Bio-inspired auxetic mechanical metamaterials evolved from rotating squares unit. (October 2022)

• Record Type: Journal Article
• Authors: Sorrentino, Andrea; Castagnetti, Davide; Mizzi, Luke; Spaggiari, Andrea
• Is Part Of: Mechanics of materials. Volume 173(2022)
• Publication Date: 2022-10
• Subjects: Auxetic metamaterials -- Bio-inspired design -- Rotating squares -- Chiral honeycombs -- Mechanical characterization; Strength of materials -- Periodicals; Mechanics, Applied -- Periodicals; Résistance des matériaux -- Périodiques; Mécanique appliquée -- Périodiques; Mechanics, Applied; Strength of materials; Periodicals; Electronic journals; 620.11
• DOI: 10.1016/j.mechmat.2022.104421
• Languages: English
• ISSNs: 0167-6636

Abstract

Abstract: This work investigates the mechanical response of bio-inspired titanium mechanical metamaterials with negative Poisson's ratio evolved from rotating squares unit. The systems were designed and optimized using finite element analysis, with peculiar focus on the shape profile at the interconnection regions of the rotating units. The proposed solution consists of a combined auxetic rotating/chiral architecture with enhanced mechanical and topological properties which exhibits a 3% of global elastic strain of the structure and a Poisson's ratio equal to −0.94. Numerical results are in good agreement with those obtained from experimental tests on a 3D printed Onyx prototype. We also examined the effect on the structural response of the metamaterial subject to off-axis mechanical conditions revealing the strong correlation to the geometrically-related anti -tetrachiral honeycombs. The work confirms the great potential of biologically inspired auxetic metamaterials, which can be designed to obtain tailored mechanical properties while improving the elastic strains capabilities of the system. Graphical abstract: Image 1 Highlights: Novel bio-inspired titanium auxetic metamaterials were proposed and investigated. The designed architecture consists of a hybrid auxetic motif with enhanced mass-to-strength mechanical properties. The off-axis mechanical behavior of the proposed metamaterials was also analyzed. The work provides a useful insight for bio-inspired oriented optimization of auxetic mechanical metamaterials.