1 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

NUMERICAL SIMULATION OF REACTION VIOLENCENUMERICAL SIMULATION OF REACTION VIOLENCETO COOK-OFF EXPERIMENTSTO COOK-OFF EXPERIMENTS

David DESAILLY - Yves GUENGANT SNPE Matériaux Energétiques - France

2 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

1. STAKES / OBJECTIVES

2. METHODOLOGY DEVELOPED BY SME

3. SIGNIFICANT RESULTS - LARGE SCALE APPLICATIONS

4. CONCLUSIONS - FUTURE PLANS

CONTENTSCONTENTS

3 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

WHAT ARE THE STAKES ?WHAT ARE THE STAKES ?

BURNING DETONATION

4 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

THERMAL SOURCE ACCIDENTSTHERMAL SOURCE ACCIDENTS

Forestall aircraft carrier DOHA camp

Ä Many research programs have been investigated at SME to reducevulnerability of systems to accidental and hostile environments

Stakes - objectivesStakes - objectives

5 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ä Supported by the European consortium EUCLID CEPA14 RTP2

Ä Sponsored by D.G.A. of the French Ministry of Defence

Stakes - objectivesStakes - objectives

« Develop and evaluate test methods and « Develop and evaluate test methods and

computer models for predicting the responsecomputer models for predicting the response

of generic explosive-loaded munitions » of generic explosive-loaded munitions »

FINANCIAL SUPPORTFINANCIAL SUPPORT

6 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

SME METHODOLOGYSME METHODOLOGY

7 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ä Characterisation tests on energetic material samples :

Methodology Methodology

KEY STEPS - MAIN IDEASKEY STEPS - MAIN IDEAS

Ä Physical model establishment - Fitting of numerical parameters

SELF-HEATING LOSS OF MASS(POROSITY) REACTIVITY

Ä Implementation of this physical model within Finite Elements codes

Predict the mechanical behaviour of systems subjectedto thermal threats

8 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ä Simulating the response of systems subjected to a thermal conditioningrequires thermo-chemical and structural analyses

ABAQUS / LS-DYNAABAQUS / LS-DYNA

WEAK COUPLING WEAK COUPLING

HYPOTHESES - NUMERICAL TOOLSHYPOTHESES - NUMERICAL TOOLS

Ä MODEL FEATURES :

Ø Accelerated combustion regimes

Ø Thermal damage prior ignition is a key parameter to reaction violence level

Methodology Methodology

9 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ä Energetic materials can exhibit endothermic and exothermicdecomposition processes

COOK-OFF EXPERIMENTS FOR MODELSCOOK-OFF EXPERIMENTS FOR MODELS

SELF- HEATING / THERMO- IGNITION SELF- HEATING / THERMO- IGNITION (1)(1)

Temperature history

ALUMINIUMCASE

THE SAMPLE IS PACKED

INSIDE ALUMINIUM PAPER

THERMOCOUPLE

STEEL OVEN

THERMOCOUPLES

ELECTRICAL

RESISTANCEUNITS

SNPE n°41/ GEMO SEN307-00

Methodology Methodology

10 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

3.3 °C/h

50 °C/h

360 °C/h

Tube diamètre 40 mm

H.200 mmEpaisseur: 4 mm

2bouchons avec colliers chauffants

de 215 watt

5 colliers chauffantsde 180 watt

un tube ONU résistance 750 barset 2 bouchons résistance 450 bars

Ignited region prediction

Ä Reactional scheme : three steps Arrhénius law

DCBA REACTIONREACTIONREACTION → → → 321

Q1 > 0 Q2 < 0 Q3 > 0

SELF- HEATING SIMULATION via ABAQUSSELF- HEATING SIMULATION via ABAQUS

Methodology Methodology

11 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

UNDER CONFINEMENT PYROLYSIS TEST UNDER CONFINEMENT PYROLYSIS TEST (2)(2)

Pressure increase

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

0

10

20

30

40

50

Pyrolyse Butalite 82/4 à 7% CrCu( C 1577-2 )

minutes

pres

sion

en

bar

196 °C

216 °C206 °C

203 °C

200 °C (*)

Ä Quantify loss of mass and increase of pressure

Ä Fit the kinetic parameters

Φ44.5

SNPE pyrolysis set-up

12 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ä Trials are performed in a HPCV Bomb under temperature control

)()()( γγγ nr PaV =

porosity ⇔ reactivity

HIGH PRESSURE CLOSED VESSEL BOMB HIGH PRESSURE CLOSED VESSEL BOMB (3)(3)

