Auxetics

Auxetic metamaterials are a type of metamaterial with a negative Poisson's ratio, so that axial elongation causes transversal elongation (in contrast to an ordinary material, where stretching in one direction causes compression in the other direction).

Auxetics can be single molecules, crystals, or a particular structure of macroscopic matter.^[1]^[2]

Auxetic materials are used in protective equipment such as body armor, helmets, and knee pads, as they absorb energy more effectively than traditional materials.^[3]^[4] They are also used in devices such as medical stents or implants. Auxetic fabrics can be used to create comfortable and flexible clothing, as well as technical fabrics for applications such as aerospace and sports equipment.^[4] Auxetic materials can also be used to create acoustic metamaterials for controlling sound and vibration.^[5]

^ Cite error: The named reference Lakes was invoked but never defined (see the help page).
^ Cite error: The named reference evans was invoked but never defined (see the help page).
^ Haid, Daniel; Foster, Leon; Hart, John; Greenwald, Richard; Allen, Tom; Sareh, Pooya; Duncan, Olly (1 November 2023). "Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance". Smart Materials and Structures. 32 (11): 113001. doi:10.1088/1361-665X/acfddf.
^ ^a ^b Duncan, Olly; Shepherd, Todd; Moroney, Charlotte; Foster, Leon; Venkatraman, Praburaj D.; Winwood, Keith; Allen, Tom; Alderson, Andrew (6 June 2018). "Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection". Applied Sciences. 8 (6): 941. doi:10.3390/app8060941.
^ Liu, Yangzuo; Zhao, Changfang; Xu, Cheng; Ren, Jie; Zhong, Jianlin (1 December 2023). "Auxetic meta-materials and their engineering applications: a review". Engineering Research Express. 5 (4): 042003. doi:10.1088/2631-8695/ad0eb1. ISSN 2631-8695.

[Lakes-1] Cite error: The named reference Lakes was invoked but never defined (see the help page).

[evans-2] Cite error: The named reference evans was invoked but never defined (see the help page).

[3] Haid, Daniel; Foster, Leon; Hart, John; Greenwald, Richard; Allen, Tom; Sareh, Pooya; Duncan, Olly (1 November 2023). "Mechanical metamaterials for sports helmets: structural mechanics, design optimisation, and performance". Smart Materials and Structures. 32 (11): 113001. doi:10.1088/1361-665X/acfddf.

[auto-4] Duncan, Olly; Shepherd, Todd; Moroney, Charlotte; Foster, Leon; Venkatraman, Praburaj D.; Winwood, Keith; Allen, Tom; Alderson, Andrew (6 June 2018). "Review of Auxetic Materials for Sports Applications: Expanding Options in Comfort and Protection". Applied Sciences. 8 (6): 941. doi:10.3390/app8060941.

[5] Liu, Yangzuo; Zhao, Changfang; Xu, Cheng; Ren, Jie; Zhong, Jianlin (1 December 2023). "Auxetic meta-materials and their engineering applications: a review". Engineering Research Express. 5 (4): 042003. doi:10.1088/2631-8695/ad0eb1. ISSN 2631-8695.

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