Investigation of Direct and Indirect Optimization Algorithms for Aerospace Structures.

摘要

This thesis investigated the performance of two direct and two indirect methods of structural optimization. A gradient calculator and overall design system was created with the finite element code FRAME. Three of the methods were employed using this system with the fourth being a commercial available code. The algorithms were applied to two different sized trusses using static constraints and were measured for accuracy, reliability, and efficiency. Results for the problems tested showed the Direct methods were sensitive to starting designs and their performance depended on the proper selection of internal parameters. They were also shown to have a high degree of accuracy and the flexibility to handle different problems. The indirect methods showed that they were very effective when applied to specific problems and were simpler to implement and manage than direct methods, but lacked the flexibility to handle a variety of problems.