Wyniki wyszukiwania - BazTech

1

Impact of the construct type on the availability of the selected groups of technical objects

Pilch Robert, Smolnik Maksymilian

Journal of KONBiN

|

2024

|

Vol. 54, iss. 1

133--155

EN

The paper concerns the quantitative assessment of the availability of the groups of machines of the two different types of construct /design/ – traditional and modular, which perform the same functions and in the analyzed groups constitute koon-type reliability structures. The main aim is to determine the size of the differences in the availability and reliability of such groups of machines at different values of the characteristics regarding the failure rate and renewal of their subassemblies and modules. The solution to the problem was obtained through digital simulation, for which the model and assumptions were developed by the authors. The obtained results indicate that the groups of the machines of modular construct /design/ are characterized by better reliability and availability, which may constitute one of the guidelines in the process of making investment decisions and planning the use and maintenance of this type of machines.

PL

Artykuł dotyczy ilościowej oceny gotowości grup maszyn o dwóch różnych typach konstrukcji: tradycyjnej i segmentowej, które pełnią te same funkcje i w analizowanych grupach tworzą struktury niezawodnościowe typu kzn. Głównym celem jest określenie, jak duże są różnice w gotowości i niezawodności takich grup maszyn przy różnych wartościach charakterystyk dotyczących awaryjności i odnowy ich podzespołów i segmentów. Rozwiązanie problemu uzyskano na drodze symulacji cyfrowej, do której model i założenia opracowali autorzy. Uzyskane wyniki wskazują, że lepszą niezawodnością oraz gotowością charakteryzują się grupy maszyn o konstrukcji segmentowej, co może stanowić jedną ze wskazówek w procesie podejmowania decyzji inwestycyjnych i planowania eksploatacji tego typu maszyn.

2

Multi-fragmental and multi-phase availability models of the safety-critical I&C systems with two-cascade redundancy

Kharchenko Vyacheslav, Ponochovnyi Yuriy, Babeshko Ievgen

International Journal of Electronics and Telecommunications

|

2024

|

Vol. 70, No. 1

211--218

EN

Traditional availability, reliability, and safety models face the dimension problem due to a huge number of components in modern systems, motivating further research in this field. This paper focuses on multi-fragmental and multiphase models for availability and functional safety assessment of the information and control (I&C) systems with two-cascade redundancy considering design faults manifestation during operation. The methodology of the research is based on Markov and semi-Markov chains with the utilization of multi-phase modeling. Several multi-phase models are developed and investigated considering different conditions of operation and failures caused by version faults. The case study of the research is based on the analysis of safety-critical nuclear power plant I&C systems such as the reactor trip systems developed using the programmable platform RadICS.

3

Failure and reliability analysis of heavy firefighting and rescue vehicles: a case study

Selech Jarosław, Rogula-Kozłowska Wioletta, Piątek Piotr, Walczak Agata, Pieniak Daniel, Bondaronok Paweł, Marcinkiewicz Jacek

Eksploatacja i Niezawodność

|

2024

|

Vol. 26, no. 1

art. no. 175505

EN

The purpose of the article was to analyse the reliability, maintainability, and availability estimates of firefighting and rescue engines. Analysing the reliability parameters of heavy firefighting and rescue vehicles over time requires knowledge of their failures. In this article, failure data from the six years of maintenance of ten heavy firefighting and rescue vehicles from ten were analysed in relation to two main subsystems. Reliability analysis was performed and the best-fit distribution was found, with the parameters calculated. For both subsystems, the chassis combined with the cabin and the superstructure, the 2P-Weibull distributionwas identified as the most suitable fit. The availability and maintenance indicators for each vehicle and the individual subsystems were calculated. It was clearly defined that there exists a significant difference between the two subsystems analysed in terms of failure characteristics, as well as maintainability and availability parameters.

