Doctoral Dissertations


"A finite element approach has been developed to simulate bit penetration from bit-rock interaction to chip formation. A mathematical rock failure model, based on a review of the existing literature on rock tests, has been proposed to represent post-failure rock behavior and applied in the penetration simulations. The finite element program has been developed for two dimensional plane strain problems with non-linear material properties, geometrical nonlinearities and fracture. An anisotropic element as well as variable stiffness and stress release methods have been used. An iteration method, using an incremental approach, has been applied for continuous penetration and modifications of material properties and displacements. Quantitative information on stress, displacement and material failure in the entire penetration process can be obtained through computer simulation. Blunt point, wedge and cylindrical bits are used in the penetration simulations. Blunt point bit penetration, with two different post-failure rock strengths, has been simulated and compared with experimental results"--Abstract, page ii.


Lehnhoff, T. F., 1939-

Committee Member(s)

Clark, George Bromley, 1912-
Barker, Clark R.
Penico, Anthony J., 1923-2011
Davis, Robert L.


Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering


University of Missouri--Rolla

Publication Date



ix, 102 pages

Note about bibliography

Includes bibliographical references (pages 69-71).


© 1975 Jaw-Kuang Wang, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type




Library of Congress Subject Headings

Bits (Drilling and boring)
Rocks -- Analysis -- Mathematical models
Rocks -- Testing
Rock mechanics

Thesis Number

T 3051

Print OCLC #


Electronic OCLC #


Link to Catalog Record

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