Opportunities in Protection Materials Science
and Technology for Future Army Applications
Committee on Opportunities in Protection Materials Science
and Technology for Future Army Applications
National Materials Advisory Board
and
Board on Army Science and Technology
Division on Engineering and Physical Sciences
NATIONAL RESEARCH COUNCIL
OF THE NATIONAL ACADEMIES
THE NATIONAL ACADEMIES PRESS
Washington, D.C.
www.nap.edu
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by Contract No. W911NF-09-C-0164 between the National Academy of Sciences and the Department of Defense. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
International Standard Book Number-13: 978-0-309-21285-4
International Standard Book Number-10: 0-309-21285-5
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Cover: A soldier wearing protective equipment (left); up-armored high-mobility multipurpose wheeled vehicle (HMMWV) (center); drawing showing penetration of target (right, upper) and interface defeat—the goal of protective material (right, lower). The lower border serves as a reminder of the continued increase in threat that drives the need for advances in protective materials.
Copyright 2011 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America
THE NATIONAL ACADEMIES
Advisers to the Nation on Science, Engineering, and Medicine
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences.
The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering.
The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine.
The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council.
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COMMITTEE ON OPPORTUNITIES IN PROTECTION MATERIALS SCIENCE AND TECHNOLOGY FOR FUTURE ARMY APPLICATIONS
EDWIN L. THOMAS, Chair, Massachusetts Institute of Technology
MICHAEL F. McGRATH, Vice Chair, Analytic Services Inc. (ANSER)
RELVA C. BUCHANAN, University of Cincinnati
BHANUMATHI CHELLURI, IAP Research, Inc.
RICHARD A. HABER, Rutgers University
JOHN WOODSIDE HUTCHINSON, Harvard University
GORDON R. JOHNSON, Southwest Research Institute
SATISH KUMAR, Georgia Institute of Technology
ROBERT M. McMEEKING, University of California, Santa Barbara
NINA A. ORLOVSKAYA, University of Central Florida
MICHAEL ORTIZ, California Institute of Technology
RAÚL A. RADOVITZKY, Massachusetts Institute of Technology
KALIAT T. RAMESH, Johns Hopkins University
DONALD A. SHOCKEY, SRI International
SAMUEL ROBERT SKAGGS, Los Alamos National Laboratory (retired), Consultant
STEVEN G. WAX, Defense Applied Research Projects Agency (retired), Consultant
Staff
ERIK SVEDBERG, NMAB Senior Program Officer
ROBERT LOVE, BAST Senior Program Officer
NANCY T. SCHULTE, BAST Senior Program Officer
HARRISON T. PANNELLA, BAST Senior Program Officer
JAMES C. MYSKA, BAST Senior Research Associate
NIA D. JOHNSON, BAST Senior Research Associate
LAURA TOTH, NMAB Senior Program Assistant
RICKY D. WASHINGTON, NMAB Administrative Coordinator
ANN F. LARROW, BAST Research Assistant
NATIONAL MATERIALS ADVISORY BOARD
ROBERT H. LATIFF, Chair, R. Latiff Associates
LYLE H. SCHWARTZ, Vice Chair, University of Maryland
PETER R. BRIDENBAUGH, Alcoa, Inc. (retired)
L. CATHERINE BRINSON, Northwestern University
VALERIE BROWNING, ValTech Solutions, LLC
YET MING CHIANG, Massachusetts Institute of Technology
GEORGE T. GRAY III, Los Alamos National Laboratory
SOSSINA M. HAILE, California Institute of Technology
CAROL A. HANDWERKER, Purdue University
ELIZABETH HOLM, Sandia National Laboratories
DAVID W. JOHNSON, JR., Stevens Institute of Technology
TOM KING, Oak Ridge National Laboratory
KENNETH H. SANDHAGE, Georgia Institute of Technology
ROBERT E. SCHAFRIK, GE Aircraft Engines
STEVEN G. WAX, Strategic Analysis, Inc.
