Wyniki wyszukiwania - Biblioteka Nauki

1

Numerical simulation of the process of a technical object state changes

100%

Landowski B.

Journal of KONBiN

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2018

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tom No. 45

247--266

EN

The article presents a construction method and an example of a model of a technical object operation process as well as the main stochastic assumption which is a mathematical model of an object state changes. The model of the operation process was built using an analysis of the state space and operationrelated events of the analyzed technical objects. An example of numerical simulation of the technical object state change process as a tool to be used to support the analysis of the considered process. Numerical simulation of the stochastic process being a model of a technical object state change process makes it possible to determine the process characteristics impossible to determine in an analytical way.

PL

W artykule przedstawiono sposób budowy i przykład modelu procesu eksploatacji obiektów technicznych oraz podstawowe założenia procesu stochastycznego będącego matematycznym modelem zmian stanów obiektu. Model procesu eksploatacji został zbudowany na podstawie analizy przestrzeni stanów oraz zdarzeń eksploatacyjnych dotyczących analizowanych obiektów technicznych. Przedstawiono przykład numerycznej symulacji realizacji procesu zmian stanów obiektu technicznego jako narzędzia wspomagającego analizy rozważanego procesu. Numeryczna symulacja realizacji procesu stochastycznego będącego modelem procesu zmian stanów obiektu technicznego umożliwia wyznaczania charakterystyk procesu niemożliwych do wyznaczenia drogą analityczną.

2

Numerical simulation of the process of a technical object state changes

100%

Landowski B.

|

tom No. 44

119--140

EN

The article presents a construction method and an example of a model of a technical object operation process as well as the main stochastic assumption which is a mathematical model of an object state changes. The model of the operation process was built using an analysis of the state space and operation related events of the analyzed technical objects. An example of numerical simulation of the technical object state change process as a tool to be used to support the analysis of the considered process. Numerical simulation of the stochastic process being a model of a technical object state change process makes it possible to determine the process characteristics impossible to determine in an analytical way.

PL

W artykule przedstawiono sposób budowy i przykład modelu procesu eksploatacji obiektów technicznych oraz podstawowe założenia procesu stochastycznego będącego matematycznym modelem zmian stanów obiektu. Model procesu eksploatacji został zbudowany na podstawie analizy przestrzeni stanów oraz zdarzeń eksploatacyjnych dotyczących analizowanych obiektów technicznych. Przedstawiono przykład numerycznej symulacji realizacji procesu zmian stanów obiektu technicznego jako narzędzia wspomagającego analizy rozważanego procesu. Numeryczna symulacja realizacji procesu stochastycznego będącego modelem procesu zmian stanów obiektu technicznego umożliwia wyznaczania charakterystyk procesu niemożliwych do wyznaczenia drogą analityczną.

3

Semi-Markov Model Of Maintenance Of Urban Transport Buse

100%

Landowski B.

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tom Vol. 4, no 2

161-168

EN

The object of the investigations is maintenance system of urban transport buses. The subject of the investigations is a determined set of the maintenance states of means of transport and their maintenance processes, as well as the relations occurring between the aforementioned elements, and between them and the maintenance process effectiveness. The paper deals with the selected issues related to modelling, forecasting and controlling the maintenance process of a certain class of technical objects being carried out in a complex maintenance system. Supporting a decision maker in the decisions making process concerning the maintenance system under analysis is to forecast the maintenance system behaviour and evaluate the influence of the selected decision making variants on the course of the maintenance process. The purpose of the work is to present a possibility to use a semi-Markov model of maintenance process of technical objects to preliminarily forecast the state of the maintenance system after changing the values of the model input parameters. Changing the value of the input parameters may simulate an impact of various factors on the system behaviour. The paper presents the assumptions to build a model of the process being performed within the investigation object and the method of analysing it. The values of the model parameters were assessed on the basis of the results of the preliminary test carried out in a real means of transport maintenance system. All the considerations have been illustrated by a computational example. Due to the assumed generalization degree of the description, the method to model and forecast the maintenance process presented herein may be used to other maintenance systems than the urban bus transport system.

