Wyniki wyszukiwania - Biblioteka Nauki

1

Identyfication of shaft line alignment with insufficient data availability

100%

Murawski L.

|

nr 1

EN

The paper presents a method of identification parameters of shaft line alignment in case of the lack of producers’ data. Proper shaft line alignment is often a problem for repair shipyards, for aged ships without sufficient documentation. Author proposed combined experimental-analytical method for identified some existing parameters and checking (and eventually correcting) power transmission system’s foundation. Specialised software has been developed for shaft line alignment calculations with influence coefficients. An example analysis has been performed for cargo ships with medium-speed main engine and second one with slow-speed propulsion system. Multivariant computations supported by measurements of the ships’ shaft line have been carried out

2

Wpływ doboru typu silnika głównego oraz jego umiejscowienia na drgania kadłuba i nadbudówki statku

100%

Murawski L.

|

2014

|

tom nr 6

7687--7696

PL

Większość statków handlowych jest wyposażonych w dwu i czterosuwowe silniki spalinowe. Silniki spalinowe są źródłem relatywnie wysokiego poziomu drgań kadłuba statku i jego nadbudówki. Wysoki poziom drgań ma duży wpływ na komfort pracy załóg statków oraz jest groźny dla wytrzymałości konstrukcji okrętowych. Obydwa elementy mają duży wpływ na bezpieczeństwo żeglugi. Jeżeli statek jest już zbudowany to ograniczenie nadmiernych drgań jest bardzo trudne i kosztowne. Z tego powodu, drgania statku powinny być możliwie dokładnie przewidziane podczas jego projektowania. Analiza dynamiczna konstrukcji okrętowych jest pracochłonna, lecz metodyka ich przeprowadzania jest dobrze opanowana przez specjalistów. Jednakże, szereg decyzji głównego projektanta, podejmowanych na bardzo wczesnym etapie projektowania (przed rozpoczęciem obliczeń), ma duży wpływ na charakterystyki dynamiczne statku. W pracy zaprezentowano obliczenia drgań własnych typowego kontenerowca. Analizie poddano charakterystyki dynamiczne kadłuba i nadbudówki statku. Porównano lokalizację silnika głównego z lokalizacją węzłów postaci drgań własnych; ich wzajemne położenie może mieć duży wpływ na drgania globalne i strukturalne statku. Również ilość cylindrów silnika głównego (oraz liczba skrzydeł śruby napędowej) jest istotna z punktu widzenia drgań statku. Przykładowo, 8.-cylindrowy silnik ma znaczące następujące rzędy wymuszeń: 3., 4., 5. i 8. W celu zapobieżenia drganiom rezonansowym częstotliwości drgań własnych kadłuba statku powinny być porównane z częstotliwościami wymuszeń.

EN

Most of the merchant ships are equipped with two or four stroke combustion engines. Combustion engines are a source of relatively high level of ship hull and superstructure vibrations. High vibrations level has a big influence on comfort of ship's crew as well as on strength of ship structures. Both elements have a big influence on safety of shipping. Reducing the level of vibrations is very difficult and costly if built ship has undesirable vibration. Therefore, the ship vibrations should be predicted (as accurately as possible) during design process. Dynamic analysis of ship structure is laborious but the methodology is well known for the specialized engineers. But, several decisions of main designer, on very early stage of ship designing, have big influence on ship hull dynamic characteristics (before start of calculations). Natural vibrations calculations of typical container ship are presented in the paper. The analyses are focused on the ship hull and superstructure dynamic characteristics. Comparison between location of main engine and location of natural vibrations nodes might have big influence on global and structural ship vibrations. Also, main engine's cylinders number (and number of propeller blades) is important from vibrations point of view. For instance, 8th cylinder engine has significant 3rd, 4th, 5th and 8th order of excitation. The ship hull natural frequencies should be compared with excitation frequencies in order to avoid resonance vibrations.

