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1
Content available The matter of decision-making control over operation processes of marine power plant systems with the use of their models in the form of semi-Markov decision-making processes
Girtler Jerzy, Rudnicki Jacek
Polish Maritime Research
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2021
|
nr 1
116--126
EN
The article presents the possibility to control the real operation process of an arbitrary device installed in the marine power plant based on the four-state semi-Markov process, being the model of the process, which describes the transition process of operational states of the device (ek , k = 1, 2, 3, 4), and the transition process of its technical states (sl , l = 1, 2, 3). The operational states ek (k = 1, 2, 3, 4) have the following interpretation: e1 – active operation state resulting from the task performed by the device, e2 – state of ready-to-operate stop of the device, e3 – state of planned preventive service of the device, e4 – state of unplanned service of the device, forced by its damage. Whereas the interpretation of the technical states sl (l = 1, 2, 3) is as follows: s1 – state of full serviceability of the device, s2 – state of partial serviceability of the device, and s3 – state of unserviceability of the device. All these states are precisely defined for the ship main engine (SG). A hypothesis is proposed which justifies the use of this model to examine real state transitions in marine power plant device operation processes. The article shows the possibility to make operating decisions ensuring a rational course of the device operation process when the proposed model of this process and the dynamic programming method based on the Bellman’s principle of optimality are applied. The optimisation criterion adopted when making operating decisions is the expected profit to be gained as a result of functioning of the device in the time interval [τ0 , τm], being the sum of the expected profit gained in interval [τ0 , τ1 ] and to be gained in interval [τ1 , τm].
2
Content available Identification of the operational state of the rotor machine using vibration parameters monitoring
Świeboda Bartosz, Hetmańczyk Mariusz Piotr
Selected Engineering Problems
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2019
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nr 8
73--78
EN
The article presents a method to identify the operational state of a rotating machine based on vibration symptoms. The tests were performed on the balancing and alignment laboratory stand. In the measurements, acceleration sensors and the IFM VSE100 diagnostic module were used. The measurements were made while maintaining the constant rotational speed of the motor shaft. The diagnosis was based on the vibration values measured from the bearing housings of the shaft (on which discs with the initial imbalance were placed).
3
Content available remote Study of the distribution of normal contact pressure between parts joined in a multi-bolted system under operational loads
Grzejda Rafał
Engineering Transactions
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2019
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Vol. 67, iss. 2
147--155
EN
Modelling and calculations of unsymmetrical multi-bolted connections treated as a system for different bolt models and contact layer models between the joined parts are presented. The modelling refers to preloaded and externally loaded connections. The systemic models of the connection for two substitute models of bolts are shown. Between the joined parts two types of the Winkler model of a contact layer are taken into consideration. Calculations were made for an exemplary unsymmetrical connection. Its models were preloaded and externally loaded with normal forces. As a result of the calculations, distributions of normal contact pressure at the interface of the parts joined in the connection are shown.
4
Content available Significance analysis of ship operational states as a factor influencing the energy efficiency of a research – training vessel
Behrendt C., Prill K., Patsch M.
New Trends in Production Engineering
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2018
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Vol. 1, Iss. 1
219--225
EN
Ship operational state is a sequence of temporary values of state variable parameters expressing the properties of a particular object and which are recognised as significant for a specific problem. They are the key elements of the operational tasks and essential to determining the Energy Efficiency Operational Indicator for a specialised vessel. In that case, the method refers directly to specific operational states and their significance for a particular operational task in the time function. Based on the surveys conducted on a population of people employed by the ship owner and involved in the ship operation, one has analysed the significance of the operational states for that vessel. The differentiated perception of the operational states of the subjected vessel results from, inter alia, the tasks performed by the responders as their duties, their experience and the level of their engagement in the ship operation. A qualitative and quantitative analysis of the states enables to conduct the planning process in terms of operational tasks of the specialized ship for effective and efficient operation.
5
Content available A stochastic model of changes in the operational states of means of transport
Landowski B., Perczyński D.
