SUPPORTING DESIGN DECISIONS BY PROLOG DATABASE

The paper presents an effort to develop an 'intelligent drawing desk': a computer program that incorporates CAD, structural analysis and optimization, database query and automatic choice of the initial design. The advantages of such an integrated software are demonstrated on the testbed of plane steel trusses. After a brief presentation of the conventional part of the package, its expert module is discussed more thoroughly. Implemented in 'Prolog', that module aids the user in choosing the initial layout of the truss. It checks and supplements, if necessary, the values of the structural attributes given by the designer. After a complete set of attributes has been established, the module searches for similar solutions in the database. The latter represents the experience, i.e. all solutions accepted by the user in the past. An initial design is obtained without strength analysis by matching the current values of the attributes against those stored in the database. Provided the latter is exhaustive enough, one obtains in this way quite reasonable initial values of the design variables. The final design can be found then by using conventional analysis, optimization and sizing procedures that belong to the procedural part of the package.