Temat: system analysis - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Stiffness characteristics of main bearings foundation of marine engine
Autorzy:: Murawski, L.
Powiązania:: https://bibliotekanauki.pl/articles/247486.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: dynamic stiffness of main engine bearings
shaft line alignment
crankshaft springing
marine propulsion system numerical analysis
Opis:: During shaftline alignment and crankshaft springing analyses, knowledge of stiffness of radial bearings is essential. Dynamic stiffness's characteristics of marine main body are difficult to estimate because of lack of available documentation and complicated shape of the body. In the literature, there is a lack of the detailed data on the stiffness of the crankshaft foundation in the frame of marine main engine. Those parameters are crucial for the shaft line alignment analysis as well as for the analysis of interactions between the shaft line and the crankshaft. Especially for the high power engines, the correct model of the boundary conditions plays a key role during the analysis. The paper presents the methodology of the characteristics determination of the marine engine’s body as well as the example of computations for a MAN B&W K98MC type engine mounted on a ~3000 TEU container ship. The model of main engine body is relatively big – it contains over 800 thousand degree of freedom. The elasticity of ship hull has been estimated and taken into account during analysis. It has been found, that static stiffness parameters recommended by the producer for the shaft line alignment are evaluated correctly, however they represent only the flexibility of the engine’s body, not taking into account the flexibility of the ship’s hull. What is more, the dynamic magnification of vibration amplitudes is not taken into account.
Źródło:: Journal of KONES; 2016, 23, 1; 239-246
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Analysis and evaluation of application of car modular systems in polish road transport
Autorzy:: Muślewski, Ł.
Lewalski, M.
Woropay, M.
Powiązania:: https://bibliotekanauki.pl/articles/246606.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: transport system
car modular system
SWOT analysis
efficiency
Opis:: This study presents an analysis and evaluation of application of European Car Modular Systems in the Polish road transport. Those systems and respective terminology have been analysed and classified. Application of such systems in other countries of the European Union has been described. SWAT analysis has also been carried out in order to enable the most optimal choice of modular system in freight transport to match the condition and characteristics of the Polish road infrastructure. The systems have also been analysed in terms of efficiency and the analysis was performed on the basis of a selected research object – a transport company. An analysis of costs and estimated profits from transport services to be provided by those systems has been carried out on the basis of the research object in comparison with costs borne by the considered company with currently used transport means. This study shows that taking into consideration the results of analyses, safety aspect, road infrastructure and energy efficiency of the vehicles it was found that the proposed oversized vehicles could be implemented to be used on the Polish roads. The analyses and tests performed for a transport logistic company discussed in this article have demonstrated that the proposed modular systems will undoubtedly allow reducing significantly the costs of transport services by increasing load capacity of vehicles.
Źródło:: Journal of KONES; 2015, 22, 4; 211-220
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A computational fluid flow analysis of a disc valve system
Autorzy:: Czop, P.
Śliwa, P.
Gniłka, J.
Gąsiorek, D.
Wszołek, G.
Powiązania:: https://bibliotekanauki.pl/articles/244640.pdf
Data publikacji:: 2011
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: valve system
computational fluid flow analysis
simulation
Opis:: Noise concerns in shock absorbers can be divided into two categories. The first is fluid flow noise, or “swish noise”, caused by the oil being forced through openings in the valves. The type and temperature of the oil, its velocity and the orifice geometry all have an effect on this. In addition, the structural design of the shock absorber shell may either reduce or amplify the noise. The second type of shock absorber noise is often described as regular operational noise or “chuckle noise”. It can be observed in vehicles during low-displacement, higher-frequency events, such as driving over a slightly rough road. This effect measurable as a force discontinuity into the vehicle and can come from a number of sources in the shock absorber, e.g. hydraulic transitions. It is often traceable to the valve discs closing and opening, but can also be caused by cavitation/aeration in the oil and air being pulled through the valves. The work on noise improvement reported in this paper has been started using conventional shock absorbers to be extended and will cover in the future variable damping shock systems as well. The paper gives an overview about the configurations of a typical valve system including three basic regimes of operation, which correspond to the amount of oil flowing through a valve cavity. The aim of this work was to propose a finite element fluid flow model, which can be used in order to reduce the velocity of fluid flow through a cavity of a shock absorber valve. High flow velocity can cause high-content frequency vibrations and, in turn, audible noise. The model will be used for initial screening of new valve concepts and on the other hand to improve the currently use ones.
Źródło:: Journal of KONES; 2011, 18, 1; 117-122
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Application of principal component analysis for optimization of a system operation assessment criteria set
Autorzy:: Muślewski, Ł.
Knopik, L.