Journal of KONES
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2018
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Vol. 25, No. 2
223--230
EN
In the article, application of a Markov process for modelling the process of transport means operational state changes whose duration times can be estimated by Erlang distribution is presented. The research object is a system of city bus transport operation, used in a selected agglomeration. A homogenous Markov process was assumed a mathematical model of the process of transport means operation. Transformation of a stochastic process, for which distributions of random variables denoting duration times of the states are Erlang distributions, into a stochastic process characterized by exponential distribution of the state duration times, was performed at the costs of the state space extension. The use of a homogeneous Markov process for mathematical modelling of the operation process was dictated by the fact that the process reflects adequately, from the point of view of the research goal, the real operation process. In order to illustrate the process, a hypothetical, simplified calculation example was provided. Reliability of technical objects needs to be maintained at appropriate level, which is the responsibility of the repair and maintenance subsystem ensuring. This subsystem consists of two subsystems. The main tasks of the mobile emergency teams include providing vehicles, that is, buses that are outside the depot with the serviceability state as quickly as possible or hauling damaged buses to technical service stations.
6
Content available remote Modelling nonlinear preloaded multi-bolted systems on the operational state
Grzejda R.
Engineering Transactions
|
2016
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Vol. 64, iss. 4
525--531
EN
Modelling and calculations of asymmetrical multi-bolted connections at the operational stage are presented. The physical model of the joint is based on a flexible flange element that is connected with a flexible support by means of the rigid body bolt models. Between the joined elements, the nonlinear Winkler model of a contact layer is taken into consideration. A computational model of the system is proposed, which makes it possible to analyse the preloaded multi-bolted connections subjected to an eccentric normal load. The results obtained from the sample calculations are presented.
7
Identyfikacja energetyczna stanów eksploatacyjnych gazowców typu Q-Flex
Adamkiewicz A., Kucharski J.
Rynek Energii
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2014
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Nr 3
101--108
PL
Artykuł podejmuje próbę oceny wpływu energii zapotrzebowanej przez instalację ponownego skraplania gazu na sprawność układu energetycznego gazowca z jednopaliwowymi silnikami o zapłonie samoczynnym, w kontekście sprawności operacyjnej i opłacalności zadania transportowego. Na tle ewolucji układów napędowych zbiornikowców LNG z wykorzystaniem naturalnie odparowującego LNG, zidentyfikowano stany eksploatacyjne wspólne dla wszystkich typów gazowców oraz szczególne stany eksploatacyjne zbiornikowców z ponownym skraplaniem gazu ładunkowego, napędzanych przez jednopaliwowe wolnoobrotowe silniki o zapłonie samoczynnym. Dokonano dekompozycji urządzeń układu energetycznego statku. Wielkości przetwarzanych strumieni energii określono w oparciu o ich obciążenia nominalne. Opisano sposób modelowania matematycznego bilansu energetycznego wybranych do analizy stanów eksploatacyjnych. Przedstawiono wyniki badań wykonanych dla danych pozyskanych w ramach doświadczeń eksploatacji gazowca typu Q-Flex. W podsumowaniu skonfrontowano otrzymane wyniki z gazowcami napędzanymi przez turbiny parowe i układy z silnikami dwupaliwowymi Dual- Fuel Diesel Electric, wskazując możliwe kierunki rozwoju gazowców.
EN
This article attempts to evaluate the influence of energy required by the gas re-condensation installation on the efficiency of the power system of a gas carrier with a mono-fuel diesel engine in the aspect of operational efficiency and profitability of the transportation task. Having in mind the evolution of LNG carrier power systems using the naturally evaporating LNG, operational states common to all types of gas carriers have been identified as well as the special operational states of carriers with recondensation of cargo gas driven by mono-fuel low speed diesel engines. Decomposition of ship power system elements has been performed. The values of transferred energy fluxes were determined basing on their load. A mathematical modelling method of energy balance of operational states chosen for the analysis has been described. Results of studies carried out for data obtained within Q-type gas carrier operational practice have been presented. In the summary, the obtained results were confronted with the results for gas carriers driven by steam turbines and dual- fuel diesel electric engine systems indicating possible trends for gas carrier development.
8
Content available remote The contemporary classification of rail vehicle technical states
Sowa A.
