Acoustic Resonance Research Articles

Synchronization characteristics of vortex shedding from in-line tube banks on weak acoustic resonance

Synchronization characteristics of vortex shedding from in-line tube banks on weak acoustic resonance

Using acoustic resonance for measuring magnetostriction

Using acoustic resonance for measuring magnetostriction

Wideband acoustic absorbance and resonance frequency measurements in Ménière’s disease – case series

Wideband acoustic absorbance and resonance frequency measurements in Ménière’s disease – case series

Flexural wave propagation characteristics of metabeam with simultaneous acoustic black hole and local resonator

This paper studies the flexural wave propagation in a metamaterial beam with the coupled acoustic black hole and local resonators (ABHLR). The main objectives are to derive the dynamic stiffness matrix of the coupled ABHLR unit cell and analyse its wave propagation characteristics. Initially, a closed-form solution of Euler–Bernoulli’s beam with an indented acoustic black hole is derived. From this, an exact dynamic stiffness matrix, incorporating local resonator effects, is derived using the spectral element method. Dispersion diagrams are generated by combining Bloch’s theorem with ABHLR transfer matrix. The coupled effects of acoustic black hole (ABH) and local resonator (LR) on the bandgap characteristics are investigated. The coupled ABHLR metamaterial shows either a positive or negative effect on bandgap formations, depending on the parametric values of the unit cell. As a positive effect, for some parametric values, the coupled ABHLR cell simultaneously produces bandgaps at lower frequencies (LR-based) and higher frequency ranges (ABH-based). Similarly, for other parametric value, as a negative effect, the bandgaps of ABHLR cell get merged but the pass bands appear on the overlapping region. This pass-band appears due to the constructive interference of ABH and LR, on each other. However, the attenuation bandgap with a higher attenuation rate is obtained on the overlapping region due to the destructive interference of LR and ABH effect. Finally, the global stiffness matrix of a finite beam with 30 unit cells is developed to analyse the frequency domain response and the results are validated with band gap analysis of the unit cell. The frequency domain response is also validated with finite element simulations using the commercial software. Results show that ABH and LR parameters have to be optimally designed to utilize the attenuation effects and avoid constructive interference due to coupling effects. The coupling of metamaterials can aid in vibration suppression and multiple-frequency filtering in mechanical and aerospace applications.

Investigation of Elastic Softening and Stiffening Effect of Aluminum Nitride Under Stress Loading by Born‐Lande Equation

As a core functional material in acoustic resonators and filters, the elasticity of aluminum nitride (AlN) piezoelectric thin film and its correlated intrinsic properties deserve priority attention. This paper presents an in‐depth investigation of elastic softening and stiffening effect induced by stress loading in AlN piezoelectric thin film. Based on the Born‐Lande equation, the physical mechanism of such new intrinsic elastic property is revealed and predicted quantitatively for the first time from the perspective of atomic interaction forces. It is found that a maximum 6.7% modulation range of elasticity coefficient can be achieved under ultimate stress loading conditions from (−2.5, −2.5) to (2.5, 2.5) GPa. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

A review of acoustic metamaterials applied to noise control in civil engineering

Over the past 10 years, the research of acoustic metamaterials has branched out in many directions, presenting numerous potentially applicable geometries for the composition of noise control structures, such as structural resonators, acoustic resonators, and membranes. Therefore, keeping track of these multiple applications can be considered a rather difficult task. Moreover, the application of this novel concept in civil engineering has a high potential. In this context, an article review is proposed, identifying the most important acoustic metamaterial concepts that were applied or could be applied in civil engineering. The study performs a qualitative survey of articles in this segment, classifying the leading literature proposals, according to physical principles of cells working and to the facility of application in civil engineering, considering the production factors and construction implementation. It was found that the number of works with this focus is incipient when compared to the strictly theoretical works. A great number of articles contain dimensions and geometric propositions that feature difficulties of precise and large-scale manufacturing in the current civil construction scenario, which is traditionally less industrialized and technological. Finally, the advantages and disadvantages of the physical principles and acoustic structures were compared to point out ways that allow the development and popularization of acoustic metamaterials in civil engineering.

