Transformative Energetics: A Pathway to Next Generation Munitions

Merran Daniel, Andrew Hart, Arthur Provatas

Energetic Systems and Effects Branch

PARARI 2017

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Introduction

DST plays a key role in positioning the ADF to fully exploit capabilities afforded by emerging weapons concepts– Army Modernisation Lines of Effort: Next Generation Munitions, Novel

Energy Weapons…

Transformative EnergeticsEnabling advanced weapons systems that offer disruptive performance gains and

increasing the safety, agility and efficiency of munitions manufacture.

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Transformative Energetics Lines of EffortUNCLASSIFIED

Advanced Materials• Nano-technology

Processing Technology• Resonant Acoustic Mixing

3D Printing of Energetics

Next Generation Munitions

Nano-energetics An emerging field of energetic materials

– China, Russia and US are leaders amongst few active players– US ARDEC labs – nano-sized polymer coated RDX, HMX, TATB, CL-20, NTO

Material properties change significantly at nano-scale (~0.1 µm)– Higher surface area– Increased chemical reactivity– Enhanced mechanical properties– Higher solubility– Altered optical properties– Smaller defect dimensions

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Enhanced performance & safety – effective energy utilisation in volume constrained, extreme environments

Nano Energetics

Perf

orm

ance

Sensitivity

Traditional Materials

Nano-Processes and MethodsUNCLASSIFIED

Top-Down Processes Bottom-Up Processes

Bead Milling• Comminution process

(media: liquid with <500µm ceramic beads)

• Maintains polymorph• Scalable

Spray Drying• Crystallisation process• Micron sized particles

containing nano-sized EM encapsulated by binder

• Simple and scalable• Best polymorph not always

retained

Complimentary techniques

Spray Drying: Büchi 290 closed loop systemUNCLASSIFIED

Rapid co-precipitationyields nanocomposite

granules

EM + BinderDissolved in

Organic solvent

Atomisation- droplets

evaporated

Nozzle

Drying Cyclone Product Outlet Chamber Separator Filter

Aspirator

Process VariablesSolution Feed Rate

Atomizing Gas Rate

Drying Temperature

Solvent Type

Concentration of Solute

Ref: Qiu et al, Powder Tech., 2015, 274, 333-337

Spray Drying: DST Program of Work

RDX/HMX and FEM RDX with PVAc binder– Alternative coatings to explore, inc. in support of 3D printing of

energetics

RDX with polyGLYN– More energetic binders to follow

Priority: Material characterisation– Sensitiveness, morphology, performance

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1-15 µm nanostructured RDX granules

Resonant Acoustic Mixing (RAM) RAM is a new processing technique that utilises low frequency

high-intensity acoustic energy to blend materials– Fast– Increased safety– Versatile– Environmental benefits– Currently used for research, development and production of energetic

materials globally

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Video: ResodynSource: Resodyn

DST Group Resonant Acoustic Mixers

LabRAM, 500g capacity

LabRAM IIH, 1kg capacity

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Industrial Resonant Acoustic Mixers

RAM 5, 37kg capacity

RAM 55, 420kg capacity

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Continuous Acoustic MixerUNCLASSIFIED

Couples to RAM 5Application Throughput (kg/hr)

Dry powder 1080

Intermediate viscosity 100

High viscosity 8.2

RAM ApplicationsUNCLASSIFIED

Dry powder mixing

High viscosity slurries

In-situ mixing

RDX + 10% MP22XF 1 min RDX + 10% MP22XF 30 min

Polymer coating Co-crystallisation

Ref: Bolton et al, Cryst. Growth Des. 2012, 12, 4311-14

Mould. powder develop.

– Disruptive technology – prospect of better exploiting gun hardware performance limits.

– Integrated propelling charge design and arbitrary propellant geometries:• Increased range, velocity, precision, uniformity, weapon life…

– More agile and cost-effective (?) propelling charge development– Reduced manufacturing footprint.

Key challenges by 3D printing technology type:– Structural integrity of print/build– Printer feedstock options

• Achievable energy content; • compatibility; • curability…

– Print precision

3D Printing of Propelling ChargesUNCLASSIFIED

– Disruptive technology – prospect of better exploiting gun hardware performance limits.

– Integrated propelling charge design and arbitrary propellant geometries:• Increased range, velocity, precision, uniformity, weapon life…

– More agile and cost-effective (?) propelling charge development– Reduced manufacturing footprint.

Key challenges by 3D printing technology type:– Structural integrity of print/build– Printer feedstock options

• Achievable energy content; • compatibility; • curability…

– Print precision

3D Printing of Propelling ChargesUNCLASSIFIED

10% m.v increase

Next Generation Gun Propelling Charges

Ballistics Research

Component

Model, optimise, design and test new gun

propelling charges which exploit advanced manufacture methods

Manufacture Research

Component

Research, develop and demonstrate additive

propellant manufacture methods and

formulations, and produce and

characterise product in the laboratory

Resolution and complexity requirements

Grain and charge designs

Mechanical requirements

Formulation requirements(Impetus, BR, etc.)

