A single and double slotting radial acoustic metamaterial plate

2017 ◽  
Vol 31 (12) ◽  
pp. 1750128
Author(s):  
Nansha Gao ◽  
Hong Hou ◽  
Hang Xin
Keyword(s):  
Frequency Band ◽  
Rational Design ◽  
Low Frequency ◽  
Band Gaps ◽  
Acoustic Properties ◽  
Coupling Mechanism ◽  
Displacement Fields ◽  
Acoustic Metamaterial ◽  
Low Frequency Vibration ◽  
Calculation Results

This paper presents the low-frequency acoustic properties of a new single and double slotting radial acoustic metamaterial plate which is arranged in the axial coordinate. The band structures, transmission spectra, and eigenmode displacement fields of this kind of acoustic metamaterial are different from previous studies. Numerical calculation results show that the first-order band gap (BG) of the radial flexible elastic metamaterial plate is below 200 Hz. A multiple-vibration coupling mechanism is proposed to explain the low-frequency band gaps. By changing the geometric parameters a, t, and g, the location and width of the low-frequency band gaps can be varied neatly. In summary, rational design of geometries and materials is the crucial pathway to open and lower BGs, and could restrain low-frequency vibration similarly. This can be used to protect infrasound, generate filters, and design acoustic devices.

Extremely low frequency band gaps of beam-like inertial amplification metamaterials

2017 ◽  
Vol 31 (27) ◽  
pp. 1750251 ◽  
Author(s):  
Mingming Hou ◽  
Jiu Hui Wu ◽  
Songhua Cao ◽  
Dong Guan ◽  
Yanwei Zhu
Keyword(s):  
Frequency Band ◽  
Low Frequency ◽  
Band Gaps ◽  
Vibration Modes ◽  
Resonance Theory ◽  
Local Resonance ◽  
Extremely Low Frequency ◽  
Low Frequency Vibration ◽  
Potential Applications ◽  
Amplification Mechanism

In this paper, extremely low frequency band gaps of beam-like inertial amplification metamaterials are investigated based on local resonance theory. Inertial amplification mechanism is proposed to obtain extremely low frequency band gaps by altering geometry parameters of the beam-like structures rather than modulating material properties, which allow first lower band gap (BG) to be attained easily compared to traditional local resonance structures. Band structures, frequency response functions (FRFs) plots and vibration modes of the beam-like structures are calculated and analyzed by employing finite element method. Numerical results show that first BG of the structure ranges from 23 Hz to 21 Hz. FRFs are in accordance with the dispersion relationship. It is found that interaction between inertial amplification and traveling wave modes in the proposed structure are responsible for formation of the first BG. This type of beam-like inertial amplification metamaterials has many potential applications in the field of low frequency vibration and noise reduction.

Locally resonant periodic structures with low-frequency band gaps

2013 ◽  
Vol 114 (3) ◽  
pp. 033532 ◽  
Author(s):  
Zhibao Cheng ◽  
Zhifei Shi ◽  
Y. L. Mo ◽  
Hongjun Xiang
Keyword(s):  
Frequency Band ◽  
Periodic Structures ◽  
Low Frequency ◽  
Band Gaps

Kinetics of Cavitation Bubble in Ultrasonic Degassing of Casting Aluminium Alloy

2017 ◽  
Vol 896 ◽  
pp. 175-181
Author(s):  
Miao Liu ◽  
Peng Zhai ◽  
Qiang Long ◽  
Chun Yang Wang ◽  
Bo Han Xiao
Keyword(s):  
Aluminium Alloy ◽  
Cavitation Bubble ◽  
Previous Experiment ◽  
Low Frequency ◽  
Silicon Alloy ◽  
Cavitation Bubbles ◽  
Low Frequency Vibration ◽  
Calculation Results ◽  
Coefficient Of Viscosity ◽  
Kinetics Of

Severe regassing was detected by previous experiment on degassing method for aluminium-silicon alloy by injecting argon with rotation. In order to further degas, ultrasonic degassing was adopted. To describe the cavitation bubbles’ movement, traditional Rayleigh-Plesset equation was modified. Classic Rayleigh-Plesset equation is strongly restricted by the applicable condition that the centre of the bubble is fixed. In this paper, a position-related Rayleigh-Plesset equation is proposed to describe the cavitation bubble's floating movement in aluminium-silicon alloy of 750°C with the coefficient of viscosity of 0.0012. As the calculation results, a bubble stimulated by high-low-frequency vibration can float up faster with violent vibration.

