Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections
Negative Poisson's ratio has been shown to enhance packing efficiency, impact absorption, indentation resistance, fracture resistance and acoustics attenuation in auxetic materials, making them useful for applications such as protective cases and stents. However, these benefits are usually real...
| Main Authors: | , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2022
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| Online Access: | https://hdl.handle.net/10356/156162 |
| _version_ | 1826123764340883456 |
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| author | Seetoh, Ian Peiyuan Leong, Brendon Lee, Edmon Yi Markandan, Kalaimani Kanaujia, Pawan Kumar Lai, Chang Quan |
| author2 | School of Mechanical and Aerospace Engineering |
| author_facet | School of Mechanical and Aerospace Engineering Seetoh, Ian Peiyuan Leong, Brendon Lee, Edmon Yi Markandan, Kalaimani Kanaujia, Pawan Kumar Lai, Chang Quan |
| author_sort | Seetoh, Ian Peiyuan |
| collection | NTU |
| description | Negative Poisson's ratio has been shown to enhance packing efficiency, impact absorption, indentation resistance, fracture resistance and acoustics attenuation in auxetic materials, making them useful for applications such as protective cases and stents. However, these benefits are usually realized at the expense of a low specific modulus and poor loading efficiencies, as auxetic structures rely on ‘soft’ strut bending and/ or joint rotation deformation modes to reach perceptible levels of negative Poisson's ratios. Here, a general 3D Anti-Tetrachiral (3ATC) structure was analyzed and shown that, in the limit of low relative density (i.e lightweight structure), the trade-off between specific relative stiffness and auxeticity is linear and the maximum attainable specific relative stiffness is 1/3. If the strut cross-section is symmetric, the maximum attainable Poisson's ratio is -0.5, while that for an asymmetric cross-section depends on the specific geometry of the cross-section. Importantly, our analysis shows that the non-zero product of inertia for asymmetric cross-sections can lead to an additional twist of the joint, thereby increasing the auxeticity of the 3ATC structure. This allows the 3ATC lattice to exhibit a large specific relative stiffness for a given Poisson's ratio, which can be more than an order of magnitude higher when compared to other auxetic designs in the literature. Our analysis was validated by finite element simulations and experiments on 3ATC lattices with strut cross-sections that were square (symmetric) and L-shaped (asymmetric). |
| first_indexed | 2024-10-01T06:09:40Z |
| format | Journal Article |
| id | ntu-10356/156162 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T06:09:40Z |
| publishDate | 2022 |
| record_format | dspace |
| spelling | ntu-10356/1561622022-09-10T23:31:49Z Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections Seetoh, Ian Peiyuan Leong, Brendon Lee, Edmon Yi Markandan, Kalaimani Kanaujia, Pawan Kumar Lai, Chang Quan School of Mechanical and Aerospace Engineering School of Materials Science and Engineering Temasek Laboratories @ NTU Engineering::Mechanical engineering Engineering::Mechanical engineering::Mechanics and dynamics Negative Poisson’s Ratio Metamaterials Auxetic Rotation-Dominated Cellular Solids Lightweight Negative Poisson's ratio has been shown to enhance packing efficiency, impact absorption, indentation resistance, fracture resistance and acoustics attenuation in auxetic materials, making them useful for applications such as protective cases and stents. However, these benefits are usually realized at the expense of a low specific modulus and poor loading efficiencies, as auxetic structures rely on ‘soft’ strut bending and/ or joint rotation deformation modes to reach perceptible levels of negative Poisson's ratios. Here, a general 3D Anti-Tetrachiral (3ATC) structure was analyzed and shown that, in the limit of low relative density (i.e lightweight structure), the trade-off between specific relative stiffness and auxeticity is linear and the maximum attainable specific relative stiffness is 1/3. If the strut cross-section is symmetric, the maximum attainable Poisson's ratio is -0.5, while that for an asymmetric cross-section depends on the specific geometry of the cross-section. Importantly, our analysis shows that the non-zero product of inertia for asymmetric cross-sections can lead to an additional twist of the joint, thereby increasing the auxeticity of the 3ATC structure. This allows the 3ATC lattice to exhibit a large specific relative stiffness for a given Poisson's ratio, which can be more than an order of magnitude higher when compared to other auxetic designs in the literature. Our analysis was validated by finite element simulations and experiments on 3ATC lattices with strut cross-sections that were square (symmetric) and L-shaped (asymmetric). Nanyang Technological University Submitted/Accepted version Funding for this project was partially provided by C.Q.L’s startup, Singapore grant (award no.: 020868–00001) 2022-04-07T07:45:50Z 2022-04-07T07:45:50Z 2022 Journal Article Seetoh, I. P., Leong, B., Lee, E. Y., Markandan, K., Kanaujia, P. K. & Lai, C. Q. (2022). Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections. Extreme Mechanics Letters, 52, 101677-. https://dx.doi.org/10.1016/j.eml.2022.101677 2352-4316 https://hdl.handle.net/10356/156162 10.1016/j.eml.2022.101677 2-s2.0-85126129702 52 101677 en 020868–00001 Extreme Mechanics Letters © 2022 Elsevier Ltd. All rights reserved. This paper was published in Extreme Mechanics Letters and is made available with permission of Elsevier Ltd. application/pdf |
| spellingShingle | Engineering::Mechanical engineering Engineering::Mechanical engineering::Mechanics and dynamics Negative Poisson’s Ratio Metamaterials Auxetic Rotation-Dominated Cellular Solids Lightweight Seetoh, Ian Peiyuan Leong, Brendon Lee, Edmon Yi Markandan, Kalaimani Kanaujia, Pawan Kumar Lai, Chang Quan Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title | Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title_full | Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title_fullStr | Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title_full_unstemmed | Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title_short | Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections |
| title_sort | extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross sections |
| topic | Engineering::Mechanical engineering Engineering::Mechanical engineering::Mechanics and dynamics Negative Poisson’s Ratio Metamaterials Auxetic Rotation-Dominated Cellular Solids Lightweight |
| url | https://hdl.handle.net/10356/156162 |
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