Achievable/manufacturable geometries and properties

Achievable formulations

Product for laboratory and live ballistic testing

Product spec for IB simulation

Research ThrustsUNCLASSIFIED

Ballistics Research StreamUNCLASSIFIED

Tool Development

• Write a fast lumped parameter IB model for arbitrary grains (version 1 complete)

• Develop grain form functions to explore simple highly-progressive geometries (some initial geometries complete)

• Develop and implement multi-objective optimisation and/or a surface-area deconvolution method

• Code a form function model for arbitrary and complex 3D grains

• Develop suitable CV analysis methods• Identify suitable gun testbed/s

Research Schedule

• Quantify theoretical gun performance improvements for highly progressive 3D grain geometries (Year 1)

• Develop methods for identifying and parametrising suitable novel 3D topologies, ready for optimisation (Years 1-2)

• Provide realistic, manufacturable, high-performance charge designs for manufacture and test (Years 2-4)

• Ballistic lab testing and analysis (Year 2-3) and live firing tests and demo (Year 4?)

Ballistics Research StreamUNCLASSIFIED

Tool Development

• Write a fast lumped parameter IB model for arbitrary grains (version 1 complete)

• Develop grain form functions to explore simple highly-progressive geometries (some initial geometries complete)

• Develop and implement multi-objective optimisation and/or a surface-area deconvolution method

• Code a form function model for arbitrary and complex 3D grains

• Develop suitable CV analysis methods• Identify suitable gun testbed/s

Research Schedule

• Quantify theoretical gun performance improvements for highly progressive 3D grain geometries (Year 1)

• Develop methods for identifying and parametrising suitable novel 3D topologies, ready for optimisation (Years 1-2)

• Provide realistic, manufacturable, high-performance charge designs for manufacture and test (Years 2-4)

• Ballistic lab testing and analysis (Year 2-3) and live firing tests and demo (Year 4?)

…could equally be rocket or high explosive charge modelling

3D Printing Techniques

Ref: Short Course – From 3D Printing to Factory Floor, Massachussets Institute of Technology, Cambridge, MA, July 2016.

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3D Printing Techniques

Ref: Short Course – From 3D Printing to Factory Floor, Massachussets Institute of Technology, Cambridge, MA, July 2016.

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3D Printing Techniques: DST

Ref: Short Course – From 3D Printing to Factory Floor, Massachussets Institute of Technology, Cambridge, MA, July 2016.

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DLP

UV Paste

3D Printing Techniques: Collaborative Partners

Ref: Short Course – From 3D Printing to Factory Floor, Massachusetts Institute of Technology, Cambridge, MA, July 2016.

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SLA

UV Paste

Binder Jet.

FDM

DST 3D Printers for EM EvaluationUNCLASSIFIED

Image from 3dprint.com

UV Paste Extrusion: Hyrel 30M

Image from kudo3d.com

DLP: Gizimate 130 Basic

High-Solids Printing Challenges: DLP and UV PasteUNCLASSIFIED

Printer Technology Challenge

SLA/DLP and UV Paste • High η and particle bridging affect reactive species mobility• Solids-light interaction affect photoinitiator absorption

SLA/DLP • Particle induced light scattering affecting precision• Solids-settling• Effective layer re-coating

UV Paste • Liquid phase migration• Achievable pressure drop for extrusion • Maximum permissible particle size vs. precision

Ref: Decker et al, Polymer, 2001, 42(13), 5531-5541 Ref: Endruweit et al, Polymer Composites, 2006, 27(2), 119-128

High-Solids Printing Challenges (eg’s)UNCLASSIFIED

Liquid Phase MigrationSolids - UV light interaction

Print PrecisionFeedstock Viscosity

Source: E. Caravaca, ARDEC (2016)

Transformative EnergeticsUNCLASSIFIED

Conventional Energetic materials

Processed by RAM

High solids loaded conventional formulations

Performance increase cf. conventional EM: +

Transformative EnergeticsUNCLASSIFIED

Performance increase cf. conventional EM: ++

Conventional Energetic materials

Nano sizing Processed by RAM

Nano energetic formulations

Transformative EnergeticsUNCLASSIFIED

Performance increase cf. conventional EM: > +++

Conventional Energetic materials

Nano sizing Processed by RAM

Nano energetic formulations

3D printed nano-energetic

formulations

Transformative EnergeticsUNCLASSIFIED

Performance increase cf. conventional EM: > +++

Conventional Energetic materials

Nano sizing Processed by RAM

Nano energetic formulations

3D printed nano-energetic

formulations

Benefits further augmented in volume limited and/or geometrically constrained applications

Transformative Energetics: Collaborative PartnersUNCLASSIFIED

Government Industry Academia

Transformative Energetics: A Pathway to Next Generation Munitions

Merran Daniel, Andrew Hart, Arthur Provatas

andrew.hart@dst.defence.gov.auPh: +61 8 7389 5520

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