recommendations for shaped charge jet, munitions test procedure … · 2017-05-30 · shaped charge...
TRANSCRIPT
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