Research On Safety And Reliability Of Pressure-bearing Special Equipment Based On FTF Metho

With the sustainable and rapid development of social economy,the increasing enhancement of science and technology level,and continuous improvement of the productivity demand,some pressure-bearing special equipment with higher parameter,larger capacity and more complexity are universally used in many fields of production and life.This kind of equipment served in the bad working condition easily lead to a variety of safety accidents,cause damage and loss to some extent,and even casualties due to the coupling effect of many complex factors.Based on the failure mechanism and failure mode of the pressure-bearing special equipment,the safety and reliability of the system are studied in this paper by using the safety system engineering theory,such as fuzzy gray correlation FTA andfuzzy FMECA.Firstly,such some problems and theories as the failure cause of pressure-bearing special equipment,the fracture mode of pressure-bearing components,the engineering method of failure analysis and the quality control of equipment manufacturing process are systematically analyzed and described.And the failure mechanism and the multiple affected factors of the welded pressure-bearing component are analyzed and studied by means of the nondestructive flaw detecting,mechanical performance testing and electron microscope scanning combined with the welding dynamic finite element simulation of the welded joint.Secondly,considering the characteristics of pressure-bearing special equipment in the systematic safety and reliability analysis,the fuzzy gray correlation FTA model is established and developed by use of the combination of fuzzy theory and gray correlation theory in view of the problem of the traditional FTA method applied in uncertainty complex system with fuzzy and gray characteristics.At the same time,the fuzzy analytic hierarchy process is introduced to improve the technique of traditional FMECA in order to enhance the accuracy of the whole risk evaluation results.Then,taking the power station boiler system as an example,the fuzzy gray correlation FTA model is established based on the top event of the "Four Tubes" failure,and related qualitative and quantitative analysis is accomplished through studying on failure cause and failure mode.And then the FMEC A is implemented for the basic event so as to form a reverse FTF analysis system.Based on the analysis above,the fuzzy FMECA technology and Bow-tie model are used to form a positive FTF analysis system for the failure mode of the pressure-bearing components.Finally,according to the characteristics of the failure cause mechanism and manufacturing quality control of the pressure-bearing special equipment,the FTF method is applied to the research of safety and reliability of the equipment by means of the combination of fuzzy gray correlation FTA method and fuzzy FMECA.And the problems of further improvement are put forward.