Staff
DENNIS CHAMOT, Acting Director
ERIK SVEDBERG, Senior Program Officer
RICKY D. WASHINGTON, Administrative Coordinator
HEATHER LOZOWSKI, Financial Associate
LAURA TOTH, Senior Program Assistant
__________
NOTE: In January 2011 the National Materials Advisory Board (NMAB) and the Board on Manufacturing and Engineering Design combined to form the National Materials and Manufacturing Board. Listed here are the members of the NMAB who were involved in this study.
BOARD ON ARMY SCIENCE AND TECHNOLOGY
ALAN H. EPSTEIN, Chair, Pratt & Whitney, East Hartford, Connecticut
DAVID M. MADDOX, Vice Chair, Independent Consultant, Arlington, Virginia
DUANE ADAMS, Carnegie Mellon University (retired), Arlington, Virginia
ILESANMI ADESIDA, University of Illinois at Urbana-Champaign
RAJ AGGARWAL, University of Iowa, Coralville
EDWARD C. BRADY, Strategic Perspectives, Inc., Fort Lauderdale, Florida
L. REGINALD BROTHERS, BAE Systems, Arlington, Virginia
JAMES CARAFANO, The Heritage Foundation, Washington, D.C.
W. PETER CHERRY, Independent Consultant, Ann Arbor, Michigan
EARL H. DOWELL, Duke University, Durham, North Carolina
RONALD P. FUCHS, Independent Consultant, Seattle, Washington
W. HARVEY GRAY, Independent Consultant, Oak Ridge, Tennessee
CARL GUERRERI, Electronic Warfare Associates, Inc., Herndon, Virginia
JOHN J. HAMMOND, Lockheed Martin Corporation (retired), Fairfax, Virginia
RANDALL W. HILL, JR., University of Southern California Institute for Creative Technologies, Marina del Rey
MARY JANE IRWIN, Pennsylvania State University, University Park
ROBIN L. KEESEE, Independent Consultant, Fairfax, Virginia
ELLIOT D. KIEFF, Channing Laboratory, Harvard University, Boston, Massachusetts
LARRY LEHOWICZ, Quantum Research International, Arlington, Virginia
WILLIAM L. MELVIN, Georgia Tech Research Institute, Smyrna
ROBIN MURPHY, Texas A&M University, College Station
SCOTT PARAZYNSKI, The Methodist Hospital Research Institute, Houston, Texas
RICHARD R. PAUL, Independent Consultant, Bellevue, Washington
JEAN D. REED, Independent Consultant, Arlington, Virginia
LEON E. SALOMON, Independent Consultant, Gulfport, Florida
JONATHAN M. SMITH, University of Pennsylvania, Philadelphia
MARK J.T. SMITH, Purdue University, West Lafayette, Indiana
MICHAEL A. STROSCIO, University of Illinois, Chicago
JOSEPH YAKOVAC, President, JVM LLC, Hampton, Virginia
Staff
BRUCE A. BRAUN, Director
CHRIS JONES, Financial Manager
DEANNA P. SPARGER, Program Administrative Coordinator
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Preface
Armor materials are remarkable: Able to stop multiple hits and save lives, they are essential to our military capability in the current conflicts. But as threats have increased, armor systems have become heavier, creating a huge burden for the warfighter and even for combat vehicles. This study of lightweight protection materials is the product of a committee created jointly by two boards of the National Research Council, the National Materials Advisory Board (NMAB)1 and the Board on Army Science and Technology (BAST), in response to a joint request from the Assistant Secretary of the Army for Acquisition, Logistics, and Technology and the Army Research Laboratory. The committee examined the fundamental nature of material deformation behavior at the very high rates characteristic of ballistic and blast events. Our goal was to uncover opportunities for development of advanced materials that are custom designed for use in armor systems, which in turn are designed to make optimal use of the new materials. Such advances could shorten the time for material development and qualification, greatly speed engineering implementation, drive down the areal density of armor, and thereby offer significant advantages for the U.S. military. We hope this report will have a revolutionary effect on the materials and armor systems of the future—an effect that will meet mission needs and save even more lives.
