Review of
Department of Defense
Test Protocols for
Combat Helmets
Committee on Review of Test Protocols Used by the DoD to Test Combat Helmets
Board on Army Science and Technology
Division on Engineering and Physical Sciences
NATIONAL RESEARCH COUNCIL
OF THE NATIONAL ACADEMIES
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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/Grant No. HQ0034-10-D-0003 between the National Academy of Sciences and the U.S. Department of Defense. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organizations or agencies that provided support for the project.
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COMMITTEE ON REVIEW OF TEST PROTOCOLS USED BY THE DOD TO TEST COMBAT HELMETS
VIJAYAN N. NAIR, University of Michigan, Ann Arbor, Chair
CHRISTINE ANDERSON-COOK, Los Alamos National Laboratory, Los Alamos, New Mexico
CAMERON R. BASS, Duke University, Durham, North Carolina
THOMAS F. BUDINGER (NAE/IOM), University of California, Berkeley
MICHAEL J. CUSHING, U.S. Army Evaluation Center (retired), Portland, Maine
ROBERT EASTERLING, Sandia National Laboratories (retired), Cedar Crest, New Mexico
RONALD D. FRICKER, Naval Postgraduate School, Monterrey, California
PETER N. FULLER, Cypress International, Springfield, Virginia
RAUL A. RADOVITZKY, Massachusetts Institute of Technology, Cambridge
ERNEST SEGLIE, Office of the Secretary of Defense (retired), Kensington, Maryland
Staff
BRUCE BRAUN, Director, Board on Army Science and Technology
NANCY T. SCHULTE, Study Director
DEANNA SPARGER, Program Administrative Coordinator
NIA D. JOHNSON, Senior Research Associate
BOARD ON ARMY SCIENCE AND TECHNOLOGY
DAVID M. MADDOX, Independent Consultant, Arlington, Virginia, Chair
JEAN D. REED, Independent Consultant, Arlington, Virginia, Vice Chair
DUANE ADAMS, Independent Consultant, Arlington, Virginia
ILESANMI ADESIDA, University of Illinois at Urbana-Champaign
STEVEN W. BOUTELLE, CISCO Consulting Services, Herndon, Virginia
MARY E. BOYCE, Massachusetts Institute of Technology, Cambridge
EDWARD C. BRADY, Strategic Perspectives, Inc., McLean, Virginia
W. PETER CHERRY, Independent Consultant, Ann Arbor, Michigan
EARL H. DOWELL, Duke University, Durham, North Carolina
JULIA D. ERDLEY, Pennsylvania State University, State College
LESTER A. FOSTER, Electronic Warfare Associates, Herndon, Virginia
JAMES A. FREEBERSYSER, BBN Technology, St. Louis Park, Minnesota
PETER N. FULLER, Cypress International, Springfield, Virginia
W. HARVEY GRAY, Independent Consultant, Oak Ridge, Tennessee
JOHN J. HAMMOND, Independent Consultant, Fairfax, Virginia
RANDALL W. HILL, JR., University of Southern California Institute for Creative Technologies, Playa Vista
JOHN W. HUTCHINSON, Harvard University, Cambridge, Massachusetts
BRUCE D. JETTE, Synovision Solutions, LLC, Burke, Virginia
ROBIN L. KEESEE, Independent Consultant, Fairfax, Virginia
WILLIAM L. MELVIN, Georgia Tech Research Institute, Smyrna
WALTER F. MORRISON, Independent Consultant, Alexandria, Virginia
ROBIN MURPHY, Texas A&M University, College Station
SCOTT PARAZYNSKI, University of Texas Medical Branch, Galveston
RICHARD R. PAUL, Independent Consultant, Bellevue, Washington
DANIEL PODOLSKY, University of Texas Southwestern Medical Center, Dallas
LEON E. SALOMON, Independent Consultant, Gulfport, Florida
ALBERT A. SCIARRETTA, CNS Technologies, Inc., Springfield, Virginia
JONATHAN M. SMITH, University of Pennsylvania, Philadelphia
DAVID A. TIRRELL, California Institute of Technology, Pasadena
MICHAEL A. VANE, DynCorp International, Lorton, Virginia
JOSEPH YAKOVAC, JVM LLC, Hampton, Virginia
Staff
BRUCE A. BRAUN, Director
CHRIS JONES, Financial Manager
DEANNA P. SPARGER, Program Administrative Coordinator
Preface
Rep. Louise Slaughter (D-NY) wrote to Secretary of Defense Leon Panetta in June 2012 to express her concerns that the new protocol for testing Advanced Combat Helmets (ACHs) posed “an unacceptably high risk” for such protective equipment. In responding to Rep. Slaughter, Dr. Michael Gilmore, Director of Operational Test and Evaluation (DOT&E) of the Department of Defense (DoD), indicated that he had requested the National Academies’ National Research Council (NRC) to conduct an independent review of DOT&E’s test protocols. The Committee on Review of Test Protocols Used by the DoD to Test Combat Helmets was formed to conduct this review. This report is the result of that study.
The committee held six meetings, including a site visit to the combat helmet test range at the Aberdeen Test Center in Maryland. It received presentations from some two dozen entities, including offices within the U.S. Army, the U.S. Marine Corps, and the Special Operations Forces; the Institute for Defense Analysis; DOT&E; manufacturers of combat helmets; and the Office of the DoD Inspector General. The committee appreciates the assistance offered by Chris Moosmann, a staff member in the DOT&E Office of Live Fire Test and Evaluation, in the course of its deliberations. The study was conducted under the auspices of the NRC Board on Army Science and Technology (BAST). The committee appreciates the assistance of Bruce A. Braun, director of BAST, and Nancy T. Schulte, study director, for their very effective support in the conduct of this study. It also offers its thanks to the BAST staff members who capably assisted in information-gathering activities, meeting and trip arrangements, and the production of this report; they include Nia D. Johnson, associate research assistant, and Deanna Sparger, senior program assistant.
