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Appendix L
Phase II Recommendations
This appendix contains the Phase II study recommendations. Phase II
resulted in nineteen findings and one overarching finding that were submitted to
the Office of the Director, Operational Test and Evaluation in the Phase II letter
report (NRC, 2010). The recommendations are summarized in Box L-1 and listed
here in full:
Recommendation 1: The Army’s medical and testing communities should be
adequately funded to expedite the research necessary both to quantify the medical
results of blunt force trauma on tissue and to use those results as the updated
mathematical underpinnings of the back face deformation (BFD) body armor
testing methodology.
Recommendation 2: The Army should develop ballistic testing performance
specifications and properties that will lead to a short-term, standard replacement
for the current Roma Plastilina #1 oil-based modeling clay.
Recommendation 3: Rheological and thermogravimetric measurements should
be carried out to better understand the properties and behaviors of clay as it is
being prepared and worked.
Recommendation 4: If it is demonstrated to achieve improved part-to-part
consistency of the clay compared to hand preparation procedures, a mechanical
compounding machine for clay preparation should be acquired, experimented
with, and used by the Aberdeen Test Center.
Recommendation 5: In-box mechanical conditioning might obviate the need for
precise temperature control and reduce the need for hand working of the clay.
Mechanical working methods should be tested.
Recommendation 6: Since oil-based modeling clay is time and temperature
sensitive, a post-drop calibration test is needed to validate that the clay remains
within specification at the end of a body armor test. The Army should add this
requirement for a post-drop calibration test of the clay to its Test Operating
Procedure (TOP 10-2-210).
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Recommendation 7: The spatial variation of modeling clay is significant and
three-dimensional. The response of the clay appears to depend on temperature,
shear history, and proximity to the edge. Given the confounding effect of box
geometry, the Aberdeen Test Center should perform a systematic set of column-
drop performance tests as experiments to assess the consequence of variation due
to the shape and size of the frame that defines the clay box. These tests should
determine if a circular box of approximately the same area as the current box
reduces the spatial variation that affects ballistic testing, or if a larger box area
eliminates the clay edge effects that affect ballistic testing.
Recommendation 8: As an alternative to the current column-drop performance
test the Army should quickly develop and experiment with a gas gun calibrator, or
equivalent device, that delivers impactors to the surface of clay boxes and that
determines local variation within a clay box at speeds and depths corresponding to
those involved in the generation of the backface deformation. These experiments
should be used to estimate as accurately as possible the variation of backface
deformation measurements both within a given box and between boxes, under
realistic testing conditions using existing test protocols.
Recommendation 9: While the committee applauds the Aberdeen Test Center
efforts to understand and attempt to measure the dynamics associated with the
creation of a backface deformation, the signal-to-noise ratio of the flash x-ray
cineradiography approach should be thoroughly analyzed to determine if the
desired spatial and temporal resolution can be achieved.
Recommendation 10: To better understand and measure the forces that create the
backface deformation the Army should experiment with inserting microscopic
temperature and displacement sensors into the clay near the site of the backface
deformation.
Recommendation 11: The Army should consider experimenting with high-speed
photographic analysis of backface deformation in ballistic gelatin as an alternative
for providing needed information on the forces that shape the backface
deformation.
Recommendation 12: The Army should conduct rheology and other studies on
ballistic gelatin as a mid-term alternative to modeling clay due to its properties,
which include the ability to directly record BFD using high-speed photography
and the elimination of the effects of shear history, time, and temperature on the
response of the backing material. However, correlation studies and tests are
needed to better understand the differences in the extent of deformation and
dynamics among gelatin and alternative clay formulations.
Recommendation 13: The Army should perform rheology and other evaluations
on microcrystalline wax mixtures as a possible long-term replacement for Roma
Plastilina #1 as a backing material for ballistic testing. Studies are needed to
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optimize the composition of the mixtures to produce the desired properties. In
addition, correlation studies are needed to compare the response of the
microcrystalline wax mixtures to the current material and/or ballistic gelatin.
Recommendation 14: The ad hoc clay working group should be empowered and
adequately resourced to gather information, influence research, and develop
working-level consensus across body armor testing organizations for the uniform
application of National Institute of Justice standards across participating test
organizations.
Recommendation 15: The Department of Defense Director of Operational Test
& Evaluation (DOT&E) and the National Institute of Justice (NIJ), in
collaboration with the military services, unified commands, other governmental
organizations, NIJ-certified laboratories, and appropriate nongovernmental and
commercial organizations should convene a nationally recognized group to
review all appropriate considerations and develop recommendations that could
lead to a single national body armor testing standard to achieve more uniform
testing results.