Analysis of Different Piezoelectric Materials on the Film Bulk Acoustic Wave Resonator

The performance of film bulk acoustic wave resonators (FBAR) is greatly dependent on the choice of piezoelectric materials. Different piezoelectric materials have distinct properties that can impact the performance of FBAR. Hence, this work presents the analysis of three different piezoelectric materials which are aluminum nitride (AlN), scandium aluminum nitride (ScAlN) and zinc oxide (ZnO) on the performance of FBARs working at resonance frequencies of 6 GHz until 10 GHz. The one-dimensional (1-D) modelling is implemented to characterize the effects of these materials on the quality (Q) factor, electromechanical coupling coefficient (k2eff) and bandwidth (BW). It is determined that employing ScAlN in FBAR results in the highest Q factor, ranges from 628 to 1047 while maintaining a relatively compact area (25 µm × 25 µm) and thickness (430 nm to 720 nm). However, ScAlN yields the narrowest BW, measuring 0.11 GHz at 6 GHz, as opposed to AlN and ZnO, which exhibit broader bandwidths of 0.16 GHz and 0.23 GHz, respectively.

Numerical analysis of dynamic acoustic resonance with deformed liquid surfaces: the acoustic fountain

Applying a focused ultrasonic field on a free liquid surface results in its growth eventually leading to the so-called acoustic fountain. In this work, a numerical approach is presented to further increase the understanding of the acoustic fountain phenomenon. The developed simulation method enables the prediction of the free surface motion and the dynamic acoustic field in the moving liquid. The dynamic system is a balance between inertia, surface tension and the acoustic radiation force, and its nonlinearity is demonstrated by studying the relation between the ultrasonic excitation amplitude and corresponding liquid deformation. We show that dynamic resonance is the main mechanism causing the specific acoustic fountain shapes, and the analysis of the dynamic acoustic pressure allows us to predict Faraday-instability atomisation. We show that strong resonance peaks cause atomisation bursts and strong transient deformations corresponding to previously reported experimental observations. The quantitative prediction of the dynamic acoustic pressure enables us to assess the potential of cavitation generation in acoustic fountains. The observed local high acoustic pressures above both the cavitation and the atomisation threshold hint at the coexistence of these two phenomena in acoustic fountains.

Sizing and Selection of Pressure Relief Valves for High-Pressure Thermal–Hydraulic Systems

This study covers the critical concerns related to the sizing, selection, installation, maintenance, and testing of pressure safety valves (PSVs). The aim is to ensure the safety of pressurized systems, hydrostatic transmission systems, and hydraulic plants, including process plants, thermal power plants, and nuclear reactor systems. PSVs are devices that ensure the safety and reliability of pressurized vessels, lines, and systems during overpressure events. The task of selecting which PSV features are of greatest value for a specific purpose is complex—especially in the design of a high-pressure experimental thermal–hydraulic facility for hydrostatic and transient testing of the reactor system—when the systems are in the design and development phases and require qualification and demonstration to prove that they have reached a given level of technological readiness. The present study highlights the required steps for users to follow the associated rules, guidelines, and recommendations. As a part of this research, case studies are presented to help readers better understand the applicable strategy and standards. A discussion and a review of PSV performance degradation and failure are summarized to provide a better understanding of varied process applications and conditions, including fluid flow dynamics, boundary-layer formation and pressure drops, gas bubble formation and collapse, geometric configurations, inlet/outlet piping, abrupt pressure fluctuations, and acoustic resonance. Moreover, this study discusses the servicing and testing of PSVs in a multiphase pressurized system. Overall, it provides a basic overview of how PSVs ensure the safety of pressurized systems, supported by case studies and industrial practices.

