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~Alamos NATIONAL LABORATORY - - - ES T. 1943 ---

Title:

Author(s):

Intended for:

Merging the Mechanical Constitutive Model ViscoSCRAM with the Henson-Smilowitz Thermal Ignition Model to Address Weak-Shock Initiation

Brad Clements, Z# 104233, T-1

NCT Explosives Workshop LANL November 3, 2011

Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by the Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA25396. By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution , or to allow others to do so, for U.S. Government purposes. Los Alamos National Laboratory requests that the publisher identify this article as work performed under the auspices of the U.S. Department of Energy. Los Alamos National Laboratory strongly supports academic freedom and a researcher's right to publish; as an institution, however, the Laboratory does not endorse the viewpoint of a publication or guarantee its technical correctness.

Form 836 (7/06)

UNCLASSIFIED

Merging the Mechanical Constitutive Model ViscoSCRAM with the HensonSmilowitz Thermal Ignition Model to Address Weak-Shock Initiation

Brad Clements

Theoretical Division, LAN L

[email protected]

ABSTRACT An approach for addressing weak-shock and non-shock initiation is proposed. The approach consists of merging the thermo-mechanical constitutive model ViscoSCRAM and the Henson-Smilowitz thermal ignition into a single algorithm. Initial studies have been done that reveal both successes but also issues that must be overcome before the approach can be deemed ready for practical applications. When completed, this approach will offer the possibility of performing simulations for many lab programs, including NCT. It will take strategic commitment from LANL programs to get to that point.

NCT Explosives Workshop LANL

November 3,2011 A Los Alamos NATI O NAL LABOR AT OR Y UNCLASSIFIED ____ EST.1943

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 _ • . W~\lAl II/IVA.'~4

UNCLASSIFIED

Merging the Mechanical Constitutive Model ViscoSCRAM with the Henson-Smilowitz Thermal Ignition Model to Address Weak-Shock Initiation.

A Los Alamos NATIONAL LABORATORY ____ EST. 1943

Brad Clements

Theoretical Division, LANL

[email protected]

NCT Explosives Workshop LANL

November 3, 2011

UNCLASSIFIED

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 IA •. w~\lAl IIVA."~'i

UNCLASSIFIED

Outline

• Technical Motivation for this work

• ViscoSCRAM and the Henson-Smilowitz Model

• Issues

• Future Approaches

• Acknowledgments

A Los Alamos NAT IONA L LABORATOR Y UNCLASSIFIED ____ ES T. 1943

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 -. ··~\lAl .VA.'~'i

UNCLASSIFIED

Shock-to-detonation transition (SOT) has received the most attention and thus our understanding has progressed far beyond other means (DDT, XOT) of approaching detonation.

Reactive Burn Model: ASC PEM HE Level 2 Review

Sept. 28, 2010 LANL

/ Brad Clements (project leader, T-1)

Now, Mark Short WX-9

_ RalPh Menikoff and M. Sam Shaw (T-1) Tariq Aslam , Charles Kiyanda, Mark Short (WX-9) John Walter (XCP-4), Toru Aida (XCP-5)

} RFMG

ABSTRACT

A new advanced engineering hot-spot-based reactive flow model for IHE will be presented . Physics incorporated yields enhanced predictive capabilities for initial temperature changes, porosity changes, dead zone generation , etc. without experimental recalibration. Comparisons with existing reactive flow models are done to demonstrate improvements. Experimental shock profile data on the IHE PBX 9502 are used to calibrate the model. The model is shown to the shock data with excellent agreement.

~Alamos

3

2.5

2

~ "'" -;1.5 'u 0

~

0 .5

0 L..-.L

0

Velocity Gauge Data shot 2 ... 0

"",

0 .5 ri me (J.ts)

I I I

-~ /1 II

1.5

O.OOmm 1.16mm 1.95m"1 2.74 mm 3.52 mm 4.31 lUlU 5.1 0 mm 5.88 mlU 6.67 nun 7.46mlll

SURF model with gauge data- Shock-to-detonation at 23 C (Shot# 2s40 on PBX 9502, P s=13.5GPa)

This project was possible because of the close collaboration of the LANL HE experimental programs (Gustavsen, Hill, Dattelbaum, Jackson, Jensen, Hooks, Sheffield, etc.) and PEM support of the RFMG HE team.

