scholarly journals Erratum to “On the conical indentation response of elastic auxetic materials: Effects of Poisson's ratio, contact friction and cone angle” [Int. J. Solids Struct. 81 (2016) 33–42]

2017 ◽  
Vol 110-111 ◽  
pp. 404 ◽  
Author(s):  
D. Photiou ◽  
E. Sarris ◽  
G. Constantinides
Keyword(s):  
Poisson’S Ratio ◽  
Cone Angle ◽  
Poisson's Ratio ◽  
Contact Friction ◽  
Auxetic Materials ◽  
Indentation Response ◽  
Conical Indentation

scholarly journals Giant negative Poisson’s ratio in two-dimensional V-shaped materials

2021 ◽  
Author(s):  
Xikui Ma ◽  
Jian Liu ◽  
Yingcai Fan ◽  
Weifeng Li ◽  
Jifan Hu ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Two Dimensional ◽  
Auxetic Materials ◽  
Negative Poisson's Ratio ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Two-dimensional (2D) auxetic materials with exceptional negative Poisson’s ratios (NPR) are drawing increasing interest due to the potentials in medicine, fasteners, tougher composites and many other applications. Improving the auxetic...

Elasto-Plastic Indentation of Auxetic and Metal Foams

2019 ◽  
Vol 87 (1) ◽  
Author(s):  
N. Kumar ◽  
S. N. Khaderi ◽  
K. Tirumala Rao
Keyword(s):  
Poisson’S Ratio ◽  
Strain Energy ◽  
Metal Foams ◽  
Poisson's Ratio ◽  
Indentation Hardness ◽  
The Finite Element Method ◽  
Yield Strain ◽  
Plastic Dissipation ◽  
Auxetic Materials ◽  
Plastic Indentation

Abstract The elasto-plastic indentation of auxetic and metal foams is investigated using the finite element method. The contributions of yield strain, elastic, and plastic Poisson’s ratio on the indentation hardness are identified. For a given yield strain, when the plastic Poisson’s ratio is reduced from 0.5, the indentation hardness decreases first and then increases. This trend was found to be valid for a wide of yield strains. For yield strains less than 0.08, the hardness of auxetic materials is much larger when compared with materials having positive plastic Poisson’s ratio. As the plastic Poisson’s ratio approaches −1, the elastic deformations dominate over the plastic deformations. The plastic dissipation, when compared with the elastic work, is lower for materials with negative Poisson’s ratio. There is no effect of elastic Poisson’s ratio on the indentation hardness when the plastic Poisson’s ratio is more than −0.8. When the plastic Poisson’s ratio is less than −0.8, the hardness increases with a decrease of elastic Poisson’s ratio. The plastic dissipation per unit strain energy is maximum for materials with vanishing plastic Poisson’s ratio.

Buckling and Vibration of Circular Auxetic Plates

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Teik-Cheng Lim
Keyword(s):  
Poisson’S Ratio ◽  
Dynamic Properties ◽  
Elastic Stability ◽  
Buckling Load ◽  
Poisson's Ratio ◽  
Circular Plates ◽  
Critical Buckling Load ◽  
Various Boundary Conditions ◽  
Load Factors ◽  
Auxetic Materials

This paper evaluates the elastic stability and vibration characteristics of circular plates made from auxetic materials. By solving the general solutions for buckling and vibration of circular plates under various boundary conditions, the critical buckling load factors and fundamental frequencies of circular plates, within the scope of the first axisymmetric modes, were obtained for the entire range of Poisson's ratio for isotropic solids, i.e., from −1 to 0.5. Results for elastic stability reveal that as the Poisson's ratio of the plate becomes more negative, the critical bucking load gradually reduces. In the case of vibration, the decrease in Poisson's ratio not only decreases the fundamental frequency, but the decrease becomes very rapid as the Poisson's ratio approaches its lower limit. For both buckling and vibration, the plate's Poisson's ratio has no effect if the edge is fully clamped. The results obtained herein suggest that auxetic materials can be employed for attaining static and dynamic properties which are not common in plates made from conventional materials. Based on the exact results, empirical models were generated for design purposes so that both the critical buckling load factors and the frequency parameters can be conveniently obtained without calculating the Bessel functions.

FLEXURAL RIGIDITY OF THIN AUXETIC PLATES

2014 ◽  
Vol 06 (02) ◽  
pp. 1450012 ◽  
Author(s):  
TEIK-CHENG LIM
Keyword(s):  
Shear Modulus ◽  
Poisson’S Ratio ◽  
Flexural Rigidity ◽  
Poisson's Ratio ◽  
Cube Root ◽  
Square Root ◽  
Isotropic Plates ◽  
Auxetic Materials ◽  
Lower Limits ◽  
Isotropic Solids