4

Simulation model of the means of transport maintenance process

100%

Landowski B.

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tom Vol. 17, No. 4

271-276

EN

The real operation and maintenance processes of technical objects are characterised by so called secondary action, it means that the values of the features describing the process states and the analysed operation and maintenance states of technical objects as well as the after-effect ofthose states depend not only on their present state, but very often on the state or sequence of the previous states, too. In spite of the fact that the mathematical models of the real processes are intrinsically a significant simplification of the actual state, it however seems that omission of a secondary action in a certain class of operation and maintenance processes is an excessive simplification and the results obtained from investigations of models of that type may be affected by a significant error. The paper presents a model of operation and maintenance process of means of transport characterised by a secondary action as well as an example of computer simulation of performance of a stochastic process describing the features of the operation and maintenance process under analysis. The elaborated model of operation and maintenance process of technical objects takes into account the specificity of the systems of the urban bus transport. The computer simulation of the maintenance process enables, among other things, to estimate the values of the chosen indicators characterising the investigated process. On the basis of the analysis of the statistical data, obtained from the operation and maintenance investigations, the values of the essential input parameters of the model were estimated. The considerations presented in the paper include an assumption that it is possible to distinguish n disjoint subsets ofhomogenous objects, from the point of view of the investigation purpose, in the set of the technical objects being operated and maintained in the system under analysis. The investigation object is a system of operation and maintenance of means of transport.

5

Application of Markov decision process as a mathematical model of operation and maintenance process

100%

Landowski B.

|

tom nr 24 (96)

12-16

EN

This paper presents an example of applying Markov decision process to model and analyse the bus operation and maintenance process within an urban transport system and to forecast the influence of the operation and maintenance strategies realised for the technical objects on the transport system behaviour. Setting the values of the indices describing the process under the analysis is performed on the basis of a computerised simulation of the Markov decision process, being a mathematical model of the technical objects operation and maintenance process. In order to simulate the operation and maintenance process (Markov decision process) and to evaluate the influence of the decisions being made on the course and effectiveness of the process being realised within the study object a simulation algorithm has been elaborated and a computer calculation program has been written. The model presented herein has been created in such a way to assure that it shall be possible to use it in as extensive as possible class of the problems regarding the operation and maintenance of the technical objects.

PL

W artykule przedstawiono przykład zastosowania decyzyjnego procesu Markowa do modelowania i analizy procesu eksploatacji autobusów komunikacji miejskiej oraz prognozowania wpływu realizowanych strategii eksploatacji obiektów technicznych na zachowanie się systemu transportowego. Wyznaczanie wartości wskaźników charakteryzujących analizowany proces realizowane jest na podstawie komputerowej symulacji decyzyjnego procesu Markowa, będącego matematycznym modelem procesu eksploatacji obiektów technicznych. W celu symulacji procesu eksploatacji (decyzyjnego procesu Markowa) i oceny wpływu podejmowanych decyzji na przebieg i efektywność procesu realizowanego w obiekcie badań opracowano algorytm symulacji i napisano komputerowy program obliczeniowy. Przedstawiony w pracy model został skonstruowany w taki sposób, by zapewnić możliwość jego wykorzystania w jak najszerszej klasie problemów związanych z eksploatacją obiektów technicznych.

6

Applying the Markov decision processes to model changes to the maintenance states of an object

100%

Landowski B.

|

tom Vol. 17, No. 3

263-270

EN

Operation and maintenance of technical objects is related to occurrence of various events, the effects of which affect the operation and maintenance process course, and particularly the courses of their use and service processes. Occurrence of those events may be of both determined and random nature. Assessing, analysing and forecasting the operation and maintenance process course, in complex technical systems, are connected with the problems of modelling the operation and maintenance processes of technical objects. Those processes are random ones which depend on one another. The paper presents an example of the Markov decision process to model changes of the analysed operation and maintenance states of technical objects. The investigation object is a real operation and maintenance system of urban transport buses in a middle-sized agglomeration (about 400 k residents). Supporting a decision maker, in the process of making decisions concerning performance of the operation and maintenance process of the means of transport, may be carried out by analysing the results of the investigations of the operation and maintenance process model. The investigations of that type are to determine values of the selected measures of technical and economic efficiency of the process being carried out for the estimated values of the model parameters. The values of the model parameters were estimated on the basis of the analysis of the results of the investigations performed in the analysed system of urban bus transport. A change to the values of the model parameters may reflect a change of influence of internal and external factors on behaviour of the system and the operation and maintenance process of the means of transport being carried out in it. Mathematical models of the operation and maintenance processes are intrinsically simplified, therefore practical conclusions resulting from investigating those models should be formulated carefully.

