The purpose of the study is to better understand the factors that affect melt-wear in the armature-to-rail contact interface of an electromagnetic launcher (EML). In order to investigate the factors, the study uses finite element analysis (FEA) to vary parameters of a lab-scale EML at the Georgia Institute of Technology. FEA is used due to the complex nature of the system, which includes the geometry and various engineering aspects that the EML incorporates. The study focuses on an uncoupled analysis of the structural, electromagnetic (EMAG), thermal, and modal aspects. The reason for the uncoupled analysis was because the system was complex and there were computational limits. Also, by uncoupling the analysis fields, the way the parameters affected melt-wear could be viewed separately. The study varied the geometry of the armature, the stiffness of the rail system (compliance layer), and the material of the armature. The structural analysis was for the initial contact of the rail to the armature and found the von Mises stresses, contact area, and contact pressure. The EMAG analysis found the Lorentz forces in the system based on a current curve used in the lab-scale EML. The thermal analysis consisted of friction heating and Joule heating. The modal analysis was for the unstressed and pre-stressed armature. Based on the study conducted, it was found that aluminum would provide the best speeds due to its lighter mass, but lacked in the thermal resistance area. Tungsten provided the better thermal resistance, but lacked in the potential speed due to its heavier mass.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

In certain plasma environments, such as that surrounding a pulsar, the electric and magnetic fields align orthogonally. In this document we discuss and derive several constraints, of particular importance the force free constraint found in certain plasma environments. We introduce Maxwell’s equations in a covariant, coordinate-free form. We showcase methods to enforce this constraint, first with a straightforward method then by a new, dynamical method. Finally we compare and contrast the two methods in an approximation of a small region above a pulsar. / Thesis to fulfill requirements for the Master of Science degree.

Thesis (Ph. D.)--Michigan State University. Electrical and Computer Engineering, 2008. / Title from PDF t.p. (viewed on Apr. 8, 2009) Includes bibliographical references (p. 148-153). Also issued in print.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [102]-116).

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 154-158).

Thesis (Ph.D.)--Syracuse University, 2007. / "Publication number: AAT 3295512."

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 76-77). Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Document formatted into pages; contains xxi, 261 p.; also includes graphics (some col.). Includes bibliographical references (p. 244-254). Available online via OhioLINK's ETD Center

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