Design of planar isotropic negative Poisson’s ratio structures

Shan, Sicong; Kang, Sung Hoon; Zhao, Zhenhao; Fang, Lichen; Bertoldi, Katia

doi:10.1016/j.eml.2015.05.002

Cited by 181 publications

(100 citation statements)

References 36 publications

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“…A variety of auxetic materials have been proposed in recent years; examples range from metamaterials [9,10,11,12,8] and foams prepared by special processing techniques [13,14,15,1] to composites [16]. The vast majority of these materials are anisotropic, meaning that the Poisson's ratio, ν, depends on the direction of applied strain; this restriction is not desirable for applications.…”

Section: Introductionmentioning

confidence: 99%

Ideal isotropic auxetic networks from random networks

et al. 2019

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Auxetic materials are characterized by a negative Poisson's ratio, ν. As the Poisson's ratio becomes negative and approaches the lower isotropic mechanical limit of ν = −1, materials show enhanced resistance to impact and shear, making them suitable for applications ranging from robotics to impact mitigation. Past experimental efforts aimed at reaching the ν = −1 limit have resulted in highly anisotropic materials, which show a negative Poisson's ratio only when subjected to deformations along specific directions. Isotropic designs have only attained moderately auxetic behavior, or have led to structures that cannot be manufactured in 3D. Here, we present a design strategy to create isotropic structures from disordered networks that leads to Poisson's ratios as low as ν = −0.98. The materials conceived through this approach are successfully fabricated in the laboratory and behave as predicted. The Poisson's ratio ν is found to depend on network structure and bond strengths; this sheds light on the structural motifs that lead to auxetic behavior. The ideas introduced here can be generalized to 3D, a wide range of materials, and a spectrum of length scales, thereby providing a general platform that could impact technology. arXiv:1904.04359v1 [cond-mat.soft]

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Section: Introductionmentioning

confidence: 99%

Ideal isotropic auxetic networks from random networks

et al. 2019

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“…Auxetic structures and materials are those that have Negative Poisson's Ratios (NPR), which exhibit counter-intuitive behavior when force is applied: the transverse cross-sectional area increases with axial stretching 1,2 . This is in contrast with the more intuitive deformation behavior of Positive Poisson's Ratio (PPR) materials, such as the common rubber band: PPR materials thin laterally as the material is stretched.…”

Section: Introductionmentioning

confidence: 99%

3D-printed biomaterials with regional auxetic properties

Warner

Gillies

Hwang

et al. 2017

Journal of the Mechanical Behavior of Biomedical Materials

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Tissue engineering is replete with methods for inducing and mediating cell differentiation, which are crucial for ensuring proper regrowth of desired tissues. In this study, we developed a 3D-printed, non-positive Poisson's Ratio (NPPR) scaffold intended for future use in stretch-mediated cell differentiation applications, such as in muscle and tendon regeneration. We utilized dynamic optical projection stereolithography (DOPsL) to fabricate multi-layered, cell-laden NPPR scaffolds – these scaffolds can not only support aggregate cell growth, but can also be printed with locally-tunable force-displacement properties at length scales appropriate for tissue interaction. These NPPR multilayered mesh scaffolds can be embedded into highly elastic hydrogels in order to couple a reduced NPPR behavior to a normally Positive Poisson's Ratio (PPR) solid bulk material. This hybrid structure may potentially enable induced ‘auxetic’ behavior at the single-cell scale while tuning the Poisson's Ratio to a more isolated value. This would be uniquely suited for providing stretch-mediated effects for various cell-types within the tendon-to-muscle tissue transition.

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“…[ 11,[13][14][15] It must be said that the concept of creating auxetics through cuts and perforations is particularly appealing since this method is likely to offer a cost-effective route to manufacture auxetics at a large scale, with all the associated benefi ts, [ 17 ] which include the ability to form dome-shaped structures [ 18 ] and improved indentation resistance. [ 19 ] Despite the considerable literature on the subject, all of these works consider primarily highly symmetric ideal systems without any randomness in their design or imperfections.…”

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confidence: 99%

“…These samples were tested in tension with measurements of dimensions and strains being made in the centermost region of the sample where the response is known to be more uniform and boundary effects are minimal. [ 14 ] The dimensions from which the strains and Poisson's ratio were derived, were measured using videoextensiometry by a Messphysik system while the samples were stretched using a Testometric tensile testing machine at a very slow strain rate. Further details are given in the Supporting Information.…”

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confidence: 99%