Wyniki wyszukiwania - BazTech

1

An approach in determining the critical level of degradation based on results of accelerated test

Hoang Anh D., Vintr Zdenek, Valis David, Mazurkiewicz Dariusz

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 2

330--337

EN

Nowadays, systems are more complex and require high reliability for their components, especially critical system components. Therefore, to avoid serious damage, system are often replaced before the actual failure. The replaced parts are considered to have “soft failure”, and the limit in which the parts are replaced is known as the critical level of the degradation process. Determining the appropriate value of the critical level for a product is an important problem in their exploitation, as well as for predicting the Mean Time to Failure (MTTF) or Remaining Useful Lifetime (RUL) of this product based on the degradation data by the mathematical models. In this article, an approach in determining the critical levels based on failure data from an accelerated test is introduced. This approach is applied with the degradation process of Light-Emitting Diodes (LED) in an accelerated test and a type of Wiener process-based model is used to predict the MTTF or RUL of LED based on their degradation data and the found critical level.

2

The use of the risk matrix method for assessing the risk of implementing rail freight services

Szaciłło Lucyna, Krześniak Mirosław, Jasiński Dobromir, Valis David

Archives of Transport

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2022

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Vol. 64, iss. 4

89--106

EN

The article presents a proposal for the use of a risk matrix for assessing the safety of the implementation of rail freight transport. The starting point for considerations related to risk assessment is the conditions arising from the business need and the obligation of entities operating in the railway market to ensure the safety of the implementation of freight tasks. The authors presented selected literature within the framework of the issues discussed. The layers of risk assessment, which include the analytical layer, the decision layer and the elimination layer, indicate the possibility of considering the problem of risk assessment from different perspectives. The identification of direct causes and consequences of undesirable events during the implementation of rail freight transport was also made. The article describes one of the methods of risk management which is the risk matrix. The authors stressed that the construction of a risk matrix should be preceded by an analysis of the factors that affect the safety of rail transportation. This is possible by determining their probability of occurrence and setting values for the consequences of adverse events. The article divides the assignment of levels of adverse events to a five-level risk matrix (slight, low, medium, high, very high). Also presented is a case study considering the risk assessment of rail freight transport in Poland using the risk matrix method for railway accidents in the area of railway lines. Thanks to the development of the risk matrix, a risk management strategy can be used. The last part of the article is a summary, which highlights the possibility of applying the presented approach to risk assessment among entities operating in the rail transport market.

3

Forecasting study of mains reliability based on sparse field data and perspective state space models

Valis David, Forbelská Marie, Vintr Zdeněk

Eksploatacja i Niezawodność

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2020

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Vol. 22, no. 2

179--191

EN

The elements of critical infrastructure have to meet demanding dependability, safety and security requirements. The article deals with the prognosis of water mains reliability while using sparse irregular filed data. The data are sparse because the only thing we know is the number of mains failures during a given month. Since it is possible to transform the data into a typical reliability measure (rate of failure occurrence – ROCOF), we can examine the course of this measure development in time. In order to model and predict the ROCOF development, we suggest novel single and multiple error state space models. The results can be used for i) optimizing mains operation and maintenance, ii) estimating life cycle cost, and iii) planning crisis management.

PL

Elementy infrastruktury krytycznej muszą spełniać wysokie wymagania w zakresie niezawodności, bezpieczeństwa i ochrony. Artykuł dotyczy prognozowania niezawodności sieci wodociągowej przy wykorzystaniu nieregularnie rejestrowanych rzadkich danych. Wykorzystane w pracy dane są rzadkie, ponieważ dostarczają jedynie informacji na temat liczby uszkodzeń wodociągu w danym miesiącu. Przekształcenie tych danych w typową miarę niezawodności (wskaźnik występowania uszkodzeń – ROCOF), pozwala zbadać przebieg rozwoju tej miary w czasie. Rozwój ROCOF można modelować i przewidywać za pomocą zaproponowanych w pracy innowacyjnych modeli przestrzeni stanów uwzględniających pojedynczy błąd lub wiele błędów. Uzyskane wyniki można wykorzystać do i) optymalizacji pracy i eksploatacji sieci wodociągowej, ii) szacowania kosztów cyklu życia, oraz iii) planowania zarządzania kryzysowego.

4

Utilisation of selected regression functions for oil data assessment

Valis David

Zeszyty Naukowe WSEI. Seria Transport i Informatyka

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2014

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T. 4, nr 1

103--116

EN

The paper deals with application of selected analytical methods for analysing field data from heavy off-road military vehicles. It is the vehicle engine and its oil data which are explored for further utilisation. The pieces of information from the engine oil are interpreted in form of deteriorated oil characteristics and polluting particles in oil. These pieces of information have good technical and analytical potential. However they are not always used for system condition determination therefore has not been explored well yet. Thanks to well working the diagnostics there are the data collected in some fields but never calculated and used of estimation neither prediction. The novelty is to providing inputs for helping to change e.g. the system maintenance policy, system operation and mission planning.

PL

Wzrastające wymagania niezawodności i trwałości środków transportu determinują zastosowanie nowoczesnych systemów diagnostycznych oraz minimalizacji operacji obsługowych. Jednym ze sposobów pozyskania sygnałów diagnostycznych jest okresowe badanie składu oleju silnikowego. Zdaniem autora jest to jeden ważniejszych źródeł pozyskani informacji o stanie obiektu technicznego. W artykule przedstawiono metodologię wykorzystania informacji diagnostycznej pozyskanej z badania oleju silnikowego do optymalizacji czynności obsługowych.

5

Selected mathematical functions used for oil field data information mining

Valis David

Zeszyty Naukowe WSEI. Seria Transport i Informatyka

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2013

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T. 3, nr 1

23--33

EN

The paper deals with application of selected analytical methods in order to analyse field data from heavy off-road military vehicles. The information from the engine oil are interpreted in form of polluting particles like particles from wear process (e.g. Fe, Pb, Cu, etc.) and particles from oil deterioration itself (like Mn, Si, Zn, etc.). These particles can give us information both about system state and about oil state. We have reasonable set of oil data from field operation available. Based on the data we assume being able to determine the system condition and propose some changes (e.g. in residual operation life, in maintenance modifications in the intervals, in mission planning, etc.). Selected methods like regression analysis and fuzzy inference system are used for the data assessment.

PL

W artykule przedstawiono zastosowanie wybranych metod analitycznych do oceny stanu technicznego ciężkich wojskowych pojazdów terenowych. Przedstawiono sposoby i metody interpretacji zawartości pierwiastków (np. Fe, Pb, Cu) w przepracowanym oleju silnikowym. Autorzy uważają, że cząstki te niosą informację o stanie systemu, w którym pracuje olej oraz o samym oleju. Bazując na wynikach analizy oleju istnieje możliwość oceny stanu technicznego systemu mechanicznego oraz wyznaczenie czasów przeglądów i działań prewencyjnych.