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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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). -317-
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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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 -318-
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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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 -319-
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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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. -320-
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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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 -321-
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PREPUBLICATION DRAFT—SUBJECT TO EDITORIAL CORRECTION 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. -322-