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CartaBlanca Update

Xia Ma, Brian VanderHeyden, Paul Giguere,

Qisu Zou, Duan Zhang

Fluid Dynamics GroupTheoretical Division

Los Alamos National Laboratory

March 21, 2006

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Los Alamos National Laboratory Wins Four 2005 R&D 100 Awards

CartaBlanca: A High-Efficiency,Object-Oriented, General-PurposeComputer Simulation Environment

MESA: Measuring Enzyme-Substrate Affinities

nanoFOAM: A Metal-Nanofoam Fabrication Technique

NESSUS: Probabilistic Analysis Software Submitted by Southwest Research Institute and Los Alamos National Laboratory

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Capabilities of CartaBlanca

• A high-efficiency, general-purpose multiphase multi-physics computer simulation package.

• Written in developer-friendly Java Language in object-oriented fashion.

• Based on advanced multiphase flow theory.

• Multiphase flows.

• Chemical reactions.

• Multi-material deformation with mechanical strength.

• Fluid-structure interactions.

• Built-in thread parallelization in shared memory machines.

• Easy parallelization in distributed memory machines.

• Portability (The same code runs on Windows, Mac and UNIX machines).

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Improvements/Other Activities

• Current Project Work

– High explosives safety– Constitutive relation for

high explosives.– Nuclear reactor safety– Turbulent two-phase

flows– Removable barrier– Projectile Target

interactions

• Received R&D 100 award 2005.

1. Improved Parallel calculations, especially for particle methods.

2. Enhanced quality control Long tests

3. Improved Graphic User Input (GUI) package

4. Draft Theory, programmer and user manuals

5. Implemented robust advection schemes

6. Added temperature effects in Johnson-Cook model

7. Implemented multi-material in phase capability.

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Two-phase flow in a nuclear reactor during an accident

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High Explosives Safety• Drop-skid experiment• Ignition model for heated

grit• Effect of skid plate heat

conduction• One-step reactive kinetics

– Effects of gas convection– Brittle damage

D tgrit

up

pus

plateD

upt

HE

Grit

HE melt

High temperature region

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Shock wave propagation in HE

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Parallel Operations• Obtained good scaling on shared memory.• Enhanced particle implementation.• Working on scaling on shared memory (JavaParty, MPI).

Shock propagation on HE, using particle-in-cell method

On shared memory JavaParty behavior on shared and distributed memory

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Material Modeling Hierarchy

Johnson-Cook

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• Typical two-phase flow codes are implemented with single pressure models for multi-phase or multi-material flows. – Suitable for disperse two-

phase flows.

• Multi-pressure model is implemented in CartaBlanca, and has Significant advantages for– Fluid-structure interaction.– Projectile-target interactions

Multi-pressure model for multi-material problems

The pressure difference tears clothesThe pressure difference tears clothes

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Spalling of brittle porous solid

0

02

h

hh

Time to damageElastic Theory: 1.18 s.Our simulation: 1.12 s.Error: 5%.

Stress Elastic Theory: 0.69 GPaOur simulation: 0.76 GPaError 11%.

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Johnson-Cook model for projectile target interactions

• Elastic Prediction

• Update yield surface

• If effective stress exceeds yield surface return the stress to the yield surface.

• Calculated plastic work

• Increase

temperature.

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X

Y

0 2 40

1

2

3

4

5

6

7

8

9

10

11

12

1000950900850800750700650600550500450400350300

o K

Frame 001 20 Mar 2006 Time = 6.60018E-005

X

Y

0 0.5 1 1.5

0

0.5

1

1.5

2

2.5

Frame 002 20 Mar 2006 Time = 6.60018E-005

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Johnson-Cook model for projectile target interactions

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Parameters in Johnson-Cook model

• We assume adiabatic heating for the rapid rate of strain.

0 0

0

0

( ) 1 ln( / ) ( )

( ) max 0.8, 1

, 0.9

n neq p p

m

p eq p

Y B C a T

T Ta T

T T

C T

Each calculation takes < 1.5 hours on this laptop.

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Graphic User Interface (GUI)

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Graphic User Interface (GUI)

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User Manual

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Theory Manual

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Programmer Manual

• For programmers to add new capabilities.

• To be done.

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Next Steps

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Next Steps

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Next Steps

• Complete and Find suitable EPIC calculation for comparison. Perform calc./comp.

• Incorporate proprietary concrete model.• Assist with concrete model/brittle

damage calculations.• Complete manuals of the code.• Tutorial/workshop of CartaBlanca.