4

Cannibalization policies: adoption in the maintenance of fleet systems

Diaz Ermilso, Muñoz-Añasco Mariela, Correcher-Salvador Antonio

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2023

|

z. 121

63--75

EN

Fleet systems are considered complex due to the interaction between their units and components. Maintenance management systems face various challenges to achieve acceptable availability and reliability rates at a reasonable cost. A critical task for making maintenance decisions is understanding the system requirements to select maintenance policies appropriate for the actual and future system state. When there is a replacement shortage in a fleet system, and it is impossible to supply new spare parts quickly, cannibalization policies can mitigate this scarcity via the interchange of components. However, this procedure presents the maintenance manager with different evaluation effects, such as increased maintenance hours, decreased system reliability rate, and unavailability in some units. Finding an equilibrium between the benefits and risks has caught the attention of researchers. This work gathers diverse proposals for applying cannibalization policies and the effects that arise from using them. Models, methods, tools, and identified gaps in understanding what parameters of the components and environments of the fleet systems favor cannibalization are discussed.

5

Influence of transients on end-to-end availability for a meshed network

Tanguy Christian

Safety and Reliability of Systems and Processes

|

2023

|

Summer Safety and Reliability Seminar 2023

207--226

EN

The disruption of services must be kept at a minimum in telecommunications networks so that the consequences are not too severe and their durations are as short as possible. Maintenance policies often rely on the steady-state availabilities of each element of the system, and focus on the system’s weak links. The end-to-end (or two-terminal) availability – a standard performance index – of a meshed network has long been studied, but mainly for small systems, and assuming constant values for the availability of each element. When taken into account, the time-dependent contributions of links and nodes to the system unavailability were computed using exponential failure and repair distributions. In this work we revisit the meshed network first proposed by Walter, Esch, and Limbourg (ESREL 2008), and compute the end-to-end availability between two nodes, where the individual contributions of links and nodes are kept. This allows the ranking of links and nodes, using well-known performance indices (Birnbaum, Risk Reduction Worth, etc.). We can thus determine the elements that should receive due attention in maintenance and resilience studies. However, as the steady-state availability may not always be a lower bound to the transient availability in the case of non-exponential failure and repair distributions, we have studied the influence of such configurations on the time-dependent behaviours of all the aforementioned quantities. We then discuss the influence of uncertainty in the availability values, and compare the results obtained for the all-terminal reliability, another often-used performance criterion of networks.

6

Availability analysis of vertical milling centre using Markov approach and Monte Carlo simulations

Kumar Girish, Mishra Ravi, Khan Tayyab

Safety and Reliability of Systems and Processes

|

2023

|

Summer Safety and Reliability Seminar 2023

117--130

EN

The purpose of this article is to investigate the availability of vertical machining centre using a Markovian technique and Monte Carlo simulation (MSC). Availability is a critical performance metric for industrial systems. Conventional methodologies focus for steady-state availability evaluation of mechanical systems. The research analyses transient availability assessment for four different system configurations. Monte Carlo simulation modelling is used to compare the results and future scope is suggested to use the developed MCS based algorithms/codes for non-exponential (time dependant) failure and repair time distributions. The research also investigates the influence of active and passive redundancy on availability, indicating that for the vertical machining centre, parallel architecture with standby redundancy outperforms active load sharing. The chapter includes a sensitivity study that modifies the repair rates of the ball screw and sub-assembly to make the component selection process easier for engineers. The authors believe that this chapter will be useful to maintenance and practising engineers because it will assist them in making informed decisions about system availability, developing maintenance/replacement policies, and determining the repair level required to achieve the desired system availability.