The influence of auxeticity on the mechanical behavior of isotropic plates is considered herein by evaluating the plate flexural rigidity as the Poisson's ratio changes from 0.5 to -1. Since the change in plate's Poisson's ratio is followed by a change in at least one of the three moduli, any resulting change to the plate flexural rigidity is only meaningful when at least one of the moduli is held constant. This was performed by normalizing the plate flexural rigidity by a single modulus, a square root of two moduli product, or a cube root of three moduli product to give a dimensionless plate flexural rigidity. It was found that the plate flexural rigidity decreases to a minimum as the plate Poisson's ratio decreases from 0.5 to 0 when only the Young's modulus is held constant. Thereafter the plate flexural rigidity increases with the plate auxeticity. Results also reveal that when only the shear modulus or when the bulk modulus is held constant, the plate flexural rigidity decreases or increases, respectively, with the plate auxeticity. Intermediate trend in the plate flexural rigidity is observed when the product of two moduli is held constant. When the product of all three moduli is held constant, the plate flexural rigidity increases with the plate auxeticity, and the change is especially drastic when the plate Poisson's ratio is near to the upper and lower limits of Poisson's ratio for isotropic solids. Results from this work are useful for structural designers to control the flexural rigidity of plate made from auxetic materials.

Circular Auxetic Plates

2012 ◽  
Vol 29 (1) ◽  
pp. 121-133 ◽  
Author(s):  
T.-C. Lim
Keyword(s):  
Poisson’S Ratio ◽  
Load Distribution ◽  
Point Load ◽  
Poisson's Ratio ◽  
Circular Plates ◽  
Auxetic Materials ◽  
Edge Conditions ◽  
Bending Stresses ◽  
The Common ◽  
Laterally Loaded

AbstractThis paper investigates the suitability of auxetic materials for load-bearing circular plates. It is herein shown that the optimal Poisson's ratio for minimizing the bending stresses is strongly dependent on the final deformed shape, load distribution, and the type of edge supports. Specifically, the use of auxetic material for circular plates is recommended when (a) the plate is bent into a spherical or spherical-like cap, (b) a point load is applied to the center of the plate regardless of the edge conditions, and (c) a uniform load is applied on a simply-supported plate. However, auxetic materials are disadvantaged when a flat plate is to be bent into a saddle-like shell. The optimal Poisson's ratios concept recommended in this paper is useful for providing an added design consideration. In most cases, the use of auxetic materials for laterally loaded circular plates is more advantageous compared to the use of materials with conventional Poisson's ratio, with other factors fixed. This is achieved through materials-based stress re-distribution in addition to the common practices of dimensioning-based stress redistribution and materials strengthening.

scholarly journals PETAL AUXETICS WITH TARGETED POISSON’S RATIO USING ISOGEOMETRIC SHAPE OPTIMIZATION

2021 ◽  
Author(s):  
Deepak Kumar Pokkalla
Keyword(s):  
Shape Optimization ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Stress Concentrations ◽  
Optimization Framework ◽  
Optimization Stage ◽  
Auxetic Materials ◽  
Potential Applications ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

Auxetic materials with negative Poisson’s ratio have potential applications across a broad range of engineering fields. Several design techniques have been developed to obtain auxetics with targeted mechanical properties. However, many of these finite element based techniques are difficult to use directly for auxetics, particularly during the design optimization stage which involves evolving boundary parts with large curvatures. This paper focusses on a series of smoothed petal auxetics, with lower stress concentrations at connecting parts, compared to the reference star shaped structures. An isogeometric shape optimization framework to achieve target Poisson’s ratios at large deformation is presented. Several smoothed petal auxetic designs with target constant Poisson’s ratios up to an effective tensile strain of 30% are shown to demonstrate the capability of the optimization framework.

Design, preparation, and characterization of auxetic weft backed weave fabrics based on Miura origami structure

2021 ◽  
pp. 004051752110505
Author(s):  
Qiaoli Xu ◽  
Longxin Gu ◽  
Gui Liu ◽  
Zhuoran Liu ◽  
Dongdong Lu ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Physical Map ◽  
Structure Type ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Auxetic Materials ◽  
Out Of Plane ◽  
Weaving Technology ◽  
Negative Poisson's Ratio

The metamaterials with negative Poisson’s ratio are called auxetic materials, which as a branch of metamaterials has drawn a lot of attention in many areas. Existing auxetic knitting textiles combine flexibility and auxeticity, however the loose structure has been a main disadvantage for its application. In this study, we fabricated Miura origami structure fabrics by weaving technology in order to acquire more stable auxetic textiles. The results show that using the combination of fabric structure type and elastic yarns, an origami structure can be realized in a jacquard loom. In the Miura origami structure, the crease pattern can be separated into three parts, unfolding areas, convex areas, and concave areas. One warp system and two weft systems are compounded together, in which a weft backed weave is used to get elastic floats in the convex and concave areas, and to make the fabrics bend to the concave side. The physical map showed that the fabrics had a clear Miura origami structure and the unfolding areas were flat and even. On the basis of the designed geometric pattern, weft backed weaves can be used to construct different folded areas, spandex wrapped PET (Polyester) and inelastic PET are selected as two weft systems for weaving. Meanwhile, the Miura origami fabrics exhibit distinct in-plane negative Poisson’s ratio and out-of-plane positive Poisson’s ratio. Apart from the Miura origami structure, other origami and paper-cut structures can be realized using this method, and these special auxetic textiles have potential in protective cloths, ornamented textiles, wearable devices, and flexible sensors.

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