NATIONAL LABORATORY UNCLASSIFIED __ EST. 1943 ____________________________________________ _

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 IIA • ,W ~lIAl /I/1V&."~4

UNCLASSIFIED

Shock-to-detonation transition (SDT) has received the most but still important questions remain veloci ~,o~2~oge Data

SOT phenomenon is rather well understood. ~ ""

2.5

2

O.OOmm 1.16mm 1.95mm 2.74mm 3.52 mm 4.31 mm 5.I Omm 5.88 mm 6.67 111m 7.46 mm

It is known that ignition sites (hot spots) playa major role in shock sensitivity, but a quantitative relation between material properties like amount of inclusions,

'i-1.5 'g ~

-~,

~-'~~ I~~ r---- - 4' boo

I damage etc .. , effects of binder concentrations, etc. are still not well defined.

SDT is largely a prompt detonation phenomena controlled by the physics of hot spots in heterogeneous explosives

A Los Alamos

0 .5 I

o~~!~~~~, ! j o 0.5 1 1.5

rime (I-ls)

SURF model with gauge data- Shock-to-detonation at 23 C (Shot# 2s40 on PBX 9502, Ps=13.5GPa)

This is a continued strategic direction for LANL through reactive flow modeling and experiments.

A focus area is shock shear and blunt rod impact experiments using the James' Energy Criteria as a framework to study the problem.

NAT IONA L LABORATOR Y UNCLASSIFIED ____ EST. 1943

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 -· ··~t1Al .VA.'~.

UNCLASSIFIED

HE mechanical properties playa role in the mechanisms of SOT, DDT and XDT, all leading to a detonation. In DDT and XDT, mechanical properties and damage playa big role. Mechanical properties can influence detonation (A), no reaction (8), and a range of intermediate reactions (C) in between, and the time for "thermal run away" may be long!

v. --::.--

Launcher

(8)

Liner ProptllantIHE I C... ~ ~ Clnnls!.r -- I

fr.g .... n! Sp.II

"l.. \ /

--- .. ~- ~- \.~.\ -\ O.magtd I I

propel •• ntIHE

In-bor. ignition

Penetration (explicit) H .. t tranl,.r1Combuldon Qmpllcit) OOT, XOT (explicit)

Computational Regimes

A Hostile Threat Example Los Alamos

(C) (A)

Developing a HE constitutive & thermal ignition model is a necessity for us to address safety, surety, and performance issues relevant to the NNSA.

This is a complicated problem requiring a strategic commitment from LANL programs

NATIONAL LABORATORY UNCLASSIFIED ____ E5T. 1943

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 11& • • W~\IA\ //IIV&'''~~

UNCLASSIFIED

A merging of two approaches has been envisioned that may produce a more predictive reactive flow model

Requires 0 Development

A Los Alamos NATIONAL LABORATORY ____ EST. ,943

A continued strategic direction for PEM C2, NCT ... , through reactive flow modeling and experiments .... approached from the high pressure side

A high fidelity reactive flow model influenced by material properties, such as porosity, inclusions, damage, binder properties, etc .. , is well defined

Also a strategic direction for JMP, PEM C2 and perhaps NCT, through linking mechanical and thermal ignition models .... approached from the low pressure side

NOTE: Experiments will be required!

UNCLASSIFIED

Operated by Los Alamos National Security, LLC for NNSA " NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011

High Pressure

Low Pressure

IIA • . wr-llAl 1/1 V A.'~ltj

UNCLASSIFIED

To be predictive for weak or non-shock ignition problems we need to couple a mechanical constitutive model with a thermal ianition model.

(1.) Impact event, modeled with a HE thermo-mechanical model

Heat Sources: • volumetric compression (EOS) • shear viscoelasticity, shear crack growth, • frictional heating of closed shear cracks, etc.


r_ ......... It>t.sr><>, J..18t,02

time (s)

20 40 60 80 100x I0·'

- T P 600 - 'new .------

Q 400 ~

~

!

ill

A crucial point: T is not the

hotspot temperature

~m

t T

(2) Couple to a HE burn mode 2

Henson/Smilowitz Thermal Initiation

Model

UNCLASSIFIED

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 11& •• W~\lAl IIVA.'~4

UNCLASSIFIED

As a first attempt, we are using the ViscoSCRAM model

20

18 f 16

.--... ~

p...

