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Introduction and Background |
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Existing Less Lethal Ammunitions |
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Design Principles |
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Biomechanics Background |
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Composite Preparation |
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Mechanical Testing |
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Blunt Impact Testing |
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Conclusions |
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To date, there is no satisfactory replacement of
traditional lethal police or military firearms with less-lethal weapon in
certain life and death situations.
(Button, Toronto Metropolitan Police Research Report, 2001) |
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Simple concept /compact / light weight (15 to 40
g) |
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Immediate incapacitation “..comparable to a
vigorous punch.” |
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Adequate stand off distance ( 2 to 15 m) |
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Consistent and reliable |
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Health safety (no chemical / electrical shock) |
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Low Cost |
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Minimum additional training requirements. |
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“Any thoracic penetration may result in an acute
life-threatening injuries such as tension pneumothorax, hemothorax, massive
cardiac injury with tamponade, great vessel injury, hemoptysis, and lung
collapse may occur.” Charles, A. et al., J. Trauma. 2002; 53:997-1000 |
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Blunt and penetrating injuries caused by rubber
bullets during the Israeli-Arab conflict in October, 2000. |
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Poor aerodynamics, not effective at long rang,
e.g bean bag and sock rounds. |
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Toxic material, e.g. lead in sock and tube
rounds. |
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Hard thermoplastics, (Shore A hardness > 80),
e.g. Baton round: Polyurethane or polypropylene. |
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Thermoset elastomers, (Shore A hardness >
60), e.g. Tube and Rocket rounds (EPDM/ SBR + inorganic filler). |
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Costly to process/ manufacture. |
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Lethal, in cold climates. |
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Material
Properties in a wide temperature and frequency range: |
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Hardness |
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Creep |
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Damping |
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Impact Biomechanics |
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Maximum Tolerable Energy/Force/Deflection |
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Aerodynamics |
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Accuracy |
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Density: 2.4 g/cm3 |
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Weight:
20 gauge- 15 grams |
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12 gauge- 25 grams |
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Ingredients: |
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Thermoplastic Elastomers: for structure
stability and ease of processing. |
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Poly(styrene-block-isobutylene-block-styrene) (SIBS), (Kaneka Corporation, Osaka, Japan). |
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Styrene-Butadiene- Styrene (SBS) |
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Styrene-Isoprene-Styrene (SIS) |
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Elastomers: for the damping and rubbery
property. |
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Butyl elastomer (IIR), (Bayer Inc, Sarnia) |
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Natural Rubber (NR) |
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Metal Powder: to increase the density of the
composite. |
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Iron powder, (Quebec Metal Powders Limited). |
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Mixing Conditions: |
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10 minutes per batch |
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35 RPM |
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140-160oC |
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Equipment: Haake’s DEFO-Elastomer instrument |
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Specimen: 10 mm diameter by 10 mm height. |
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DMA in tension: GABO EPLEXOR |
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10 Hz |
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-100 to 100 oC |
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DMA in compression: MTS 831 |
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50, 0 and –50 oC; |
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0.01 to 500 Hz; |
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7% static and 3% dynamic deformation; |
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Sample: 10 mm diameter by 10 mm height. |
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Analyzed Samples: |
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Rubber Rocket, Triple Ball, Lead Filled Rubber |
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(Tube) and the Mono-Ball projectiles. |
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The newly developed composites. |
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Impact frequency at 12% deformation and 250 ft/s
is equivalent to: |
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21,111 Hz for the 20-gauge projectile. |
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16,170 Hz for the 12 gauge projectile. |
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DOW Styrofoam SM and Defender 1 mounted on a
robot. |
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Equipment Setup: |
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Materials and Manufacturing Ontario MMO. |
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MERC group. |
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Elisabeth Takacs, Research Engineer |
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McMaster University |
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Prof. Dr.-Ing.Volker Altstädt, Ph.D. |
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Department of Polymer Engineering,
University of Bayreuth, Germany. |
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Notes