7

An example of a technical object operation process model describing influence of engine damages on the operation process course

100%

Landowski B.

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2014

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tom Vol. 9, no 3

33--42

EN

The authors of this paper present, a method for building a model of technical objects operation whose sequence of successive operation states, their duration times, incomes and costs connected with the objects being in these states and the way a given state is reached depend not only on the object current state but also on other factors. The model describes, among others, influence of damages of the powertrain, being a compression-ignition internal combustion piston engine, of the analyzed object on the operation process of that object. The analysed technical object is a means of transport (a vehicle). A simplified computing model has been presented in order to illustrate the discussion. The model of operation process was built basing on the analysis of spaces of states and operation events concerning technical objects used in a real transportation system. In result of identification of the analyzed system and its multi-state process of technical objects operation, operation states and possible transitions between these states, significant for this research, have been determined. Sets of source data indispensable for the model assessment and its initial verification were obtained on the basis of experimental tests with the use of passive experiment method from a real research object. In order to perform mathematical modelling of the technical object operation process the Markov decision process was applied.

8

Zarys metody wyznaczania wartości zmiennych decyzyjnych w systemach eksploatacji autobusów komunikacji miejskiej

100%

Landowski B.

Zeszyty Naukowe. Mechanika / Akademia Techniczno-Rolnicza w Bydgoszczy

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2000

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tom Z. 48 (229)

5--19

PL

W artykule przedstawiono zarys metody pośredniego wyznaczania wartości wybranych zmiennych decyzyjnych do racjonalnego sterowania procesem eksploatacji, realizowanym w systemie eksploatacji autobusów komunikacji miejskiej. Opisano również podstawowe założenia modelu procesu eksploatacji stanowiącego istotny element metody oraz zdefiniowano, wyróżnione w procesie identyfikacji procesu eksploatacji realizowanego w rzeczywistym systemie miejskiej komunikacji autobusowej, stany eksploatacyjne autobusu.

EN

The paper presents an outline of a method of intermediate calculation of selected variables to enhance the municipal bus-transport system control. The paper provides basic assumptions of a model of operation, which is an essential element of the method presented, and givesthe condition of busses run in the real-world transport system.

9

Analiza przyczyn i postaci uszkodzeń wybranych środków transportu oraz ich wpływu na możliwość realizacji zadań transportowych

63%

Landowski B. , Kobędza K.

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tom nr 3

3641--3649

PL

Przedstawiona w pracy problematyka dotyczy zagadnień związanych z analizą uszkodzeń środków transportu oraz ich wpływu na możliwość realizacji zadań transportowych. Przedstawiono wybrane wyniki badań dotyczące między innymi przyczyn, postaci, sposobu naprawy i skutków na realizację zadań przewozowych uszkodzeń zaistniałych w analizowanych środkach transportu drogowego. Na podstawie identyfikacji obiektu badań wybrano pojazdy do badań w sposób losowy spośród marek i modeli środków transportu najczęściej użytkowanych w analizowanym przedsiębiorstwie realizującym zadania przewozowe. Obiektem badań jest ogólnie traktowany system eksploatacji pojazdów. Jako przykład obiektu badań, na którym zilustrowano rozważania podjęte w pracy wybrano przedsiębiorstwo będące tzw. korporacją taksówkarską realizująca zadania transportowe różnymi środkami transportu w wybranej aglomeracji miejskiej. W obiekcie badań najczęściej użytkowanymi pojazdami są samochody osobowe następujących typów (modeli): VW Passat B5 FL, Ford Mondeo Mk3, Mercedes Benz W210, Audi A6 C5 oraz Skoda Octavia I. Wyniki badań przedstawione w opracowaniu dotyczą pojazdów wymienionych modeli Pojazdy są własnością kierowców, świadczących usługi przewozu osób w celach zarobkowych.

