title: Orthotropic Laminated Open-cell Frameworks Retaining Strong Auxeticity under Large Uniaxial Loading.
abstract: Anisotropic materials form inside living tissue and are widely applied in engineered structures, where sophisticated structural and functional design principles are essential to employing these materials. This paper presents a candidate laminated open-cell framework, which is an anisotropic material that shows remarkable mechanical performance. Using additive manufacturing, artificial frameworks are fabricated by lamination of in-plane orthotropic microstructures made of elbowed beam and column members; this fabricated structure features orthogonal anisotropy in three-dimensional space. Uniaxial loading tests reveal strong auxeticity (high negative Poisson's ratios) in the out-of-plane direction, which is retained reproducibly up to the nonlinear elastic region, and is equal under tensile and compressive loading. Finite element simulations support the observed auxetic behaviors for a unit cell in the periodic framework, which preserve the theoretical elastic properties of an orthogonal solid. These findings open the possibility of conceptual materials design based on geometry.
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Hiro
authors.initials: H
authors.lastname: Tanaka
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Kaito
authors.initials: K
authors.lastname: Suga
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Iwata
authors.affiliation: Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Yoji
authors.initials: Y
authors.lastname: Shibutani
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002070:Butadienes / Q000737:chemistry; D019245:Compressive Strength; D017076:Computer-Aided Design; D004548:Elasticity; D008422:Materials Testing; D008954:Models, Biological; D011137:Polystyrenes / Q000737:chemistry; D066330:Printing, Three-Dimensional; D013718:Tensile Strength
chemical_list: D000180:Acrylic Resins; D002070:Butadienes; D011137:Polystyrenes; C024636:ABS resin