~ '--" Vl Vl

~ ... C.Il

Damage by micro- to macro-crack growth

~/ PBX 9501 Room Temperature

l r~ ________ 1.05-1

I~ ~

0.02 0.03 0.04 0.05 Strain

Macrocrack: In situ observations in tension

Experimental stress-strain data from D. Graff-Thompson, C. Cady, C. Liu et al. (LANL)

Viscoelastic temperature and rate rate dependence (derived

ViscoSCRAM is a macro-scale model that captures the essence of the viscoelastcity and the micro-scale crack growth through continuum solid mechanics modeling from polymer binder)

--QAlamos NATIONAL LABORATORY UNCLASSIFIED __ EST. 1943 __________________________________ _

Operated by Los Alamos National Security, LLC for NNSA " NCT Explosives Workshop Brief" , Brad Clements, Nov. 3, 2011 /,-,J ;,.1,SJ:J..

35

30

25 'itj' a.. ~ 20 I.Il I.Il IJ.J 15 a: I-I.Il

10

5 ~.D"'" \ ~

o IY 0 0.01 0.02 0.03

UNCLASSIFIED

ViscoSCRAM fits to PBX 9501 60

PBX9501 50

-100 e, 0.15'1 'itj'

40 a.. ~ ~ 30 I.Il I.Il IJ.J a: I-

25° C, 0.15-1 I.Il 20

25° C, 0.01 5-

74°C, 0.15-1 1 10

I 0.04 0.05 0.06 0.07 0.08 0

0 0.05

PBX9501 -20005-1

0.15

Data is from C. Liu, C. Cady, P. Rae, D. Thompson, and R. Deluca

0.2

- 95 wt%> HMX, 2.5wt% Estane,

2.5 wt%) nitroplasticizers

-1.834 g/cm3, 1.4%) voids

- 6.9 vol% binder

STRAIN 0.1

STRAIN

50

I ~~~_~5?2 40

& 30 ~ I.Il I.Il

li! 20 I-I.Il

10

0 0.01

A Los Alamos NATIONAL LABORATORY ___ EST. 19 43

50° C ...... .. 20° C ·· .. · ..

74°C .. ,.. -200 C-

0,02

STRAIN

0.03

Operated by Los Alamos National Security, LLC for NNSA

and to PBX 9502

0.04

50r, ----~------~----~----~------r_----,

40

& 30 6

PBX 9502 -1400 S-l

Kel-F 800 Binder TATB HE Grains

Inclusion of a Plastic Flow Model

The stress plateau is attributed to slip in the

o~'--~--~--~--~--~~

0.00 om 0.02 0.03 0.04 0.05 0 .06 TATS grains STRAIN

UNCLASSIFIED

"NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 - • . "~Q'Al II/IV&,'~'i

UNCLASSIFIED

Experiments are critical for obtaining the mechanical properties of any explosive

PBXN-9 (L) and PBX 9501 (R)

Velocity determined f rom Image analysis and rising edge of lasers 2 & 3

Brazilian Disk

80" Barrel

Taylor Impact

Launch Tuberrransition Section Hydraulic Clamp

Launch Tube

Los Alamos Plate Impact Shock

NATIONAL LABORATORY

Tube

Pump TubelBreech Hydraulic Clamp

UNCLASSIFIED

Breech

E I

---""5 ER

Split Hopkinson Pressure Bar

Including shaped impactors to simulate non-planar loading

(shock-shear) common to 1M hazards

__ EST. 1943 ____________ ______________________________________ _

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 ItA •. w~Q'All ///IVA.'~:S

UNCLASSIFIED

The Henson-Smilowitz thermal ignition model is physically based and parameterized to many experiments

p-HMX. ~ b-HMX kl

P-HMX + b-HMX. ~ b-HMX sublimation

k b-HMX • 2a ~ £-HMX

vap orization

k2b ~ 4CH20 + 4N20

8~ 2N02 + 4HCN + 2NO + 2H20 k2c

~ CH20 + N02 • ~ HCO + HONO

HCO + N02 -C CO + HONO

H+C02 +NO k4 A HCN-HNC

Los Alamos NAT IONAL LABORATOR Y ____ E5T. 1943

Process begins with the ~-8 1sLorder phase transition

Captures the chemistry of both "dark" and "bright" zone burning of HMX

Ends in with a gas phase concentration [g]

a1~] = k2JC:](lOha +8hb ) P = [g]RT

aT a[f3] Cave at = - (fill! Tt + fill2bk2b (P - [8])