Powiązania:: https://bibliotekanauki.pl/articles/247903.pdf
Data publikacji:: 2013
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: quality
criteria
transport system
analysis
canonical correlations
optimization
Opis:: The analysis of results of experimental tests and a literature survey of the issue reveal that the subject matter connected with determination of the optimal number of a given transportation system operation assessment criteria has a direct influence on the result of the considered assessment. The analysis was made within the research on operation quality of a selected transportation system. In order to optimize the analysed system assessment criteria, a theoretical description has been made and an example of canonical correlations application has been presented. Analysis of canonical correlations involves determination of linear combination parameters of the studied sets so that the obtained correlation coefficient will have maximal value. In the successive step, the next pair of linear combination are not correlated with the combinations determined in the first step. The determined correlations can measure the power of relation between two sets of variables and are useful in the process of choosing significant criteria for a given research object operation quality assessment.
Źródło:: Journal of KONES; 2013, 20, 4; 307-312
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Vibrations resonance estimation in marine structures
Autorzy:: Murawski, L.
Powiązania:: https://bibliotekanauki.pl/articles/247863.pdf
Data publikacji:: 2014
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: vibration
dynamic analysis
marine structures
propulsion system
crankshaft
resonance
Opis:: Dynamic analyses of marine structures are one of the most important during design process as well as during exploitation. Typically, two parts of vibrations calculations are performed. Firstly, natural vibrations frequencies and modes are determined. Forced vibrations analysis is the second step of calculations. Natural vibrations give us information about possibility (e.g. at which main engine speed) of dangerous vibrations amplitudes (resonances threat). Exact values of vibrations amplitudes are results of forced vibrations analysis. Confidence level (error value) of forced vibration calculations is much lower in comparison to uncertainty of natural vibration analysis. What is more, form engineering practice point of view, natural vibrations frequencies estimation (resonance avoidance) is the most important during dynamic analysis of marine structures with propulsion systems. In the paper some examples of dynamic characteristics estimation and their changing methods (possibility) was presented. Utility of relatively simple models, with low degree of freedom number, was discussed. Modelling methods depending on the analysis target of marine slow-speed crankshafts was presented. Advantages and disadvantages of subcritical and supercritical design of marine propulsion system were discussed. An example of propulsion system natural torsional vibrations simplified analysis was presented. Location of the main torsional resonance is one of the most important decisions during design process of the marine propulsion system. Methods of fast and easy estimation as well as changing possibility of natural vibrations frequencies of marine structures is the main objective of presented paper.
Źródło:: Journal of KONES; 2014, 21, 1; 175-182
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Application of principal component analysis for optimization of a system operation assessment criteria set
Autorzy:: Muślewski, Ł.
Knopik, L.
Powiązania:: https://bibliotekanauki.pl/articles/242963.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: quality
criteria
transport system
analysis of main components
optimization
Opis:: The analysis of results of experimental tests and a literature survey on the issue reveal that the subject matter connected with determination of the optimal number of a given transportation system operation assessment criteria has a direct influence on the result of the considered assessment. Whole study has been made on the basis of the analysis of data obtained from tests performed in a real municipal transportation system, providing transport tasks in a 400 thousand urban agglomeration. On the basis of the tests, there was determined a set of sixteen criteria for the system operation assessment, depending on preferences of drivers, passengers, workers of the system providing vehicles with serviceability and the last group of results is a final assessment. The research involved tests of significance for correlation coefficients between the assessment criteria. The method of main factors involving analysis of a linear transformation of existing vector of variables X into Y has been used to study the task dimensioning. Proper values, providing basis for determination of a new space correspond to coordinates of the newly created vector Y. On this basis, the dimension of the criteria and their significance space has been concluded. The determined criteria have been accepted for the development of a resultant model for assessment of a transportation system operation quality.
Źródło:: Journal of KONES; 2012, 19, 4; 481-486
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Analysis of civil engineering structures vibroisolation effectiveness
Autorzy:: Bednarz, J.
Targosz, J.
Powiązania:: https://bibliotekanauki.pl/articles/241751.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: vibration analysis
discrete-continuous model of vibration isolation system
Opis:: A properly designed and manufactured vibration isolation system of railroads and civil engineering structures has a decisive influence on the reduction of vibrations caused by crossing trains, trams and subway transferred to residential buildings This article presents an overview of current vibration isolation systems of railroads and civil engineering structures. Based on the effectiveness of the protection of residential and industrial buildings from vibrations the ranking of vibration isolation systems was proposed. The article also attempts to assess the effectiveness of vibration isolation systems currently used in rail trails. For this purpose, a discrete-continuous model of vibration isolation system of railway and tramway rails was build. For this model, dynamic analysis was carried out. Performed analysis allowed determining range of the natural frequency of vibration isolation system. The results of dynamic analysis allow pitching shift the natural frequency of the system under consideration from the frequency of excitation, which in turn is a fundamental condition for the proper operation of the vibration isolation. As part of work on a physical model of vibration isolation system there was also developed one-level crossings of roads and railroads. The work was carried out in a research project 4875/B/TO2/2010/38 financed by Ministry of Science and Higher Education.