Journal of Mechanical and Transport Engineering
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2014
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Vol. 66, No. 1
69--84
EN
The article presents a variety of the meanings of an object state term (notion), depending on the point of view at which it is discussed. Each of the presented meanings can constitute an identification subject in contemporary operational states. The first of these meanings is a structural state of an object. It refers to the number of the elements active in a given set and the interactions between them. Another equally important meaning is a technical state, which can be identified on the basis of both the evaluation of physical features or the correctness of the functioning of an object’s constituent elements. The operational state of an object depends on both the state of the structure and the technical state. It is the third meaning of the term of an object state. The principles of classification within all three groups of the meaning of the object state term and mutual connections between them are shown in this article.
PL
W artykule przedstawiono znaczenia pojęcia „stan obiektu” w zależności od punktu widzenia, z jakiego jest ono rozważane. Każde z przedstawionych znaczeń może być prze d-miotem identyfikacji we współczesnych systemach eksploatacji. Pierwszym z nich jest stan strukturalny obiektu, odnoszący się do liczby czynnych elementów w danym układzie oraz oddziaływań pomiędzy nimi. Drugim, również bardzo ważnym, znaczeniem jest stan techniczny, który może być identyfikowany na podstawie oceny cech fizykalnych lub poprawności funkcjonowania elementów składowych obiektu. Zarówno od stanu struktury, jak i od stanu technicznego jest uzależniony stan eksploatacyjny obiektu, będący trzecim znaczeniem pojęcia „stan obiektu”. W artykule przedstawiono zasady klasyfikacji w obrębie wszystkich trzech grup znaczeniowych pojęcia „stan obiektu”, a także powiązania między nimi.
9
Content available Effects of nonlinearity on determination of bolt forces for the operational state of a bolted flange connection
Grzejda R.
International Journal of Applied Mechanics and Engineering
|
2014
|
Vol. 19, no. 1
39--48
EN
Modelling and calculations of an asymmetrical bolted flange connection at the operational stage are presented. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of hybrid elements, which substitute bolts. Between the flange element and the support, the linear Winkler model of a contact layer is taken into account. The bolted flange connection is preloaded and then subjected to an eccentric normal load. The influence of nonlinearity of the contact layer between the joined elements on computational values of bolt forces has been investigated. Results of calculations for several different values of the joined element’s thickness are described.
10
Content available Effects of Nonlinearity on Bolt Forces for the Operational State of a Multi-bolted Connection
Grzejda R.
Technical Sciences / University of Warmia and Mazury in Olsztyn
|
2013
|
nr 16(3)
221--231
EN
In the paper modelling and calculations of an asymmetrical multi-bolted connection at the operational stage are presented. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of linear spring elements, which substitute bolts. Between the flange element and the support, the linear Winkler model of a contact layer is taken into consideration. The multi-bolted system is preloaded and then subjected to an eccentric normal load. Influence of nonlinearity of the contact layer between joined elements on computational values of bolt forces has been investigated. Results of calculations for several different values of the joined element’s thickness are pointed out.
11
Content available Determination of bolt forces for the operational state of a bolted flange connection
Grzejda R.
Advances in Manufacturing Science and Technology
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2013
|
Vol. 37, nr 3
73--83
EN
In the paper modelling and calculations of an asymmetrical bolted flange connection at the operational stage are presented. The physical model of the joint is based on a flexible flange element that is connected with a rigid support by means of hybrid elements, which substitute bolts. Between the flange element and the support, the nonlinear Winkler model of a contact layer is taken into consideration. A computational model of the system is proposed, which makes it possible to analyze any preloaded bolted flange connection subjected to an eccentric normal load. Results obtained from the calculations are compared with described experimental research.
PL
W pracy przedstawiono modelowanie i obliczenia asymetrycznego kołnierzowego połączenia śrubowego w stanie eksploatacyjnym. Model fizyczny połączenia jest zbudowany z odkształcalnego kołnierza mocowanego do nieodkształcalnej ostoi za pomocą elementów hybrydowych, modelujących śruby. Pomiędzy elementami łączonymi wprowadzono nieliniową warstwę sprężystą typu winklerowskiego. Zaproponowano model połączenia umożliwiającego analizę dowolnego kołnierzowego połączenia śrubowego, wstępnie naprężonego i obciążonego zewnętrznie mimośrodowo siłą normalną. Uzyskane wyniki obliczeń porównano z wynikami wykonanych badań doświadczalnych.
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