EN

The problems presented in this paper deal with the issues related to the analysis of damages of the means of transport and their influence on the possibility to perform transport tasks. Selected results of investigations regarding, among other things, the reasons for, nature, method of repair and influence of the damages occurred in the analysed means of road transport on performance of the transport tasks are presented herein. Based on identification of the investigation object the vehicles to be investigated were randomly selected from among the brands and models of means of transport being used most frequently in the analysed enterprise performing transport tasks. The investigation object is a generally defined vehicle utilisation system. As an example of the investigation object, based on which the considerations undertaken in the paper were illustrated, a company being so called taxi corporation performing transport tasks by various means of transport in the selected urban agglomeration 3649 was chosen. The most frequently used vehicles in the investigation object are personal cars of the following types (models): VW Passat B5 FL, Ford Mondeo Mk3, Mercedes Benz W210, Audi A6 C5 and Skoda Octavia I. The investigation results presented herein refer to the vehicles of the mentioned models. Those vehicles are the property of the drivers providing passenger transport services for profit purposes.

10

Analiza wpływu uszkodzeń podsystemów autobusów na zagrożenia w systemie transportowym

63%

Wdzięczny A. , Landowski B.

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tom nr 3

6644--6651

PL

W pracy poddano analizie zagrożenia jakie wynikają z działalności komunikacji miejskiej. W pracy wykorzystano metodę analizy rodzajów i skutków niezdatności (FMEA), polegającą na określeniu prawdopodobieństwa wystąpienia uszkodzenia oraz jego skutków w odniesieniu do badanego obiektu technicznego lub jego elementów, do wyznaczania zagrożeń związanych z komunikacją miejską. Badania przeprowadzono w rzeczywistym systemie eksploatacji autobusów komunikacji miejskiej na wybranej losowo próbce. W analizowanym systemie autobusowej komunikacji miejskiej eksploatowanych było 210 środków transportu (autobusów miejskich) różnych marek i typów. Badania eksploatacyjne dotyczyły trzech wybranych typów autobusów, użytkowanych w analizowanym systemie autobusowej komunikacji miejskiej. Do badań wybrano 21 autobusów. Każda grupa składała się z 7 pojazdów tego samego typu. Analizie poddano uszkodzenia podsystemów pojazdów, które przyjęto za najistotniejsze z punktu widzenia celu pracy czyli oceny poziomu ryzyka. W celu określenia wartości stopnia ryzyka poszczególnych podsystemów autobusów miejskich przeprowadzono analizę stopnia skuteczności napraw ich uszkodzeń.

EN

The analyses of the threats in the activity of the municipal transport was contained in the paper. The methods of the sorts analysis and the methods of the unfitness result analysis was used. The FMEA depends on qualification of pronouncement probability in reference damage. This analysis are useful for marking of the municipal transport threats. The research was in the real systems of the bus municipal transport used the random sample of the data. In the analyzed system of municipal bus transportation there are used 210 transport means (city buses) of different makes and types. Experimental tests applied to three selected types of buses, used in the analyzed system of bus transportation. 21 vehicles were chosen for the analysis. Each group consisted of 7 buses of the same type. The analysis covered damage to the vehicle subsystems which were assumed to be of the biggest significance in terms of the paper goal, that is risk. In order to determine the value of risk degree of particular subsystems (assemblies) of city buses, an analysis of their damage and repair degree was carried out.

11

Simulation of the granular flow of grinding media inside a ball mill

63%

Landowski B. , Kostek R.

