Date of Award

5-2019

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Committee Member

Georges Fadel, Committee Chair

Committee Member

Gang Li

Committee Member

Nicole Coutris

Abstract

Advances in additive manufacturing expand the possibilities of what can be designed and produced. One such example is producing structures that possess designed properties. Because the structure itself has the designed property, it does not require the structure's base material to have it. This allows the use of materials that lack a property to gain that property through geometry. Most elastic materials such as steel do not possess any form of energy loss under loading in their elastic regime. This research asks if a structure made from an elastic material could be designed in such a way to provide energy loss.

One structure of interest is curved-bistable beam switches found in MEMs machines. These switches are of interest because they have dierent loading and unloading force-displacement curves, resulting in dierent energy levels between loading and unloading. This results in the system having a hysteresic energy loss. Because individual beams have energy loss, this begs the question if a system of these beams could be designed to produce a structure with energy loss. This structure could then be used to substitute existing systems, such as a suspension system. The goal of this research is to investigate the behavior and to optimize a structure featuring these curved-bistable beams. On the system level, the deformation pattern, stresses throughout the structure, and total energy loss is calculated. To better understand how the variables of the curved beam aect energy loss, a surrogate model for Eloss is produced. This model is then used to optimize both a single beam and a structure of multiple beams. Finally, the material selection's role in optimization is discussed.

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