Design and modeling of film bulk acoustic resonator considering temperature compensation for 5G communication

Design and modeling of film bulk acoustic resonator considering temperature compensation for 5G communication

Enhanced combustion reaction and energy output of Al based energetic materials through introducing perfluorocarbon

Introducing additional oxidizers in aluminized explosives is an effective way to improve energy performance by enhancing the secondary combustion reaction. In this work, perfluorocarbon as oxidizer has been introduced into TATB/Al based energetic materials to improve combustion reaction and energy output performance. The uniform TATB/Al/perfluorocarbon composites are prepared through acoustic resonance mixed technology, and the energy and pressure output performance are fully studied in air blast and underwater explosion. A significantly exothermic peak derived from the reaction between fluorine and Al is observed between 540 ℃ and 580 ℃ for TATB/Al/perfluorocarbon. The heat of explosion of TATB/Al/perfluorocarbon is increased first and then decreased with F/Al ratio from 0 to 0.608. The highest heat of explosion is 6021 J/g for TATB/Al/perfluorocarbon with F/Al ratio of 0.274. Furthermore, the enhanced working capacity, the significantly enlarged fireball and relatively high overpressure are obtained for TATB/Al/perfluorocarbon. More importantly, the shock impulse and first bubble oscillation time of TATB/Al/perfluorocarbon have been increased by 23.2% and 21.18% during underwater explosion, respectively. The results further illustrate that adding perfluorocarbon is a feasible approach to enhance energy output due to combustion reaction between fluorine and Al, which can be applied in explosives and propellants.

Fast-response humidity sensors based on all-inorganic lead-free Cs2PdBr6 perovskite integrated with bulk acoustic wave resonators for motions monitoring

Halide perovskites have arisen extensive concerns due to their distinguished achievements in optoelectric fields. However, the intrinsic toxicity of lead and instability have limited their applications in humidity sensing. Herein, all-inorganic lead-free Cs2PdBr6 perovskite incorporated with a bulk acoustic wave resonator for humidity detection is demonstrated for the first time. The proposed sensor exhibits faster response and recovery speed than most other perovskite-based humidity sensors, indicating its potential utilization in real-time monitoring of body movements. Apart from that, the perovskite-based sensor shows remarkable logarithmic linearity response as well as superior repeatability and stability in the relative humidity range of 11%-85%. Owing to its fast response and good stability, the sensor is successfully applied in finger movements monitoring, suggesting the potential of application in human–machine interactions. Furthermore, the underlying sensing mechanism of the sensor is analyzed by the Langmuir adsorption model and density functional theory. Therefore, above results have demonstrated the feasibility of perovskite for humidity detection and more perovskites with similar structures could be also be utilized for further exploration.

High-Performance SAW Resonator with Spurious Mode Suppression Using Hexagonal Weighted Electrode Structure.

Surface acoustic wave resonators are widely applied in electronics, communication, and other engineering fields. However, the spurious modes generally present in resonators can cause deterioration in device performance. Therefore, this paper proposes a hexagonal weighted structure to suppress them. With the construction of a finite element resonator model, the parameters of the interdigital transducer (IDT) and the area of the dummy finger weighting are determined. The spurious waves are confined within the dummy finger area, whereas the main mode is less affected by this structure. To verify the suppression effect of the simulation, resonators with conventional and hexagonal weighted structures are fabricated using the micro-electromechanical systems (MEMS) process. After the S-parameter test of the prepared resonators, the hexagonal weighted resonators achieve a high level of spurious mode suppression. Their properties are superior to those of the conventional structure, with a higher Q value (10,406), a higher minimum return loss (25.7 dB), and a lower ratio of peak sidelobe (19%). This work provides a feasible solution for the design of SAW resonators to suppress spurious modes.

