3D cellular models with negative compressibility through the wine‐rack‐type mechanism

Self Cite

Three 3D models with negative compressibility have been presented in our previous paper [X. Q. Zhou et al., Phys. Status Solidi B 2016, 253, 1977]. However, the 2D mechanism (i.e., wine‐rack mechanism) which we used to design 3D models is so symmetrical that the axial properties of it are equivalent, so we have only focused on geometry features. In this work, an extended study is conducted in order to find a more efficient method to design 3D structures with evident negative compressibility. Through theoretical modeling, the compressibility properties of three 3D models made from hinging hexagonal truss mechanism are analyzed and the conditions for negative compressibility to be exhibited are discussed. The study shows that in addition to the geometry features, negative compressibility effects can also be significantly affected by the arrangement of the framework and layout orientations of 2D mechanism.

Section: Introductioncontrasting

confidence: 62%

X_{1} = X_{2} = 2 l \cos θ

X_{3} = 2 l \sin θ + h

…”

Section: Analytical Modeling Of 3d Modelsmentioning

confidence: 99%

Negative Compressibility of 3D Cellular Models Constructed by Hinging Hexagonal Truss Mechanism

Zhou

Lü

et al. 2018

Self Cite

“…Such behaviour where hinging and flexing occur simultaneously in an additive manner is concordant with what was predicted by Evans and Masters in their work on honeycombs and had also been observed when studying the flexyne/re‐flexyne systems . Also worth noting is that models by Barnes et al suggest that models involving ‘flexing wine‐rack‐like’ structures are not dissimilar to the models deforming through hinging such as those presented by Grima et al and Zhou and Zhang …”

Section: Resultssupporting

confidence: 85%

On the Compressibility Properties of the Wine‐Rack‐Like Carbon Allotropes and Related Poly(phenylacetylene) Systems

Degabriele

Attard

Grima‐Cornish

et al. 2018

Poly(phenylacetylene) sheets that mimic the geometry of a wine-rack-like structure have been predicted to exhibit negative Poisson's ratios off-axis. However, their potential to exhibit negative linear compressibility (NLC) has remained largely unexplored. In this work, the compressibility and other mechanical properties of wine-rack-like poly(phenylacetylene) networks with 1,2,4,5 tetra-substituted phenyls as well as their equivalent with allene or cyclobutadiene centres are simulated to assess their ability to exhibit negative linear compressibility on-axis and off-axis. It is shown that some of these systems can indeed exhibit negative linear compressibility whilst others exhibit a near-zero compressibility. The results are compared to the compressibility properties of other poly(phenylacetylene) networks reported in literature as well as with those predicted from the analytical model for an idealised wine-rack structure deforming through hinging. Results suggest that these mechanical properties are arising from a wine-rack-like mechanism, and there is a good agreement with the theoretical model, especially for systems with longer acetylene chains whose geometry is closer to that of the idealised wine-rack.

“…The first model to consider is model 1, as shown in Figure . This structure has been studied in detail in our previous work and the projections of the 3D unit cell in the OX i directions are given by

X_{1} = 2 l_{1} \cos θ_{1}

X_{2} = 2 l_{2} \cos θ_{2}

X_{3} = 2 l_{1} \sin θ_{1} = 2 l_{2} \sin θ_{2}

…”

Section: Analytical Modelmentioning

confidence: 99%

A Comparison of Negative Compressibility between 3D Cellular Models Constructed by 2D Hinging Wine‐Rack and Hexagonal Honeycomb Mechanisms

Lü

et al. 2020

Self Cite

Herein, two kinds of 3D hexagonal honeycomb equivalent models are proposed, enlightened by the octahedron model constructed by the wine‐rack mechanism. They differ in their unit‐cell arrangement forms, which are array and homogeneous arrangements, respectively. Referring to the analysis of the octahedron model, the expressions of compressibility properties of the two new models are given and the conditions for obtaining negative compressibility are analyzed. Comparing these two models with the octahedron model, it is found that although the three models are quite different in externality, they have similar mechanical properties (Young's modulus, Poisson's ratio, and compressibility), and all have image symmetry in both horizontal directions. Further analysis shows that these three models are so unified that they can be expressed by a more general model, from which another model with negative compressibility can be deduced. Finally, a new method to improve negative compressibility property is concluded from comparing the three models, that is, increasing the number or length of rods without deformation in vertical direction can effectively improve negative compressibility property in this direction and weaken negative compressibility property in the other two directions.