scholarly journals Double-Negative Mechanical Metamaterials Displaying Simultaneous Negative Stiffness and Negative Poisson's Ratio Properties

2016 ◽  
Vol 28 (46) ◽  
pp. 10116-10116 ◽  
Author(s):  
Trishan A. M. Hewage ◽  
Kim L. Alderson ◽  
Andrew Alderson ◽  
Fabrizio Scarpa
Keyword(s):  
Poisson’S Ratio ◽  
Negative Stiffness ◽  
Poisson's Ratio ◽  
Double Negative ◽  
Negative Poisson’S Ratio ◽  
Mechanical Metamaterials ◽  
Negative Poisson's Ratio

Qualitative Analysis and Design of Mechanical Metamaterials

2017 ◽  
Author(s):  
Sreekalyan Patiballa ◽  
Girish Krishnan
Keyword(s):  
Qualitative Analysis ◽  
Poisson’S Ratio ◽  
Compliant Mechanisms ◽  
Flow Behavior ◽  
Load Flow ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Analysis And Design ◽  
Mechanical Metamaterials ◽  
Negative Poisson's Ratio

This paper presents a new mechanics-based framework for the qualitative analysis and conceptual design of mechanical meta-materials. The methodology is inspired by recent advances in the insightful synthesis of compliant mechanisms by visualizing a kinetostatic field of forces that flow through the mechanism geometry. The framework relates load flow behavior in the microstructure geometry to the global behavior of the materials, such as auxetic (negative poisson’s ratio), high bulk modulus, and high shear modulus. This understanding is used to synthesize and demonstrate novel planar microstructures that exhibit negative poisson’s ratio behavior. Furthermore, the paper identifies three unique classes of qualitative design problems for planar mechanical microstructures that can be potentially solved using this framework.

scholarly journals Tunable Negative Poisson’s Ratio in Van der Waals Superlattice

Research ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaowen Li ◽  
Xiaobin Qiang ◽  
Zhenhao Gong ◽  
Yubo Zhang ◽  
Penglai Gong ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Electronic Band Structure ◽  
Hexagonal Boron Nitride ◽  
Van Der Waals ◽  
Poisson's Ratio ◽  
Negative Poisson’S Ratio ◽  
Electronic Band ◽  
Mechanical Metamaterials ◽  
Wide Range ◽  
Negative Poisson's Ratio

Negative Poisson’s ratio (NPR) materials are functional and mechanical metamaterials that shrink (expand) longitudinally after being compressed (stretched) laterally. By using first-principles calculations, we found that Poisson’s ratio can be tuned from near zero to negative by different stacking modes in van der Waals (vdW) graphene/hexagonal boron nitride (G/h-BN) superlattice. We attribute the NPR effect to the interaction of pz orbitals between the interfacial layers. Furthermore, a parameter calculated by analyzing the electronic band structure, namely, distance-dependent hopping integral, is used to describe the intensity of this interaction. We believe that this mechanism is not only applicable to G/h-BN superlattice but can also explain and predict the NPR effect in other vdW layered superlattices. Therefore, the NPR phenomenon, which was relatively rare in 3D and 2D materials, can be realized in the vdW superlattices by different stacking orders. The combinations of tunable NPRs with the excellent electrical/optical properties of 2D vdW superlattices will pave a novel avenue to a wide range of multifunctional applications.

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