+ fill3k3JN0zJ[CH20] + fill4k4JHCN])

UNCLASSIFIED

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 I . • . Will!!' \YA~ IIVA.'~4

UNCLASSIFIED

Translates into a set of coupled PDEs to solve a[f3] -=-kl , [f3]+k,J8]-(k -k .)[{3][8] ~ , --k k -(k -k ) at if I, Ig{ Ig, "- -- - m~____ -.- Y I - III! YI + lllrY2 Igf Igr YIY2

a[ 8] a[{3] _ k [ c:] -=- -:'I 2a at ot

..... , , k Y 2 = -Y 1- 2aY3 ,-

a[c:] = k [8] at 2/}

..... y'3 = k2bY2 ,-

a[NO ] a 2 = 2k2 (p - [8]) t a ..... y'4 = 2k2a (p - Y2) - 2k3a y4ys - 2k4aY6 ,-

- 2k3J N0 2 ][CH 20] - 2k4JHCN]

a[CH zO] = 4k2l,(p - [8]) - k

3J N0

2][CHzO] ..... y's = 4k2b (p - Y2) - k3ay4ys ,-

a[HCN] = 4k, (p - [8]) - k4JHCN] at .a

..... y'6 = 4k2a (p - yJ - k4aY6 ,-

a~~] = k2a[c:]( 1 0 ~a + 8~b ) P = [g]RT ..... y'7 = k2aY3 (10~a +8~b ) ,-

aT a[f3] Cave at = -(Mil Tt + Mi2bk2b (P - [8]) _ ________________ _ _on H_~ "_ _ ~ Y'g = -(Mfly\+ Mi2bk2b (P- y)

+ Mi3k3JN02 ] [CH20] + Mf4k4JHCN])

A ki = k~T Qie(Tt,S:-t.E:)1RT <4---

Los Alamos NATIONAL LABORATORY ____ EST _1943

+ Mf3k3aY4Ys + Mi4k4ay6) / Cave

Coefficients are temperature dependent Arrhenius exponentials

UNCLASSIFIED

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 IA •. "~\lAl /I/IVA.'~4

500

450

400

350 U 0 '-' 300 E-

250

200

150

100 0

------------------------------------------------------------------~~~~~~~~~~~~=---------------,

UNCLASSIFIED

Solutions of Henson-Smilowitz Thermal Ignition Model l000~,----~----~--~~--~----~--~~

Solutions of the Henson-Smilowitz Thennal Ignition Model

PBX 9501

Tinit = 200°C

900

,,-... 800 ~ '-'

E-700

Solutions of the Henson-Smilowitz Thermal Ignition Model

PBX 9501

Tinit = 600°C

600 1-1 ----------~

100 200 300 400 500 600 700 800 900 Time (s)

500 o 10 20

10000 .... , ---.----..-------.,....-----r---.-----,--, [0]

'" 8000 r [eJ .§ [N02]

~ ~~m -5 6000 [HCN]

s:: o

.~ 4000 s:: <I) u s:: o

Solutions of the Henson-Smilowitz Thermal Ignition Model

PBX 9501

-

.'

/ /

/

, i ,

u 2000 Tinit = 6000 C ..... "-,.;,/'. ,,, ......... ...

30 Time (fls)

40 50 60

o o 20

-..... . -'H1;.;;.:;:.::;.::.:.~ . ..:..: ... :.-----.---------: ------

60 10 30 40 50 Time (Ils) ~Alamos

NATIONAL LABORATORY ___ EST. 1943 ____________________________________________ _

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 _ .... Jr"lIAl !II V A.'~itj

UNCLASSIFIED

Henson-Smilowitz thermal ignition model merged with thermal mechanical ViscoSCRAM model to address HE safety & surety, for example

A FEM simulation of a steel rod impacting a PBX 9501 cylinder. The HE has begun to initiated in regions of high shear heating in the simulation. ..a.

Temperature (K)

Dim inishing of /)

Los Alamos NATIONAL LABORATORY ____ EST. 1943

(1)

600 m/s Impact of Steel on PBX 9501 10 mm Diameter Rod

T=45j.1 s

HCN Concentration


T

(2)

Henson/Smilowtiz Therma l Initiation

Model

~-HMX ---. 8-HMX k,

~-HMX + 8-HMX ---. 8-HMX sublimation

8-HMX ~ e-HMX vaporizalion

~ 4CHp + 4Np +- k,. 2N02 + 4HCN + 2NO + 2Rp

CR20 + N02 ~ RCO + RONO

RCO + N02 -C CO + HONO

H + C02 + NO k,

HCN-HNC

Merging the Henson-Smilowitz thermal ignition model with mechanical HE models allows the study of HE initiation under non-shock-todetonation conditions, thus making it possible to study the performance and sensitivity of energetic materials for a wide range of impact and thermal scenarios.

