Doctoral Dissertations


"Additive Manufacturing (AM) is a set of manufacturing processes which has promise in the production of complex, functional structures that cannot be fabricated with conventional manufacturing and the repair of high-value parts. However, a significant challenge to the adoption of additive manufacturing processes to these applications is proper process control. In order to enable closed-loop process control compact models suitable for control design and for describing the layer-by-layer material addition process are needed. This dissertation proposes a two-dimensional modeling and control framework, with an application to a specific metal-based AM process, whereby the deposition of the current layer is affected by both in-layer and layer-to-layer dynamics, both of which are driven by the state of the previous layer. The proposed modeling framework can be used to create two-dimensional dynamic models for the analysis of layer-to-layer stability and as a foundation for the design of layer-to-layer controllers for AM processes. In order to analyze the stability of this class of systems, linear repetitive process results are extended enabling the treatment of the process model as a two-dimensional analog of a discrete time system. For process control, the closed-loop repetitive process is again treated as a two-dimensional analog of a discrete time system for which controllers are designed. The proposed methodologies are applied to a metal-based AM process, Laser Metal Deposition (LMD), which is known to exhibit layer-to-layer unstable behavior and is also of significant interest to high-value manufacturing industries"--Abstract, page iii.


Bristow, Douglas A.
Landers, Robert G.

Committee Member(s)

Balakrishnan, S. N.
Liou, Frank W.
Sarangapani, Jagannathan, 1965-


Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering


National Science Foundation (U.S.)
United States. Department of Education. Graduate Assistance in Areas of National Need


Financial support of the National Science Foundation (CMMI1301414) and the US Department of Education GAANN Fellowship (P200A120062).


Missouri University of Science and Technology

Publication Date

Summer 2016


x, 151 pages

Note about bibliography

Includes bibliographic references (pages 145-150).


© 2016 Patrick Michael Sammons, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11577

Electronic OCLC #