Doctoral Dissertations

Abstract

"A novel technique for controlling fragmentation of explosively loaded metal cylinders was created during this research program. The research consisted of both an experimental and computational approach, as both were critical for validating the hypothesis used in this dissertation. High speed photography, witness plates, and two hydrocodes were used to gain an understanding of the phenomena of the dynamic environment of explosive fragmentation.

There are three primary means of fragmentation; natural fragmentation, controlled fragmentation, and preformed fragments. If the explosive charge is detonated in a casing made of homogeneous material, the case wall expands, splitting into various sized fragments through either shear and/or radial fractures. Controlled fragmentation can be split into three main techniques; external grooves, internal grooves, and zone embrittlement within the casing. The goal of controlled fragmentation is regular sized fragments, without under or oversized fragments. Preformed fragments allow flexibility in the choice of size and number of fragments produced, but these types of cases have low structural rigidity, and often require either an inner or outer casing for structural strength, if the expected tensile bending and torsional loading is too great for these cases to survive alone.

There are multiple advantages to this novel fragment design approach, as related to cylindrical cases. The most significant is the ability to tailor fragment size and shape to exactly what is desired. By retaining control of the reflection and rarefaction waves within the structure of the case, it is possible to create fragments of a predetermined shape and size, eliminating both the smaller and larger fragments. As the design approach involves no manipulation of the actual case (scoring or preformed fragments), it is possible to also achieve significantly higher fragment velocities than with alternative methods, as well as maintain structural strength. Additional advantages to such a case design are reduced manufacturing costs, eased demilitarization, and enhanced munitions insensitivity"--Abstract, page iii.

Advisor(s)

Worsey, Paul Nicholas

Committee Member(s)

Baird, Jason, 1955-
Grayson, R. Larry
Nanni, Antonio
Summers, David A.

Department(s)

Mining Engineering

Degree Name

Ph. D. in Mining Engineering

Publisher

University of Missouri--Rolla

Publication Date

Spring 2006

Pagination

xii, 228 pages

Note about bibliography

Includes bibliographical references (pages 223-227).

Rights

© 2006 Mark Frederick Cersen Schmidt, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

ExplosivesMetals -- FractureShock waves -- Mathematical modelsMetals -- Viscosity -- Computer simulationMaterials -- Compression testing

Thesis Number

T 8977

Print OCLC #

123018416

Electronic OCLC #

930785394

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