No description available.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1922. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed June 10, 2009) Includes bibliographical references (p. 9).

No description available.

Thesis (Ph.D.)--University of Tulsa, 1994. / Includes bibliographical references (leaves 110-112).

No description available.

Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 334-335).

published_or_final_version / Civil Engineering / Master / Master of Philosophy

Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 315-332).

Missions to Mars aim to characterize rock and subsurface soil samples and possibly bring some back to Earth for more thorough and sophisticated examination. The Martian surface is covered with basalt which has high compressive strength (andamp;gt;130 MPa), and is more difficult to drill than the much softer sedimentary formations that are presently being drilled using diamond core drills. The main objective of this thesis work is to provide the requisite groundwork towards the development of improved and sustainable drills for subsurface drilling applications on Mars, when their goals are obtaining samples. Since progressive drill-wear is substantial in sustained drilling, the experiments were designed and conducted to study the tool-wear mechanisms and understand the associated effects on drilling performance in subsurface drilling of basalt. Core drilling experiments are conducted with different drill geometries and cutting conditions in a Martian simulant, basaltic rock; monitoring thrust force, torque and measuring tool-wear for a series of successive depth-increments. Based on the experimental results an optimization model has been developed for maximizing drilling depth with minimum tool-wear. This preliminary work will help the development of smart and sustainable drills for dry drilling applications for future NASA missions to Mars.

My thesis is considering the options of manufacturing of the core drill. One of these options is technology of the laser welding, which was described in details in the theoretical part of this thesis. In applied part of this thesis there were experimentally manufactured two pieces of core drills by using Yb-YAG fibre laser technology. One core drill was used for testing of the welding parameters and in the next step, these parameters were applied in real working conditions and were evaluated in final. Result is written down in the final part of my thesis. The second core drill was welded using the best values measured in the fixture, which was especially designed for this purpose.