RecommendationsFor Shaped Charge Jet,

Munitions Test Procedure

Part 2 : Gun Propellant

Dr Frédéric PEUGEOT, March 2003

Shaped ChargeJet

VelocityDiameterComposition

PropellantBallisticsProperties

ImpetusBurn rate IgnitionTemperature

Propellant PhysicalProperties

CompositionParticle sizesBed loading density %TMD (voidage)HomogeneityGlass transition temp.Binder/Filler interaction

Propellant ShockSensitivity

CJ parametersHugoniotCritical energyCritical Diameter

PropellantConfiguration

ShapePerforations(number, size,…)Web SizeOuter diameterMassConfinement

IntroductionInfluencing factors

GB 19T - 120mmGB Bp - 120 mm

GB Se - 12.7 mm

ShortcomingsScaling effects

 

NOL Large Scale Gap test

The greater, the less shock sensitive

LOVA-4

Triplebase-2

Triplebase-1

0 0.80.60.40.2 1.0 1.2 1.4 1.6 1.8 2.0

0.8

0.6

0.4

0.2

1.0

1.2

1.4

Web (mm)

Reaction level

The thicker,the more shock sensitive

U shape?

Resolving ShortcomingsScaling effects

The response is driven bythe bed properties

The response is driven bythe grains properties

Actual Size

AREA 1

Jet tip / Grainsinteraction

Mechanism:

Shock Detonation Transition

Reaction Mechanisms (1/2)Macroscale

AREA 2

Grains / Grainsinteraction

Mechanism: ?

Type IV-VNO

YES

Area 1 ProtocolInteraction Jet-Grain(s)

Confinement

JetBow Shock

Cavity

CompressedPropellant

Type IV-V

Energy providedby the jet impact

>Formulation Critical energy ?

Grains dimensions >

Grains critical dimensions ?

YESNO

YES

Area 1 ProtocolInteraction Jet-Grain(s)

ShortcomingsCritical diameters

What is the influence of a perforation or several perforationson the critical diameter?

Formulation

A

BC

FormulationCritical Diameter

(mm)

2.9-4.1

3.8-4.72.7-3.8

 But, Debenham obtained a high order response even with a web lowerthan the critical web….

Formulation Grains

Slotted TubeCritical Outer

Diameter (mm)

4.5-5.3

8.3-10.77-8.3

Slotted TubeCritical Web

(mm)

1.7-2.0

2.5-3.22.1-2.5

-40/50% +30/55%

WATSON (1992)

X rays

ZIMMERMANN(1996)

X rays

43.9 µs

49.2 µs

Sympatheticdetonation

PEUGEOT (1996)

Reaction Mechanisms (2/2)Area 2 - Macroscale

Layerstransmission

Sympathetic DetonationArea 2 - Mesoscale Mechanisms

donordonor donor

IDT

IDT

XDT I

XDT II

NOType II-III

YES

Type I

Propellant BedArea 2

Area 2 ProtocolInteraction Grain(s)-Grain(s)

Sympathetic Detonationof the grains?

Bow Shock+Cavity

Area 1

Jet

Test conditions

Test configuration

Represent the life cycleconfiguration

ConclusionsTesting Recommendations

No jet particulationNo inverted gradient effect

No spallLongest credible path

Stripper plate

Min attenuator thickness

Stand off

Test instrumentation

Threat & Reaction level

X-Ray

Witness plate

Representative casingRepresentative shieldingRepresentative dimensionsSufficient amount of prop.No additional Confinement

ü Dimensional characteristics that reduce the risk ofSympathetic Detonation

ü The best mechanical properties (XDT issues)

ü The lowest bed loading density (opposite to ballisticsproperties) not to favour SD

ü The lowest Hugoniot

ü The highest pressure dependent critical energy curve

ü The highest critical diameter

ConclusionsThe best LOVA propellant

Gun propellant vulnerability to SCJI is drivenby 2 mechanisms:

- the sensitivity to shock of the gun propellant- the mechanical behavior of the gun propellant

Any Questions?f.peugeot@hq.nato.int