Coincidentally, six weeks after the final committee meeting, the Army announced a draft program calling for establishment of a collaborative research alliance for materials in extreme dynamic environments.2 Since the committee did not review the Army’s preliminary request for proposal, it is not discussed in the study.
The committee was composed of a wide range of experts whose backgrounds in processing and characterization of ceramics, metals, polymers, and composites, as well as theory and modeling and high-rate testing of protection materials, combined wonderfully to make this report possible. I want to thank each and every one of the committee members for their hard work, camaraderie, and dedicated efforts over the past year and in particular, Mike McGrath, the vice chair, and chapter leads Richard Haber, John Hutchinson, Nina Orlovskaya, Don Shockey, Bob Skaggs, Raúl Radovitzky, and Steve Wax. Staff of the NMAB and the BAST did a great job supporting the study and in bringing the report to fruition.
Edwin L. Thomas, NAE, Chair
Committee on Opportunities in
Protection Materials
Science and Technology for
Future Army Applications
__________
1In January 2011 the National Materials Advisory Board (NMAB) and the Board on Manufacturing and Engineering Design combined to form the National Materials and Manufacturing Board. The move underscored the importance of materials science to innovations in engineering and manufacturing.
2U.S. Army. 2010. A Collaborative Research Alliance (CRA) for Materials in Extreme Dynamic Environments (MEDE), Solicitation Number W911NF-11-R-0001, October 28. Available online at https://www.fbo.gov/index?s=opportunity&mode=form&id=48a13a80653b1fabe3f83ede9ddc641b&tab=core&tabmode=list&=. Last accessed March 31, 2011.
Acknowledgment of Reviewers
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s (NRC’s) Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:
Charles E. Anderson, Jr., Southwest Research Institute,
Diran Apelian, Worcester Polytechnic Institute,
Morris E. Fine, Technological Institute Professor
Emeritus, Northwestern University
Peter F. Green, University of Michigan,
Julia R. Greer, California Institute of Technology,
Wayne E. Marsh, DuPont Central Research and Development,
R. Byron Pipes, Purdue University,
Bhakta B. Rath, Naval Research Laboratory,
Susan Sinnott, University of Florida, and
Edgar Arlin Starke, Jr., University of Virginia
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its release. The review of this report was overseen by Elisabeth M. Drake, NAE, Massachusetts Institute of Technology Laboratory of Energy and the Environment. Appointed by the National Research Council, she was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee and the institution.
Contents
2 FUNDAMENTALS OF LIGHTWEIGHT ARMOR SYSTEMS
Armor System Performance and Testing in General
Definition of Armor Performance
Exemplary Threats and Armor Designs
Design Considerations for Fielded Systems
Design Considerations for Fielded Systems
Design Considerations for Fielded Systems
From Armor Systems to Protection Materials
3 MECHANISMS OF PENETRATION IN PROTECTIVE MATERIALS
Penetration Mechanisms in Metals and Alloys
Penetration Mechanisms in Ceramics and Glasses
Penetration Mechanisms in Polymeric Materials
Failure Mechanisms in Cellular-Sandwich Materials Due to Blasts
Three Examples of Current Capabilities for Modeling and Testing
Projectile Penetration of High-Strength Aluminum Plates
Projectile Penetration of Bilayer Ceramic-Metal Plates
All-Steel Sandwich Plates for Enhanced Blast Protection: Design, Simulation, and Testing
The State of the Art in Experimental Methods
Definition of the Length Scales and Timescales of Interest
Evaluating Material Behavior at High Strain Rates
Investigating Dynamic Failure Processes
Investigating Impact Phenomenology
Background and State of the Art
New Protection Materials and Material Systems: Opportunities and Challenges
Computational Materials Methods
5 LIGHTWEIGHT PROTECTIVE MATERIALS: CERAMICS, POLYMERS, AND METALS
Crystalline Ceramics: Phase Behavior, Grain Size or Morphology, and Grain Boundary Phases
