Abstract: In this paper, a new developing branch of computer science-expert system is used to deal with the structural layout optimization of aircraft wings.As well know, general structural optimizations deal only with the characteristic dimensions of finite elements as design variables. The number of elements which is the most import parameter for structural layout optimization can not be considered at present. Otherwise, the order of the structural stiffness matrix will be changed, that will cause tremendous difficulties to programming.In order to solve this difficulty, man-machine interactive technique was used in our structural layout problem and a program named SLOW (Structural Layout of Wings) was created for engineering application. Users can give different layouts of wings to SLOW, and SLOW will reply different optimum results (in every layout scheme the number of elements is not a variable). Then the users can select the best one of these layouts. The problem is that users who have no rich design experience can not obtain a useful layout.Expert system -a new branch of computer science can be used to provide the design experience to the users. ES(Expert System) is an artificial intelligent program which can give a lot of advice to help the users get a reasonable layout scheme. ESSLOW is a combination of SLOW and its expert system shell ES. The obtained schemes of optimum structural layouts are satisfied from the point of view of engineering application.

Key words: expert system, structural layout optimization, man-machine interactive technigue