Showing 3 results for Fmea
Mohsen Omidvar, Fereshteh Nirumand,
Volume 7, Issue 1 (4-2017)
Abstract
Introduction: FMEA method is one of the most used techniques in risk assessment and prioritization. But, due to several reasons, its application has been limited to the real-world settings. The aim of this study was to deal with these restrictions using the combined fuzzy (in terms of the Z-numbers) and grey (in terms of the grey relational analysis) theories.
Material and Method: The current study is an analytical cross-sectional survey that was performed to prioritize the failure modes of the overhead cranes. Initially, an FMEA team including 4 specialists was established. Then, the opinions of the team members were gathered in terms of the Z-numbers and the weights of the risk factors (O، S, and D) were determined using the fuzzy AHP method. Finally, the failure modes were prioritized using the GRP method.
Result: From 13 cases of the identified failure modes, the conventional FMEA was assigned equal priority to the 7 cases and as a result 9 risk priorities were determined. But, in the proposed method, because of the elimination of the restrictions of conventional FMEA, 13 risk priorities were assigned to the failure modes.
Conclusion: Relying upon the fuzzy AHP, Z-numbers and GRP method, the proposed method dealt with the equal weights of the risk factors, fuzziness of the data (expert’s judgments) and the prioritization of the failure modes. The proposed method has more capabilities in relation to the conventional FMEA for prioritization of the failure modes.
Manouchehr Omidvari, Zahra Rafighi, Samareh Omidvari,
Volume 10, Issue 4 (11-2020)
Abstract
Introduction: The main purpose of this study was to identify and evaluate environmental problems and their ranking and to determine the conceptual model of environmental impact assessment (EIA) in industrial parks. Accordingly.
Material and Methods: In this study, environmental infrastructure issues were classified into five sections. The decision-making trial and evaluation laboratory (DEMATEL) technique was also employed to establish the relationships between the criteria. Moreover, the analytic network process (ANP) was utilized to determine their weight.
Results: Examining the internal relationships between the variables correspondingly revealed that cultural and economic criteria were the most influential. On the other hand, the biological criterion was very effective. The ANP results also showed that the “low share of environmental investment” as an indicator was an economic criterion with a normal weight of 0.80, which was of utmost importance among the other defined cases.
Conclusion: It was concluded that the definition of conceptual models in EIA processes can make it possible to examine and analyze the criteria and indicators affecting evaluation processes.
Rajabali Hokmabadi, Esmaeil Zarei, Ali Karimi,
Volume 12, Issue 3 (9-2022)
Abstract
Introduction: Failure modes and effects analysis (FMEA) method is used in industries to identify, assess and prioritize risks. Multi-criteria decision-making methods (MCDM) select the best option from different criteria. Therefore, this study aims to identify, assess and prioritize risks using FMEA based on SWARA-VIKOR multi-criteria decision-making methods in a gas pressure reduction station.
Material and Methods: In this descriptive and analytical study, stepwise weight assessment ratio analysis (SWARA) and decision-making optimization and compromise solution (VIKOR) methods were used to rank the risks of failure modes identified in FMEA. SWARA method was employed to determine the severity, probability and discovery weights, and VIKOR technique was applied to rank the failure modes of the system equipment. Finally, an operational example of the pressure reduction station was presented to show the application and feasibility of the proposed model. A comparative study was conducted to confirm the practicality and effectiveness of the proposed model.
Results: In total, 35 main failure modes were identified in the pressure reduction station. Failure of regulator sleeve and safety valve and regulator diaphragm rupture were assigned the first, second and third ranks of risk priority, respectively. The sensitivity analysis results showed the proposed approach had desirable stability and only the failure mode of increasing the heater flame temperature was very sensitive to changes in the weight of the criteria. Results of ranking the failure modes of the station indicated there were many changes in the ranking of failure modes based on the proposed approach.
Conclusion: The proposed approach could provide more reasonable and accurate results for ranking risks because the criteria were weighed step by step based on the experts’ opinion.
