Applied Research Of Fuzzy-FMECA In Marine Main Engine System

Safety is the focus and the most important issue in the filed of shipping. At the same time, it is the ultimate requirement for all kinds of ships. MO has brought in Formal Safety Assessment (FSA for short), which has been widely applied in the formulation of safety regulations, the management of safe shipping and the ship designing process. Failure Mode Effects and Criticality Analysis (FMECA for short) has become an efficient and common method for risk analysis both at home and abroad. However, most existing analyses are qualitative analyses, owning to the characteristic of FMECA and the complexity and particularity of marine systems. Since the application of Fuzzy FMECA could make the conclusion more quantitative and elaborate, profound research on it is necessary in the maritime field in China.Main tasks of this thesis are as follows:Firstly, this thesis analyzes the feasibility of using FMECA method on the safety assessment of the system in marine main engine, explains the basic theory of reliability and Fuzzy Comprehensive Evaluation, and introduces FMECA method in detail.Secondly, this thesis assesses the reliability of the main engine system by FMECA. It specifies the boundary before actualizing FMECA, summarizes the failure modes of the main engine systems, sets up FMECA tables, gains relevant data by investigation form, figures out the RPN values for every failure mode, and at last sequences of the criticality of each failure according the RPN values. Then, for the sake of making the results of FMECA more accurately, this thesis sets up the risk decision model of Fuzzy-FMECA and assesses the overall reliability of the main engine system further more. It introduces Fuzzy Comprehensive Evaluation method and Analytic Hierarchy Process method in detail, transforms the investigated data to the corresponding fuzzy matrixes of each failure modes with Fuzzy Comprehensive Evaluation method. It also gets the weight distribution of every failure mode with Analytic Hierarchy Process method, and assesses the overall reliability of the main engine systems.Thirdly, in order to validate the Fuzzy-FMECA method, this thesis investigates and analyzes the "YUKUN" teaching-training vessel, and gives the analysis conclusion..This thesis develops an effective method to do Fuzzy-FMECA for the main engine systems, which is verified on the teaching-training vessel. It is hoped that the research findings of this thesis can be of some help to the reliability research into main engine systems on other vessels, and also can foster the development of reliability engineering system.