Safety Assessment Of Water Jet And Its Hydraulic System Based On FMEA

The paper introduces the water jet and its system on board high speed passenger ship HAIYAN, and some methods usually applied in project assessment are introduced in detail. Among these assessment methods, Failure Modes and Effects Analysis (FMEA) is available to evaluate high speed ro-ro ships. Based on FMEA method, a survey of water jet and hydraulic system troubles is made and the questionnaires are distributed. With the questionnaires retrieved, RPN value of each potent trouble yields. Since many evaluation elements are involved in FMEA and their concepts are fuzzy, a Fuzzy Comprehensive Evaluation model is put forward to analyze the whole system. The process is as follow:Firstly, to get Fuzzy set with RPN values from questionnaires retrieved;Secondly, to get the weights of each potent trouble with the degree of difficulty tables, through AHP (Analytic Hierarchy Process) method;Thirdly, with Fuzzy set and weights, to get a vector result through Fuzzy operation;Fourthly, by the method of weighted mean defuzzification, to convert the vector into a single value.The analyzing result indicates that FMEA combined with Fuzzy method is feasible and comprehensible to the ship safety assessment, and the method is easy to handle. Because FMEA questionnaire is complemented by Fuzzy Comprehensive Evaluation, the application of FMEA on high speed ro-ro ships is more scientific.