

Analysis of the Impact of the Technological Parameters Pad Welding Steel C45E Wire CASTOMAG 4554S on Geometry Padding Weld Method Taguchi

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 301 - 306

Zusammenfassung

Abstract

Using the pad welding technique it is possible to regenerate machine parts or improve surface properties such as abrasion, corrosion and aging resistance. The regeneration process with the use of pad welding can be performed using the same equipment, which we use for welding. Metals and their alloys with required properties in the form of wire, rod or powder are selected for the additional material. To ensure optimum processing conditions and economic efforts should be made, while providing a high deposition efficiency for the small amount of metal in the pad weld substrate. The pad welding process for the test subject should be carried out by preheating to evaporate the moisture and reduce the porosity of the weld. This treatment is required depending on the carbon equivalent. This article is an introduction to a series of investigations that will allow you to choose the best parameters of pad welding GMA (gas metal arc) method, steel C45E with wire CASTOMAG 4554S. Steel samples were prepared and preheated to 300°C. Using the orthogonal experiment plan, the influence of selected parameters on the geometry and depth of fusion was determined. The analysis was based on current and wire feed speed. The test was carried out for three current values: 60, 75, 90 A and wire feed rate of 1.5, 2, 2.5 m/min. The purpose of the analysis was to select appropriate technological parameters. Obtaining the smallest share of the base material in the weld pad and impact assessment parameters for welding seam geometries. For the analysis of the results of multiple regression was used.

Schlüsselwörter

  • pad welding
  • regression
  • analysis
  • GMA
  • padding weld
Uneingeschränkter Zugang

Investigation of Friction Loss in Internal Combustion Engine of Experimental Microgeometry Piston Bearing Surface

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 307 - 313

Zusammenfassung

Abstract

The piston is the most mechanically and thermally loaded engine component. The energy required to overcome the mechanical losses in the combustion engine is approx. 10% of the energy supplied to the engine in a fuel. The main node piston-pin-piston rings are most responsible for the formation of mechanical losses. It is advisable to reduce friction losses in the piston-cylinder group lead to an increase in the overall efficiency of the engine and thus reduce the fuel consumption. The way of achieving these objectives is modification of microgeometry of the piston-bearing surface, which cooperates with the cylinder wall. The geometry of the gap between the piston skirt and the cylinder liner greatly affects the friction loss inside combustion engine. A way to reduce the area covered by the oil film is the application of a stepped profile of the piston skirt. The stepwise profile can be obtained covering the cylindrical or tapered piston-bearing surface with a thin layer graphite. Covering the piston bearing surface with a thin layer of graphite one can get an extremely advantageous tribological properties of the piston assembly which means the expected parameters of oil film and reduction friction loss. In this article, the results of research on experimental pistons on friction loss in combustion engine are presented.

Schlüsselwörter

  • combustion engine
  • friction
  • lubrication
  • piston
  • microgeometry bearing surface
Uneingeschränkter Zugang

Advanced Communication System: for the Survey of Rail Tracks to Improve Safety of Rail Transportation

Online veröffentlicht: 04 Nov 2019
Seitenbereich: 315 - 322

Zusammenfassung

Abstract

Railway transportation is a backbone of any country for transporting people and cargo. At present Indian railway is the largest network in Asia. So that safety is always big concern. Here in this article low cost railway track surveillance and monitoring system is proposed which will identify drastic and minor changes into the railway track. It consist a high-resolution CMOS camera mounted on robot. It is designed like: it can easily roll on railway track. In case of any obstacle or train coming on track, robot folds itself and provides a path to pass the train. It is controlled by wireless control system, which can be operated from remote location or station. For accurate results, a live video streaming is done to the remote station for future references and comparison of results. On the assembly of robot, a GPS (Global Positioning System) is mounted to know the location of robot on the rail track. An obstacle detector sensor is also mounted on the front of the robot to detect any coming obstacle. In this article ultrasonic method (Non-Destructive Method) is also explained to detects presence of cracks on rail track in real time. Overall, power utilization of this system will be very low by operating this system by solar power. Signal processing and wireless communication system is used as technology, which cuts off the overall cost. By implementing this surveillance system, we can improve the safety parameters of Indian railway by minimizing the errors and reducing the time and cost.

Schlüsselwörter

  • rail transport
  • smart communication
  • video streaming
  • crack detection

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