7

Reliability and availability modelling of a retrofitted Diesel-based cogeneration system for heat and hot water demand of an isolated Antarctic base

Coronado Miguel, Kadoch Benjamin, Contreras Jorge, Kristjanpoller Fredy

Eksploatacja i Niezawodność

|

2023

|

Vol. 25, no. 3

art. no. 169779

EN

The reduction of greenhouse gas emissions is a relevant challenge for a sustainable development. Waste heat could be used to produce hot water by using a recovery system. This article studies the availability of a combined heat and power systems (CHP) in extreme area (Antarctic) through the integration of a waste heat recovery system with a diesel generator to produce hot water. The reliability and availability principles are incorporated to explore how the profile of hot water consumption and the hot water storage tank size affect system availability. Different combined heat and power systems are thus classified, and their availability indexes modelled by adopting the continuous Markov approach and the state space model. The results indicate that the CHP systems availability is strongly influenced by the daily hot water demand profile. As a useful recommendation, one of the considerations for increasing availability, reducing costs and greenhouse gas emissions with the CHP system is to include a hot water tank in the analysis.

8

Access to education in terms of the elimination of architectural barriers – on the example of selected Polish universities located in historic buildings

Nowak-Pieńkowska Małgorzata, Brutkowski Michał

Architecturae et Artibus

|

2023

|

Vol. 15, no. 2

1--12

EN

Many universities in Poland are based in historic buildings. As public facilities, they must have accessibility for people with disabilities. Therefore, historic buildings undergo regular reconstruction to ensure accessibility on the basis of technical and construction regulations and the Convention on the Rights of Persons with Disabilities. For the purpose of the study, those with exceptional architectural, cultural and historical are presented. The article is concerned with determining the current state of accessibility of selected Polish universities for students with mobility disabilities. The first part of the paper deals with the verification of the background material in the form of statistical data and support programmes for the studied group of users. The second part presents historical information about the historic buildings along with a qualitative analysis of the elements already applied to eliminate architectural barriers. Nine selected historical teaching facilities located both in Warsaw and scattered throughout the country were analysed using the field observation method. The conclusion presents the results indicating the application in the realizations of the principle of rational improvement stating that the preservation of historic value can become paramount to ensuring full accessibility. Still, monuments should be treated individually, and the same applies to disabilities, where each is different and requires individual perception and treatment.

9

Reliability, availability, and maintainability analysis of the propulsion system of a fleet

Bayraktar Murat, Nuran Mustafa

Zeszyty Naukowe Akademii Morskiej w Szczecinie

|

2022

|

nr 70 (142)

63--70

EN

New systems are produced and developed to meet specific needs, and their reliability is the most important issue. In the maritime industry, evaluating failures in a ship’s propulsion system results in high costs and the loss of prestige for the company. Land/sea fleet employees need to detect and minimize the failures that may occur in ship propulsion systems in advance to ensure the continuity of the ships’ operations. In this study, the recorded failure data of four different ships belonging to a fleet in the last 10 years are used. Failures were examined as a whole since the ships have similar propulsion systems. The obtained failure data were grouped, and the average time to fix the failures was determined by the chief engineer and made suitable for reliability, availability, and maintainability (RAM) analysis. A suitable model was created for grouped failures by Isograph’s RWB software. As a result of the analysis of the propulsion system and its subsystems, the main engine of the ship was shown to have the best reliability. Furthermore, the most important components were the cylinders of the main engine as subsystems. This study highlights the components that are important to the reliability of a propulsion system. Thanks to the RAM analysis, improvements can be pinpointed on a ship’s propulsion system, which will increase the operations of the maritime industry. Reducing failures will further increase the confidence in maritime transport and strengthen its place among the modes of transportation. This study provides a valuable resource for academicians, experts, as well as companies working on reliability, availability, and maintainability in the future.

