SUBJECT: Ph.D. Dissertation Defense
   
BY: Christopher Williams
   
TIME: Wednesday, December 12, 2007, 1:00 p.m.
   
PLACE: MARC Building, 201
   
TITLE: Design and Development of a Layer-Based Additive Manufacturing Process for the Realization of Metal Parts of Designed Mesostructure
   
COMMITTEE: Dr. David Rosen, Co-Chair (ME)
Dr. Farrokh Mistree, Co-Chair (ME)
Dr. Joe Cochran (MSE)
Dr. Hamid Garmestani (MSE)
Dr. Dave McDowell (ME)
Dr. Shreyes Melkote (ME)
 

SUMMARY

Low-density cellular materials, metallic bodies with gaseous voids, are a unique class of materials that are characterized by their high strength, low mass, good energy absorption characteristics, and good thermal and acoustic insulation properties. In an effort to take advantage of this entire suite of positive mechanical traits, designers are tailoring the cellular mesostructure for multiple design objectives. Unfortunately, existing cellular material manufacturing technologies limit the design space as they are limited to certain part mesostructure, material type, and macrostructure. The opportunity that exists to improve the design of existing products, and the ability to reap the benefits of cellular materials in new applications is the driving force behind this research. As such, the primary research goal of this work is to design, embody, and analyze a manufacturing process that provides a designer the ability to specify the material type, material composition, void morphology, and mesostructure topology for any conceivable part geometry. The accomplishment of this goal is achieved in three phases of research: - Design: Following a systematic design process and a rigorous selection exercise, a layer-based additive manufacturing process is designed that is capable of meeting the unique requirements of fabricating cellular material geometry. Specifically, metal parts of designed mesostructure are fabricated via three-dimensional printing of metal oxide ceramic powder followed by post-processing in a reducing atmosphere. - Embodiment: The primary research hypothesis is verified through the use of the designed manufacturing process chain to successfully realize metal parts of designed mesostructure - Analysis: Three components of the manufacturing process are modeled so as to gain a better understanding. In addition to an analysis of primitive creation and the fabrication of thin trusses, build time and cost models are developed in order to verify claims of the process’s economic benefits. The main contribution of this research is the development of a novel manner for realizing parts of designed mesostructure.