This document summarizes research done at Lawrence Livermore National Laboratory on using 3D printing to create cellular materials with controlled architectures. It shows how printing ordered porous structures enables better control over the materials' mechanical properties compared to traditional random porous materials. In particular, it demonstrates that a "face centered tetragonal" structure exhibits different stress-strain behavior under compression and shear than a "simple cubic" structure, despite both having the same material composition and 50% porosity. This controlled architecture printing process could enable new material designs with targeted performance properties.

1. LLNL-PRES-654659
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
Eric Duoss, Engineer

2. Defense/Aerospace Sporting/Consumer Goods Packaging/Transportation
 Dampen shock and vibrations
 Distribute and relieve stress
 Maintain relative positioning
 Mitigate the effect of size variation
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3. 1. Difficult to control mechanical properties
2.Exhibit non-uniform properties
3. Little control over directional properties
4.Difficult to develop predictive models
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4. Additive Manufacturing enables the ability to pattern cellular materials
with controlled, complex architectures. We use a 3D printing process called
“Direct Ink Writing” to produce ordered, cellular elastomers.
1. Enable better control of mechanical properties
2. Exhibit more uniform properties
3. Enable better control over directional properties
4. Enable a predictive modeling capability
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6. “Face centered tetragonal” (FCT)
Uniaxial compression
“Simple cubic” (SC)
Pre-compression + shear
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7. • Same base elastomer material
• Same volume fraction (or
degree of porosity) = ~50%
• Different printed architecture
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8. 0% “Simple cubic” 500 mm

9. 5% “Simple cubic” 500 mm

10. 10% “Simple cubic” 500 mm

11. 15% “Simple cubic” 500 mm

12. 20% “Simple cubic” 500 mm

13. 25% “Simple cubic” 500 mm

14. 0% “Face centered tetragonal” 500 mm

15. 5% “Face centered tetragonal” 500 mm

16. 10% “Face centered tetragonal” 500 mm

17. 15% “Face centered tetragonal” 500 mm

18. 20% “Face centered tetragonal” 500 mm

19. 25% “Face centered tetragonal” 500 mm

20. • Same base elastomer material
• Same volume fraction (or
degree of porosity) = ~50%
• Different printed architecture
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21. FCT structure pre-compressed (25%) and sheared (dynamic strain sweep)
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22. SC structure pre-compressed (25%) and sheared (dynamic strain sweep)
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25.  Existing prototype—patent applications filed
 Currently being scaled up for production
 Ready for commercialization
 New designs possible to achieve new performance
for new market applications
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26. Charity Follett
follett2@llnl.gov
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