10

Rozwój środowiska mieszkaniowego na dawnych terenach przemysłowo--usługowych a dostępność zielonych przestrzeni publicznych – przypadek obszaru „Ludwinów-Mateczny" w Krakowie

Wantuch-Matla Dorota

Środowisko Mieszkaniowe

|

2022

|

nr 38

23--39

PL

W ostatniej dekadzie zabudowa mieszkaniowa w Krakowie rozwija się szczególnie intensywnie. Brak planów miejscowych w wielu częściach miasta powodował dotąd i nadal jeszcze nierzadko powoduje sytuację, w której tereny inwestycyjne są maksymalnie zabudowywane bez całościowej wizji dla obszaru na jakim się znajdują. Nierzadko wpływa to niekorzystnie na jakość przestrzeni publicznych, których charakterystyka staje się zaledwie wypadkową procesu zabudowy rozwijanej z niewielkim udziałem zieleni publicznej. Niniejszy artykuł prezentuje analizę przekształceń funkcjonalno-przestrzennych obszaru „Ludwinów-Mateczny” w Krakowie, zabudowywanego dotąd mimo braku planu miejscowego, atrakcyjnego nie tylko pod względem lokalizacyjnym, ale także ze względu na sąsiedztwo obszarów przyrodniczo cennych. Przedstawiono w nim wyniki badań procesu rozwoju lokalnego środowiska mieszkaniowego w okresie od ok. 2010 do 2022 roku. Badania oparto na analizach dostępnych dokumentów planistycznych, statystycznych, autorskiej analizie ilościowej zmian w strukturze przeznaczenia i użytkowania terenu, a także badaniach terenowych.

EN

In the last decade residential development in Krakow has been particularly intensive. In consequence of many parts of the city being left without any local zoning plan, land designated for property development is developed to the maximum while the overreaching vision for the area is missing. This often has an adverse effect on the quality of public spaces, the characteristics of which is merely resultant from the development process developed with little public green space. This article presents an analysis of the functional and spatial transformation of the “Ludwinów-Mateczny” area in Krakow, which has been developed so far in spite of the lack of a local zoning plan, attractive not only in terms of its location, but also because of its proximity to valuable natural areas. It presents the results of a study of the local housing development process over the period starting approximately in 2010 and ending in 2022. The research was based on analyses of available planning and statistical documents, the author’s quantitative analysis of changes in the land designation (purpose) and use structure, as well as on the field research.

11

Po co przedsiębiorcy tajemnica przedsiębiorstwa?

Smolarska Marzena

Systemy Wspomagania w Inżynierii Produkcji

|

2022

|

Vol. 11, iss. 1

1-9

PL

W artykule przedstawiono jak należy rozumieć tajemnicę przedsiębiorstwa i jakie korzyści płyną z jej wdrożenia. Jakie wymogi musi spełniać informacja żeby mogła być chroniona tajemnicą przedsiębiorstwa. Zdefiniowano również główne obszary, które musi wziąć pod uwagę przedsiębiorca decydując się na rozwiązania związane z bezpieczeństwem informacji. Jak istotny jest człowiek w procesie oraz monitoring wdrożonych rozwiązań prawnych, organizacyjnych i technicznych. Przedstawiono również kierunki prawidłowego zarządzania informacjami szczególnie ważnymi dla organizacji. Wskazano obszary monitoringu wdrożonych rozwiązań takich jak audyt, klasyfikacja informacji czy analiza ryzyka. W artykule przedstawiono również obszary które warto objąć wewnętrznymi regulacjami tajemnicy przedsiębiorstwa. Przeanalizowano co przede wszystkim stanowi o bezpieczeństwie aktywów w przedsiębiorstwie. Zwrócono również uwagę na konieczność odpowiedniego zarządzania informacjami stanowiącymi tajemnicę przedsiębiorstwa i co to oznacza w praktyce funkcjonowania organizacji. Jak ogromne znaczenie ma ciągły monitoring zastosowanych środków bezpieczeństwa poprzez cykliczne audyty i analizę ryzyka.

EN

The article presents how to understand a trade secret and what are the benefits of its implementation. The main areas that an entrepreneur must take into account when deciding on solutions related to information security have also been defined. How important is the human being in the process and monitoring of implemented legal, organizational and technical solutions. What requirements must the information meet in order to be protected by a trade secret. The directions for proper information management of particular importance to the organization were also presented. The areas of monitoring the implemented solutions, such as audit, information classification or risk analysis, were indicated. The article also presents the areas that should be covered by internal regulations of trade secrets. It was analyzed what primarily determines the security of assets in the enterprise. Attention was also drawn to the need of proper management of information constituting a trade secret, as it has a crucial meaning in the practical functioning of the organization.

