Pentamode metamaterials are a very interesting set of artificial solids. They difficult to compress but flow easily, hence imitating somehow the behaviours liquids. In this paper, three-dimensional (3D) pentamode based on asymmetric double-cone element (ADCE) proposed. The ADCE is composed by two connected truncated cones with different thin diameters. phonon band structures ADCEs numerically analysed using finite method (FEM). Besides single mode, complete 3D gaps also found in structures....

Locally resonant phononic crystals have excellent low-frequency characteristics and can result in a small size controlling long wavelength. Based on the locally crystal theory, pentamode metamaterials with composite materials are proposed studied. The acoustic band frequencies of were found to be two orders magnitude smaller than those conventional Bragg-Scattering same lattice constant. Therefore, single-mode frequency regions bandgaps which under 110 Hz obtained by centimeter-scale figure...

For three-dimensional pentamode metamaterials, it is of great significance to realize underwater low frequency acoustic wave control. Therefore, in order compare with traditional double-cone two multilayer composite cylindrical metamaterials and broad band gaps are proposed this paper. By using lattice constants on the centimeters, phononic below 60 Hz single-mode area 30 can be obtained. In addition, compared asymmetrical locally resonant lower edge frequency, relative bandwidth figure...

Drawing upon the principles of digital coding metasurfaces, we propose double-split ring resonators metasurface that can switch between different frequency bands with varying amplitudes. Under transverse-magnetic (TM) polarized terahertz wave incidence, same meta-atom structure utilizes amplitude to achieve spatial imaging functionality. Due limitations in device size and fabrication techniques, actively controlled metasurfaces range are rare. In order enhance flexibility a phase-change...

The method for tuning the first phononic band gaps (PGBs) of locally resonant pentamode metamaterials (PMs) is proposed in this paper. Based on equivalent relationship between mode at lower edge PBGs and spring-mass system, approximate relationships structure parameters are obtained. theoretical numerical results show that PMs can be tailored 52 Hz 548 by a small-sized PMs. In addition, single expanded 6.5 times, pentamodal characteristics improved 13.7 times.

Abstract The topological simulation of acoustic waves has induced unconventional propagation characteristics, thereby offering extensive application potential in the field acoustics. In this paper, we propose a machine learning-assisted method for inverse design wave edge states and demonstrate its practical applicability. Leveraging predictions from trained artificial neural network algorithm, wide-bandwidth insulators is achieved, with results indicating an approximately 2.8-fold...

We propose herein four types of anisotropic pentamode metamaterials (PMs) created by shifting the thin-end contention points along space-diagonal, x-axis, y-axis, and z-axis directions. The phononic band structure figure merit (FOM) PMs are systematically investigated using finite-element method. Compared with isotropic PMs, first bandgaps appear in low-frequency regions, FOM increases a factor 6.9 when connection area shifts direction. This study investigates how anisotropy affects PM...

In this paper, we propose a class of pentamode metamaterials for which the frequency range acoustics band gaps can be tuned and large figures merit obtained. The structures are calculated systematically by using finite element method. numerical results show that lower edge first between 3.72 kHz 10.6 changing diameters bottom top touch cones slightly, relative bandwidth also expanded. addition, compared with seen in previous research area, volume filling fraction decreased 15.7%–24.4%...

The Valley Hall effect and topological chiral boundary states play a crucial role in investigating elastic wave transmission properties. In this study, to construct the phononic crystal plate structure, periodic scatterer structures are arranged on bottom at certain thickness. Simulation analysis reveal that modulating edge of designed achieves greater degrees freedom enhanced backscattering suppression capabilities. Straight boundary, right-angle turning valley transport with defect...

In this paper, a broadband polarized switchable circularly (PSCP) antenna is proposed. The comprised of radiator, feeding network, and four metal feed posts. A stepped radiating loop circular patch are applied to form the radiator improve bandwidth PSCP antenna. Two switches, short-circuit coupled-line, an open-circuit coupled-line two couplers network. network outputs signals sequential ±90° phase, which transmitted through copper SRL-based can achieve conversion LHCP or RHCP radiation...

The precise measurement of wheat moisture content is a key issue to ensure the quality and safety wheat. However, high-precision, rapid, non-destructive detection remains challenging. In this paper, we proposed system with single-layer low-frequency metasurface plane wave lens antenna for in frequency range 5.8GHz - 5.9GHz. Based on propagation characteristics waves multilayer dielectric, container error de-embedding algorithms are reduce errors introduced by parameters during process....

<title>Abstract</title> The integration of multiple functionalities into a single, planar, ultra-compact metasurface has presented significant opportunities for enhancing capacity and performance within compact 5G/6G communication systems. Recent advances in multifunctional metasurfaces have unveiled comprehensive wavefront manipulations utilizing phase, polarization transmission/reflection, coding apertures. Despite these developments, there remains critical need with expanded channel...

The band-gap characteristic is an important feature of acoustic metamaterials, which has theoretical and practical significance in devices. Pentamode metamaterials (PMs) with phonon characteristics based on asymmetric double-cone outside profile are presented studied this paper. band structures these PMs calculated by using the finite element method. In addition to single-mode band-gaps, complete 3D band-gaps also obtained changing double-cone. Moreover, adjusting diameter reduce symmetry...

Abstract The study of optical topological insulators (PTIs) has revealed intriguing properties that diversify the ways in which light can be manipulated, offering significant potential for a wide range applications. This paper presents machine learning (ML)-based approach reverse design PTIs. Using finite element methods, addresses challenge computing band structure dual-band model, enabling construction dataset suitable ML training. With goal maximizing bandgaps, employs random forest...

Because of the position motor and excitation suspension system, a wheel-driven electric bus produces low-frequency noise, which is difficult to resolve through traditional sound absorption noise reduction technology. Through an interior test bus, we found that had considerable influence on driver. In order solve this problem, locally resonant phononic crystal was used meet requirements vibration for bus. The intrinsic relationship between band gap distribution topology established by...

Abstract Acoustic metasurfaces can manipulate acoustic waves at subwavelength scales, thus proved to have advantages in constructing novel compact analog computing (CAC) systems. Here, we design an CAC system based on a nondispersive focusing metasurface (FM) and reconfigurable reflective (RRM), which perform broadband tunable mathematical operations. The FM consists of the sandwich-like-structured units, featuring non-dispersive effective refractive indexes high transmission efficiency. RRM...

The reverse design method of acoustic structure based on a deep learning algorithm has been developed as an important means metamaterial design. In this paper, multi-band topological insulator is designed, and the improved competitive search Long Short-Term Memory (LSTM) model used to predict its potential optimal parameter combination assist on-demand working frequency band topology insulator. Finally, numerical simulation established using optimized structural parameters, topologically...

In this paper, we devise a pentamode metamaterial plate exhibiting topological characteristics. By organizing structural elements, boundary states are attained, effectively safeguarding propagation of elastic waves. Moreover, based on the numerical simulation model, employ polymer to fabricate macro-scale specimen via additive manufacturing. Through assessing vibrational response sample, corroborate its attributes in governing wave transmission. This discovery paves way for novel approach...

The adjacent double-cones of the pentamode metamaterials form a connection overlap for non-180° angle connection, and leads to deviation between actual effective narrow touch diameters d' defined d. increases with increasing wide D linear outside profile cones. In order decrease influence on metamaterials, three types small (second third polynomial cones structures stacked by cylinders-frustums) are proposed studied in this paper. deviations different analyzed, phononic band calculated,...