3

Optymalizacyjny model synchronizacji ruchu tramwajów w sieci

100%

Murawski L.

|

tom nr 3

3405--3415, CD 1

PL

W pracy przedstawiono metodę identyfikacji parametrów ułożenia linii wałów, w przypadku niewystarczającej ilości danych producentów. Przeprowadzono dyskusję nad wpływem różnych parametrów (reakcje łożyskowe, momenty gnące i siły tnące oddziaływujące na wał korbowy lub przekładnię oraz rozkład naprężeń wzdłuż linii wałów) ułożenia linii wałów na niezawodność pracy okrętowych układów napędowych. Poprawne ułożenie linii wałów jest często trudne dla stoczni remontowych, w przypadku starych statków z powodu niepełnych danych. Autor proponuje obliczeniowo-pomiarową metodę identyfikacji i optymalizacji (korekcji) wybranych parametrów ułożenia linii wałów wraz ze sprawdzeniem posadowienia układu napędowego. Wykonano specjalistyczne oprogramowanie (bazujące na Metodzie Elementów Skończonych) do analiz ułożenia linii wałów. Główne nowości oprogramowania to: elastyczne podparcie (model łożysk - warunki brzegowe) linii wałów; zamodelowanie łożyska rufowego, jako podparcia ciągłego oraz wyznaczanie współczynników wpływu. Przykładowe obliczenia wraz z dyskusją zostały przeprowadzone dla uniwersalnego statku zaopatrzeniowego z średnio-obrotowymi silnikami napędu głównego. Przeprowadzono wielowariantowe obliczenia wsparte przez badania pomiarowe okrętowej linii wałów.

EN

The paper presents a method of identification parameters of shaft line alignment in case of the lack of producers’ data. The discussion about shaft line parameters (bearings' reactions, bending moment and shear forces acting on crankshaft or gear box, and stresses distribution in the shaft line) which has an influence on marine propulsion system reliability was presented. Proper shaft line alignment is often a problem for repair shipyards, for aged ships without sufficient documentation. Author proposed combined experimental-analytical method for identified and optimization (correction) some existing parameters and checking power transmission system’s foundation. Specialised software (based on Finite Element Method) has been developed for shaft line alignment calculations. Main novelties of the software are: elastic supports (model of bearings - boundary conditions) of the shaft line, continuous support as a model of stern tube bearing and influence coefficients calculations. An example analysis with discussion has been performed for cargo ships with medium-speed main engine. Multi-variant computations supported by measurements of the ships’ shaft line have been carried out.

4

Analiza porównawcza metod wyznaczania grubości skrzydeł okrętowych śrub napędowych

100%

Murawski L.

|

tom z. 10

237-242

PL

W pracy zaprezentowano analizę porównawczą obliczeń wytrzymałości okrętowych śrub napędowych. Przeprowadzono obliczenia według zaleceń dwóch międzynarodowych towarzystw klasyfikacyjnych - ABS i DNW. Wyniki analiz porównano z obliczeniami przeprowadzonymi Metodą Elementów Skończonych. Obliczenia MES pozwalają na zmniejszenie grubości skrzydeł okrętowych śrub napędowych.

EN

Different analysis method of the marine propeller's blade strength haw been described in the paper. Calculations have been done by two international classification societies formulas - ABS and DNV. Finite Element Method analysis (NASTRAN program) has been used as a comparison calculations method to the empirical formulas. Propeller blade thickness might be reducted after FEM method analysis.

5

A FEM - based procedure for strength calculation of ship propellers and analysis of its results

100%

Murawski L.

|

tom Vol. 8, nr 2

10-13

EN

This paper concerns a new strength calculation method of ship propellers. Within its scope a propeller modelling technique with the use of a CAD pre-processor (PATRAN), calculation procedure based on Finite Element Method software (NASTRAN)), as well as a way of performing numerical calculations, was developed. Results of example propeller calculations for a tanker are also attached.