Photoinduced Nonthermal Reduction of the Coercive Field in FePt and FePt0.84Rh0.16 Epitaxial Thin Films in the L10 Phase

The time-resolved magneto-optical Kerr effect in epitaxial thin films of the FePt compound and the FePt0.84Rh0.16solid solution with the perpendicular magnetic anisotropy on MgO (001) substrates has been studied. The evolution of hysteresis loops at short (100 fs–1 ns) and long (1–20 ms) time scales after the excitation by a femtosecond light pulse has been studied. Long-lived nonthermal reduction of the coercive field has been detected. The coercive field is recovered in several milliseconds. It has been proposed to explain the observed phenomenon by the excitation of high-Q-factor acoustic resonances in the substrate/film system and to the strong magnetoelastic interaction in FePt and FePt0.84Rh0.16films.

Magnetostrictive strain monitoring in Non-Oriented Si-Fe steels using a SAW resonator sensor

The aim of this study is to introduce a new technique for characterizing the magnetostrictive behavior of non-oriented ferromagnetic steel sheets using miniaturized wireless surface acoustic wave sensors (SAW). Unlike conventional optical and electromechanical techniques, this type of sensor offers advantages such as on-board capability, high-temperature resistance (up to 400 °C), and the ability to be connected remotely. The final objective is to monitor magnetic stresses in electrical machines, aligning with the requirements of Industry 4.0 and predictive maintenance. The focus of the present study is the measurement of magnetostriction in ferromagnetic steel sheets, employing a wireless surface acoustic wave resonator operating within the 433 MHz ISM band, under various mechanical fixation configurations. To ensure the accuracy and reliability of SAW measurements, a commercial strain gauge is employed as a reference sensor. Measurements are conducted at different excitation frequencies to explore the phenomenon comprehensively.

Research Progress of Acoustic Energy Harvesters Based on Nanogenerators

In the wake of the rapid development of the Internet of Things (IoT) and artificial intelligence (AI) technology, a huge amount of wireless sensing nodes (WSNs) is urgently in demand in all aspects of daily production and living, such as smart cities, smart transportation, and intelligent monitoring. However, it has become one of the crucial challenges in the development of IoT technology to fulfill the requirements of energy consumption for enormous amounts of WSNs. Therefore, it not only possesses great potential to realize in situ power supply of WSNs by harvesting environmental energy but also can address the problems of durability, maintenance, and cost that exist in battery power supply. In particular, acoustic energy is ubiquitous in the environment but not efficiently utilized. Meanwhile, piezoelectric nanogenerators (PENG) and triboelectric nanogenerators (TENG) are capable of accomplishing efficient conversion of broadband, high entropy, and weak energy as the new energy conversion technology. Therefore, the basic principle of acoustic energy harvester based on nanogenerators (NGs) is firstly discussed. Then, the advances of acoustic energy harvesters based on NGs in the viewpoint of acoustic energy resonator structures are systematically reviewed for the first time. This review not only covers the working mechanism, structural design, and application scenarios of acoustic energy harvesters but also explores the advances in ultrasonic energy harvesting based on NGs. Finally, existing challenges and prospects for future development are systematically discussed, which will facilitate the development of acoustic energy harvesting based on NGs.

Research on acoustic-structural coupling model and tire parameters of tire acoustic cavity resonance noise

Tire acoustic cavity resonance (TACR) noise is one kind of low-frequency and narrowband noise that particularly annoys passengers, especially becomes more prominent in electric vehicles. This paper demonstrates a numerical investigation on the TACR noise via the acoustic-structural coupling finite element model. The accuracy of this coupling finite element model is validated both by the analytic method based on the superposition theory of traveling waves and experimental modal tests of tire cavities. According to the simulated models, the influences of external factors including the inflation pressure and road load on the TACR noise are studied. Meanwhile, as the main constituent component in the tire model, the effect of belt cord is also discussed. To design the low-TACR noise tire, various design parameters of the inner contour in tire cavity are analyzed. By the orthogonal test and range analysis, it is found that the contour parameters can slightly affect the modal frequency and sound pressure of TACR noise. Among these, the curvature radius of the tire shoulder ρ 4, tire sidewall ρ 5, and half-section height H have a more obvious influence on the TACR noise than the curvature radius of the tire crown region ρ 2 and transition region ρ 3. Meanwhile, it also illustrates that increasing the curvature radius at the tire shoulder ρ 4 and reducing the half-section height H has a reduction effect on the TACR noise. This study can contribute to the design of low road noise tires.