Źródło:: Journal of KONES; 2012, 19, 4; 33-41
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The possibility of diagnosis EGR systems defects by vibration analysis
Autorzy:: Kaźmierczak, A.
Wróbel, R.
Powiązania:: https://bibliotekanauki.pl/articles/244781.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: EGR system
fast Fourier transform
automotive diagnosis
vibroacustic analysis
Opis:: The Exhaust Gas Recirculation is a popular system of recirculation of the automotive vehicle emission. The principle of working depends on the forcing in the part of outlet gas to the combustion chamber. Majority of the users of automotive vehicles with EGR systems claim that system has negative effect on the performance of the car. Nonetheless, that opinion is subjective, because the generally available research on the subject does not exist. However, EGR system, as the most of automotive vehicle is being subjected to physic's rules - it uses up. The polluted flowing valve of circuit has an influence on stability of engine's work, and what follows on a performance of a car. The authors present a new in - vitro way of diagnosis in automotive vehicle, which depend on detection and measure of vibroacustic vibrations of the diesel engine. It seems that EGR circuit that does not work properly should not have an influence on vibrations generated by an engine. However, authors indicate that this statement is wrong. EGR system has an influence on engine's vibration, what was described in the article. On that way, detection of vibrations must be accomplished with high quality diagnostic systems. Therefore, vibrometric laser scanner Polytec had been used. To achieve full diagnostic results multidimensional vibration's function has been researched, where the torque moment has been used as an extra parameter. Measured vibrations were subjected to digital signal processing like windowing, fast Fourier transform, filtration by finite impulse response. The results of measure and processing perform in form of 3D plots, which indulge in speed estimate of the usefulness of presented method. Moreover authors presents principle of working EGRs' systems of different generations and its evolution.
Źródło:: Journal of KONES; 2008, 15, 4; 217-225
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Influence of environmental, ergonomic factors and properties of operators on the reliability of ships propulsion systems
Autorzy:: Frąckowiak, W.
Powiązania:: https://bibliotekanauki.pl/articles/247900.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: propulsion system
operator
reliability
analysis
operator functions
Performance Shaping Factor
Opis:: Analyzing the systems in terms of reliability, we often treat them as the technical objects only, omitting human interaction or assuming that operator has constant characteristics. This significantly distorts the results obtained in this way, since human is a part of the system with special properties that can change together with the predisposition of the operator and the conditions under which he operates. These attributes may have a major influence on the reliability of the systems. Therefore, analysis of systems reliability should include a reliability of operator and its properties. In this paper presented the antropotechnical reliability structure based on selected installation, which is a part of ships propulsion system. Also operator’s functions were defined and the analysis of human reliability, taking into account various properties of the operator and the external conditions, were performed. Then, there is assessed the influence of operator and environmental factors on the value of the entire system reliability. The study used the reliability data of the container ship propulsion system equipped with low-speed piston engine, fixed pitch propeller and auxiliary installations. These data were obtained from studies of expert judgments (Brandowski A., Frąckowiak W. et al.) in the years 2007–2009. For HRA (human reliability analysis), HEART technique (Human Error Assessment and Reduction Technique) was used, together with the human unreliability values and correction factors developed by the authors of this method. Study results illustrate influence of environmental, ergonomic factors and the properties of the operator on the reliability of the antropotechnical systems. The studies were subjected exemplification on fuel treatment installation as a part of ships propulsion systems.
Źródło:: Journal of KONES; 2012, 19, 2; 145-151
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Application of multibody simulation for semitrailer optimization
Autorzy:: Korta, J.
Martowicz, A.
Gallina, A.
Uhl, T.
Powiązania:: https://bibliotekanauki.pl/articles/247963.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: multibody dynamic system
response surface
design of experiment
sensitivity analysis
Opis:: This paper presents an approach of optimization of a truck semitrailer suspension system, with utilization of multibody model; its purpose was to find the best values of operational parameters: stiffness and damping factors, in order to minimize the disadvantageous influence of force distribution in the high risk areas, where preceding strength analysis has pointed out dangerous load values. The model contains elements of two different types: flexible and rigid bodies, in purpose of increasing the accuracy level of conducted numerical calculations. A number of simulations with different parameters and under different load cases have been carried out, combined with a parametric and structural sensitivity analysis, what has enabled an estimation of individual factors influencing particular forces that have been the objectives of optimization procedure. The stiffness and damping coefficients of the construction suspension system have been adjusted by applying metamodeling techniques. Basing on the chosen design of experiment results, this procedure allows for an approximation of the behaviour of the analysed construction in the whole design space. In this process, two different approaches have been used: Kriging and polynomial regression, and both have been compared to the simulations results. Finally, using a desirability function, the most optimal solution has been found.
Źródło:: Journal of KONES; 2012, 19, 1; 171-182
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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