12

LAN performance evaluation based on access to transmission media

Wibowo Sastya Hendri, Toyib Rozali, Danita Yuli, Muntahanah

Przegląd Elektrotechniczny

|

2022

|

R. 98, nr 10

80--85

EN

Local Area Network as a computer network on small scale. The limited distance between a room, building, or office. The factor of LAN is performance, where the performance can do by using availability, reliability, response time, and throughput. Its function of it is to know the performance of LAN. Availability, use to measure the time of the network. It’s working at all work of the network it is called MTBF and MTTR. Reliability, use to measure the time of the network, which is work to transmit the data and avoid data from errors. Response time, use to measure the time that needs by the data to begin from the computer transmission. The process does in host and time. It’s needed to give back the data to the sender. Throughput, use to measure the total data that it’s transmitted at a certain time.

PL

Sieć lokalna jako sieć komputerowa na małą skalę. Ograniczona odległość między pokojem, budynkiem lub biurem. Czynnikiem sieci LAN jest wydajność, gdzie wydajność może być realizowana przy wykorzystaniu dostępności, niezawodności, czasu odpowiedzi i przepustowości. Jego funkcją jest poznanie wydajności sieci LAN. Dostępność, użyj do pomiaru czasu sieci. Działa przy wszystkich pracach sieci o nazwie MTBF i MTTR. Niezawodność, służy do mierzenia czasu sieci, czyli pracy nad przesyłaniem danych i unikaniem błędów danych. Czas odpowiedzi służy do pomiaru czasu potrzebnego na rozpoczęcie transmisji danych przez komputer. Proces odbywa się w gospodarzu i czasie. Jest potrzebny do oddania danych nadawcy. Przepustowość służy do pomiaru całkowitej ilości danych przesyłanych w określonym czasie.

13

Dostępność budynków mieszkalnych dla osób ze szczególnymi potrzebami : Strefy instalacyjne i rozmieszczenie osprzętu oraz urządzeń elektrycznych

Gorgolewski Łukasz

Elektro Info

|

2022

|

nr 6

54--57

14

Gas turbine reliability estimation to reduce the risk of failure occurrence with a comparative study between the two-parameter Weibull distribution and a new modified Weibull distribution

Djeddi Ahmed Zohair, Hafaifa Ahmed, Iratni Abdelhamid, Kouzou Abdellah

Diagnostyka

|

2022

|

Vol. 23, No. 1

no. art. 2022107

EN

Responding to the needs of quality and robustness of analysis and management of degradation of equipment, to increase their life cycle and to expand these facilities to become more and more sophisticated and agronomic. This work proposes a contribution to increase the survival of a gas turbine, installed in a gascompression plant, with a comparative study between the two-parameter Weibull distribution. A new modified Weibull distribution was proposed also to reduce the risk of occurrence of failure in this rotating machine. A Statistical analysis and validation on the synthesis of turbine's reliability data and failures were considered, with a particular focus on the use of this data to increase the availability of this type of machine. So, developing a maintenance plan based on their reliability indices for scheduled inspections.

15

Divagations on the appropriate satellite system from GNSS for aviation

Fellner Andrzej, Konieczka Robert

Transactions on Aerospace Research

|

2021

|

Nr 1 (262)

75--92

EN

American military satellite GPS system is an element of the global GNSS. It emits two codes: the precise and civil one. As late as in 2000, intentional interference that decreased precision of localization was introduced, allowing navigation accuracy of 20 m. GPS was made available to civil users, however, at their own responsibility. So, if we use GPS for our own goals, we must consider the errors that occur and their consequences. Nonetheless, commercial and operational needs determine the necessity of permanent access to satellite signal with appropriate consistency, accessibility, reliability and precision. Hence, natural and intentional errors are compensated for, using appropriate methods, based on a given activity.

