A New Approach for Prioritization of Failure Modes in Design FMEA using ANOVA

The traditional Failure Mode and Effects Analysis (FMEA) uses Risk Priority Number (RPN) to evaluate the risk level of a component or process. The RPN index is determined by calculating the product of severity, occurrence and detection indexes. The most critically debated disadvantage of this approach is that various sets of these three indexes may produce an identical value of RPN. This research paper seeks to address the drawbacks in traditional FMEA and to propose a new approach to overcome these shortcomings. The Risk Priority Code (RPC) is used to prioritize failure modes, when two or more failure modes have the same RPN. A new method is proposed to prioritize failure modes, when there is a disagreement in ranking scale for severity, occurrence and detection. An Analysis of Variance (ANOVA) is used to compare means of RPN values. SPSS (Statistical Package for the Social Sciences) statistical analysis package is used to analyze the data. The results presented are based on two case studies. It is found that the proposed new methodology/approach resolves the limitations of traditional FMEA approach.

Authors:

• Sellappan Narayanagounder
• Karuppusami Gurusami

Keywords:

• Failure mode and effects analysis
• Risk priority code
• Critical failure mode
• Analysis of variance.

References:

[1] K. G. Johnson and M. K. Khan, "A Study into the use of the Process
Failure Mode and Effects Analysis (PFMEA) in the Automotive Industry
in the UK", Journal of Materials Processing Technology, 2003, vol.139,
pp. 348-356.
[2] John B. Bowles and C. Enrique Peláez, "Fuzzy logic prioritization of
failures in a system failure mode, effects and criticality analysis",
Journal of Reliability Engineering and System Safety, 1995, vol. 50, pp.
203-213.
[3] D. H. Stamatis, Failure Mode and Effects Analysis: FMEA from Theory
to Execution, Productivity Press India Pvt. Ltd., Madras, 1997.
[4] Paul Palady, Failure Modes and Effects Analysis: Predicting &
Preventing Problems before they Occur, PT Publications Inc., FL 33409,
1995.
[5] Rudiger Wirth, Bernd Berthold, Anita Kramer and Gerhard Peter,
"Knowledge-based Support of System Analysis for the Analysis of
Failure Modes and Effects", Journal of Artificial Intelligent, 1996, vol.
9, no. 3, pp. 219-229.
[6] Fiorenzo Franceschini and Maurizio Galetto, "A New Approach for
Evaluation of Risk Priorities of Failure Modes in FMEA", International
Journal of Production Research, 2001, vol.39, no.13, pp. 2991-3002.
[7] N. Ravishankar and B. S. Prabhu,"Modified Approach for Prioritization
of Failures in a System Failure Mode and Effects Analysis",
International Journal of Quality and Reliability Management, 2001, vol.
18, no. 3, pp.324-335.
[8] Anand Pillay and Jin Wang, "Modified failure mode and effects analysis
using approximate reasoning", Journal of Reliability Engineering and
System Safety, 2003, vol. 79, pp. 69-85.
[9] Seung J. Rhee, and Kosuke Ishii, "Using Cost based FMEA to Enhance
Reliability and Serviceability", Journal of Advanced Engineering
Informatics, 2003, vol.17, pp. 179-188.
[10] S. M. Seyed-Hosseini, N. Safaei and M. J. Asgharpour, "Reprioritization
of failures in a system failure mode and effects analysis by decision
making trial and evaluation laboratory technique", Journal of Reliability
Engineering & System Safety, 2006, vol. 91, issue 8, pp. 872 - 881.
[11] V. P. Arunachalam and C. Jegadheesan, "Modified Failure Mode and
effects Analysis: A Reliability and Cost-based Approach", The ICFAI
Journal of Operations Management, 2006, pp. 7-20.
[12] Chensong Dong, "Failure mode and effects analysis based on fuzzy
utility cost estimation", International Journal of Quality & Reliability
Management, 2007, vol. 24, issue 9, pp. 958 - 971.
[13] Jih Kuang Chen, "Utility Priority Number Evaluation for FMEA",
Journal of Failure Analysis and Prevention, 2007, vol. 7, no. 5, pp. 321 -
328.
[14] Ying-Ming Wang, Kwai-Sang Chin, Gary Ka Kwai Poon and Jian-Bo
Tang, "Risk evaluation in failure mode and effects analysis using fuzzy
weighted geometric mean", Journal of Expert Systems with
Applications, to be published.