On the Design of Multimaterial Honeycombs and Structures with T‐Shaped Joints Having Tunable Thermal and Compressibility Properties

Abstract

Honeycombs made from more than one material are proposed and analyzed with the help of finite element simulations. It is shown that such honeycombs are designed to change their shape when subjected to a change in temperature or pressure and can be tailor-made to exhibit particular thermomechanical properties. It is also shown that the anomalous properties of negative thermal expansion/ compressibility can be manifested from honeycombs built from common everyday conventional materials. Applications of such constructs are discussed including their role in the manufacture of smart grips which tighten upon heating.

Smart Honeycomb “Mechanical Metamaterials” with Tunable Poisson's Ratios

“…This will hopefully pave the way to the development of novel smart systems based on this concept which have the potential to exhibit particular variations in their Poisson's ratios when they are subjected to external stimuli of changes in temperature, pressure and/or extent of dryness. Bearing in mind the results of earlier work, [75] this study suggests that one may design smart multifunctional mechanical metamaterials which exhibit concurrent negative linear compressibility, negative thermal expansion, and/or negative Poisson's ratio.…”

“…The procedure used for these simulations has been well validated and described in more detail in previous studies. [75] In all cases, Figure 2. Reported variations in the CTEs at low temperatures for pure metallic iron and zinc.…”

“…A more detailed description of these systems, including their potential to exhibit negative thermal expansion and/or negative compressibility has been provided in previous studies. [66,75,81] As shown in Figure 1, the manner of construction is such that the systems include what can be referred to as a bimaterial interface, which can be likened to the classic bimaterial strips which bend upon heating, [95] and which, as recently shown could also bend upon a change in pressure. [70] Such strips, typically made of different metals have been extensively used for more than a century in various practical applications and products.…”

Auxetics and Other Systems with “Negative” Characteristics

“…The first of them, 'On the Design of Multimaterial Honeycombs and Structures with T-Shaped Joints Having Tunable Thermal and Compressibility Properties' by Reuben Cauchi et al, shows that the composite honeycombs having T-shaped junctions, which were also the subject of the last paper of the previous section, can exhibit negative thermal expansion and/or negative compressibility, the magnitude of which could be fine-tuned though design. [27] The second article of this section, 'Negative Hygrothermal Expansion of Reinforced Double Arrowhead Microstructure', discusses another very interesting anomalous phenomenon, which is being referred to as "negative hygroscopic expansion", the condition where a substance is shrinking rather than expanding when subjected to immersion in a fluid. In this work Teik-Cheng Lim [28] studies a 'double arrowhead' microstructure and studies its and "negative thermal expansion" characteristics.…”

“…The first of them, ‘On the Design of Multimaterial Honeycombs and Structures with T‐Shaped Joints Having Tunable Thermal and Compressibility Properties’ by Reuben Cauchi et al, shows that the composite honeycombs having T‐shaped junctions, which were also the subject of the last paper of the previous section, can exhibit negative thermal expansion and/or negative compressibility, the magnitude of which could be fine‐tuned though design. [ 27 ]…”