Novel designs of metamaterials and structures with. Origami structures with a critical transition to bistability arising from. Unimode metamaterials exhibiting negative linear compressibility and negative thermal expansion. We refer to such transformations as negative compressibility transitions. Threedimensional poroelastic metamaterials with extremely. Mechanical metamaterials with negative compressibility. Extreme composite materials with negative stiffness inclusions. Because this sort of foam is compliant, it is easy to apply such a constraint. A novel mechanical metamaterial exhibiting auxetic. Each unit cell contains only a single hollow cube, sealing the air within by six thin membranes. Structures with a negative compressibility proposed by the malta group. Auxetics negative poissons ratio and materials with negative linear compressibility nlc exhibit the anomalous mechanical properties of getting wider rather. Consider the onedimensional system governed by the potential energy v vx,y,h,f in eq. For this reason, when tensioned, ordinary materials expand along the direction of the applied force.
Negative compressibility metamaterials unit university. Soft mechanical metamaterials with unusual swelling. Wegener, mechanical metamaterials with anisotropic and negative effective massdensity tensor made from one constituent material, phys. Materials with such properties have not been discovered in nature, but they can be constructed as metamaterials. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned or expansion when pressured. How to make a metamaterial that expands under pressure and contracts in tension. Membranetype acoustic metamaterial with negative dynamic mass pdf.
Mechanical metamaterials with negative compressibility transitions article pdf available in nature materials 117. The straindriven counterpart of negative compressibility transitions is a. Vibrant times for mechanical metamaterials dtu orbit. Emerging mechanical metamaterials advanced science news. When tensioned, ordinary materials expand along the direction of the applied force. Giant negative area compressibility tunable in a soft. In our recent nature materials paper, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when. Unimode metamaterials made from rotating rigid triangles are analysed mathematically for their mechanical and thermal expansion properties. Experiments on metamaterials with negative effective static. Metamaterials with negative compressibility a novel concept with a. Research pair theorize metamaterials that exhibit negative. Mechanical metamaterials with negative compressibility transitions when tensioned, ordinary materials expand along the direction of the applied force. This is the first nac reported in metalorganic frameworks. The results indicate that the bibo crystal exhibits the second largest nlc among all known inorganic materials over a.
This is characteristic of materials with a negative poissons ratio and. Pdf mechanical metamaterials with negative compressibility. Auxetics negative poissons ratio and materials with negative linear compressibility nlc exhibit the anomalous mechanical properties of getting wider rather than thinner when stretched and expanding in at least one direction under hydrostatic pressure, respectively. In the past decade, mechanical metamaterials have garnered increasing attention.
Our metamaterials, in contrast, maintain their mechanical efficiency over a broad density regime without substantial degradation in specific stiffness, owing to the nearly linear e. Mechanical metamaterials have emerged and received increasing interests in recent years due to their unique properties and unprecedented mechanical behaviorsultrahigh strengthtodensity ratios, extraordinary resilience with brittle constituents, tunable stiffness, negative poissons ratio, negative compressibility, and vanishing shear modulusowing to its novel design principles in. We combine analytic modeling, finite element analyses, and experiments to design a type of soft mechanical metamaterials that can achieve large effective negative swelling ratios and tunable stressstrain curves, with desired isotropicanisotropic features. Among them, we find methanol monohydrate, which is a relatively simple molecular crystal showing negative linear compressibility along with negative and anisotropic thermal expansion. Longitudinal inverted compressibility in superstrained. Other publications predict a negative bulk modulus transi. Here, we would like to show that similar concept is used by the nature and a nice example for this kind of metamaterial can be seen even in a glass of water. However, poor mechanical stability has hampered progress in moving toward commercialization. Negative and positive stiffness in auxetic magneto. Nicolaou proposed the concept of negative compressibility transition to design mechanical metamaterials with negative compressibilities.
Continuous contraction of a material in the same direction of an applied tension, and in response to this tension, is inherently unstable. Mechanical metamaterials are materials whose macroscale properties such as. Grima 1,2 and daphne attard 1, 1 metamaterials unit, faculty of science, university of malta, msida msd 2080, malta. We develop a statistical physics theory for solidsolid phase transitions in which a metamaterial undergoes longitudinal contraction in response to increase in external tension.
