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Development and Improvement of Failure Modes and Effects Analysis under Uncertainty (Fuzzy- epistemic) for Maintenance Planning

Seiti, Hamid Reza | 2013

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44481 (01)
  4. University: Sharif University Technology
  5. Department: Industrial Engineering
  6. Advisor(s): Houshmand, Mahmoud; Imani, Din Mohammad
  7. Abstract:
  8. Most of designers, manufacturers and all of the agents involved in product development processes are using the failure modes and effects analysis to reduce the potential failure of new products. Risk priority number (RPN) is calculated by multiplying occurrences (O), severity (S) and detection (D). This value is used as FMEA performance measure. Although the value of the RPN gives a good sight to product design and development, but firstly it ignores relative importance of the risk factors, secondly it is difficult to calculate the RPN value where there is shortage of product failure records and thirdly it is difficult to express risk factors with crisp values. In the above conditions FMEA measure of performance is obtained in an uncertainty conditions, therefore the FMEA measure of performance should consider uncertainty conditions. There are two types of uncertainties: fuzzy uncertainty and epistemic uncertainty. Fuzzy uncertainty deals with uncertainties in expert’s linguistic expressions to evaluate failure modes, whereas epistemic uncertainty covers the lack and shortage of equipment failure records. In this work two separate models were developed to evaluate failure modes. They consider the relative weight of risk factors. The first model is fuzzy axiomatic design (FAD). FAD is applied for evaluating failure modes under fuzzy conditions. This model also uses fuzzy analytic hierarchy process for specifying the weight of risk factors. To facilitate of FAD model implementation a practical algorithm for group decision support system is presented. The second model is Dempster Shafer-Fuzzy Axiomatic Design (DS-FAD). This model uses extended fuzzy axiomatic design and Dempster Shafer method to evaluate failure modes under epistemic uncertainty. At the end, two case studies are solved by proposed models. The results show good performance of proposed models in solving failure modes and effect analysis related problems and ease in implementing it
  9. Keywords:
  10. Failure Mode And Effect Analysis (FMEA) ; Fuzzy Axiomatic Design ; Epistemic Uncertainty ; Evidence Theory ; Risk Management

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