Low Porosity Metallic Periodic Structures with Negative Poisson's Ratio

Abstract

Auxetic behavior in low porosity metallic structures is demonstrated via a simple system of orthogonal elliptical voids. In this minimal 2D system, the Poisson's ratio can be effectively controlled by changing the aspect ratio of the voids. In this way, large negative values of Poisson's ratio can be achieved, indicating an effective strategy for designing auxetic structures with desired porosity.

Lattice Metamaterials with Mechanically Tunable Poisson’s Ratio for Vibration Control

“…Among them, the mechanical metamaterials with a negative Poisson's ratio (NPR) are of particular interest [17][18][19][20][21][22][23][24][25][26]. For instance, by tailoring the geometric features of the ligaments in cellular structures, auxetic behavior can be achieved over a wide range of geometric parameters [24,25]. In addition, by integrating topology optimization with 3D printing technique, architected materials with non-straight ligaments have been optimized and display a nearly constant Poisson's ratio over large deformations [26].…”

“…The metamaterial concept has been rapidly extended from photonic systems to acoustic [7][8][9][10] and mechanical systems [11][12][13][14][15][16]. Among them, the mechanical metamaterials with a negative Poisson's ratio (NPR) are of particular interest [17][18][19][20][21][22][23][24][25][26]. For instance, by tailoring the geometric features of the ligaments in cellular structures, auxetic behavior can be achieved over a wide range of geometric parameters [24,25].…”

Engineering the shape and structure of materials by fractal cut

“…In two dimensions, periodic geometries have been adopted to tune the mechanical properties of membranes (3-8, 10, 12-14). From simple shapes such as circles (3), triangles (6,7,12,13), and quadralaterals (4,5,14) to more complex shapes (8,10), a broad range of mechanical behavior has been observed, including pattern transformation, negative Poisson's ratio (auxetic), elastic response, and isostaticity. Origami and kirigami, the arts of paper folding and paper cutting, create beautiful patterns and shapes that have attracted the attention of scientists to two-dimensional materials (e.g., graphene, polymer films, and so on) (11,(17)(18)(19).…”

“…Among these, engineering the geometry of the sample can provide a direct, intuitive, and often materialindependent approach to achieve a predetermined set of properties. Metamaterials are fabricated based on geometric concepts (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). In two dimensions, periodic geometries have been adopted to tune the mechanical properties of membranes (3-8, 10, 12-14).…”

Auxetic piezoelectric energy harvesters for increased electric power output

“…For the AS-bimorph, the auxetic substrate shown in Fig. 1 (b) was used, which is a 2D metallic sheet with a square array of mutually orthogonal elliptical voids and was previously studied by Taylor et al 13 The auxetic behavior of the substrate can be controlled by the aspect ratio a/b. When the aspect ratio is small, the substrate has a positive Poisson's ratio.…”