Adaptive Multiscale Modeling and Simulation for Munitions Simulations* Progress Report

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Adaptive Multiscale Modeling and Simulation for
Munitions SimulationsProgress Report

• PIs Jacob Fish and Mark S. Shephard
• Post-docs Gal Davidi, Caglar Oskay
• Students Zheng Yuan, Rong Fan

AFRL support leveraged by support from NSF, ONR
and General Motors
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Roadmap of Developments

• Assessment of commercial code capabilities
• Mesh sensitivity studies (Gal Davidi)
• Validation studies (Rong Fan)
• Fragmentation capabilities for metals
• Homogenization based approach (Gal Davidi)
• Integration of homogenization in ABAQUS (Zhen
  Yuan)
• PUM based (Zhen Yuan and Rong Fan)

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Roadmap of Developments (cont)

• Fragmentation capabilities for composites
• Reduced order methodology (Oskay)
• Validation studies (Oskay)
• Integration in ABAQUS
• Multiscale Enrichment based PUM
• Applications

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Fragmentation in MetalsExperimental setup
The experimental parameters considered Steel
target plate DH36 steel 3/16 inch thick 6 inch
diameter Impact velocity In the range
between 920 ft/sec. Backing material
Polyurea 0.215 inch Impactor non-deformable
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Experiment vs ABAQUS simulation (without backing)
Mises stress (without backing)
Equivalent plastic strain (without backing)
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Experiment vs SimulationDH36
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Drawbacks of commercial software

1. Cost of 3D simulations (4 days for 21
   layer-model, r-adaptivity)
2. Mesh dependency of both 3D and shell models

3.00E05
3D models (4-8 layers)
2.50E05
2.00E05
1.50E05
Fine (160)
1.00E05
Coarse (80)
Very Coarse (40)
5.00E04
0.00E00
0
0.00005
0.0001
0.00015
0.0002
0.00025
0.0003
0.00035
0.0004
0.00045
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Remedy Multiscale Enrichment

• Global (structure) Enrichment
• Enrich the kinematics of the global mesh with
  failure characteristic (delamination, shear
  banding, fragmentation) characteristic computed
  on the local patch
• For computational efficiency
• Local (material) Enrichment
• Embed discontinuities (strong or weak) into
  material (micromechanical) model
• For regularization of failure models

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Global Enrichment (MEPU)
Better
(Superposition)
(Domain decomposition)
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Global Enrichment (metals)3D simulations
300
DH36 ERC (3D-21 layers)
250
MEPU
200
Velocity of Impactor (m/s)
150
100
50
0
0
0.0001
0.0002
0.0003
0.0004
Time (s)
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Local Enrichment (metals)(in progress)

• Calculate discontinuity direction at each Gauss
  point
• Align the RVE local coordinate system with one of
  the axis normal to the localization plane
• Develop a 3-point RVE model as follows

Constrained RGB
Gauss point
Constrained periodicity
Shell
master
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Impact Fragmentation of composites

• Phenomenological
• Advantages
• Fast
• Disadvantages
• Reliability
• Experiments architecture
• dependent

• Direct Homogenization
• Advantages
• Reliability
• Architecture independent Exp.
• Disadvantages
• Computationally formidable

• Eigendeformation-based Reduced Order
  Homogenization

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Validation Tube Crush Experiment

• Experiments by Oak Ridge (Starbuck et al.)
• Impact Velocity 4000 mm/sec
• Microstructure Woven composite

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Model Validation (composites)