ANP/RPN: a multi criteria evaluation of the Risk Priority Number

Abstract

This paper presents an advanced version of the failure mode effects and criticality analysis (FMECA), whose capabilities are enhanced; in that the criticality assessment takes into account possible interactions among the principal causes of failure. This is obtained by integrating FMECA and Analytic Network Process, a multi-criteria decision making technique. Severity, Occurrence and Detectability are split into sub-criteria and arranged in a hybrid (hierarchy/network) decisionstructure that, at the lowest level, contains the causes of failure. Starting from this decision-structure, the Risk Priority Number is computed making pairwise comparisons, so that qualitative judgements and reliable quantitative data can be easily included in the analysis, without using vague and unreliable linguistic conversion tables. Pairwise comparison also facilitates the effort of the design/maintenance team, since it is easier to place comparative rather than absolute judgments, to quantify the importance of the causes of failure. In order to clarify and to make evident the rational of the final results, a graphical tool, similar to the House of Quality, is also presented. At the end of the paper, a case study, which confirms the quality of the approach and shows its capability to perform robust and comprehensive criticality analyses, is reported.

A Modified Metric of FMEA for Risk Evaluation Based on ASIL of Safety System

“…Liu et al(2011) and Liu et al(2012) explained several shortcomings such as possible same RPN values for different risk implications, ignored differency of relative importance among the three risk factors, possible misleading due to mathematical product of meaningless ordinal numbers, and etc. Similar drawbacks are pointed out by many authors like Chin et al(2009aChin et al( , 2009b, Chang and Sun(2009), Abdelgawad and Fayek(2010), , Tay and Lim(2010), Cheng(2010, 2011), Zhang and Chu(2011), Gargama and Chaturvedi(2011), Zammori and Gabbrielli(2011), Yang et al(2011), Kutlu and Ekmekcioglu(2012), Xiao et al(2011) and so on. The frequently mentioned limitations may be summarized as (i) unrealistic assumption of equally weighted RPN elements, (ii) same RPN values possible even with totally different risk context, (iii) possible inconsistent rating among FMEA team members, and (iv) lack of scientific basis for RPN calculation.…”

FlowSort-GDSS – A novel group multi-criteria decision support system for sorting problems with application to FMEA

“…The same technique was also used later in Carmignani (2009). Zammori and Gabbrielli (2012) further decomposed the occurrence, severity and detectability into subcriteria and used analytic network process (ANP) to evaluate their weights. In addition to the multiplication reported in Eq.…”

Hybrid MCDM based methodology for selecting the optimum maintenance strategy for ship machinery systems

“…AHP has been chosen mainly because it provides a framework to manage conflicting multicriteria problems involving both qualitative and quantitative facets. Additionally the quality of expert opinions involved in the process can be mathematically proven using the consistence index (Zammori and Gabbrielli 2012;Saaty 1980). However AHP has limitations one of the main ones being the computational complexity in the analysis process when the decision criteria for selecting alternatives is more than 15.…”

“…From the analysis, condition based maintenance (CBM) was considered as the optimum maintenance strategy for the cruise ship diesel generator. However some doubts remain with regard to the practical use of the fuzzy approach because of the difficulty in testing and developing extensive sets of fuzzy rules (Zammori and Gabbrielli 2012;Braglia 2000). Additionally some important decision criteria such as applicability for maintenance strategy selection especially when dealing with the problem from the system failure modes perspective were not taken into account by Lazakis et al (2012).…”