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tom Vol. 6, no 3

65-68

EN

The ball mills are often applied in mineral processing, they are e.g. an important part of the cement industry. A key factor, which influences the milling process, is the granular flow of grinding media. The flow determines: energy consumption, time of milling and capacity; thus there is a need to describe the phenomenon. The discrete element method - DEM is a computational method, which allows to simulation of the granular flow, thus it has been applied in this article. The received results of simulation have been compared with experimental results.

12

Analysis of the working process of an automated high bay racking system

63%

Landowski B. , Pawlikowski A.

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tom Vol. 6, no 3

75-86

EN

This paper analyses selected aspects of effectiveness and reliability of one of the supply chain links, i.e. an automated high bay racking system (a stacker crane). The primary purpose of the research was to determine and analyse reliability indicators as well as to assess and analyse characteristics of changes of the working process being carried out. The research was performed according to the passive experiment method in natural operating conditions. The stacker crane and the individual operations of the working process were decomposed for the needs of the research. Identification of the object and subject of the research made it possible to identify significant (for the purposes of the paper) operational states of the investigated stacker crane. The working process being carried out was identified, a model of the working process was built and the performed operations were decomposed within the extent of the research. The paper presents selected results of the research performed.

13

A simulation study of mixing granular materials

63%

Kostek R. , Landowski B.

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tom Vol. 6, no 3

57-64

EN

Mixing the granular materials is a critical process in many industries, especially in pharmaceutical one, where homogeneous blends of ingredients are required. The homogenisation process is time and energy consuming, thus this article is focused on the process. The mixing process has been simulated with the discrete element method – DEM, which gives an opportunity to study the granular flow of mixed ingredients. Following stages of the mixing process have been presented for various shapes of blenders and analysed, which gives an opportunity to understand the process and mechanisms of homogenisation. Apart from the three basic mechanisms of homogenisation: diffusion, convection and shear, one more has been found.

14

Prognozowanie stanu systemu w markowskim modelu procesu rezerwowania obiektów technicznych

51%

Woropay M. , Landowski B. , Perczyński D.

|

tom Vol. 53, nr 5

95-106

PL

W niniejszym artykule przedstawiono sposób oceny (prognozowania) zachowania się podsystemu rezerwowego przy założeniu, że modelem procesu rezerwowania jest jednorodny proces Markowa (proces urodzin i śmierci). Przedstawiony w artykule sposób wyznaczania prawdopodobieństw znajdowania się obiektów technicznych w danej chwili czasu w podsystemie rezerwowym umożliwia wyznaczenie niezbędnej liczby obiektów rezerwowych dla przyjętego kryterium ryzyka wyczerpania się rezerwy. Całość rozważań zilustrowano na przykładzie systemu eksploatacji autobusów komunikacji miejskiej.

EN

The unique manner of estimating (including the prognosis) the behaviour of the reserve subsystem is shown in the paper. There is an assumption, that the model of the reserve process can be designed and described with the homogeneous Markov's one (so called the birth and death process). The way of evaluating values of finding probabilities the technical objects in the reserve subsystem (at the moment of time t) is shown. A forementioned way of evaluation enables of computing indispen sable quantity of the technical objects for every assumed reserve run low risk criterion. All considerations have been illustrated and exemplified with the urban bus transport maintenance system.

15

Analiza procesu transportowego wybranej klasy materiałów niebezpiecznych

51%

Muślewski Ł. , Musiał J. , Landowski B. , Bojar P.

|

2014

|

tom nr 6

7713--7721

PL

Ogół rozważań niniejszego opracowania dotyczy analizy porównawczej kosztów wykorzystania dwóch alternatywnych środków transportu, takich jak transport kolejowy i samochodowy w przewozie materiałów niebezpiecznych. Omówiona została definicja ładunków niebezpiecznych oraz przedstawiony został podział na klasy wyróżnionych materiałów. Wyszczególnione zostały ograniczenia, restrykcje i obowiązujące przepisy prawne dotyczące materiałów niebezpiecznych. W kolejnej części opracowania przedstawiony został obiekt badań oraz scharakteryzowano przewożony ładunek, czyli MPZ - Mieszanina Poreakcyjna Zasiarczona. Następnie dokonano analizy kosztów transportu niniejszego materiału, dwoma alternatywnymi gałęziami transportu. Zrealizowano analizę dotyczącą kosztów transportu z wykorzystaniem środków transportowych: kolejowego i samochodowego. W podsumowaniu opracowania wyszczególniono główne zalety wynikające z zastosowania danego środka transportu, który stanowi optymalne rozwiązanie dla przedsiębiorstwa stanowiącego obiekt badań i specyfiki transportowanego towaru.

