FMEA analysis is a tool of quality improvement that has been widely used for decades. Its classical version prioritizes risk of failure by risk priority number (RPN). The RPN is a product of severity ...(S), occurrence (O), and detection (D), where all of the factors have equal levels of significance. This assumption is one of the most commonly criticized drawbacks, as it has given unreasonable results for real-world applications. The RPN can produce equal values for combinations of risk factors with different risk implications. Another issue is that of the uncertainties and subjectivities of information employed in FMEA analysis that may arise from lack of knowledge, experience, and employed linguistic terms. Many alternatives of risk assessment methods have been proposed to overcome the weaknesses of classical FMEA risk management in which we can distinguish methods of modification of RPN numbers of employing new tools. In this study, we propose a modification of the traditional RPN number. The main difference is that severity and occurrence are valued based on subfactors. The detection number remained unchanged. Additionally, the proposed method prioritizes risk in terms of implied risk to the systems by implementing functional failures (effects of potential failures). A typical fluid power system was used to illustrate the application of this method. The method showed the correct failure classification, which meets the industrial experience and other research results of failures of fluid power systems.
Hydraulic systems are widely used in the aeronautic, machinery, and energy industries. The functions that these systems perform require high reliability, which can be achieved by examining the causes ...of possible defects and failures and by taking appropriate preventative measures. One of the most popular methods used to achieve this goal is FMEA (Failure Modes and Effects Analysis), the foundations of which were developed and implemented in the early 1950s. It was systematized in the following years and practically implemented. It has also been standardized and implemented as one of the methods of the International Organization for Standardization (ISO) 9000 series standards on quality assurance and management. Apart from wide application, FMEA has a number of weaknesses, which undoubtedly include risk analysis based on the RPN (Risk Priority Number), which is evaluated as a product of severity, occurrence, and detection. In recent years, the risk analysis has been very often replaced by fuzzy logic. This study proposes the use of matrix analysis and statistical methods for performing simplified RCA (Root Cause Analysis) and for classification potential failures for a variable delivery vane pump. The presented methodology is an extension of matrix FMEA and allows for prioritizing potential failures and their causes in relation to functions performed by pump components, the end effects, and the defined symptoms of failure of the vane pump.
The key to the functioning of enterprises in today's market is the concept of flexibility, which is mainly associated with adapting to very dynamically changing customer requirements. The basis for ...this approach is, among others, the realisation of serial production, products created for the customer's order in the quantity and time defined in orders. The LEAN Managemnt and LEAN production approach is a solution dedicated to meeting market assumptions. The LEAN concept, which both in the organization of production and management is focused on dynamic response to changes in the environment. The term LEAN represents numerous improvements to the organization, tools and techniques used to reduce and eliminate individual processes (or parts thereof) that are unnecessary activities. The key to analysing entire processes and defining unnecessary activities is thorough observation and selection of dedicated solutions. In the set of LEAN tools, you can find a lot of possibilities, from organization of a workstation itself, to a thorough quantitative analysis of times and process sequences, from simple facilities to complex technological solutions. The article presents the results of the assembly process analysis, indicates the point of product differentiation (marking for the client) and presents the map of organizational and preparatory activities for this process. The presented results are part of the activities within organization of the LEAN approach, currently having priority for the Research entity organisation improvement team.
Today’s market determinants and most importantly, very dynamically changing customer requirements significantly shortened the product life cycle. This situation reflects in companies by common ...extension of the assortment offered and personalised serial production. The result of a flexible approach to market changes is the implementation of LEAN concept, which, both in terms of management and production aims to develop efficiency within an organisation, which will then enable quick and dynamic response to changes in the environment. The popularity of LEAN concept (in management and production) among managers comes from its universality and a wide range of instruments used to maximise the use of existing potential. The main assumptions of LEAN concept are aimed at the maximum use of an organisation’s resources, defining the activities necessary to execute an order and identifying the areas generating losses and then minimising them and eventually eliminating. LEAN concept is based on flagship-main tools for identification and modernisation of processes, the difficulty in using them results from the need to recognise and select the most effective ones that meet the expectations of a given organisation. The article presents issues related to the first stage of implementing LEAN concept in a company’s structures, i.e. identification of opportunities and selection of appropriate tools.
In aquaculture, new production technologies are under development and testing. One promising type of technology is the closed floating cage. Egget® is one of these newly developed technologies, which ...is egg-shaped and vertically floating. One of the challenges is to determine hydrodynamic loads. Therefore, this study focuses on estimating the resistance and the resistance coefficient for steady flow with various velocities and Reynolds numbers on a scaled model. It includes simulations using Computational Fluid Dynamics (CFD) for two depths and experiments in the MarinLab at Western Norway University of Applied Sciences (HVL). As the cage is partially submerged, the simulations are performed using the Volume of Fluid (VOF) technique for modeling free surface flow. The comparison of experimental and simulation results show good agreement.
This paper presents an analysis of potential failures of hydraulic components on the example of a hydraulic gear pump with the use of instruments of quality management. The “five why” method was ...implemented to evaluate failures as well as the bases for the causes which have an influence on pumps failures. The causes are connected with operation condition of gear pumps and the quality of working fluid. In the next step, by using a systematic diagram, appropriate improvement actions for the identified causes were determined.
The main purpose of the work which was carried out and is presented in this paper was to examine the possibility of using fuzzy logic inference for conducting a risk analysis with the help of a ...sheet-based Failure Mode and Effects Analysis method (FMEA). At the beginning, the main features of the analysed method were presented, with particular emphasis put on the Risk, Priority and Number parameters. Then, a proposal has been made which suggests using Matlab Fuzzy Logic Toolbox package in order to convert the factors into the form of fuzzy sets and to define rules for fuzzy inference process has been made. Finally, the created fuzzy logic model was used to present an example analysis of a turbocharger failure in the fuzzified form.
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