Different Approaches for Analyzing the Fuzzy Reliability of a Marine Power Plant

Abstract

One of the important engineering tasks in design and development of a technical system is reliable engineering. It is well known that the conventional reliability analysis, using the probabilities, has been found to be inadequate to handle uncertainty of failure data and modeling. Fuzzy sets theory can be the best tool to solve the above mentioned problem, which is able to analyze the fault events without the need for exact information of fault probability. In this thesis fuzzy reliability of marine power plant has been analyzed using different approaches and the results are compared. The main topics are fuzzy qualitative analysis of marine power plant using cut set approach, fuzzy reliability analysis using fuzzy number arithmetic operations, fuzzy reliability analysis using LR type fuzzy numbers, fuzzy reliability analysis using interval of confidence, fuzzy reliability analysis using with different types of membership functions. The chapter-wise summary of the thesis is as follows: Chapter 1 is introductory in nature. This chapter includes basic definitions, operations and concepts used throughout the work. It also presents brief review of the work done in the area of fuzzy reliability analysis. In Chapter 2, to overcome the shortcoming of a fuzzy qualitative analysis of marine power plant existing in literature, a new approach has been developed for the fuzzy qualitative analysis. In Chapter 3 using the proposed fuzzy qualitative analysis and arithmetic operations between trapezoidal fuzzy numbers, the fuzzy reliability of marine power plant has been evaluated. In Chapter 4 according to real life situations, instead of trapezoidal fuzzy numbers LR type fuzzy numbers have been used for analyzing the fuzzy reliability of marine power plant. Also the some expressions existing in literature, for - ary possibilistic AND, OR and NEG operations has been corrected and the corrected expressions are used for analyzing the fuzzy reliability of marine power plant. In Chapter 5 the shortcomings of chapter 3 and chapter 4 have been pointed out and the arithmetic operations between interval of confidence have been used to analyze the fuzzy reliability of marine power plant. In the last chapter an algorithm has been proposed to find the arithmetic operations between different types of fuzzy numbers and hence using this algorithm the fuzzy reliability of marine power plant has been evaluated.