Elastic properties of 2D auxetic honeycomb structures- a review

Hierarchical honeycomb auxetic metamaterials

Most conventional materials expand in transverse directions when they are compressed uniaxially resulting in the familiar positive Poisson's ratio. Here we develop a new class of two dimensional (2D) metamaterials with negative Poisson's ratio that contract in transverse directions under uniaxial compressive loads leading to auxeticity. This is achieved through mechanical instabilities (i.e., b...

Phonons in conventional and auxetic honeycomb lattices

A review on auxetic structures and polymeric materials

Auxetic polymeric materials are a special kind of materials that exhibit negative Poisson’s ratio (NPR) effect. They get fatter when stretched and thinner when compressed. Auxetic behavior is a scaleindependent property which can be achieved at different structural levels from molecular to macroscopic levels. The internal structure of material plays an important role in obtaining auxetic effect...

Singularities in auxetic elastic bimaterials

In this paper we study the effects of negative Poisson’s ratios on elastic problems containing singularities. Materials with a negative Poisson’s ratio are termed auxetic. We present a brief review of such materials. The elasticity problem of a bimateral wedge is presented, then two particular cases of this problem are investigated: the free-edge problem and the interface crack problem. We stud...

Active inflatable auxetic honeycomb structural concept for morphing wingtips

This paper describes a new concept of an active honeycomb structure for morphing wingtip applications based on tubular inflatable systems and an auxetic cellular structure. A work-energy model to predict the output honeycomb displacement versus input pressure is developed together with a finite element formulation, and the results are compared with the data obtained from a small-scale example o...