UNCLASSIFIED

"NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 -·· .. ~Q'Al //I' V A.'f~/tj

UNCLASSIFIED

Issues:

1.) For each explosive (CHE, IHE, non-ideal), thermo-mechanical properties must be obtained - note ViscoSCRAM itself may need to be modified (rubbery propellants has demonstrated this).

2.) For each explosive (CHE, IHE, non-ideal), the Henson-Smilowitz model needs to be parameterized.

3.) The physics of ViscoSCRAM must be correct, to get an accurate representation of the temperature.

4.) Regions of high distortion are regions of high temperature rise, and FEM meshing is usually most problematic in these regions.

5.) HE properties in extreme conditions, just below burn initiation, are not well known.

6.) The combined ViscoSCRAM-ignition algorithm will need to be implemented in other LANL codes.



UNCLASSIFIED

"NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 IA • . Will::!' Q'Al /I/IVA'~4

UNCLASSIFIED

Issue 3: The temperature plays a crucial role (unlike pressure in other reactive flow models) ... how good is the ViscoSCRAM temperature calculation?

Gun Penetration Experiments and Simulations

A Los Alamos NATI O NAL LA BOR ATORY ____ EST.1 943


Experiments: P. Rae, J. Furmanski & C. Cady

Hardened Steel Ball .....

V

UNCLASSIFIED

Well-characterized Mock HE

IE Cu Plates

"NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 - . ... ~lrAl /I/IV&,'~ltJ.

UNCLASSIFIED

Issue 3: A New Experimental Diagnostic For Assessing Temperature Increase in an Impact Scenario Relevant to Bullet Penetration

Los Alamos NAT IONAL LABORATORY ____ E5T. 1943


Note this ViscoSCRAM work also impacts 000 programs

• ARL Excalibur safety analysis . • Excalibur base gap compression modeling,

looking at the adiabatic compression of air bubbles in HE billet under gun launch.

• Applications to the pyrotechnic Iliuminant. • AFRL Munitions/Weapons Simulations

T-3oo K

T- 350 K

T- ,00K

Ball Impact Experiment 80

-. 70

() ~ 60

~ :::J 50

1ij IE"-..... Q) 40 Q.

E Q) 30

F 20 "I

Time (s) UNCLASSIFIED

4.

+5.000et02 .4.8316+02 +4.662e+02 +4.493e+02 +4.3248+02 +4. 1556+02 +3.986e+02 +3.817e+02 +3.648e+02 +3.4798+02 +3.310e+02 +3.1 41e+02 +2.972e+02

Ball Impact Simulation

"NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 IIA •. w lilt:!' \/'A' /#IVA.'~4

Issue 4. Mesh distortion

) . - ............ _ ... .

Los Alamos NATIONAL LABORATORY ____ EST. 1943


UNCLASSIFIED

How you handle mesh distortion influences the calculated temperature

• cohesive zone, MPM, element deletion, AMR --- and when you activate them --- all influence the answer,

UNCLASSIFIED

"NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 IIA •. " r-1b11 11/1 V Itt.'~:;.

UNCLASSIFIED

Issue 5. HE is in extreme conditions before initiation ...

:mm

6

4

2

o ""'," "lid

o

SOVl19 IAvg ' 75~)

..... 470e+O +4 ]41e+02 +4212e+02 +-4 DBJe+02 +3954e+02 +-3825e+02 +-3596u.02 +3567e+02 +-34J8e+02 +330ge+02 +31SQe+02 +3D51e+02 +-2922u.02

Yet, mechanical properties are typically determined at temperatures not exceeding 350K.

A Los Alamos NAT I ONAL LABORATORY ____ ES1. '943


UNCLASSIFIED

"NCT Explosives Workshop Brief", Brad Clements, Nov. 3,2011 IIA .... ~Q;fl II/IVA.'~4

UNCLASSIFIED

Future approaches also include replacing ViscoSCRAM with our next generation HE models to include micro-structural features and statistics ...

