A novel design method to produce 3D auxetic metamaterials with continuous pores exemplified through 3D rotating auxetic systems. (February 2023)

• Record Type: Journal Article
• Authors: Galea, Russell; Farrugia, Pierre-Sandre; Dudek, Krzysztof K.; Attard, Daphne; Grima, Joseph N.; Gatt, Ruben
• Is Part Of: Materials & design. Volume 226(2023)
• Publication Date: 2023-02
• Subjects: Perforations -- Subtractive manufacturing -- Negative Poisson's ratio -- 3D auxetic structures; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2023.111596
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: A novel method to produce 3D auxetic metamaterials has been proposed. The proposed method involved the application of continuous voids with constant cross-sectional area in multiple perpendicular planes. The potential of using subtractive manufacturing, additive manufacturing, or casing to fabricate these 3D auxetic structures was shown. Using continuous voids with a diamond shaped cross-sectional area were shown to produce novel 3D auxetic structures. Nonlinear simulations and experimental testing showed that the Poisson's ratio of these structures is strain independent up to 7% deformation. Abstract: Prototyping of three-dimensional mechanical metamaterials that exhibit negative Poisson's ratio is usually performed through additive manufacturing. Although this technique has a huge potential, its use to engineer mechanical metamaterials for consumer products is still challenging. In this work, a novel design method is being proposed where 3D auxetic metamaterials can be produced by introducing continuous voids of constant cross-sectional area. Such voids would be inserted at strategic positions in different perpendicular planes of a solid block to obtain a continuous three-dimensional mechanical metamaterial that can exhibit the desired mechanical characteristics. The use of continuous voids to design the 3D meatamaterial makes it possible to use additive manufacturing, subtractive manufacturing as well as casting to produce these systems. The proposed design method is explained by using continuous voids having a diamond shaped cross-sectional area. The resulting group of structures can be described as connected polygons and were found to exhibit a negative or zero Poisson's ratio. The analysed systems were also found to have a strain independent Poisson's ratio up to at least 7% strain. The proposed design method can thus facilitate the availability of three dimensional auxetic metamaterials in the consumer market which to date is conspicuous by their absence.