materiały: Acoustic metamaterial

Evidence: 100 • authority: 72

Acoustic metamaterials, sometimes referred to as sonic or phononic crystals, are architected materials designed to manipulate sound waves or phonons in gases, liquids, and solids. By tailoring effective parameters such as bulk modulus (β), density (ρ), and in some cases chirality, they can be engineered to transmit, trap, or attenuate waves at selected frequencies, functioning as acoustic resonators when local resonances dominate. Within the broader field of mechanical metamaterials, acoustic metamaterials represent the dynamic branch where wave control is the primary goal. They have been applied to model large-scale phenomena such as seismic waves and earthquake mitigation, as well as smal…

Evidence: 59 • authority: 88

Active acoustic metamaterials with independently programmable bulk modulus and full mass density tensor. Active acoustic metamaterials consist of unit cells with sensor-driver pairs that produce a coherent response to incident waves. The effective acoustic properties of the metamaterials depend on the gains programmed between the sensing and driving components. The strength of the monopole response to the local pressure determines the effective bulk modulus and the dipole response to the local particle velocity determines the effective mass density. The unit cells are controlled individually, so in theory the metamaterials can be scaled to an arbitrary size and geometry, but prior realizati…

Evidence: 54 • authority: 72

Mechanical metamaterials are metamaterials derived from their unique internal structures rather than the materials from which they are made. Inspiration for mechanical metamaterials design often comes from biological materials (such as honeycombs and cells), from molecular and crystalline unit cell structures as well as the artistic fields of origami and kirigami. While early mechanical metamaterials had regular repeats of simple unit cell structures, increasingly complex units and architectures are now being explored. Mechanical metamaterials can be seen as a counterpart to optical metamaterials and electromagnetic metamaterials. Mechanical metamaterials are the broad umbrella term, define…

Evidence: 54 • authority: 92

Hybrid mechanical metamaterials: Advances of multi-functional mechanical metamaterials with simultaneous static and dynamic properties.. Mechanical metamaterials are architected structures with unique functionalities, such as negative Poisson's ratio and negative stiffness, which are widely employed for absorbing energy of quasi-static and impact loads, giving improved mechanical response. Acoustic/elastic metamaterials, their dynamic counterparts, rely on frequency-dependent properties of their microstructure elements, including mass density and bulk modulus, to control the propagation of waves. Although such metamaterials introduced significant contribution for solving independently stati…

Evidence: 43 • authority: 72

A metamaterial (from the Greek word μετά meta, meaning 'beyond' or 'after', and the Latin word materia, meaning 'matter' or 'material') is an engineered material whose properties arise not from the chemical composition of its base substances, but from their deliberately designed internal structure. These properties are often rare or absent in naturally occurring materials. Metamaterials are typically fashioned from multiple materials, such as metals and plastics, and arranged in repeating patterns at scales that are smaller than the wavelengths of the phenomena they influence. Their shape, geometry, size, orientation, and arrangement give them their properties of manipulating electromagneti…

Evidence: 43 • authority: 88

Active acoustic metamaterials with on-demand bulk modulus and full mass density tensor. Abstract Active metamaterials address fundamental limitations of passive media and have widely been recognized as necessary in numerous compelling applications such as cloaking and extreme noise absorption. However, most practical devices of interest have yet to be realized due to the lack of a suitable strategy for implementing bulk active metamaterials—those that involve interacting cells and functionality beyond one dimension. Here, we present such an active acoustic metamaterial design with bulk modulus and anisotropic mass density that can be independently programmed over wide value ranges. We demon…

Evidence: 38 • authority: 80

Flute-model acoustic metamaterials with simultaneously negative bulk modulus and mass density

Evidence: 38 • authority: 80

Scalable active acoustic metamaterials with programmable bulk modulus and mass density tensor

Evidence: 38 • authority: 80

Hilbert fractal acoustic metamaterials with negative mass density and bulk modulus on subwavelength scale

Evidence: 33 • authority: 92

Background and emerging applications of acoustic metamaterials: a forum on classical waves.. Advancements in physical concepts and manufacturing technology such as 3D printing have generated an exciting field of research in recent years that is known as 'metamaterials'. When applied to electromagnetic waves, novel applications have emerged in sensing or cloaking devices. In contrast, acoustic metamaterials may provide solutions to acoustic problems as well as a conceptual and developmental platform for condensed-matter physics. National Science Review invited Prof. Hong Chen of Tongji University to organize a forum to discuss this unique field of acoustic metamaterials in physical research.…

Evidence: 33 • authority: 92

Metamaterials and Fluid Flows.. Understanding and controlling the dynamic interactions between fluid flows and solid materials and structures-a field known as fluid-structure interaction-is central not only to established disciplines such as aerospace and naval engineering, but also to emerging technologies such as energy harvesting, soft robotics, and biomedical devices. In recent years, the advent of metamaterials has provided exciting opportunities to rethink and redesign fluid-structure interactions. The idea of engineering the internal structure of materials that interface with fluid flows opens a new horizon for the precise and effective manipulation and control of coupled fluidic, ac…

Evidence: — • authority: 92

Vibroacoustic Metamaterials for Low-Frequency Sound and Vibration Attenuation in Electric Vehicles: A Review.. The transition from internal combustion engine vehicles to battery electric vehicles has changed the acoustic design problem in automotive engineering. The absence of combustion-related masking increases the perceptibility of tonal and narrowband sources, including gear whine, electric motor orders, inverter-related components, tire cavity resonances, auxiliary system noise, and lightweight-panel radiation. At the same time, mass-based acoustic treatments conflict with electric vehicle lightweighting, range, cost, and sustainability targets. Vibroacoustic metamaterials offer an alt…