6

Forces exciting vibrations of ship's hull and superstructure

100%

Murawski L.

|

nr 4

EN

The paper presents identification of main excitation forces of vibrations of ship hull and itssuperstructure, as well as investigation of influence of the analyzed excitation on shipvibration level. The following excitation forces were analyzed: dynamic pressure on thetransom deck, propeller-generated hydrodynamic forces, as well as internal and externalengine-generated forces. Rigidity and attenuation characteristics of lubricating oil filmwere taken into account in the analysis of the excitations transmitted by the propulsionsystem bearings (stern tube bearing, intermediate bearing, engine’s main and thrust bea-rings). The dynamic characteristics of ship’s power transmission system were also taken into account.Results of the analyzes were verified by comparing results of the computations and measurements

7

Method of determining the structural parameters of wood-polymer composite

63%

Kyzioł L. , Murawski L.

|

tom Vol. 21, No. 2

177--184

EN

A composite material consisting of woody skeleton and polymerized methacrylate has been developed and characterized. This paper presents an experimental program and the results concerning mechanical properties and strength of wood modified with polymerized methacrylate. In the article, there are examples of structural elements made of natural wood. Wood is a composite consisting of the layers of soft and hard wood. Wood is a composite and porous material. The porosity, which is a serious defect of wood, may be simultaneously its advantage. Wood saturation with different impregnates to minimize its disadvantages. If the wood pores will fill the monomer there is obtained the wood polymer composite. This composite is classified as of fiber composites. Such composite is effectively protected against degradation; it is durable in use, and show an improvement in mechanical properties. Design constructions of surface modified wood require the determination of fundamental material constants. Therefore, for the determination of these parameters is very important obtaining the appropriate research material. The surface impregnation of wood allows obtaining strength characteristics in a function of polymer content. This allows to model it's, and then design and perform specific ship structures. In the wood, there are three directions in relation to the annual rings. Wood properties, especially mechanical properties, are different in the selected directions. For the computation takes the orthogonal anisotropy in which there are three mutually orthogonal planes of symmetry, for which there is symmetry properties of the wood.

8

Adjustment of cylinder lubricating oil of marine slow-speed engines

63%

Van Doan D. , Murawski L.

|

tom Vol. 24, No. 1

113--119

EN

The article refers to the common task of lubrication system. The fast development of the world's maritime sector, makes competition among countries increasing. Because of the deterioration of the global economy, the shipping companies, ship-owners want to reduce freight rates, to meet safety requirements, as well as improving conditions of exploitation and operating the machines to prevent the pollution of the marine environment. While exploiting the diesel engine in general and Sulzer diesel engines in particular, ship owners are always eager to reduce the operating cost and still ensure the engine running are safe and reliable. Provide an example of how to calculate the amount of cylinder lubricating oil according to the theory of slow-speed marine engines. The article refers to the costs of the operation and exploitation of ship, offer solution to reduce extraction costs by optimizing the amount of lubricating oil for the cylinders. The analyses in the article are based on Sulzer RTA engines. The article also refers to the level of actual lubrication oil for the cylinders of slow-speed marine engines during operation and exploitation based on the practical experience of the chief engineers, who had ever worked with these engines. The optimal adjustment of cylinder lubricating oil of Sulzer RTA diesel engines to reduce the operating cost but still ensure the engine running are safe and reliable and the problems need to be noted in the process of adjustment.

9

Mixed electronic-ionic conductivity in vanadate oxide glasses containing alkaline ions

63%

Barczyński R. J. , Murawski L.

Materials Science Poland

|

2006

|

tom Vol. 24, No. 1

221--227

EN

The conductivity of glasses in 50V2O5-(50-x)P2O5-xA2O (A = Li, Na, K, Rb) systems was investigated as a function of composition. In vanadate-phosphate glasses containing various alkali ions, the conductivity decreases with increasing alkali ion content. The decrease in conductivity is larger for heavier alkali ions and reaches more than seven orders of magnitude in the case of glass containing 40 mol % of Rb2O. Only glasses containing lithium exhibit relatively small conductivity changes - less than one order of magnitude - and an increase for high lithium contents.

