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Lawrence Livermore
National Laboratory 1
Joshua Kuntz, Eric Duoss, Wayne King, Melissa Marggraff,
Robert Maxwell, Tom Wilson, Matt Wraith, Todd
Weisgraber, Andrew Pascall, Cheng Zhu, Rayne Zheng,
James Frank, Joshua DeOtte, Chris Harvey, Tom Metz,
Kyle Lange, Marcus Worsley, George Farquar, Tammy
Olson, Sergei Kucheyev, Chris Orme, Kyle Sullivan, William
Smith, Maxim Shusteff, Luis Zepeda-Ruiz, Scott Fisher,
Tom Wilson, Alex Gash, & John Vericella
Academic Partners: Professors J. Lewis (Harvard), N. Fang
(MIT), D. Tortorelli (UIUC), J. Hopkins (UCLA)
LLNL-PRES-646626
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC
Lawrence Livermore
National Laboratory 2
Additive Manufacturing
Commercial AM tools, custom AM processes
Synthesis
Tunable nanomaterials, nanoparticles, crystal
growth, polymers, aerogels, feedstocks
Modeling and Design
HPC, multi-scale, multi-physics, topology
optimization, analytical design
Predator UAV, Air Force
Certification
Process modeling, in-situ characterization
By integrating optimization, design and modeling, tailored synthesis, and additive
manufacturing methods, we can enable high performance materials and components.
Lawrence Livermore
National Laboratory 3
Order-of-magnitude performance improvement and decoupling of material properties is possible
102
1
10–2
10–4
Yo
un
g’s
mo
du
lus
(sti
ffn
ess
), G
Pa
1 10 102 103
Density, kg/m3
Designed microarchitecture Stretch-dominated lattices can provide these properties
Lawrence Livermore
National Laboratory 4
Material selection chart for thermal expansion and stiffness
Jefferson, et al., Int.
Jrl. Of Solids and
Structures, 2009.
Steeves, et al., Jrl. Of Mechanics and
Physics of Solids, 2007.
Lakes, et al.,
APL, 2007.
Theoretical
structures:
Lawrence Livermore
National Laboratory 5
1
10
100
1000
10000
0 2 4 6 8
Pro
pagation v
elo
city (
m/s
)
Energy density (kcal/cc)
Monomolecular
materials
Binary materials and thermites
Al/KClO4
HMX
PETN
TNT
Al/CuO Al/MoO3
Desired
performance
Co
ntr
ol
of
str
uctu
re
Reduce particle size and
optimize organization of
fuel/oxidizer microassembly
Irregular distribution of binary
constituents limits performance
Al
2 µm
Highly ordered and optimized
microstructure
MoO3
Al
Co
ntr
ol
of
str
uctu
re
10’s µm
Lawrence Livermore
National Laboratory 6
Lattice of unit cells
Topology optimization A computational design method
Freedom and constraint topologies
An analytical design method
Multimaterial microlattices with prescribed thermal expansion coefficient
Al
ABS
Void
Unit Cell Periodic Material
LLNL is developing new manufacturing technologies and using HPC to
deterministically design and fabricate architected materials.
Lawrence Livermore
National Laboratory 7 A broad range of extreme thermo-structural properties can be rapidly designed.
Hopkins, et al., “Polytope Sector-based Synthesis and Analytical
Optimization of Microstructural Architectures with Tunable Thermal
Expansion,” manuscript under review.
Lawrence Livermore
National Laboratory 8
Material is comprised of unit cells arranged periodically.
Mesh a unit cell
• Assign each element phase concentrations
• Interpolate to obtain element properties
Use homogenization theory to determine unit cell properties
Use optimization algorithm to assign the concentrations to
• Minimize the cost function (e.g. RMS error)
• Satisfy constraints (e.g. isotropy)
Unit Cell Periodic Material Finite Element
Lawrence Livermore
National Laboratory 9
Aluminum
Invar
Void Constraints:
• Minimize CTE subject to lower bound on
stiffness
• Maintain vol. fraction ~25% for solids
CTE value
Lawrence Livermore
National Laboratory 10
• Copper/ PMMA system
• CTE = -1.3e-6 mstrain/K
• Thermal conductivity = 57 W/m-K
• Density of 2600 kg/m3
• Stiffness = 21.3 GPa
• Manufacturing constraints are included
• Copper phase is continuous due to thermal conductivity constraint
LLNL’s computational resources make 3D designs and additional
physical constraints possible.
Topology optimization is being used to design microlattice-based materials
for specific applications requiring additional physics and constraints.
Lawrence Livermore
National Laboratory 11
Unit cell architecture at various heights
3D unit cell with refinement
We are advancing the state of the art in topology optimization beyond currently
available capabilities by utilizing HPC.
Actual fabricated component
(2 polymers)
Lawrence Livermore
National Laboratory 12
Projection Microstereolithography (PµSL) A photochemical and optical technique
Direct Ink Writing (DIW) Utilizes unique flow and
gelling properties
Electrophoretic Deposition (EPD) Electric fields transport nanoparticles
LLNL has been developing a combination of additive micro- and nanomanufacturing technologies
Lawrence Livermore
National Laboratory 13
Projection Microstereolithography (PµSL) A photochemical and optical technique
Direct Ink Writing (DIW) Utilizes unique flow and
gelling properties
Electrophoretic Deposition (EPD) Electric fields transport nanoparticles
LLNL has been developing a combination of additive micro- and nanomanufacturing technologies
200 mm
200 µm
5 mm 5 mm
Lawrence Livermore
National Laboratory 14
Projection Microstereolithography (PµSL) - a photochemical and optical technique
Lawrence Livermore
National Laboratory 15
Zheng, et al., “Ultralight, ultrastiff mechanical
metamaterials,” Science, June 20, 2014.