PL

Amerykański, militarny system satelitarny GPS stanowi element globalnego GNSS. Emituje dwa kody: precyzyjny i cywilny. Dopiero w 2000 r. wyłączono celowe zakłócanie zmniejszające precyzję wyznaczania pozycji, pozwalające uzyskać dokładność nawigacji do 20 m. GPS został udostępniony użytkownikom cywilnym, ale na ich własną odpowiedzialność. Toteż o ile stosujemy GPS dla swoich potrzeb to musimy liczyć się z powstałymi błędami i wynikającymi z nich konsekwencjami. Jednak potrzeby komercyjne, operacyjne determinują konieczność permanentnego dostępu do sygnału satelitarnego, charakteryzującego się odpowiednią: ciągłością, dostępnością, wiarygodnością, dokładnością. W związku z tym naturalne i celowe błędy kompensuje się stosując odpowiednie metody, w zależności od prowadzonej działalności.

16

Zabytek dostępny – ograniczenia historyczne i wyzwania projektowe

Nowak-Pieńkowska Małgorzata, Wierzbicka Anna Maria, Brutkowski Michał

Środowisko Mieszkaniowe

|

2021

|

nr 37

46--54

PL

W Warszawie istnieje wiele zabytkowych budynków o wyjątkowych walorach architektonicznych, kulturowych i historycznych. Każdy obiekt publiczny, powinien ewoluować wraz ze zmieniającym się społeczeństwem, wymaganiami dostępności dla osób z niepełnosprawnościami i aktualizacją przepisów techniczno-budowlanych. Dostępność ma na celu umożliwienie korzystania z otaczającej przestrzeni czy miejsca zamieszkania za pomocą różnych urządzeń technicznych. Dotyczy wszystkich a w szczególności, osób z niepełnosprawnościami. Podczas modernizacji obiektów należy wskazać możliwości realizacji rozwiązań technicznych, które mogą być wyzwaniami projektowymi. Ponadto trzeba uwzględnić ograniczenia historyczne, aby zminimalizować wpływ ingerencji na istniejący obiekt. Artykuł poświęcony jest zdiagnozowaniu obecnego stanu i kierunków przystosowania wybranych warszawskich obiektów historycznych, a w szczególności Wydziału Architektury Politechniki Warszawskiej, dla wszystkich użytkowników z uwzględnieniem poszanowania zabytkowej struktury obiektu.

EN

There are many monuments of exceptional architectural, cultural and historical value in Warsaw. Each public facility should evolve with a changing society and accessibility requirements for people with disabilities and updating technical and construction regulations. Accessibility is intended to enable the use, also of the surrounding space or place of residence. It applies to everyone, especially people with disabilities, using various technical devices. During the modernization, should be indicated the possibilities of implementing technical solutions witch may be design challenges. Moreover, taking into account historical constraints to minimize the impact of modernization on the existing facility. The article is devoted to diagnosing the current state and directions of adaptation of selected historical buildings in Warsaw, in particular the Faculty of Architecture of the Warsaw University of Technology (ADTUW), for all users, taking into account the respect for the historic structure of the facility.

17

Maximization problem of three tasks operation process subject to constraint of availability in semi-Markov reliability model

Grabski Franciszek, Rutkowska Maria

Safety and Reliability of Systems and Processes

|

2021

|

Summer Safety and Reliability Seminar 2021

129--138

EN

Semi-Markov decision processes theory delivers the methods which allow to control the operation processes of the systems. The infinite duration semi-Markov decision processes are presented in the chapter. The gain maximization problem of three tasks operation processes subject to constraint of an availability of the semi-Markov reliability model is discussed. The problem is transformed on some linear programing maximization problem.

