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Ballistic Helmet Standard Technologies for Critical Incident Preparedness Conference and Exposition San Francisco, November 6-8, 2007.

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Presentation on theme: "Ballistic Helmet Standard Technologies for Critical Incident Preparedness Conference and Exposition San Francisco, November 6-8, 2007."— Presentation transcript:

1 Ballistic Helmet Standard Technologies for Critical Incident Preparedness Conference and Exposition San Francisco, November 6-8, 2007

2 TCIP Conference and Exposition, November 6-8, 2007 Motivation new lightweight composite helmets have increased protection against penetration non-penetrating impacts may results in large backface deformation increase risk of serious skull/brain injuries ? current test procedures address penetration resistance but lack injury risk evaluation for non-penetrating impacts

3 TCIP Conference and Exposition, November 6-8, 2007 R&D Review mid 90’DRDC Valcartier initiated study on backface impact force / deformation 1997NATO BABT TG Natick Soldier Center: developed skull fracture injury function (UVa) 2002TSWG funded development of ballistic helmet test method 2005TSWG funded additional efforts to evaluate threat severity

4 TCIP Conference and Exposition, November 6-8, 2007 U.S Army NSC R&D Program Research approach: Identify injury mechanism Determine physical response measurement Develop injury function Develop physical surrogate Work conducted by Bass et al. (University of Virginia

5 TCIP Conference and Exposition, November 6-8, 2007 Injury Function animal model cadaver model epidemiology Injury Model Physical Response loads, acceleration, etc. Surrogate loads, acceleration, etc. Transfer Function

6 TCIP Conference and Exposition, November 6-8, 2007 Injury Function animal model cadaver model epidemiology Injury Model Physical Response loads, acceleration, etc. Physical Response Probability of injury Surrogate loads, acceleration, etc. Physical Response Probability of injury Transfer Function

7 TCIP Conference and Exposition, November 6-8, 2007 Outcomes Skull peak pressure is best correlated with injury Injury function for non-penetrating ballistic impacts

8 TCIP Conference and Exposition, November 6-8, 2007 NIJ Standard (1981) Penetration Resistance Limited number of test samples required: 2 helmets / test ammunition 1 st helmet tested at ambient conditions 2 nd helmet wet-conditioned (immersion 2-4hr) 4 impact locations / helmet: rear, front, left, right Requirement for Level I, II-A and II only No ballistic limit tests (V50)

9 TCIP Conference and Exposition, November 6-8, 2007 NIJ Standard (1981) Transmitted Force 1 helmet / test ammunition tested at ambient conditions 4 impact locations / helmet: rear, front, left, right Peak linear acceleration <400g Correlation with injury unknown

10 TCIP Conference and Exposition, November 6-8, 2007 Other Test Procedures HPW-TP B (1995) Measure maximum deformation in clay Correlation with injury unknown STANAG 2920 No requirement for non- penetrating impacts ACH Specifications Measure maximum deformation in clay Correlation with injury unknown clay

11 TCIP Conference and Exposition, November 6-8, 2007 Proposed Test Method confirm penetration resistance with separate headform implement an impact force measurement headform based on injury model developed by Bass et al. (2003) using localized skull pressure predict risk of skull fracture from dynamic force measurements evaluate BABT protection performance of ballistic helmets

12 TCIP Conference and Exposition, November 6-8, 2007 Penetration Headform

13 TCIP Conference and Exposition, November 6-8, 2007 Impact Force Measurement Load Cell Module Pressure Sensitive Film

14 TCIP Conference and Exposition, November 6-8, 2007 Parametric Study Energy Absorbing (EA) Material Standoff Helmet Shell

15 TCIP Conference and Exposition, November 6-8, 2007 Peak Force vs. Impact Speed Test Sample DescriptionSize Standoff (mm) Wt (kg) AD (kg/m 2 ) ABaseline design, no EA liner matlMLHH BBaseline design with EA liner matlMMHH CNew lightweight designMLLL D LHLL

16 TCIP Conference and Exposition, November 6-8, 2007 Energy Absorbing Liner

17 TCIP Conference and Exposition, November 6-8, 2007 Outcomes Current design & new lightweight helmets can have comparable BABT attenuation  standoff  peak impact force EA materials  peak impact force (load distribution)

18 TCIP Conference and Exposition, November 6-8, 2007 Standards Activities The Canadian Standards Association (CSA) has formed a new CSA Technical Committee to create a National Standard on ballistic helmets (CSA Z613). The National Institute of Justice Ballistic Helmet standard is under revision.

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