EN

The subject of this paper is a comparative analysis of costs connected with using two alternative types of transport such as railway and car transports for carrying hazardous materials. A definition of hazardous materials has been discussed and a division of the materials into classes has been presented. Restrictions and applicable law regulations concerning hazardous materials have been specified. In the next part of the study there has been presented the research object and the carried load that is sulfur containing post-reaction mixture has been characterized. Also an analysis of costs involved in transport of these materials with the use of two alternative transport branches has been made. An analysis of transport costs with the use of transport: railway and car. The summary deals with the main advantages of using the transport means which appears to be the best solution for an enterprise which was the research object and specificity of the transported cargo.

16

Assessment of the suitability of the fuels with component power engines

51%

Markiewicz-Patalon M. , Muślewski Ł. , Kaszkowiak J. , Landowski B.

|

tom Vol. 24, No. 4

187--192

EN

The article presents the results of laboratory tests of selected properties of fuels available on the market and fuels with higher density component B100 obtained from rapeseed oil (10, 30, 50 and 100%). An analysis of the cetane number, viscosity, and weight of the ash remaining after combustion of fuel samples was made. It was found that the cetane number of pure biocomponent is higher than diesel oil of mineral origin and it slowly decreased along with a decrease in the Extras component. All tested samples of fuels have appropriate cetane number to power internal combustion engines with compression ignition. The viscosity of the fuel samples measured at a temperature of 30ºC increased along with an increase in the content of biocomponent and approached the limit values for fuels. According to the results presented by other authors in their studies ash mass decreased along with an increase in the content of the component. Only premium diesel showed less ash mass than other fuel. The study includes also the energy value and the calorific value of liquid fuels with addition of a biocomponent, which power diesel engines. The results of the tests indicate a slight decrease in the calorific value of the fuel along with an increase in the content of biocomponent, which does not affect the ability to power the engines. Laboratory tests have proved that use of methyl esters of fatty acids in diesel fuel is the right choice to power diesel engines.

17

Implementation of modular trucks into road transport

51%

Muślewski Ł. , Landowski B. , Woropay M. , Migawa K.

|

tom No. 44

97--118

EN

In this article, an analysis of modular truck application in the road transport in Poland has been made. Terminology has been unified. Classification and law regulations applicable in different European countries and all over the world have been discussed. An analysis of existing solutions has been made and an optimal variant for road freight transport, including the condition and parameters of the road infrastructure in Poland, has been proposed. The study presents initial conceptual assumptions of this project as well as advisability of using these modular trucks, on the basis of a selected research object – the analyzed transport company. On this example, an analysis of costs and potential profits to be generated from transport services performed using the proposed modular trucks and with reference to costs borne by the investigated company with the use of currently operated transport means, has been made.

PL

W niniejszym artykule zrealizowano analizę i ocenę zastosowania systemów modułowych w transporcie drogowym w Polsce. Dokonano ujednolicenia terminologii, klasyfikacji oraz uwarunkowań prawnych obowiązujących w innych krajach europejskich i na świecie. W pracy dokonano analizy funkcjonujących rozwiązań i zaproponowano wybór optymalnego wariantu dla samochodowego transportu towarowego w Polsce, z uwzględnieniem stanu i parametrów krajowej infrastruktury drogowej. W opracowaniu opisano wstępne założenia koncepcyjne w tym obszarze, jak również dokonano analizy celowości zastosowania niniejszych zestawów modułowych na przykładzie wybranego obiektu badań - analizowanego przedsiębiorstwa transportowego, stanowiącego obiekt badań. Na jego przykładzie dokonano analizy kosztów i szacunkowych zysków z realizowanych procesów transportowych, z wykorzystaniem proponowanych zespołów modułowych, w odniesieniu do kosztów ponoszonych przez badane przedsiębiorstwo z zastosowaniem obecnie eksploatowanych środków transportowych.