18

Big Data i Data Mining w polskim budownictwie

Gajzler Marcin

Przegląd Budowlany

|

2021

|

R. 92, nr 7-8

150--153

PL

W artykule podjęto dyskusję nad występowaniem w polskim sektorze budownictwa bardzo dużych zasobów danych, określanych jako Big Data. W innych sektorach, np. finansowym czy usług, obserwuje się dostępność dużych baz danych i ich wykorzystanie w celu poprawy jakości usług, lepszego dostosowania się do wymagań klienta czy poprawy konkurencyjności na rynku. Sektor budowlany, a przede wszystkim jego produkt na tle innych dziedzin gospodarki cechuje specyfika. Czy jej występowanie powoduje brak zasobów Big Data? Artykuł wskazuje na występowanie zasobów Big Data w polskim budownictwie, możliwości i sposoby ich wykorzystania.

EN

The article discusses the work in Polish for the construction of very large data resources, referred to as Big Data. In other sectors, e.g. financial or services, the availability of the database market and their use to improve the quality of services is observed, a test version for customer testing or improvement of market competitiveness. The construction sector, and above all its product, is specific compared to other sectors of the economy. Does its occurrence result in a lack of Big Data resources? An article on the occurrence of Big Data resources in Polish construction, possibilities and ways of using them.

19

Maintenance Evaluation and Optimization of a Multi-State System Based on a Dynamic Bayesian Network

Dahia Zakaria, Bellaouar Ahmed, Dron Jean-Paul

Management and Production Engineering Review

|

2021

|

Vol. 13, No. 3

3--14

EN

Nowadays, the main challenge in maintenance is to establish a dynamic maintenance strategy to significantly track and improve the performance measures of multi-state systems in terms of production, quality, security and even the environment. This paper presents a quantitative approach based on Dynamic Bayesian Network (DBN) to model and evaluate the maintenance of multi-state system and their functional dependencies. According to transition relationships between the system states modeled by the Markov process, a DBN model is established. The objective is to evaluate the reliability and the availability of the system with taking into account the impact of maintenance strategies (perfect repair and imperfect repair). Using the proposed approach, the dynamic probabilities of system states can be determined and the subsystems contributing to system failure can also be identified. A practical application is demonstrated by a case study of a blower system. Through the result of the diagnostic inference, to improve the performances of the blower, the critical components C, F, W, and P should be given more attention. The results indicate also that the perfect repair strategy can improve significantly the performances of the blower, while the imperfect repair strategy cannot degrade the performances in comparison to the perfect repair strategy. These results show the effectiveness of this approach in the context of a predictive evaluation process and in providing the opportunity to evaluate the impact of the choices made on the future measurement of systems performances. Finally, through diagnostic analysis, intervention management and maintenance planning are managed efficiently and optimally.

20

Degrading systems availability analysis: analytical semi-Markov approach

Kumar Varun, Kumar Girish, Singh Rajesh Kumar, Soni Umang

Eksploatacja i Niezawodność

|

2021

|

Vol. 23, no. 1

195--208

EN

This paper deals with modeling and analysis of complex mechanical systems that deteriorate with age. As systems age, the questions on their availability and reliability start to surface. The system is believed to suffer from internal stochastic degradation mechanism that is described as a gradual and continuous process of performance deterioration. Therefore, it becomes difficult for maintenance engineer to model such system. Semi-Markov approach is proposed to analyze the degradation of complex mechanical systems. It involves constructing states corresponding to the system functionality status and constructing kernel matrix between the states. The construction of the transition matrix takes the failure rate and repair rate into account. Once the steady-state probability of the embedded Markov chain is computed, one can compute the steady-state solution and finally, the system availability. System models based on perfect repair without opportunistic and with opportunistic maintenance have been developed and the benefits of opportunistic maintenance are quantified in terms of increased system availability. The proposed methodology is demonstrated for a two-stage reciprocating air compressor with intercooler in between, system in series configuration.