A multiple-criteria decision analysis for criticality of boiler tube failures in interval type-2 fuzzy environment

This paper presents a multi-factor decision-making approach for prioritising criticality of failure modes as an alternative to traditional approach of failure mode effect and criticality analysis (FMECA). A review of the literature reveals that although a number of studies have been done on these issues, but none of them have explicitly studied the variations in expert's opinion (intra-personal uncertainty) and the variations in the understanding among experts (inter-personal uncertainty) together. To deal with this problem, this literature proposes a new fuzzy FMECA approach based on IT2 fuzzy sets, which has the ability to capture both intra-personal and inter-personal uncertainty. This approach introduces a more accurate representation of the aggregated data by presenting variations among the individual judgements into type-2 fuzzy numbers, allowing suitable weights for each risk factor by decision makers and thereby developing a flexibility for analysis. The proposed method is applied to evaluate the criticality of different failure modes of boiler tubes of a coal-fired thermal power plants. Interval type-2 fuzzy sets with signed distances, a multi criteria decision-making tool, is used to evaluate the criticalities of the different failure modes (alternatives) of the system.