Abstract Acoustic/elastic metasurfaces as a kind of two-dimensional metamaterials are subwavelength thickness and show remarkable ability acoustic/elastic wave manipulation. They have potential applications in various fields such acoustic imaging, communications, cloaking, camouflage, vibration/noise control, energy harvesting, nondestructive testing. In this review, we mainly summarize recent developments phase gradient metasurfaces, including design principles, functional elements, field...

Abstract Extreme impedance mismatch causes sound insulation at water–air interfaces, limiting numerous cross‐media applications such as ocean‐air wireless acoustic communication. Although quarter‐wave transformers can improve transmission, they are not readily available for acoustics and restricted by the fixed phase shift full transmission. Here, this limitation is broken through impedance‐matched hybrid metasurfaces assisted topology optimization. Sound transmission enhancement modulation...

Flat bands have empowered novel phenomena such as robust canalization with strong localization, high-collimation and low-loss propagation. However, the spatial symmetry protection in photonic or acoustic lattices naturally forces flat to manifest pairs aligned at an inherently specific angle, resulting a fixed bidirectional canalization. Here, we report flat-band metasurface, allowing not only unidirectional all in-plane angles but also tunability band alignment. The twist, tilt, skew of...

Seismic metamaterials (SMs) are expected to assist or replace traditional isolation systems owing their strong attenuation of seismic waves. In this work, a one-dimensional inverted T-shaped SM (1D ITSM) composed arrays structures on half space is proposed, which have an ultra-wide first bandgap (FBG) from 6.7 17.2 Hz. We find that the FBG two parts; part 1 with surface evanescent waves 11.0 Hz and 2 no modes by using complex band structures. The propagation in 1D ITSM different these...

High-performance and lightweight waterborne acoustic devices have provided important support for the development of ocean exploration, health monitoring, etc. In this work, we propose a high-efficiency ultrathin nonlocal metasurface. Due to strong interaction between unit cells induced by fluid-solid interaction, design concept based on diffraction theory optimization approach is proposed metasurfaces, in contrast local generalized Snell's law. The theoretical efficiency limitation law can...

Abstract We propose a reconfigurable phononic crystal (PnC) for detecting the concentration of solutes in liquids. The designed PnC consists liquid-filled hollow pillars and connecting bars. finite element method is used to calculate transmission spectra band structures filled with various fabricate 3D printed samples conduct corresponding experiments. results show that sound velocity key parameter affecting frequency passing band. As increases, resonance shifts down. For both NaCl solution...

Abstract Exceptional point (EP), a special degeneracy in non‐Hermitian systems, has exhibited various distinctive wave characteristics. However, the conventional synthesis of scattering EPs acoustics is confined to rather limited methods for breaking Hermiticity, typically requiring intrinsic losses or open interfaces. Here, concept synthesizing theoretically and experimentally demonstrated by leveraging metasurface with fluid‐solid interaction (FSI) water. The incorporation FSI offers novel...

Abstract Bidirectional controllable propagation of waterborne sound holds significant importance in developing multifunctional underwater acoustic and mechanical devices. However, the existing metasurfaces have rarely explored bidirectional modulations. Here, a class Janus metasurface, enabling two‐faced arbitrarily asymmetric wavefront manipulations is reported. A three‐degree‐of‐freedom system facilitated by acoustic‐structure interaction proposed to introduce bianisotropic responses unit...

Acoustic metasurfaces can reshape a reflected wavefront rather arbitrarily, despite being much thinner than the wavelength, thus allowing on-demand modulation in variety of applications. Recent passive metasurfaces, however, have suffered from bandwidth limitations, restricting their range operation. In this work, we propose systematic design ultra-broadband by combining broadband local reflection rule with an optimization method. The validation technique is demonstrated fabrication and...

In this paper, a tunable arc-shaped acoustic metasurface (AAM) carpet cloak has been proposed and systematically investigated. The AAM consists of covers, rotors, bolts nuts. rotors can be rotated continuously within the covers to form reconfigurable hook channel mechanism. By setting various rotational angles, we construct two-dimensional (2D) cloaks achieve excellent stealth performances under different operating conditions. Numerical simulations experimental results for 2D show good...

Moiré effects arising from mutually twisted metasurfaces have showcased remarkable wave manipulation capabilities, unveiling tantalizing emerging phenomena such as acoustic moiré flat bands and topological phase transitions. However, the pursuit of strong near-field coupling in layers has necessitated to be tightly stacked at narrow distances subwavelength range. Here, beyond interlayer acoustics are reported concept coupling-immune is proposed. Remote decoupled distance theoretically,...

Electric vehicles generally have a better noise, vibration, and harshness quality than traditional due to the relatively quiet electric motors. By contrast, issues of driveline system become more outstanding significant in absence “masking effect” by engine. The electrification powertrain has also brought many changes sources or transmission which led some new issues. Specifically, intense vibration prototype bus appears when driving third gear, makes passengers uncomfortable. This paper...

Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based the combination of orthogonal testing and numerical simulation, this paper optimizes structure a drainage trough typical low-specific speed pump, determines priority various geometric factors pump performance, obtains optimal impeller scheme. The influence tank internal flow is also analyzed. First, based experimental validation initial model, it determined that simulation method...

Self-accelerating beams have applications in optic and acoustic fields due to their peculiar properties. As a promising artificial two-dimensional metamaterial, metasurface can be used as the generator of self-accelerating beams. However, restricted by generalized Snell's law, most research hotspots focus on flat metasurfaces. In this Letter, law an arbitrary curved reflective surface is discussed. Then, phase profile for generated from derived based caustic theory. The consisting tunable...

The acoustic impedance mismatch between water and air limits the communication through water–air interface. Here, based on resonances of bubbles, we propose a metasurface consisting bubbles sealed with membranes for perfect sound transmission at We have experimentally achieved enhancement over 20 dB 380–510 Hz, thickness about 1/180 times wavelength. By flexibly adjusting immersion depth, is able to operate multiple frequencies. effects viscosity geometry are discussed simulatively. present...

Deep soil mixing techniques have been widely adopted in China since the late 1970s and mainly used for ground improvement structural support earth-retaining structures excavations. A comprehensive state-of-practice review on development, applications, soil-cement properties, mechanistic studies, design methods, quality control of deep is presented. These research results will serve as a reference advancing United States other countries.

Dynamic Acoustic Beamshaping Coupling-immune acoustic moiré metasurfaces are first proposed in acoustics to achieve remote effects decoupled from the interlayer distance. Twist-angle-controlled dynamic beam shaping will significantly enhance practical applications of devices detection and multiplexed underwater communication. More details can be found article number 2313004 by Yan-Feng Wang, Yue-Sheng Cheng-Wei Qiu, co-workers.