Mechanical Properties of a Diamond Schwarzite: From Atomistic Models to 3D-Printed Structures
10 Jan 2020
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Felix Levi C.
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Gaal Vladimir
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Woellner Cristiano F.
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Rodrigues Varlei
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Galvao Douglas S.
Triply Periodic Minimal Surfaces (TPMS) possess locally minimized surface
area under the constraint of periodic boundary conditions. Different families
of surfaces were obtained with different topologies satisfying such conditions...Examples of such families include Primitive (P), Gyroid (G) and Diamond (D)
surfaces. From a purely mathematical subject, TPMS have been recently found in
materials science as optimal geometries for structural applications. Proposed
by Mackay and Terrones in 1991, schwarzites are 3D crystalline porous carbon
nanocrystals exhibiting the shape of TPMS. Although their complex topology
poses serious limitations on their synthesis with conventional nanoscale
fabrication methods, such as Chemical Vapour Deposition (CVD), TPMS can be
fabricated by Additive Manufacturing (AM) techniques, such as 3D Printing. In
this work, we used an optimized atomic model of a schwarzite structure from the
D family (D8bal) to generate a surface mesh that was subsequently used for
3D-printing through Fused Deposition Modelling (FDM). This D schwarzite was
3D-printed with thermoplastic PolyLactic Acid (PLA) polymer filaments. Mechanical properties under uniaxial compression were investigated for both the
atomic model and the 3D-printed one. Fully atomistic Molecular Dynamics (MD)
simulations were also carried out to investigate the uniaxial compression
behavior of the D8bal atomic model. Mechanical testings were performed on the
3D-printed schwarzite where the deformation mechanisms were found to be similar
to those observed in MD simulations. These results are suggestive of a
scale-independent mechanical behavior that is dominated by structural topology.(read more)