Optimal design of nonlinear structures and mechanical systems

This paper presents an optimal structural design system based on a variational theory of design sensitivity analysis for linear and nonlinear structures and mechanical systems. So called flexible systems and structures, as well as design and control variables, are treated within a unified frame. The concept of an auxiliary system the principle of virtual work, and a Lagrangean-Eulerian description of the deformations and design variations, are used to develop the unified viewpoint. Finite element and finite difference methods are used for spatial and time discretization of the sensitivity equations. The isoparametric concept of the finite element formulation is related to the concept of control volume. The concept of a design element is used for the design modeling of the structure and to generate the analysis model from the design model. Structural analysis and optimization codes are combined to create art optimal design capability. Optimality criteria methods and nonlinear programming are applied as optimizers. Numerical applications are performed.