AUTOMATED-SYSTEM FOR STRUCTURAL DESIGN USING DESIGN WINDOW SEARCH APPROACH - ITS APPLICATION TO FUSION FIRST WALL DESIGN

Some practical structures are required to be operated in severe enviro nments where various mechanical, thermal or electromagnetic loadings o ccur in a complicated manner and various failure phenomena such as yie lding, fracturing and melting compete among others. In designing such structures, it seems very useful to determine the design window (DW) t hat schematically indicates an area of satisfactory solutions in a per missible design space. The DW may give us more meaningful information than one satisfactory or optimum solution. However very little researc h has been performed on this topic so far. This paper describes a nove l automated system for structural design based on the DW concept. The present system consists of three main modules and one sub-engine, that is, (a) the Analyzer, (b) the DW Search Engine, (c) the Design Modifi er as the main modules and (d) a multilayer neural network as the sub- engine of the DW Search Engine. The Analyzer takes care of computation al mechanics simulations for various sets of design parameters. To mai ntain high flexibility and extensibility, the Analyzer is constructed using an object-oriented knowledge representation and a data-flow proc essing technique. Some DW search methods are incorporated into the DW Search Engine. Using neural network technology, DWs are searched very efficiently. The Design Modifier has the role of finding one satisfact ory solution, which is given to the DW Search Engine so that some sear ch methods can start searching. To demonstrate the practical performan ce of the present system, it is applied to design one of the typical s tructures to be operated in a severe environment, i.e. the first wall structure of ITER (International Thermonuclear Experimental Reactor). (C) 1997 Elsevier Science Limited.