Lawrence Livermore
National Laboratory 16
Zheng, et al., “Ultralight, ultrastiff mechanical
metamaterials,” Science, June 20, 2014.
Lawrence Livermore
National Laboratory 17
Solid polymer
r ~ 80 kg/m3
(11% rel. density)
Hollow tube Ni-P
r ~ 40 kg/m3
(0.5% rel. density)
Hollow tube Al2O3 (ALD)
r ~ 0.9 kg/m3
(0.025% rel. density)
Solid (sintered) Al2O3
r ~ 320 kg/m3
(8% rel. density)
Zheng, et al., “Ultralight, ultrastiff mechanical metamaterials,” Science, June 20, 2014.
Lawrence Livermore
National Laboratory 18
This architected material has orders of magnitude higher stiffness than any other
material in this low density regime.
Zheng, et al., “Ultralight, ultrastiff mechanical metamaterials,” Science, June 20, 2014.
Lawrence Livermore
National Laboratory 19
This architected material has orders of magnitude higher stiffness than any other
material in this low density regime.
Zheng, et al., “Ultralight, ultrastiff mechanical metamaterials,” Science, June 20, 2014.
Lawrence Livermore
National Laboratory 20
Heterogeneous multi-material micro-structures
500μm 1 mm
Designed
heterogeneous helix
HD
DA
Optical image of
fabricated part
diameter = 1 mm
Encapsulation of functional particles
11% octet truss
2mm 2mm
20% octet truss
3 mm
3D multimaterial Al2O3
polymer
Negative CTE
multimaterial
architectures
designed using
our analytical
method.
3D multimaterial microarchitectures are enabled by our unique additive
manufacturing platform.
Lawrence Livermore
National Laboratory 21
Direct Ink Writing (DIW) - utilizes unique flow and gelling properties
Lawrence Livermore
National Laboratory 22
Direct write of a siloxane material with designed porosity and structure for specific compressive and shear properties –
control of filament size, pitch, and microarchitecture
Large square front zoom
(scale in 100ths of an inch)
Simple cubic
Face centered tetragonal
Soft materials with tailored mechanical response have broad application for NNSA.
Lawrence Livermore
National Laboratory 23
“Simple Cubic” Axial Response “Centered Tetragonal” Axial Response
Duoss, et al., “Three dimensional printing of elastomeric cellular architectures with negative
stiffness,” Advanced Functional Materials, published online April, 2014.
1 mm 1 mm
Lawrence Livermore
National Laboratory 24
Isostress contours reveal columnar stack up of stress in simple cubic
geometry whereas stress is more distributed in face centered tetragonal.
Modeling and simulation has reveal a possible instability in the simple cubic architecture.
Duoss, et al., “Three dimensional printing of elastomeric cellular architectures with negative
stiffness,” Advanced Functional Materials, published online April, 2014.
Lawrence Livermore
National Laboratory 25
“Centered Tetragonal”
“Simple
Cubic”
Negative stiffness region
“snap through” effect
Simple cubic
Face centered tetragonal
Duoss, et al., “Three dimensional printing of elastomeric cellular architectures with negative
stiffness,” Advanced Functional Materials, published online April, 2014.
Lawrence Livermore
National Laboratory 26
1 cm 1 cm
1 cm
Dimensionality: DIW is now capable of
patterning arbitrarily complex
structures by co-printing a fugitive
support material that is removed after
printing
Material Set: Al, Al2O3, CuO, B4C,
Bi2Te3, Sb2Te3 and silicone-based inks
have been developed.
Octet-truss
unit cell
Inter-digitated
structure
“Inter-woven”
lattice
Lawrence Livermore
National Laboratory 27
Electrophoretic Deposition (EPD) - electric fields transport nanoparticles
Lawrence Livermore
National Laboratory 28
Drop-cast versus EPD Al-CuO thermite
• EPD samples exhibit ~2 the power density of their drop-cast counterparts (~½ burn time and ~2 burn velocity)
• Flame from EPD Al-CuO thermite propagates around progressively tighter corners
Bend test for EPD Al-CuO thermite
10 mm
10 mm
Drop-cast film
EPD film 0 ms 5 ms 10 ms 15 ms
EPD
0 ms 5 ms 10 ms 15 ms
Drop cast
~5 cm
~5 cm
Lawrence Livermore
National Laboratory 29
Channels
Hurdles
“Hurdles” v = 42 m/s
“Channels” v = 138 m/s
High-speed optical imagery Thermal imagery
1 mm
1 mm
Lawrence Livermore
National Laboratory 30
Small A
Large A
L = ½ film thickness
Data shows that there is more than one relevant length-scale.
K. T. Sullivan, J. D. Kuntz and A. E. Gash, JAP, 2013.
Lawrence Livermore
National Laboratory 31
1
10
100
1000
10000
0 1 2 3 4 5 6 7 8
Pro
pagation V
elo
city (
m/s
)
Energy Density (kcal/cc)
MONOMOLECULAR MATERIALS
HMX
PETN
TNT
DESIRED
PERFORMANCE
Micron-Al + nano-CuO EPDed
Nano-Al + nano-CuO EPDed
Nano-Al + nano-CuO EPDed on DIW wide strips
Nano-Al + nano-CuO EPDed in DIW channels
Nano-Al + nano-CuO EPDed and confined in microcapillary
Al / CuO
Nano-Al + nano-CuO EPDed and confined in microcapillary
Lawrence Livermore
National Laboratory 32
LLNL research and
development directions:
• Microarchitecture and
“New” Material
Properties – “Boutique
Materials”
• Next Generation
Processes
• Qualification &
Certification
• Exotic materials
• Process Understanding
& Performance Modeling