In The Safety Assessment Of Pressure Vessels Containing Defects Decision-making Support System

The pressure vessel will suffer a lot of hidden trouble in the course of using,it is important to check the system regularly and to assess its safety. In the course of customary safety inspection of pressure vessel, a large number of date are accumulated. In order to manage effectively those date and formative information of pressure vessel, to understand the pressure vessel's current situation, and prevent the emergence of the accident more effectively, so it is necessary to build assessing decision support system for defects based on that.Such system can be used to efficiently assess, abstract and handle all kinds of defects in pressure vessels, and automatically and smartly assess defects. Then the reliability of pressure vessels can be improved in the using, managing, detecting, repairing, and replacing processes, which can greatly prevent accidents.In the thesis, According to"The Pressure Vessel Defects Assessment Norm"(CVDA-84),"The Safety Assessment Regulation of The Pressure Vessel in Service"(SAPV-95) and"Safety assessment for in-service pressure vessels containing defects"(GB/T 19624-2004), based on computer technique, database technique, fuzzing mathematics, and information technique, flow and technique route of safety assessment for in-service pressure vessels containing defects, are studied, and also fuzzy assessment on pressure vessels was studied. Main points of this thesis are the following:1. Correlative theory of pressure vessels containing defects are analyzed such as elasticity mechanics and rupture mechanics. According to last standard, general situation and flow of safety assessment are expatiate, also, problem of safety assessment is explain.2. Establishment of assessing decision support system is analyzed on requirement, models of system function are set up by using tradition, structural and O.O.ways, then main system function correspondingly is decided.3. Based on fuzzy mathematics, fuzzy control etc. theory, fuzzy assessment of pressure vessels is studied. Two methods for fuzzy assessment of pressure vessels are put forward, on the one hand, fuzzy assessment on constituting consecutive subjection function, on the other hand, fuzzy assessment on constituting inconsecutive(point) subjection function. And their difference are put forward.4. To system require, and to combine with database technique, decision support system technique,assessing decision support system are developed by software of Visual Basic6.0 and database tool of SQL Server 2000.Above all, the present project set up defects database and assessing decision support system for pressure vessels according to the principle of corresponding to use and using computer techniques, simulation techniques, and etc.. This project can be widely applied in engineering.