Investigation of a Novel Chiral S‐Shaped Auxetic Structure under Large Tensile Deformation

Abstract

The behavior of the chiral S‐shaped structure subjected to large tensile loads in both X and Y directions is reported herein. The physical samples of stainless steel 316L are fabricated by the selective laser melting technique and experimental tests are conducted on a universal tensile testing machine. The results of tensile tests in the form of deformation patterns, tensile stress–strain curves, and Poisson's ratios are shown pictorially and graphically. The orientation of the S‐shaped structure with X‐direction loading is found to exhibit higher auxeticity over the large range of tensile loading. Nonetheless, the structure is also found auxetic when loaded from Y‐direction albeit the values of negative Poisson's ratios are not as high as of the X‐directional loading.

Additively Manufactured Multilevel Voronoi-Lattice Scaffolds with Bonelike Mechanical Properties

“…The porous scaffolds designed in this study were mainly used in bone implantation . The quasi-static compressive test could be used to determine the mechanical properties of the scaffold under uniaxial compressive load, including elastic modulus, yield strength, compressive strength, plateau stress, energy absorption, etc. − It also included structure Poisson’s ratio, which was determined by the material, structure, additive manufacturing technology, and loading direction. − The compressive mechanical properties of various scaffolds with the same porosity were significantly different and related to various deformation modes during compression. The Gibson–Ashby model described the power relationship between porosity and elastic modulus and compressive strength to evaluate the mechanical properties and deformation modes of porous scaffolds. , where E is the elastic modulus of the scaffold; E 0 is the elastic modulus of the titanium alloy material; Q is the yield stress of the scaffold; Q 0 is the yield stress of the titanium alloy material; P is the porosity of the scaffold; and k 1 , k 2 , m 1 , and m 2 are fitting constants.…”

Fatigue response of auxetic structures: A review

“…19 On the other hand, star shapes are connected to one another by beams T A B L E 1 Typical geometries used in different auxetic structures. [14][15][16][17][18][19][20][21]…”

“…In this case, when the structure is compressed, the inclined segments deform into elliptical shapes, forcing the inclined cells to align with the load direction, causing the material to compress laterally. 32 Compared with the other geometries, this one has the largest compression when compressed and the least sensitivity to defects, which makes it ideal for AM. 21 New auxiliary geometries are currently being proposed in the literature, resulting from the combination or arrangement of those described above, in order to take advantage of each one.…”

“…32 Compared with the other geometries, this one has the largest compression when compressed and the least sensitivity to defects, which makes it ideal for AM. 21 New auxiliary geometries are currently being proposed in the literature, resulting from the combination or arrangement of those described above, in order to take advantage of each one. For example, a hybrid auxetic geometry was proposed by Abbaslou et al, 33 combining the re-entrant with a meta-trichiral auxetic geometry, and a highly negative Poisson's ratio of À4.91 was obtained with this hybridization.…”

Quasi‐Static Mechanical Properties of a Modified Auxetic Re‐Entrant Honeycomb Metamaterial

“…[17,18] Many researchers have investigated auxetic metamaterials and discovered more types of auxetic structures. [19][20][21][22][23] Auxetic structures have mechanical properties superior to conventional structures, [24][25][26][27][28] such as increased shear modulus, [29,30] good indentation resistance, [31,32] enhanced fracture toughness, [33] higher impact resistance, [34,35] variable stiffness, [36,37] and better energy absorption. [38,39] Therefore, auxetic structures have high potential in practical applications, such as collision safety for automobiles, [40] structural protection, [41] and smart sensors.…”