Structural optimization: From continuum and ground structures to additive manufacturing.

摘要

This work focuses on optimal structural systems, which can be modeled using discrete elements (e.g. slender columns and beams), continuum elements (e.g. walls or slabs), or combinations of these. Optimization problems become meaningful only after the objective function, or benchmark, that evaluates a given design has been defined. Thus, it is logical to explore a variety of objectives, with emphasis on the ones that yield distinct results. The design may include constraints in response to performance or habitability, which must be included in the optimization to yield feasible designs.;Structural optimization can be used to improve structural designs by giving cheaper, stronger, lighter and safer structures. Gradient based optimization is the preferred approach in this work, for it consciously improves a design using the gradient information, as opposed to making random guesses. The optimization problem has an internal dependency on structural analysis, which may require modifications or careful analysis, in order to obtain meaningful gradient information.;Simple problems composed solely of discrete elements are of particular interest to engineers in practice. The design of lateral bracing systems falls into this category. A novel discrete element topology optimization algorithm is proposed, and to facilitate the adoption by industry and academia, the implementation is also provided. Discrete element topology optimization has the potential to aid in the discovery of new closed form solutions for common problems in structural engineering. These closed form solutions, while often impractical to build, give insight into the physics of the optimal structural system. This information can be used to steer civil structural projects towards more efficient load transfer systems.;The manufacturing of optimal structures often lags behind our ability to analyse and design them. Additive manufacturing presents itself as the (much sought) final stage required for a complete structural optimization design process. A clean and streamlined methodology for manufacturing optimal structures is proposed. This includes optimal structures obtained from density based methods as well as the ground structure method. The goal of this work is to improve the current sequential design process of civil structures. It does so by facilitating the integration of optimization techniques into existing design processes, in addition to extending optimization algorithms to address a wider variety of problems. Despite being centered primarily on civil structures, this work has the potential to impact other disciplines. In particular, an example that incorporates optimization techniques into the medical field is shown.