14 research outputs found
ASSESSMENT OF THE INFLUENCE OF PREVENTIVE MAINTENANCE ON THE RELIABILITY AND AVAILABILITY INDEXES OF DIESEL LOCOMOTIVES
Modernisation of LEMACH 6 Design-Research Method as a Reliability Engineering Tool
The article presents the developed design-research method for mechanical objects, which is a modernisation of the sequential-iterative design method LEMACH 6. As part of the design process organised by method guidelines, a number of activities related to designed object鈥檚 reliability testing and engineering were included. The article charac-terises selected design methods, with particular emphasis on the LEMACH 6 method. Next, assumptions were made regarding the development and use of the proposed solution, and a diagram and detailed analysis of individual elements of the new method were presented. The developed method enables the organisation of design works, allowing one to rapidly create new solutions and avoid mistakes during designing
Journal of the European TRIZ Association - INNOVATOR
Selected papers presented at the 17th International TRIZ Future Conference
Bridging Creativity in Science, Entrepreneurship, Industry and Education
October 4-6, 2017, Lappeenranta, Finland
Metoda szybkiej oceny niezawodno艣ci uk艂ad贸w typu k z n
IEC 61508 standard could be used in the evaluation of safety of the k-out-of-n technical systems, including elements which may remain in one out of four different reliability states. Such a model leads to the huge complexity of analytical calculations and the limitations of its practical application possibilities. Therefore, a computerised method using Markov processes for estimating the reliability of k-out-of-n systems was developed. The algorithmization of the applied computational procedure was performed. It allowed one to analyse systems including a huge number of elements. An algorithm that may be applied for complex k-out-of-n systems was developed and used for exemplary calculations. The developed method was verified by comparing the obtained results with the ones obtained from analytical method as well as simulation method. The compatibility of results obtained in the two methods confirms the correctness of the developed procedure and proposed computer program which now offers the possibility of doing calculations for k-outof-n structures with more than three elements required for the system鈥檚 proper functioning and significantly accelerates calculations. Reliability and safety are priorities in the operation of technical systems. This decides of the applicability of the calculation methods described. The operational safety aspects are of particular significance in cases when the occurrence of a failure is a hazard to people鈥檚 health and life, ecological risk or considerable financial loss.Norma IEC 61508 mo偶e by膰 stosowana do oceny poziomu bezpiecze艅stwa uk艂ad贸w technicznych typu k z n, w kt贸rych elementy mog膮 pozostawa膰 w jednym z czterech r贸偶nych stan贸w. Przyj臋cie takiego modelu prowadzi do ogromnej z艂o偶ono艣ci oblicze艅 analitycznych i ogranicze艅 w praktycznych mo偶liwo艣ciach ich zastosowania. W zwi膮zku z tym, do oceny niezawodno艣ci tego typu uk艂ad贸w opracowano komputerow膮 metod臋 wykorzystuj膮c膮 procesy Markowa. Nast臋pnie przeprowadzono algorytmizacj臋 opracowanej procedury obliczeniowej, co pozwoli艂o na analiz臋 system贸w obejmuj膮cych du偶膮 liczb臋 element贸w. Na podstawie opracowanego algorytmu przeprowadzono przyk艂adowe obliczenia. Opracowan膮 metod臋 zweryfikowano por贸wnuj膮c otrzymane wyniki z wynikami uzyskanymi metod膮 analityczn膮 oraz metod膮 symulacyjn膮. Zgodno艣膰 wynik贸w uzyskanych w tych dw贸ch metodach potwierdza prawid艂owo艣膰 opracowanej procedury i proponowanego programu komputerowego, kt贸ry oferuje obecnie mo偶liwo艣膰 wykonywania oblicze艅 dla struktur typu k z n z wi臋cej ni偶 trzema elementami wymaganymi do prawid艂owego funkcjonowania ca艂ego systemu i znacz膮co przyspiesza obliczenia. Niezawodno艣膰 i bezpiecze艅stwo s膮 priorytetami w eksploatacji system贸w technicznych i maj膮 szczeg贸lne znaczenie w przypadkach, gdy wyst膮pienie awarii stanowi zagro偶enie dla zdrowia i 偶ycia ludzi, powoduje ryzyko ekologiczne lub znaczne straty finansowe
Model adaptacyjnej strategii prewencyjnej odnowy z艂o偶onych obiekt贸w technicznych