Orbital topological edge states and phase transitions in one-dimensional acoustic resonator chains

Topological phases of matter have attracted significant attention in recent years, due to the unusual robustness of their response to defects and disorder. Various research efforts have been exploring classical and quantum topological wave phenomena in engineered materials, in which different degrees of freedom (DoFs) – for the most part based on broken crystal symmetries associated with pseudo-spins – induce synthetic gauge fields that support topological phases and unveil distinct forms of wave propagation. However, spin is not the only viable option to induce topological effects. Intrinsic orbital DoFs in spinless systems may offer a powerful alternative platform, mostly unexplored to date. Here we reveal orbital-selective wave-matter interactions in acoustic systems supporting multiple orbital DoFs, and report the experimental demonstration of disorder-immune orbital-induced topological edge states in a zigzag acoustic 1D spinless lattice. This work expands the study of topological phases based on orbitals, paving the way to explore other orbital-dependent phenomena in spinless systems.

Contact acoustic nonlinearity and local damage resonance for the detection of kissing bonds in structural adhesive joints

Adhesively bonded joints are susceptible to contamination of surfaces during manufacture and environmental deterioration in real operating conditions. These may cause the generation of so-called “kissing bonds” that can dramatically alter the strength of the joint leading to premature failure. Nonlinear acousto-ultrasonic (AU) techniques have shown great potential for monitoring kissing bonds with piezoelectric sensors permanently installed on the structural joint, thus enabling online and in-situ inspection. This paper investigated the combined contact acoustic nonlinearity (CAN) and local damage resonance (LDR) effects in the presence of kissing bonds in adhesive joints. Experimental nonlinear AU tests showed the formation of LDR frequency down-shifts and “jumps” of the fundamental damage resonance in adhesively bonded aluminium joints, with the kissing bond located internally to the overlapping region between the two adherends. These results were supported by a theoretical model based on the solution of the nonlinear Duffing's equation, under the assumption that the debonded region is a damped nonlinear harmonic oscillator subject to harmonic forcing. The Harmonic Balance Method was used to solve the nonlinear differential problem, showing the generation of frequency down-shifts via the dependence of the ratio between the excitation and LDR frequencies with the amplitude of the fundamental damage resonance. Additionally, two-dimensional finite element simulations using a reduced order model based on the Craig-Bampton technique were carried out to support experimental AU tests for the identification of the LDR frequency and the generation of nonlinear resonance effects. Good agreement between analytical, numerical, and experimental results revealed that a monitoring approach combining CAN and LDR is an extremely efficient and sensitive tool for ensuring integrity and safety of structural adhesive joints.

Heteroepitaxy of N-polar AlN on C-face 4H-SiC: Structural and optical properties

To date, it has remained challenging to achieve N-polar AlN, which is of great importance for high power, high frequency, and high temperature electronics, acoustic resonators and filters, ultraviolet (UV) optoelectronics, and integrated photonics. Here, we performed a detailed study of the molecular beam epitaxy and characterization of N-polar AlN on C-face 4H-SiC substrates. The N-polar AlN films grown under optimized conditions exhibit an atomically smooth surface and strong excitonic emission in the deep UV with luminescence efficiency exceeding 50% at room temperature. Detailed scanning transmission electron microscopy (STEM) studies suggest that most dislocations are terminated/annihilated within ∼200 nm AlN grown directly on the SiC substrate due to the relatively small (1%) lattice mismatch between AlN and SiC. The strain distribution of AlN is further analyzed by STEM and micro-Raman spectroscopy, and its impact on the temperature-dependent deep UV emission is elucidated.