Study On Assessing Decision Support System Of Pressure Vessel Defects Based On Database

As using pressure vessels, all kinds of dangerous defects maybe produce. On the one hand, the paranormal defects possibly bring serious accident and result in great economic loss; on the other hand it is not necessary to repair or replace vessels containing defects if not choosing and it will bring adverse effect to production and management of enterprise. So according to practicable rules, it is very important for safety and high efficiency use of pressure vessels to establish defects database and assessing decision support system by adopting advanced technology of security assessing at home and overseas.Based on all above reasons, the paper applies synthetically large numbers of data, assembles numerous math models, assistants decision personnel to complicate scientific decision of defects safety assessment by man-machine conversation. It applies synthetically diversified knowledge in multifarious study domains, makes use of computer technology, simulation technology and information technology etc, provides necessary data and select defects assessing project; It makes analysis, contrast and estimation by man-machine conversing and offers help for correct assessing. The system consists of three subsystems, including defects assessing system, model base system and database system. The studying content and main conclusions of the paper are follows:1. According to theory of engineering rupture mechanics, associating with pressure vessel defects assessing criterion including CVDA-1984, SAPV-95 and R6 etc, depending on the safety evaluation for air vessels and a lot of basic data, at last skilled route and course of defects safety assessment is confirmed.2. By using traditional data flow diagram (DFD), structured analysis method IDEFO diagram and object oriented method based on UML language, requirements analysis of defects assessing decision support system is accomplished.3. According to thought of software engineering, systematic configuration or the system is set up. By using object oriented programming language, modularity design is completed. The structural design of database system and data format conversion, model base system and defects assessing model design is implemented.4. The key technology, which includes database technology, model technology, artificial intelligence expert system, decision trees, man-machine conversation technology, integration technology etc, is discussed. At last, by using VB/VB.NET, SQLServer2000 etc development tools, practical application software is brought to success.5. Based on fuzzy mathematics theory, the academic discussion and practice study about defects fuzzy assessment is come true. By creating mathematics model, the fuzzy conception about defects invalidation degree is described accurately and the orientation for next development and study is pointed.In conclusion, this thesis has great practicability and comprehensive application value.