The paper presents results of the analysis of the developed models for complex technical objects preventive maintenance scheduling. Models based on two different sets of assumptions were developed. The general problem solved was to determine the joint time of preventive renewal for a group of parts or subassemblies. The purpose of the first model (the model of scheduled preventive maintenance strategy) is to determine the profitability of constant application of a previously developed preventive maintenance schedule for a part undergoing post-failure renewal. The second model (the model of adaptive strategy of a system鈥檚 preventive maintenance) allows one to determine a new joint time of preventive renewal for a group of parts each time when one of them is undergoing a post-failure renewal. The initial preventive maintenance strategy for each part or subassembly was obtained using typical tools for maintenance planning (decision-random models based on dynamic programming and Bellman鈥檚 principle of optimality). Exemplary simulation calculations with the use of both models were made and their results presented as the total maintenance costs estimated for the renewal strategies developed. The object of the analysis were the chosen geometrical features of a rail vehicle wheel changing due to its wear during operation. Based on this kind of analysis, one can choose a better preventive maintenance model for a specific application area.W artykule przedstawiono wyniki analizy opracowanych modeli do planowania odnowy profilaktycznej z艂o偶onych obiekt贸w technicznych, kt贸re oparto o dwa r贸偶ni膮ce si臋 od siebie zestawy za艂o偶e艅. Rozwi膮zywany problem dotyczy okre艣lenia wsp贸lnego czasu odnowy profilaktycznej grupy cz臋艣ci lub podzespo艂贸w z艂o偶onego obiektu. Pierwszy z opracowanych modeli (model planowej strategii odnowy prewencyjnej) pozwala okre艣li膰 zasadno艣膰 przeprowadzenia ustalonego wcze艣niej, planowego odnowienia prewencyjnego cz臋艣ci obiektu, kt贸ra zosta艂a ju偶 odnowiona poawaryjnie. Drugi model (model adaptacyjnej strategii odnowy prewencyjnej) umo偶liwia wyznaczenie najbli偶szego wsp贸lnego czasu odnowy profilaktycznej grupy cz臋艣ci, z kt贸rych jedna aktualnie podlega odnowie poawaryjnej. Pocz膮tkowe (wyj艣ciowe) strategie odnowy profilaktycznej ka偶dej cz臋艣ci b膮d藕 podzespo艂u wyznaczone zosta艂y za pomoc膮 standardowych narz臋dzi do planowania odnawiania profilaktycznego (modeli decyzyjno-losowych wykorzystuj膮cych programowanie dynamiczne Bellmana). Pos艂uguj膮c si臋 opracowanymi modelami odnowy, przeprowadzono przyk艂adowe obliczenia symulacyjne, kt贸rych wyniki przedstawiono w postaci ca艂kowitych koszt贸w obs艂ugiwania dla ka偶dej z uzyskanych strategii. Przedmiotem analizy by艂y wybrane cechy geometryczne ko艂a pojazdu szynowego, kt贸rych warto艣ci zmieniaj膮 si臋 na skutek zu偶ycia w procesie eksploatacji. Na podstawie tego rodzaju analiz mo偶na wybra膰 lepszy (tj. efektywniejszy ekonomicznie) z modeli dla konkretnego zastosowania w praktyce
Assessment of the influence of preventive maintenance on the reliability and availability indexes of diesel locomotives
The article investigates the influence of preventive maintenance on the reliability and availability indexes of the railway means of transport, which also determine the economic aspects of their operation and maintenance. The research was done using the method based on fault tree analysis (FTA) and Monte Carlo simulation. The authors performed a cause and effect analysis of the occurrence of undesirable events during the operation of selected vehicles. They identified the weakest components of the rail vehicle that affect the downtime and mean availability most significantly. Specialized software including Weibull++, BlockSim, and MiniTab aided calculations were used to illustrate the application of the results of a modernization project involving a 6Dg diesel locomotive, carried out in cooperation with the biggest Polish rail carrier. The applicability of the proposed tools has been verified on the example of a selected sample of 75 diesel locomotives employing data on their use and maintenance acquired in the real operation process. The obtained results indicate that the proposed approach can be particularly useful in practice when assessing the applied rail vehicle maintenance strategy, and while developing new strategies and selecting the best one to implement
A Simulation Model for Regenerated Objects with Multiparameter Evaluation of Technical Condition Reliability Estimation
The paper presents the developed simulation model allowing one to estimate the reliability of objects whose technical condition is described by a set of geometrical features. Their values change during operation because of the wearing processes of the part under consideration. The operational availability (or unavailability) of a technical object is determined by the evaluation conducted using a set of criteria referring to its analysed features. In addition, the proposed model enables one to take into account the regeneration of such objects