Component reliability assessment using quantitative and qualitative data

The estimation of a component failure rate depends on the availability of p lant specific numerical data. The purpose of this study was development of a new method that explicitly includes numerical and linguistic information into the assessment of a specific failure rate. The basis of the method is the Bayesian updating approach. A prior distribution is selected from a gen eric database, whereas likelihood is assessed using the principles of fuzzy set theory. The influence of component operating conditions on component f ailure rate is modeled using a fuzzy inference system. Results of fuzzy rea soning are then used for building an appropriate likelihood function for th e Bayesian inference. The method was applied on a high voltage transformer. Results show that wit h the proposed method, one can estimate the specific failure rate and analy ze possible measures to improve component reliability. The method can be us ed for specific applications including components for which there is not en ough numerical data for specific evaluation. (C) 2001 Elsevier Science Ltd. All rights reserved.