Recommendation 16: Before adopting the proposed statistically based protocol,
the Department of Defense Director, Operational Test & Evaluation (DOT&E),
should explicitly compare the risks of the proposed protocol and those of the
existing Army and U.S. Special Operations Command (USSOCOM) protocols, in
order to establish which test plan increases soldier safety while balancing the
manufacturer’s risk and incentives to overdesign. The committee notes that the
USSOCOM first article test protocol may not be intended as a comprehensive
technical test, and clarifying this issue would also help in the comparison of the
protocols.
Recommendation 17: The committee recommends that testers and statisticians
continue to work together as a team (1) to quantify in a statistically rigorous
manner the amount of variation in backface deformation attributable to the testing
process and that attributable to the plates, and (2) to ensure these results are
appropriately reflected in an updated protocol. In particular, the statisticians
involved with developing and implementing the statistically based protocol
should be involved with the experimentation recommended in Recommendations
2-8. It would be helpful for statisticians to be part of the process of understanding
and quantifying test system variation.
Recommendation 18: The Department of Defense should develop standard
statistically based body armor Lot Acceptance Testing (LAT) protocols that
incorporate aspects of MIL-STD-1916, particularly those related to quality control
and improvement and switching procedures. Adopting and incorporating modern
statistical process control methods into the manufacturing processes is specifically
recommended so that plate quality can be managed and assessed prior to lot
acceptance testing. This could potentially reduce testing effort and costs. Note
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that while MIL-STD-1916 states that the “sampling plans and procedures of this
standard are not intended for use with destructive tests,” these aspects of the
military standard are relevant to body armor LAT testing.
Recommendation 19: The Department of Defense (DoD) Director, Operational
Test & Evaluation (DOT&E) should provide briefings to and receive feedback
from all stakeholders in DoD (military service Program Executive Officers,
testers, users) and non-DoD organizations (National Institute of Justice, National
Institute of Standards and Technology, certified private testing laboratories,
vendors) concerning the statistically based protocol. This feedback, as well as the
results of the experiments and analyses proposed in this report, should be used as
due diligence to carefully and completely assess the effects, large and small, of
the proposed statistically based protocol before it is formally adopted across the
body armor testing community. DOT&E should act on feedback from the
community to improve the proposed protocol as necessary, to ensure that testing
terms and concepts make sense to a nontechnical audience, and it should promote
the use of statistically based protocols in future national standards for body armor
testing, as appropriate.
Overarching Recommendation: The committee applauds DOT&E for assuming
a national-level leadership role in bringing the body armor test community
together. The committee recommends that the DOT&E (1) work with Congress,
DoD, the military services, and other organizations to find the resources necessary
to implement the recommendations described in this report and summarized in
[Box L-1] and (2) oversee, review, track, and assist designated action
organizations with implementing these recommendations. This approach should
result in more consistent test results that will provide equally survivable but
lighter-weight body armor to our military service members and civilian police
forces.
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Box L-1 Phase II Recommendations to Improve Body Armor Testing
Achieving Greater Part-to-Part Consistency in Clay
1. Quantify the Medical Results of Blunt Force Trauma on Tissue and Incorporate Results
into the BFD Methodology
2. Determine Short-Term Standard Clay Specification
3. Conduct Rheological and Thermogravimetric Measurements
4. Procure and Experiment with a Clay Compounding Machine
5. Examine Technologies for “In Box” Mechanical Clay Working
6. Modify TOP 10-2-210 Procedures to Add a Post-calibration Drop (ATC, 2008)
7. Experiment with Various Clay Box Sizes and Shapes
8. Develop and Experiment with a Gas Gun Calibrator or Equivalent Device
Analyzing Backface Deformation Dynamics
9. Analyze the Signal-to-Noise of Flash X-Ray Cineradiography
10. Experiment with Microscopic Temperature and Displacement Sensors in Clay
11. Experiment with the High-Speed Photographic Analysis of BFD Creation in Ballistic
Gelatin
Determining Possible Replacements for Modeling Clay
12. Study Ballistic Gelatin as a Mid-Term Alternative to Modeling Clay
13. Study Microcrystalline Waxes as a Long-Term Alternative to Modeling Clay or Ballistic
Gelatin.
Achieving a Single National Clay Standard for Body Armor Testing
14. Empower and Resource the Ad Hoc Clay Working Group
15. Convene a Nationally Recognized Group to Establish a Single National Standard for
Handling and Validating Clay
Implementing Statistically Based Protocols
16. Compare the Proposed Statistically Based Protocol with the Existing USSOCOM Protocol
17. Quantify the Variation in the Body Armor Test Process and Incorporate in the Protocol
18. Develop a Statistically-Based LAT Protocol
19. Conduct Due Diligence Before Implementing and Formally Adopting a Set of Statistically
Based Protocols
SOURCE: NRC, 2010
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REFERENCE
NRC (National Research Council). 2010. Phase II Report on Review of the
Testing of Body Armor Materials for Use by the U.S. Army: Letter Report.
Washington, D.C.: National Academies Press.
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