专家系统在机翼结构布局优化中的应用研究

APPLICATION RESEACHES ON EXPERT SYSTEM USED FOR STRUCTRAL LAYOUT OPTIMIZATION OF WINGS

1.方法原理 一般结构优化仅将离散化后的有限元特征尺寸作为设计变量(例如板杆结构中的杆元横截面积和板元厚度),而其它布局参数(如板、杆元的数目、位置和材料等)在一次上机优化过程中是不变的。当然,可以将元件位置(用节点坐标表示)

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.