Date of Award

3-1-2019

Document Type

Thesis

Degree Name

Master of Science in Aeronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Ryan O'Hara, PhD

Abstract

Space systems require materials with superior stiffness to weight ratios to provide structural integrity while minimizing mass. Additive manufacturing processes enable the design of metamaterials that exceed the performance of naturally occurring materials in addition to allowing the integration of non-structural functions. This research explored the use of a high stiffness, high density, small melt pool track width AM material, Inconel 718, to enable the production of metamaterials with finer features possible than can possibly be created using a lower density aluminum alloy material. Various metamaterials were designed utilizing thin wall triply periodic minimal surface infilled sandwich structures. The performance characteristics of these metamaterials were evaluated through modal analysis; demonstrating a 16-18% greater stiffness-to-weight ratio than 7075-T6 aluminium. These results were successfully applied to a multifunctional, lightweight, 3U CubeSat chassis design, fabricated from Inconel 718; resulting in a structurally mass efficient satellite bus. Additionally, modal analysis was conducted on the CubeSat chassis loaded with representative payload masses to evaluate the dynamic modal response of the final structure. Vibration testing was conducted in accordance with NASA General Environmental Verification Standard qualification standards, demonstrating the survivability of the chassis under launch conditions. It was shown this metamaterial based design approach could provide a lighter, stiffer chassis than manufactured from traditional aluminum alloy components.

AFIT Designator

AFIT-ENY-MS-19-M-230

DTIC Accession Number

AD1073883

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