Review of Department of Defense Test Protocols for Combat Helmets (2014)

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

THE NATIONAL ACADEMIES PRESS
Washington, D.C.
www.nap.edu

THE NATIONAL ACADEMIES PRESS   •   500 Fifth Street, NW   •   Washington, DC 20001

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.

International Standard Book Number-13: 978-0-309-29866-7
International Standard Book Number-10: 0-309-29866-0

Copyright 2014 by the National Academy of Sciences. All rights reserved.

Printed in the United States of America

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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

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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.

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Contents

SUMMARY

1   INTRODUCTION

1.0   Information Gathering

1.1   Summary of the Report

1.2   References

2   EVOLUTION OF COMBAT HELMETS

2.0   Summary

2.1   Introduction

2.2   New Materials and Designs

2.3   Recent Developments and Directions

2.4   References

3   THREATS, HEAD INJURIES, AND TEST METHODOLOGIES

3.0   Summary

3.1   Introduction

3.2   Historical Patterns of Treatable Injuries

3.3   Threats

3.4   Advanced Combat Helmet Test Methodology and Links to Biomechanics

3.5   References

4   COMBAT HELMET TESTING

4.0   Summary

4.1   Introduction

4.2   Ballistic Testing Methodology

4.3   Sources of Test Variation

4.4   Additional Measurement and Testing Issues

4.5   References

5   HELMET PERFORMANCE MEASURES AND TRENDS IN TEST DATA

5.0   Summary

5.1   Introduction

5.2   Performance Measures

5.3   Summary of Results from Available Test Data

5.4   Implications for First Article Testing Protocols

5.5   References

6   FIRST ARTICLE TESTING PROTOCOLS FOR RESISTANCE TO PENETRATION: STATISTICAL CONSIDERATIONS AND EVALUATION OF DOD TEST PLANS

6.0   Summary

6.1   Introduction

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

6.5   Post-Test Analysis

6.6   Future Test Protocols: Helmet as the Unit of Test

6.7   References

7   TEST PROTOCOLS FOR BACKFACE DEFORMATION: STATISTICAL CONSIDERATIONS AND ASSESSMENT

7.0   Summary

7.1   Introduction

7.2   Backface Deformation First Article Acceptance Testing Protocols and Their Properties

7.3   Discussion

8   LOT ACCEPTANCE TESTING

8.0   Summary

8.1   Introduction

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

8.6   References

9   CHARACTERIZATION TESTS FOR THE ADVANCED COMBAT HELMET AND FUTURE HELMETS

9.0   Summary

9.1   Introduction

9.2   Characterization of the Advanced Combat Helmet Using Existing Test Data

9.3   Expanded Characterization Requiring Additional Data

9.4   V₅₀ Testing

9.5   Comparison with Industrial Practices

9.6   Concluding Remarks

9.7   References

10  LINKING HELMET PROTECTION TO BRAIN INJURY

10.0   Summary

10.1   Introduction

10.2   Brain Injuries

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

10.7   Conclusion

10.8   References

APPENDIXES

A   Study Origination Documents

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

E   Synopsis of Brain Injury Detection Methods

F   Biographical Sketches of Committee Members

Tables, Figures, and Box

TABLES

FIGURES

BOX

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Acronyms and Abbreviations