Bib 3 o 6 bibo is comprehensively investigated using firstprinciples calculations and highpressure synchrotron xray diffraction experiments. In joint work with takashi nishikawa, he discovered the phenomenon of asymmetryinduced symmetry. Mechanical metamaterials with negative compressibility transitions, nature materials 2012 doi. Destabilisation conditions role of degenerate equilibria. Metamaterials with negative longitudinal and volume compressibility transitions. Ultralight, ultrastiff mechanical metamaterials science. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes. Smart hexagonal truss systems exhibiting negative compressibility through constrained angle stretching, smart materials and structures, 22, 8, 084015, 20. These metamaterials may enable new applications, including the development of new protective mechanical devices and actuators a type of assembly for operating or controlling a system, and the enhancement of microelectromechanical. Novel designs of metamaterials and structures with negative poisson ratio and negative linear compressibility ghaedizadeh, a 2017, novel designs of metamaterials and structures with negative poisson ratio and negative linear compressibility, doctor. When we contrast digital mechanical metamaterials to the traditional approach of augmenting objects with electronic microcontrollers, sensors, and actuators 26, 31, our approach results in an entirely mechanical solution and can be. This leads to a completely different behaviour of the structure in terms of stability. The straindriven counterpart of negative compressibility transitions is a force amplification phenomenon, where an increase in deformation induces a discontinuous increase in response force. It is also reported that the investigated mechanical metamaterials may exhibit both negative stiffness and negative poissons ratio at the same time.
How to make a metamaterial that expands under pressure and. Pdf mechanical metamaterials and their engineering. A soft porous material znl2oh2nguest where l is 41hnaphtho2,3dimidazol1ylbenzoate, and guest is water or methanol exhibits the strongest ever observed negative area compressibility nac, an extremely rare property, as at hydrostatic pressure most materials shrink in all directions and few expand in one direction. Blueprint and illustration of mechanical metamaterials with tailored static effective compressibility. Rational design approaches based on computational models could, therefore, be used to devise topological designs that result in the desired properties. Mechanical metamaterials associated with stiffness, rigidity and compressibility. K geometry can be the basis for acoustic activity a.
Mechanical metamaterials with negative compressibility transitions. Consequently, mechanical metamaterials can be divide into stronglightweight e. Shapematching soft mechanical metamaterials tu delft research. Double negative mechanical metamaterials displaying simultaneous negative stiffness and negative. Negative stiffness is possible in mechanical metamaterials, which assists the imposed deformation. Such transitions, which are forbidden in thermodynamic equilibrium, have recently been shown to be possible during the decay of metastable, superstrained states. We suggest that the proposed materials could be useful for the design of actuators, force amplifiers, micro mechanical controls, and protective devices. Negative linear compressibility nlc, a rare and important mechanical effect with many application potentials, in a crystal of. A 3d hybrid zinc formate framework, nh4znhcoo3, possessing an acs topology, shows a high degree of mechanical anisotropy and negative linear compressibility nlc along its c axis. Mechanical metamaterials with negative compressibility transitions zachary g.
However, in the spirit of metamaterials, various micromechanisms have been designed to obtain materials that exhibit negative compressibility. Lightweight mechanical metamaterials with tunable negative. Flexible mechanical metamaterials universiteit leiden. Lightweight mechanical metamaterials with tunable negative thermal expansion. Morrison professor of physics at northwestern university, where he has helped develop the concept of synthetic rescue in network biology as well as methods to control the nonlinear dynamics of complex networks. Motter born january 1, 1974 in brazil, is the charles e. In a closed thermodynamic system in equilibrium, both the longitudinal and volumetric compressibility are necessarily non negative because of stability constraints. Expressions for the peak magnitude have been derived based upon available models describing the first order phase transition. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions.
Negative compressibility transitions are distinct from negative poissons ratio 18,19 and negative normal stress 20, where the unusual response is transverse to the applied force. Nature materials 11, 6086 2012 mechanical metamaterials with negative compressibility transitions zachary g. The elastic properties of mechanical metamaterials are direct functions of their topological designs. Materials free fulltext a novel mechanical metamaterial. In mechanical metamaterials, the unusual properties are mechanical. In their work, they demonstrated the switching via manual means. Mechanical metamaterials and their engineering applications. It is hard to say when the first mechanical metamaterial was conceived. We have shown that these high mechanical efficiencies are possible across a range of constituent materials. Highpressure singlecrystal xray diffraction studies and density functional theory calculations indicate that contraction of the zno bonds and tilting of the formate ligands with increasing pressure. Structural design and properties of mechanical metamaterials associated with stiffness. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned or. Metamaterials with negative compressibility a novel.
733 1195 409 266 621 234 1307 4 712 1048 1325 1022 849 1231 570 908 38 195 890 841 197 316 167 1120 1039 180 557 457 143 411 1258 191 811 548 969 132 134 527 450 1089 1305 275 592 127 883 1285 1378 299 133 109 362