THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Wednesday, July 12, 2017

2:00 PM
in GTMI 201

will be held the

DISSERTATION DEFENSE

for

Christopher Oberste

"Design, Modelling, and Fabrication of Interlaced Thermoplastic Composites by Additive Manufacturing"

Committee Members:

Prof. Ben Wang, Advisor, MSE/ISYE

Prof. Satish Kumar, MSE

Prof. Donggang Yao, MSE

Prof. Kenneth Gall, MECH, Duke University

Dr. Robert Maskell, Cytec Solvay Group

Abstract:

The aerospace and automotive industries both have incentives to improve fuel economy. The use of composite materials is a strategy that is being pursued in both industries. The current composite manufacturing value stream can be characterized as an assembly of batch processes, which results in limited design options, production inefficiency, and material waste. These limitations have prevented composites from achieving broad adoption, particularly in high-volume industries such as automotive manufacturing.

A method of design that combines a top-down definition of functional requirements with a bottom-up approach through the use of elementary steps was developed to address the composite material needs of the aerospace and automotive industries, while also integrating lean manufacturing into the total composite value chain. Using this methodology, two composite manufacturing processes were developed, one optimized for the automotive industry and one more appropriate for the aerospace industry. Prototype machines for each process were designed, constructed, and evaluated in the context of the specific functional requirements for each industry. These composite manufacturing processes enhance composite properties, reduce manufacturing costs and material waste, and increase production rate when compared to existing composite manufacturing processes. A model was developed to link machine parameters to macrostructural features in the final composite in order to predict mechanical behavior under specified load conditions. This model allows users to optimize composite structures and export print commands directly to the composite forming machine.