An expert system for the design of single-storey steel portal frames using the plastic design method

[摘要] ENGLISH ABSTRACT: The purpose of this study project is to develop an expert system, PFEXPERT, for the designof single-storey steel portal frames with the plastic design method according to theSABS 0162-1:1993.The development tool LEVEL5/OBJECT, an expert system shell, was selected for thedevelopment of PFEXPERT. PFEXPERT consists of two basic parts, an inference engineand a knowledge base. The inference engine, (reasoning mechanism), searches through theknowledge base looking for answers and solutions. The knowledge is expressed in the formof rules and explanatory text in the knowledge base. A menu-driven user interface, thatconsists of different screens which allow the user to interact with the knowledge base, hasbeen developed and is supplemented by warning messages, explanations andrecommendations.The knowledge base cf PFEXPERT consists of an input phase, an analysis phase and adesign phase. The input phase requires structural data, material section properties and load-casedata. PFEXPERT interfaces with a steel section properties data base file for theselection of properties. The analysis phase consists of the elastic analysis and the plasticanalysis of the structure for different load-case combinations. The elastic analysis is done onthe structure subjected to nominal loads. The plastic analysis is done on the structuresubjected to factored loads. PFEXPERT interfaces with an analysis program or theseanalyses. In the design phase, PFEXPERT checks all SABS 0162-1:1993 code requirementsfor serviceability and ultimate limit state design.The expert system, PFEXPERT, is a useful tool for the design engineer for the plastic designof portal frames because it can be maintained and updated to reflect any future code revisionswithout too much difficulty.

[发布机构] Stellenbosch University