10

Wykorzystanie programów bazujących na metodzie elementów skończonych do nauczania projektowania złożonych i wielkogabarytowych konstrukcji cienkościennych

51%

Murawski L. , Muc A. , Szeleziński A.

|

2017

|

tom Nr 52

93--98

PL

W artykule przeprowadzono ocenę oprogramowania wykorzystywanego do nauki projektowania złożonych i wielkogabarytowych konstrukcji cienkościennych. Większość oferowanych środowisk graficznych umożliwia zamodelowanie struktury przestrzennej obiektu i przeprowadzenie badań symulacyjnych obejmujących np.: analizę wytrzymałościową i statyczną, obliczenia drgań własnych i wymuszonych. Moduł obliczeniowy w tego typu programach bazuje na metodzie elementów skończonych. W pracy zamieszczono przykładową ścieżkę projektową i analizę pokładu okrętu typu RO-RO, na którym zaparkował samochód ciężarowy. W przedstawionym przykładzie wykorzystano oprogramowanie firmy MSC z preprocesorem Patran i modułem obliczeniowym Nastran.

EN

In the paper the software to the teaching of designing of complex and large-scale thin-walled structures was evaluated by the authors. The bundle of MSC software, named Patran-Nastran, was presented. The software is based on Finite Element Method. The authors, during the teaching process, focus on basic analyses: linear static strength analysis, normal mode (eigenvectors) analysis and frequency response analysis (forced vibrations calculations). An example of RO-RO ship's deck analysis was presented. The deck was loaded with the wheels of truck. A short description of the modeling process as well as the results of the analyses are presented in the paper. Discussion about objectives of the teaching process was carried out. In the authors' opinion, knowledge of that very specialized software is important not only for a calculating engineer. All mechanical engineers should have basic knowledge about the calculations process because they will be recipients of the calculations performed during structure designing. Thin-walled structures are very useful for teaching because during the structure modeling we have to choose types of FEM elements. Stiffeners may be modeled by 1-D elements (with offset) and the plates should be modeled by 2D elements. Differences between beam and rod 1D elements as well as shell, plate and membrane 2D elements should be stressed during the teaching process.

11

Identification of Inertia, Damping, and Stiffness Parameters for Low-Pressure Steam Turbine Frame

51%

Krawczuk M. , Murawski L. , Ostachowicz W.

Machine Dynamics Problems

|

2003

|

tom Vol. 27, No. 1

41-54

EN

The paper deals with modern methods of investigating the low-pressure frame of a steam turbine. The objective of this paper is to estimate typical parameters of the low-pressure frame of a steam turbine. The numerical calculations are presented for the frame of 200 MW low-pressure turbine. In particular, methods of calculating inertia, damping, and stiffness parameters are investigated. These data form a basis for new symptoms of the turbine technical condition. The identification process uses dynamic amplitude-frequency and phase-frequency characteristics. Those parameters are estimated using a finite element method approach, which calculates the dynamic flexibility of the structure. Natural frequencies and modes are determined for the turbine frame. The paper describes a physical and numerical model of the frame as well the results of calculations for the above-mentioned inertia, damping, and stiffness matrix.

12

Ocena żywotności turbiny parowej o mocy 26MW

51%

Ostachowicz W. , Krawczuk M. , Murawski L. , Rymkiewicz J.

|

tom z. 7

411-416

PL

W pracy przedstawiono wyniki obliczeń numerycznych mających na celu określenie możliwości dalszej eksploatacj i turbiny parowej o mocy 2 6 MW . Analizę wykonano w oparciu o metodę elementów ekończonych i prawa mechaniki pękania.

EN

The paper presents results of numerical calculation s performed in the aim to determine durabilit y of 26 MW steam turbine . The analysis was performed using finite element method and rules of fracture mechanics.

