Transcript Adaptive Multiscale Modeling and Simulation for Munitions

Adaptive Multiscale
Modeling and Simulation
for Munitions Simulations*
Progress 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
Roadmap of Developments
Assessment of commercial code
capabilities
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
Mesh sensitivity studies (Gal Davidi)
Validation studies (Rong Fan)
Fragmentation capabilities for metals
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Homogenization based approach (Gal Davidi)
Integration of homogenization in ABAQUS
(Zhen Yuan)
PUM based (Zhen Yuan and Rong Fan)
Roadmap of Developments (cont)
Fragmentation capabilities for composites


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Reduced order methodology (Oskay)
Validation studies (Oskay)
Integration in ABAQUS
Multiscale Enrichment based PUM
Applications
Fragmentation in Metals
Experimental setup
Target Assembly
Impactor in
Sabot
DH36 Steel Plate
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
Experiment vs ABAQUS simulation
(without backing)
Mises stress (without backing)
Equivalent plastic strain (without backing)
Experiment vs Simulation
DH36
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
3.00E+05
3D models (48 layers)
2.50E+05
Shell 21
layers
2.00E+05
1.50E+05
Fine (160)
1.00E+05
3D model (21 layers)
Coarse (80)
Very Coarse (40)
5.00E+04
0.00E+00
0
0.00005
0.0001
0.00015
0.0002
0.00025
0.0003
0.00035
0.0004
0.00045
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
Global Enrichment (MEPU)
Global deformation modes
N b di b
Failure deformation modec ij
shapes
Cell problems on Q
delamination
fracture
Rigid body+
Failure modes
Coarse Scale
G5Enrichment
5 5 5 55H
G5 5H
ui = N bdBetter
i b + N a c iA (x )a a A
(Superposition)
ui = N a
GH
cˆ iA
(x )a a A
(Domain decomposition)
Global Enrichment (metals)
Velocity of Impactor (m/s)
3D simulations
300
DH36 & ERC (3D-21 layers)
250
DH36 & ERC (Shell)
200
MEPU
150
100
50
0
0
0.0001
0.0002
Time (s)
0.0003
0.0004
Local Enrichment (metals)
(in progress)
Calculate discontinuity direction at each Gauss point


det nT Dn  0
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
4
7
Gauss point
8
n
Constrained
3
1
periodicity
6
5
2
Shell
Discontinuity plane
RVE
master
Impact Fragmentation of composites
Phenomenological
Direct Homogenization
Material
Point
Component
-
Advantages
Fast
Disadvantages
Reliability
Experiments architecture
dependent
-
Advantages
Reliability
Architecture independent Exp.
Disadvantages
Computationally formidable
Eigendeformation-based Reduced Order Homogenization
Matrix point (s)
Interface point (s)
Fiber point (s)
Engineering Accuracy
Fast
Architecture independent
Experiments
Validation: Tube Crush Experiment
Experiments by Oak Ridge (Starbuck et al.)
Impact Velocity: 4000 mm/sec
Microstructure: Woven composite
Model Validation (composites)