- MOC/GMC, STFA, 2-scale FEM, and DNS

-Take into account contributions from grain-binder interface

-Address particle size effects

-Address properties of the binder and HE grains, separately

-Address aging effect of binder materials

-Detailed local fluctuation addressing accidental scenario (STFA model).

~

Next Generation Model (with micro-structure info) J + ~

Henson/Smilowitz Thermal ignition model /

'- /~I Reactive Flow Model ~

A dependent on micro-structure

Los Alamos NATI O NAL LABOR AT OR Y ____ EST. 1943


UNCLASSIFIED

"NCT Explosives Workshop Brief", Brad Clements, Nov. 3,2011 IIA • . W lit!!' \btl ff/lVA.'~.

UNCLASSIFIED

Next Generation Model: Our HE project uses hybrid micromechanics models to handle the grain size distribution in an efficient manor

i r €

0 - Bf(i -i" - iD ,_ .. -J

r .... ~, r ,

Dirty Binder / Method of Cells Theory Applied to PBXs

PBX 9501 Micro-graph

0.2 0 i Ii II i Ii 1,[", 'l' "ii' Ii 'I' ", ,,11'1' I I 'I

o 1 5 ~.. Aspect Ratio Distribution , ~ Sampled over 4800 Grains

e 0,10 ~.

" 0,05

0,00 " ""! " , , .,, ! ,' 1 I . , " "...,...,,, •• i 0,0 0,50 1.0 1.5 2,0 2,5 3,0 3,5 4,0

P

Fig. 2.Image analysis produces microstructural information. " Fines" l-~O IIDI

ContiuuUUl-lf''n·l Ellipsoidal h.dusioll Analysis

Fig. 1. Bridging the length scales

~Alamos NATIONAL LABORATORY

Impact Speed 515 inls

0.0020 ~' , ' ~ '~' ' I "I ' 'l In.c.lJ Transmitted: 0.0015

0.0010

.: 0.0005 ...

Experiment Theory

~ 0.0000 t--' Vote. ~ lfIrr -0.0005

-0.0010

-0.0015 t, , , , , , , , , , , , , , ' , , , , , , , , , , , , , "

so 100 1 SO 200 250 300 350 Time (I1S) UNCLASSIFIED

E I ER

__ EST, 1943 ____________________________________________ _

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief", Brad Clements, Nov. 3, 2011 _ • . w Jlt"'Q'Al III'V&,'~4

UNCLASSIFIED

Conclusions

An approach for addressing weak-shock and non-shock initiation is proposed. The approach consists of merging the thermo-mechanical constitutive model ViscoSCRAM and the Henson-Smilowitz thermal ignition into a single algorithm. I nitial studies have been done that reveal both successes but also issues that must be overcome before the approach can be deemed ready for practical applications. When completed, this approach will offer the possibility of performing simulations for many lab programs, including NCT. It will take strategic commitment from LANL programs to get to that point.



UNCLASSIFIED

"NCT Explosives Workshop Brief', Brad Clements, Nov. 3, 2011 _ • . "~9'Al /I/'VA.'~4.

UNCLASSIFIED

Acknowledgments

The LANL JMP Constitutive Properties of Energetic Materials HEPO Team:

B. Grier, C. Liu, P. Rae, C. Cady, E. Brown, and J. Furmanski Materials Experiment

D. G. Thompson and R. Deluca HE Characterization Experiments

D. Dattelbaum, R. Gustavsen, S. Sheffield, Dynamic Experiment D. Hooks, J. Yeager, and N. Sanchez

M. Lewis and P. Rangaswamy

T. Williams, D. Zhang, Z. Ma, M Cawkwell E. Mas, A. lonita and B. E. Clements

Engineering Simulations

HE Constitutive Theory and Simulation

Collaboration with B. Henson and L. Smilowitz ---- Henson-Smilowitz thermal ignition model and experiments

Funding through: JMP (Eric Mas), C2 (Rick Martineau! Dan Hooks and Dana Dattelbaum) and ASC-PEM-HE (Bob Little and Mark Short) and NCT

A (James Koster! David Robbins). Los Alamos NATI O NAL LABORATORY UNCLASSIFIED ---- EST. 1943

Operated by Los Alamos National Security, LLC for NNSA "NCT Explosives Workshop Brief', Brad Clements, Nov. 3,2011 IIA···~~l II V &'''~ltj

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