Anomalous elastic response of a 3D anti-tetrachiral metamaterial
The elastic modulus and Poisson's ratio of a 3D anti-tetrachiral (3ATC) metamaterial design was investigated using an exact analytical model, finite element simulations and experiments on additively manufactured Ti6Al4V lattices. The 3ATC structure was found to undergo a unique symmetric-to-asy...
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sg-ntu-dr.10356-1466362021-03-06T20:12:06Z Anomalous elastic response of a 3D anti-tetrachiral metamaterial Lai, Chang Quan Markandan, Kalaimani Lu, Zhen Temasek Laboratories @ NTU Engineering::Materials::Mechanical strength of materials Size Effect Additive Manufacturing The elastic modulus and Poisson's ratio of a 3D anti-tetrachiral (3ATC) metamaterial design was investigated using an exact analytical model, finite element simulations and experiments on additively manufactured Ti6Al4V lattices. The 3ATC structure was found to undergo a unique symmetric-to-asymmetric transition as the number of unit cells in the lattice decreases, an observation that has not been reported to date. A reduced lattice size also increases the influence of shear forces introduced by the fixed boundary conditions, which can lead to a higher elastic modulus in certain orientations and reduce it in others. These shear forces also drive the joints in small lattices into an out-of-plane rotation that causes the Poisson's ratio of such structures to range from -1.2 to 1 for different relative densities, in contrast to a constant value of -0.5 for bulk 3ATC lattices that do not undergo this joint twisting. Our results strongly indicate that the 3ATC structure belongs to a new ‘rotation-dominated’ geometric class in the Ashby framework for cellular materials, in addition to the well-established bending- and stretch- dominated topologies. The main contributor of strain for this class of materials is rigid joint rotation, with novel, distinctive traits such as a nonlinear elastic stress-strain response and multiple relative modulus vs. relative density relationships. For the 3ATC structure, one of these relations is linear, similar to stretch-dominated structures, while the other is disjointed and does not follow the power law, which is atypical of a cellular material. Accepted version Temasek Research Fellowship Funding for this project was partially provided by C.Q.L.’s Temasek Research Fellowship, for which he gives thanks. Samples for experimental testing were provided by SLM Solutions Singapore Pte Ltd. 2021-03-04T00:58:30Z 2021-03-04T00:58:30Z 2021 Journal Article Lai, C. Q., Markandan, K., & Lu, Z. (2021). Anomalous elastic response of a 3D anti-tetrachiral metamaterial. International Journal of Mechanical Sciences, 192, 106142-. doi:10.1016/j.ijmecsci.2020.106142 0020-7403 https://hdl.handle.net/10356/146636 10.1016/j.ijmecsci.2020.106142 192 106142 en International Journal of Mechanical Sciences © 2020 Elsevier Ltd. All rights reserved. This paper was published in International Journal of Mechanical Sciences and is made available with permission of Elsevier Ltd. application/pdf |
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Engineering::Materials::Mechanical strength of materials Size Effect Additive Manufacturing Lai, Chang Quan Markandan, Kalaimani Lu, Zhen Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
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The elastic modulus and Poisson's ratio of a 3D anti-tetrachiral (3ATC) metamaterial design was investigated using an exact analytical model, finite element simulations and experiments on additively manufactured Ti6Al4V lattices. The 3ATC structure was found to undergo a unique symmetric-to-asymmetric transition as the number of unit cells in the lattice decreases, an observation that has not been reported to date. A reduced lattice size also increases the influence of shear forces introduced by the fixed boundary conditions, which can lead to a higher elastic modulus in certain orientations and reduce it in others. These shear forces also drive the joints in small lattices into an out-of-plane rotation that causes the Poisson's ratio of such structures to range from -1.2 to 1 for different relative densities, in contrast to a constant value of -0.5 for bulk 3ATC lattices that do not undergo this joint twisting. Our results strongly indicate that the 3ATC structure belongs to a new ‘rotation-dominated’ geometric class in the Ashby framework for cellular materials, in addition to the well-established bending- and stretch- dominated topologies. The main contributor of strain for this class of materials is rigid joint rotation, with novel, distinctive traits such as a nonlinear elastic stress-strain response and multiple relative modulus vs. relative density relationships. For the 3ATC structure, one of these relations is linear, similar to stretch-dominated structures, while the other is disjointed and does not follow the power law, which is atypical of a cellular material. |
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Temasek Laboratories @ NTU |
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Temasek Laboratories @ NTU Lai, Chang Quan Markandan, Kalaimani Lu, Zhen |
format |
Article |
author |
Lai, Chang Quan Markandan, Kalaimani Lu, Zhen |
author_sort |
Lai, Chang Quan |
title |
Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
title_short |
Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
title_full |
Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
title_fullStr |
Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
title_full_unstemmed |
Anomalous elastic response of a 3D anti-tetrachiral metamaterial |
title_sort |
anomalous elastic response of a 3d anti-tetrachiral metamaterial |
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2021 |
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https://hdl.handle.net/10356/146636 |
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1695706148711170048 |