reactive materials in mines and demolitions systems

Approved for Public Release (03-S-1859)

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Reactive Materials in Mines and Demolitions Systems

Mark Cvetnic

Technical Director of Advanced Programs

ATK Missile Systems

4700 Nathan Lane North

Plymouth, MN 55442-2512

(763) 744-5184

[email protected]


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Reactive Materials in Mines

• “Dial-a-yield” effects – Tiered response - reactive materials in a blast weapon can tailor the blast effect to range from non-lethal (disorientation / discomfort / incapacitation) to lethal force.

• Improved lethality – reactive materials improve performance against personnel and vehicles.


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Reactive Material in Demolitions

• Material Defeat – Shoulder fired systems that can defeat bunkers without penetrating. Increased target set and effectiveness of SLAM.

• Road Cratering– smaller binary shaped charge jets can create the same hole as the current two stage demolition system (shaped charge jet for hole drilling and C-4 for enlarging hole and upheaval of debris).


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Reactive Materials (RM)

• What is a Reactive Material? – Any composition that is compatible with explosives, shock initiated, and has dependable release of energy (rate and amount).

• Intermetallics – SHS reactions – Metals + Al, C or B– Primary Reaction: metal + metal = alloy + heat– Secondary Reaction: alloy + oxygen = oxide + heat

• Thermites – Metal + Metal Oxide– High reaction temperatures, no gas.

• Metal / Halogen – Al + Teflon reaction– Key focus area of reactive fragments.

• Ultra Fine Aluminum Particles – nano-energetics– Used with AP or KP to form rocket propellants.

• Metal Hydrides – AlH3 and TiH4.

– Use compounds with hydrogen to as energy carriers.


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Control of RM Reaction Rates.

Explosive energy – high pressure short duration

Reactive A – stoichiometric mix with small particles designed to minimize total reaction time.

Reactive B – stoichiometric mix with larger particles designed to increase total reaction time

from Reactive A.

Reactive C – fuel rich mix designed to maximize total reaction time.

• Why control the rate of oxidation? – To tailor the peak pressure and duration of the blast wave to maximize vulnerability of target.


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Generic Pressure – Impulse Curves for target

• Blast wave interaction with target• Diffraction Loading – differences of pressure occurs when blast wave passes. Function

of overpressure. Coupling is optimum when blast wave duration is ¼ the natural frequency of target. Light weight targets are most susceptible.

• Drag Coupling – Targets damaged due to drag loading of rapid moving air. Drag load damage increases when duration (impulse) of blast increases. Harder targets more susceptible.


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Bowen PI Curves for Personnel

Data shown are human tolerance predictions for a 70-kg man in a free-stream blast wave (References 1 and 2).

1 Gibson, Philip W., “Blast Overpressure and Survivability Calculations for Various Sizes of Explosive Charges,” United States Army Natick Research, Development and Engineering Center, Natick, Massachusetts, Report Number Natick/TR-95-003 (DTIC Accession Number AD-A286212), November 1994.

• White, C.S., et al., “The Biodynamics of Airblast,” Defense Nuclear Agency, Report Number DNA2738T, July 1971.

10

100

1000

0.1 1 10 100 1000

Over Pressure Pulse Duration (milliseconds)

Pe

ak

Ov

er

Pre

ss

ure

(p

si)

1% Survival 50% Survival Damage Threshold


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RM in Blast / Fragmentation warheads

• Reactive materials, used in conjunction with variable initiation schemes, can tailor the blast / fragmentation warhead effects:

• Lethal fragments patterns using reactive fragments.• Lethal blast combining the blast from the explosives and the reactive fragments.• Non-lethal blast – using the explosives and reactive fragments to create

incapacitating blast wave.• Non-lethal discomfort – high temperature impulse, with low pressure blast, create

discomfort zone.• Non-lethal disorientation – explosives and reactive materials to create high

intensity light

ATK’s goal is a single RM blast / fragmentation warhead that can be tailored to deliver a tiered response from disorientation to discomfort to incapacitation to lethal.


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Effects of RM in AP mines

• Non-Lethal Blast Effects• The energy release from reactive materials can be tailored to react and emit

specific bands of light that cause temporary flash blindness• The longer reaction rates of reactive materials can produce significant heat and

sustained low pressures (large impulse) that can cause discomfort and disorientation

• “Dial-a-yield” effects – Tiered response - reactive materials in a blast weapon can tailor the blast effect to range from non-lethal incapacitation to lethal force.

LethalNon-Lethal


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Lethal Effects of RM in mines

• RM Fragmentation Lethal Effects• Equivalent Kinetic Energy as steel fragments - Current generation ATK Thiokol

reactive materials have same density as steel, thus giving RM fragmentation weapons the same fragment kinetic energy.

• Additional Chemical Energy from RM event –reactive fragments can produce a large amount of chemical energy in the form of temperature, light and/or pressure.

• Blast Lethal Effects• Thermobaric - reactive materials can enhance the blast wave of conventional

explosives.

Reactive fragment event in test chamberThermobaric event in open


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RM in Explosively Formed Penetrators

• Improved Performance– Kinetic Energy

• Multiple Penetrators

– Chemical Energy• Overpressure• Temperature

Impact of Reactive EFP on concrete wall Reactive EFP vs. Fuel Drum


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Reactive Material Shaped Charge Jet

Flamethrower & Fuel Air Explosive – same fuel and oxidizer, different methods of delivery.


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How to control energy release in a RM SCJ

• Reaction rates in explosives are controlled by:• Fuel type, size, and distribution• Oxidizer type, size, and distribution• Binder

• RM SCJ are dynamic and additional parameters must be examined:• Fuel size and distribution are function of liner material and process used to create jet.• Oxidizer size and distribution function of jet interaction

Fuel Choice & SCJ Process

Jet & OxidizerInteraction


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Range of RM SCJ tested

Slow reaction rates

Medium reaction rates

Fast Reaction Rates

•Maximum Penetration•Minimal Overpressure•Minor improvement over inert SCJ

•Minimum Penetration•Maximum Overpressure•Best suited for cratering

•Maintain penetration•Significant overpressure damage•Best suited for bunker defeat


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RM SCJ Bunker Defeat

• Improved Effects– Penetration

– Overpressure

– Impulse

– Heat / Temperature

Thermobaric Reaction after Reactive SCJ penetrates concrete wall


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Binary Road Cratering System

Target – Concrete Slab with rebar

8 ft wide

+24 ft long

5 ½ inches thick with soil underneath.

Shaped Charge Jet

Conical

Diameter = 7.87 inches

Explosive weight = 11.65 lbs

Oxidizer

Entrainment system


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Crater formed by binary system

Damage to Target

Crater Diameter > eight feet

Crater Depth = 52 inches

•Depth of hole and upheaval of concrete demonstrates energy release of SCJ.•Potential for Road Cratering demonstrated.


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Contributions to this effort

ATK Ordnance and Ground Systems

ATK Thiokol Propulsion

Mike Matthews Consultant

Sigma Labs

AFRL HERD

ATK Ammunition and Powder

ARDEC – Picatinny Arsenal

Aerospace Group HeadquartersATK Thiokol PropulsionATK Composites

NAVSEA - Dahlgren

Lawrence Livermore National Labs.

General Science Inc

ATK Missile Systems

Los Alamos National Labs

Aveka Inc

Technanogy

Battelle

NAVAIR - China Lake


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Questions?

Mark Cvetnic

Technical Director of Advanced Programs

ATK Missile Systems

4700 Nathan Lane North

Plymouth, MN 55442-2512

(763) 744-5184

[email protected]

reactive materials in mines and demolitions systems

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