18

Fuzzy identification of the reliability state of the mine detecting ship propulsion system

51%

Pajak M. , Muslewski L. , Landowski B. , Grzadziela A.

|

tom 26

|

nr 1

EN

The study presents the evaluation and comparative analysis of engine shaft line performance in maritime transport ships of the same type. During its operation, a technical system performs functions for which it was designed. It goes through different states. Dynamic state changes of a rotational system can be identified by means of its vibration measurement. For this purpose, a research was carried out which involved recording vibrations of the analysed rotational systems. The recordings were used for calculating selected characteristics in the time-domain, where one of the most unique is the value of the normalized mutual correlation function. On the basis of the concentration values, the characteristics which unambiguously determine the ability state were selected for further studies. Then an identification method for rotational system non-coaxiality was proposed. The method involves using fuzzy clustering. According to this method the values of input signal characteristics were used to formulate fuzzy clusters of system ability and inability states. The method can be used for identifying the current state of the system. The study presents the results of the application of this method in engine turbine shaft lines of minesweepers, with the rotational system selected as an example. It needs to be noted that the efficiency of identifying the operating state of the system with this method is higher than with other methods described in the literature by authors who deal with this issue. The research results have a significant impact on the evaluation of mechanical properties of the studied objects and directly affect operational states of mechanical systems, including those installed in minesweepers, thus determining their reliability

19

Possibilities of extension of gear oil service life in rail vehicles

51%

Muślewski Ł. , Sójka M. , Landowski B. , Markiewicz-Patalon M.

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tom Vol. 25, No. 4

309--316

EN

The study deals with the results of operational tests of gear oils used in a regional railway transport system. The character of the aging process and the impact of gear oil operation on the main factors determining further usability of gear oil have been defined on the basis of the results of carried out tests. It was proved that transport systems lack reliable convenient diagnostic methods for gear oil used during the process of operation. One of the criteria taken into consideration in decision-making is the period of oil change imposed by the gear manufacturer. The long process of oil application is accompanied by physicochemical changes, which cause degradation of its properties. This phenomenon is referred to as oil aging. This fact can cause loss of viscosity, increase in the amount of pollution, and in effect a decrease in the ability to provide a durable boundary film. The lubricating ability of oil decreases as well. An increase in the amount of pollution is caused by interaction of the collaborating friction elements and by pollutants coming from the gear environment. These changes are of permanent character and reflect the state of new characteristics referred to as operational characteristics. Gear oils have a certain lubricating ability, which is a critical parameter. This study is an attempt to find a way of the oil service life extension and convince the propulsion systems manufacturers that reduction of costs connected with rail vehicle maintenance does make sense.

20

A method for determining the usability potential of ship steam boilers

51%

Muślewski Ł. , Pająk M. , Landowski B. , Żółtowski B.

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tom nr 4

105--111

EN

Ship large-power steam boiler may serve as an example of complex critical technical system. A basis for rational control of operation of such system is knowledge on its capability of fulfilling the tasks to which it was intended. In order to make it possible to apply computer aiding to operational decision-making the capability should be described analytically. In this paper it was proposed to express the capability of ship steam boiler ( considered a complex system) to perform service tasks, by calculating components of its usability potential in a given instant t. To this end , was distinguished a set of steam boiler fundamental features which formulate space of its technical states. Values and characteristic intervals of the features were defined and this way sub-spaces of serviceability and non-serviceability states of the object in question were determined. Next, in the considered space, technical state of the boiler and its usability potential was determined. Owing to this it become possible to quantitatively express the steam boiler functioning capability which served as a basis for elaborating an algorithm for controlling the operational processes of a complex technical system under action. In this paper is also described a way of application of the presented method to calculation of ship steam boiler usability potential, which may be especially instrumental in the case of operational control of the boilers of the kind , equipped with interstage reheaters, i.e. those operating with high values of operational parameters.