Crystalline Structure of Silicon Carbide
Availability of Ceramic Powders
Processing and Fabrication Techniques for Armor Ceramics
Transparent Crystalline Ceramics
Effect of Fiber Diameter on Strength in High-Performance Fibers
Relating Tensile Properties to Ballistic Performance
Approaching the Theoretical Tensile Strength and Theoretical Tensile Modulus
The Need for Mechanical Tests at High Strain Rates
Ballistic Testing and Experimental Work on Fabrics
Important Issues for Ballistic Performance of Fabrics
Metals and Metal-Matrix Composites
Desirable Attributes of Metals as Protective Materials
Adhesives for Armor and for Transparent Armor
General Considerations for the Selection of an Adhesive Interlayer
Important Issues Surrounding Adhesives for Lightweight Armor Applications
Testing, Simulation, and Modeling of Adhesives
Other Issues in Lightweight Materials
Nondestructive Evaluation Techniques
Recommendations for Protection Materials by Design
Element 2—Advanced Computational and Experimental Methods
Element 3—Development of New Materials and Material Systems
Element 4—Organizational Approach
Critical Success Factors for the Recommended New Organizations
DoD Center for the PMD Initiative
Time Frame for Anticipated Advances
A Background and Statement of Task
B Biographical Sketches of Committee Members
E Processing Techniques and Available Classes of Armor Ceramics
G Failure Mechanisms of Ballistic Fabrics and Concepts for Improvement
H Metals as Lightweight Protection Materials
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Tables, Figures, and Boxes
Acronyms and Abbreviations
AlON | aluminum oxynitride |
ARL | Army Research Laboratory |
ARO | Army Research Office |
ATC | Aberdeen Test Center (Maryland) |
ATH | aluminum trihydroxide |
ATPD | Army Tank Purchase Description |
BAST | Board on Army Science and Technology |
CIP | cold isostatic pressing |
CNT | carbon nanotubes |
CTE | coefficient of thermal expansion |
CZM | cohesive zone models |
DARPA | Defense Advanced Projects Research Agency |
DMC | dynamic magnetic compaction |
DoD | Department of Defense |
DoE | Department of Energy |
ERDC | Engineer Research and Development Cente (U.S. Army) |
ESAPI | enhanced small arms protective insert |
FGAC | functionally graded armor composites |
FGM | functionally gradient material |
FSP | fragment simulating projectiles |
GHz | gigahertz |
GPa | gigapascals |
HEL | Hugoniot elastic limit |
HMMWV | high-mobility multipurpose wheeled vehicle (Humvee) |
HP | hot pressing |
IBA | Interceptor body armor |
ICME | Integrated Computational Materials Engineering (an NRC report) |
ITAR | International Traffic in Arms Regulations |
JHB | Johnson, Holmquist, and Beissel |
M&S | modeling and simulation |
MMC | metal matrix composites |
MPa | megapascal |
MZ | Mescall zone |
NDE | nondestructive evaluation |
NIJ | National Institute of Justice |
NMAB | National Materials Advisory Board |
NRC | National Research Council |
NSF | National Science Foundation |
NVI | normal velocity interferometer |
OHPC | Omnipresent High-Performance Computing program |
PAN | polyacrylonitrile |
PBO | polybenzoxazole |
PBZT | poly(benzobisthiazole) |
PC | polycarbonate |
PE | polyethylene |
PMC | polymer matrix composite |
PMD | protection materials-by-design |
PMMA | polymethyl methacrylate |
PPTA | polyparaphenylene terephthalamide |
PU | polyurethane |
PVB | polyvinyl butyral |
QMU | quantification of margins and uncertainties |
RHA | rolled homogeneous armor |
SAN | poly(styrene-co-acrylonitrile) |
SAPI | small arms protective insert |
SCS | shear compression (test) |
SEM | scanning electron microscope |
SiC | silicon carbide |
SiSiC | siliconized silicon carbide |
SPS | spark plasma sintering |
TDI | transverse displacement interferometer |
TEM | transmission electron microscopy |
TPU | thermoplastic polyurethanes |
UHMWPE | ultrahigh molecular weight polyethylene |
UQ | uncertainty quantification |
UV | ultraviolet |
VISAR | velocity interferometry system for any reflector |
V&V | verification and validation |
XCT | x-ray computed tomography |