Finally, and most importantly, I want to express my appreciation to my fellow committee members for all of their work in developing the findings and recommendations and in preparing the report. This was an especially collegial group of experts, and I learned a lot from interacting with them. Rob Easterling and Ernest Seglie, two of the committee members, deserve special mention for their contributions as part of the editorial team. I am also grateful to Naveen Narisetty at the University of Michigan for his work on the numerical studies to examine the robustness properties of test plans.
Vijay Nair, Chair
Committee on Review of Test Protocols
Used by the DoD to Test Combat Helmets
Acknowledgments
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:
Gordon R. England, NAE, E6 Partners LLC,
Karen Kafadar, Indiana University,
Harvey S. Levin, Baylor College of Medicine,
William Q. Meeker, Jr., Iowa State University,
James R. Moran, The Boeing Company,
John E. Rolph, University of Southern California, and
Dean L. Sicking, The University of Alabama at Birmingham.
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 James O. Berger, NAS, Duke University. Appointed by the National Research Council, he 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
2.3 Recent Developments and Directions
3 THREATS, HEAD INJURIES, AND TEST METHODOLOGIES
3.2 Historical Patterns of Treatable Injuries
3.4 Advanced Combat Helmet Test Methodology and Links to Biomechanics
4.2 Ballistic Testing Methodology
4.4 Additional Measurement and Testing Issues
5 HELMET PERFORMANCE MEASURES AND TRENDS IN TEST DATA
5.3 Summary of Results from Available Test Data
6.2 Statistical Considerations in Designing Test Plans for Resistance to Penetration
6.3 Statistical Evaluation of DoD Protocols for Resistance to Penetration
6.4 Examination of Separate Test Plans by Helmet Size
6.6 Future Test Protocols: Helmet as the Unit of Test
7 TEST PROTOCOLS FOR BACKFACE DEFORMATION: STATISTICAL CONSIDERATIONS AND ASSESSMENT
7.2 Backface Deformation First Article Acceptance Testing Protocols and Their Properties
8.2 Lot Acceptance Testing Protocols
8.3 Evaluating Performance: Comparison of Operating Characteristic Curves
8.4 ANSI Standard and the Acceptance Quality Limit
8.5 Using the Helmet as the Unit of Testing
9 CHARACTERIZATION TESTS FOR THE ADVANCED COMBAT HELMET AND FUTURE HELMETS
9.2 Characterization of the Advanced Combat Helmet Using Existing Test Data
9.3 Expanded Characterization Requiring Additional Data
9.5 Comparison with Industrial Practices
10 LINKING HELMET PROTECTION TO BRAIN INJURY
10.3 Head and Brain Injury Tolerances
10.4 Brain Tissue Injury: Experimental Results
10.5 Computational Modeling and Simulation
10.6 Mechanical and Constitutive Properties of Tissues
B Protocols for First Article and Lot Acceptance Testing
C Committee Meetings and Data-Gathering Activities
D Test Range Description and the Ballistic Testing Process
Tables, Figures, and Box
TABLES
FIGURES
BOX
Acronyms and Abbreviations
ACH |
advanced combat helmet (Army) |
ANSI |
American National Standards Institute |
AQL |
acceptance quality limit |
ATC |
U.S. Army Aberdeen Test Center |
ATD |
anthropometric test device |
BFD |
backface deformation |
BTD |
ballistic transient deformation |
DAI |
diffuse axonal injury |
DCMA |
Defense Contract Management Agency |
DoD |
Department of Defense |
DOT |
Department of Transportation |
DOT&E |
Director, Operational Test and Evaluation |
DTI |
diffusion tensor imaging |
ECH |
enhanced combat helmet |
FAST |
Future Assault Shell Technology |
FAT |
first article testing |
FMJ |
full metal jacket |
FSP |
fragment simulating projectile |
GSW |
gunshot wounds |
HEaDS-UP |
Helmet Electronics and Display System – Upgradeable Protection |
HIC |
head injury criteria |
ICP |
intracranial pressure |
IED |
improvised explosive device |
IG |
Inspector General |
ISO |
International Standards Organization |
L |
large |
LAT |
lot acceptance testing |
LWH |
lightweight helmet (Marine Corps) |
M |
medium |
M&S |
modeling and simulation |
MICH |
Modular Integrated Communications Helmet |
MIL-STD |
military standard |
MRI |
magnetic resonance imaging |
mTBI |
mild traumatic brain injury |
NHTSA |
National Highway Traffic Safety Administration |
NIJ |
National Institute of Justice |
NIST |
National Institute of Standards and Technology |
NRC |
National Research Council |
OC |
operating characteristic (curve) |
OEF |
Operation Enduring Freedom (Afghanistan) |
OIF |
Operation Iraqi Freedom |
P |
probability |
PASGT |
Personnel Armor System for Ground Troops |
PEO-S |
U.S. Army Program Executive Office Soldier |
PET |
positron emission tomography |
P(nP) |
probability of no penetration |
Pr(pen) |
probability of penetration |
R&R |
repeatability and reproducibility |
RCC |
right circular cylinder |
RTP |
resistance to penetration |
S |
small |
SIMon |
simulated injury monitor |
TBI |
traumatic brain injury |