Automated Structural Synthesis Using a Reduced Number of Design Coordinates

The automated synthesis of large structural systems using a reduced number of design variables is investigated. The synthesis is accomplished by generating a Fiacco-McCormi ck Penalty function which is minimized with a deflected gradient procedure. The optimization algorithm is modified using a reduced set of design variables which greatly reduces the computer effort usually required for large structural problems and provides an upper bound solution. A rational procedure based on the external loads and constraints on the system is developed for generating the reduced set of coordinates. Examples of truss systems subjected to stress constraints, displacement constraints, and constraints on the design variables are studied in detail. For the examples considered, the results show large reductions in computer effort and demonstrate the effectiveness and efficiency of the method. The method provides a powerful tool for preliminary design studies, and appears to be the most effective method for obtaining near optimal designs of large systems.