Multidisciplinary structural design and optimization for performance, cost, and flexibility

Abstract

Reducing cost and improving performance are two key factors in structural design. In the aerospace and automotive industries, this is particularly true with respect to design criteria such as strength, stiffness, mass, fatigue resistance, manufacturing cost, and maintenance cost. This design philosophy of reducing cost and improving performance applies to structural components as well as complex structural systems. Design for flexibility is one method of reducing costs and improving performance in these systems. This design methodology allows systems to be modified to respond to changes in desired functionality. A useful tool for this design practice is multi-disciplinary design optimization (MDO). This thesis develops and exercises an MDO framework for exploration of design spaces for structural components, subsystems, and complex systems considering cost, performance, and flexibility. The structural design trade off of sacrificing strength, mass efficiency, manufacturing cost, and other "classical" optimization criteria at the component level for desirable properties such as reconfigurability at higher levels of the structural system hierarchy is explored in three ways in this thesis. First, structural shape optimization is performed at the component level considering structural performance and manufacturing cost. Second, topology optimization is performed for a reconfigurable system of structural elements. Finally, structural design to reduce cost and increase performance is performed for a complex system of structural components. A new concept for modular, reconfigurable spacecraft design is introduced and a design application is presented.