MULTICRITERIA RANKING OF COMPONENTS ACCORDING TO THEIR PRIORITY FOR INSPECTION

Inspection can play a significant role in reducing the likelihood of unexpected structural failures. However, for many critical components and systems that are required to maintain pressure boundary integrity or that are subjected to severe service conditions, inspection requirements for these vital components are either established based upon prior experience and engineering judgment or are non-existent. Most inspection requirements or guidelines, if they exist, are usually established with only an implicit consideration of risk. Recent catastrophic structural failures over the past decade highlight the societal need to relate more explicitly risk-based methods and uncertainty with inspection programs. In this study, fuzzy multi-criteria risk-based ranking methodology with uncertainty evaluation and propagation was developed for the purpose of developing inspection strategies. The methodology results in establishing priority ranking lists for components where actions need to be taken accordingly. The ranking priority list for inspection purposes was based on the assessments of the probabilities of failure, resulting consequences, expected human and economic risks and thc uncertainties associated with these assessments. The fuzzy-based multi-criteria decision making method was utilized for prioritizing the components of a system for inspection purposes. Interval analysis and logic diagram techniques were utilized to propagate uncertainties for the process of assessing the magnitude of failure probabilities, consequences and risk due to failure.