Ä Effect of thermal damage γ on an explosive composition reactivity :

Methodology Methodology

0

50

100

150

200

250

0 20 40 60 80 100

P (MPa)

V(P) (mm/s)

PBXN 109 - Pristine

PBXN 109 8 H - 134°C

PBXN 109 16 H - 140°C

PBXN 109 8 H - 160°C

PBXN 109 8 H - 150°C

PBXN 109 4 H - 148°C

13 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

COUPLED STRUCTURAL/BURNING MODEL V.R.E.M.E. COUPLED STRUCTURAL/BURNING MODEL V.R.E.M.E. 

Ä Physical representation :

Ø Burning : surface regression model

Ø Two-phases flow model with compressible solid and gas phases

ve

eVR

BeVR

Ap VRvR ωωω+

−+

−= −− 21

21

11

Ø Laws of mixture : pressure equilibrium - additivity of volumes and internal energies

21

21

)1(

)1(

FeeFexe

FvvFvxv

ii

ii

+−=∑=+−=∑=

Methodology Methodology

- FOG method : )(γα rVdtdF

=

- « Level - Set » method (front « capturing » approach) :→→→

∇=∇+∂∂

FVFutF

r )(. γ

14 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

SURFACE REGRESSION (HAMILTON - JACOBI)SURFACE REGRESSION (HAMILTON - JACOBI)

Methodology Methodology

15 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

SIGNIFICANT RESULTSSIGNIFICANT RESULTS

(Application to large scale tests)(Application to large scale tests)

16 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ø Energetic material : B2238 explosive (RDX, PBHT binder)

Ø Thermal conditioning : fast cook-off conditions (heating profile 360 °C/h)

VIOLENCE PREDICTION TO FAST HEATING RATESVIOLENCE PREDICTION TO FAST HEATING RATES

Significant resultsSignificant results

Ä Description - boundary conditions

Heat source

17 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

ILLUSTRATIONILLUSTRATION

Significant resultsSignificant results

18 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

FRACTURE IN THE MIDDLE PLANE

Significant resultsSignificant results

19 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ø Full-scale warhead - Strong confinement

Ø Energetic material : PBXN109/SNPE explosive (I-RDX based)

Ø Thermal conditioning : slow cook-off conditions (heating profile 3.3 °C/h)

Significant resultsSignificant results

WARHEADS BEHAVIOUR TO SLOW HEATING RATESWARHEADS BEHAVIOUR TO SLOW HEATING RATES

20 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

I-RDX BASED WARHEAD – THERMO-CHEMICALI-RDX BASED WARHEAD – THERMO-CHEMICALANALYSISANALYSIS

Temperature

Significant resultsSignificant results

Test : 163 °CCalculation : 165°C

Mass loss

21 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

NON -VIOLENT EVENTTYPE IV REACTION

I-RDX BASED WARHEAD - VIOLENCE LEVELI-RDX BASED WARHEAD - VIOLENCE LEVEL

22 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

CONCLUSIONS CONCLUSIONS

FUTURE PLANSFUTURE PLANS

23 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ø Prediction of the reaction violence of multi-dimensionnal systems (ABAQUS / LS-DYNA)

In combustion modes, we can estimate :

Ä SNPE developed a methodolgy for predicting the violence level ofsystems submitted to a thermal threat :

Ø Characterisation tests on samples of energetic material

PRESSURISATION&

EXPANSION VELOCITY

Ø Fitting of the numerical model parameters

Conclusions - future plansConclusions - future plans

ACHIEVEMENTSACHIEVEMENTS

REACTION TYPESIII, IV, V

24 NUMERICAL SIMULATION TO COOK-OFF EXPERIMENTSNUMERICAL SIMULATION TO COOK-OFF EXPERIMENTS 2003 IMEMTSMarch 10-13

Ø Violence level prediction : need a validation phase by precise measurements

Moderate reaction due to good microstructural and morphologicalproperties of PBXN109/SNPE explosive (I-RDX based)

Ø Improve the model by incorporating physical components for simulatingmore violent events (DDT for instance)

FURTHER WORKFURTHER WORK

Conclusions - future plansConclusions - future plans

REACTION TYPESI, II, III, IV, V

Ø Thermochemical processes : good agreement with tests (< 5 % variations)for explosive and propellant

RESULTS ACCURACYRESULTS ACCURACY