13

Finite Element Method in Modeling of Ship Structures. Part I – Theoretical Background

51%

Doan D. , Szeleziński A. , Murawski L. , Muc A.

|

tom nr 100

51--62

EN

The paper presents basic knowledge about Finite Element Method including the modeling method of ship structures. Numerical modeling methods were also shortly described. A ship hull and an upper works is typical thin-wallded structure. Modeling method of plates (typical 2-D elements) with stiffeners (1-D elements) is presented in details. In the part II of the article the practical example of Ro-Ro ship's deck analyses was performed with using Patran-Nastran software (MSC Software). The most common and dangerous risks and errors occurring in the process of ship structure modeling were discussed.

PL

W pracy przedstawiono podstawową wiedzę o metodzie elementów skończonych ze szczególnym uwzględnieniem metod modelowania konstrukcji okrętowych. Metody modelowania numerycznego zostały również krótko omówione. Kadłub statku oraz jego nadbudówka to typowa konstrukcja cienkościenna. Dokładnie przedstawiono metodę modelowania płyt (typowe elementy 2-D) wraz z usztywnieniami (elementy 1-D). W części 2 artykułu zaprezentowano szereg analiz przeprowadzonych na przykładzie pokładu statku typu ro-ro, z wykorzystaniem oprogramowania Patran-Nastran (MSC Software). Omówiono najpopularniejsze i najgroźniejsze błędy występujące podczas modelowania konstrukcji okrętowych.

14

Analysis of ability to detect defects in welding structures with usage of dynamic characteristics spectrums

51%

Szeleziński A. , Murawski L. , Muc A.

Journal of KONES

|

2016

|

tom Vol. 23, No. 2

365--372

EN

Non-destructive methods of testing (NDT) welded joints are nowadays intensively developing due to their numerous advantages. The most significant of them are the possibility of objects diagnosis in the place of their work without the necessity of disassembling or long outage, lower costs of realization as well as considerably lower insalubrity for people conducting the tests. Study of dynamic characteristics of welded elements creates a good possibility for welded joints assessment in comparison to other known non-destructive testing methods. The main reasons are Fourier analysis (FFT), damping analysis, differences in signals or their answers. Presented method can be used in classical NDT tests as well as in structural health monitoring (SHM). Assumptions for quality evaluation methods of welded plates using spectrums analysis of dynamic characteristics are presented in the article. In order to provide the high quality of research, the measuring devices of Bruel & Kjaer Company are used. Both, the testing methodology and possibility of using vibration method in welded joints testing are presented. The attention is also drawn to the vital testing elements like proper selection of impact hammer ending and impact place as well as the problem of repeatability of diagnostic signals. The value of repeatability of obtained signals will be of critical importance in the comparative method, which is under development. The results of initial testing of plates with proper and faulty welded joints have been analysed. Among welding faults, the boundary bonding and crevice have been considered. The analysis of impact hammer dispersion values in correlation to the spectrum of dynamic characteristic has been conducted. Statistic methods have been used for the assessment.

15

Vibrodiagnostic of welded thin-walled plates with the usage of laser sensors in network infrastructure

51%

Szeleziński A. , Muc A. , Murawski L.

|

tom Vol. 25, No. 4

415--419

EN

The article presents a non-destructive welded joints assessment (vibrodiagnostics) method, in which, with the use of the Internet, computer networking technologies and laser displacement sensors, the quality of welded steel plates may be monitored. The article also describes the possibilities of analysis of received vibrodiagnostics data on the base of diagnostic parameters analysed in function of time and frequency. The method described in the article allows remotely registering, analysing and diagnosing mechanical systems using vibrodiagnostics and information technologies. Modern, computerized methods exhibit efficiency and reliability of results – they are currently the best measuring tools that can be used in automatic monitoring (structural health monitoring - SHM) of marine structures. It is essential to make objective assessment of the results by NDT users, which is tightly connected with the expertise of norms and regulations of NDT. It may be helpful in this respect to monitor responses from a few sensors, arranged in a few measuring points. NDT results quite often trigger further analysis of durability of an object. The NDT of welded joints method as presented in the article allows remotely and in an IT-aided way analysing and diagnosing mechanical systems with the use of vibrodiagnostics method.