Design of High Precision Power Supply for Low-Frequency Vibration Cutting

2004 ◽  
Vol 471-472 ◽  
pp. 494-497
Author(s):  
X.G. Jiang ◽  
D.Y. Zhang
Keyword(s):  
Power Amplifier ◽  
High Precision ◽  
Frequency Band ◽  
Power Supply ◽  
High Stability ◽  
Low Frequency ◽  
Sine Wave ◽  
Vibration Cutting ◽  
Low Frequency Vibration ◽  
Small Band

The frequency of piezoelectric transducer requires high stability and can also be continuously changed. The voltage requires smooth and stable sine wave. To the two problems, a high precision power supply for vibration cutting is designed. It divides the whole frequency band into several small bands. By means of CPLD, the sine wave is digitally fitted individually at each small band. So the sine wave can be always suitable at a wide frequency band. At the power output, OCL power amplifier is adopted. The output sine voltage becomes smooth and stable by adding voltage negative feedback to the power amplifier. The experiment results show its feasibility.

scholarly journals Accordion-like metamaterials with tunable ultra-wide low-frequency band gaps

2018 ◽  
Vol 20 (7) ◽  
pp. 073051 ◽  
Author(s):  
A O Krushynska ◽  
A Amendola ◽  
F Bosia ◽  
C Daraio ◽  
N M Pugno ◽  
...  
Keyword(s):  
Frequency Band ◽  
Low Frequency ◽  
Band Gaps

Low-frequency band gaps in a metamaterial rod by negative-stiffness mechanisms: Design and experimental validation

2019 ◽  
Vol 114 (25) ◽  
pp. 251902 ◽  
Author(s):  
Kai Wang ◽  
Jiaxi Zhou ◽  
Qiang Wang ◽  
Huajiang Ouyang ◽  
Daolin Xu
Keyword(s):  
Frequency Band ◽  
Experimental Validation ◽  
Low Frequency ◽  
Band Gaps ◽  
Negative Stiffness

scholarly journals Vibration Attenuation Investigations on a Distributed Phononic Crystals Beam for Rubber Concrete Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Chao Li ◽  
Sifeng Zhang ◽  
Liyong Gao ◽  
Wei Huang ◽  
Zhaoxin Liu
Keyword(s):  
Band Gap ◽  
Frequency Band ◽  
High Frequency ◽  
Concrete Beam ◽  
Vibration Isolation ◽  
Civil Engineering ◽  
Low Frequency ◽  
Band Gaps ◽  
Spring Force ◽  
Rubber Concrete

Locally resonant phononic crystals (LRPCs) beam is characterized by the band gaps; some frequency ranges within which flexural waves cannot propagate freely. So, the LRPCs beam can be used for noise or vibration isolation. In this paper, a LRPCs beam with distributed oscillators is proposed, and the general formula of band gaps and transmission spectrum are derived by the transfer matrix method (TMM) and spectrum element method (SEM). Subsequently, the parameter effects on band gaps are investigated in detail. Finally, a rubber concrete beam is designed to demonstrate the application of distributed LRPCs beam in civil engineering. Results reveal that the distributed LRPCs beam has multifrequency band gaps and the number of the band gaps is equal to that of the oscillators. Compared with others, the distributed LRPCs beam can reduce the stress concentration when subjected to vibration. The oscillator interval has no effect on the band gaps, which makes it more convenient to design structures. Individual changes of oscillator mass or stiffness affect the band gap location and width. When the resonance frequency of oscillator is fixed, the starting frequency of the band gap remains constant, and increasing oscillator mass of high-frequency band gap widens the high-frequency band gap, while increasing oscillator mass of low-frequency gap widens both high-frequency and low-frequency band gaps. External loads, such as the common uniform spring force provided by foundation in civil engineering, are conducive to the band gap, and when the spring force increases, all the band gaps are widened. Taken together, a configuration of LRPCs rubber concrete beam is designed, and it shows good isolation on the vibration induced by the railway. By the presented design flow chart, the research can serve as a reference for vibration isolation of LRPCs beams in civil engineering.

scholarly journals Low-Frequency Vibration and Radiation Performance of a Locally Resonant Plate Attached with Periodic Multiple Resonators

2020 ◽  
Vol 10 (8) ◽  
pp. 2843
Author(s):  
Qi Qin ◽  
Meiping Sheng ◽  
Zhiwei Guo
Keyword(s):  
Boundary Conditions ◽  
Band Gap ◽  
Low Frequency ◽  
Expansion Method ◽  
Acoustic Power ◽  
Radiation Efficiency ◽  
Band Gaps ◽  
Periodic Arrays ◽  
Low Frequency Vibration ◽  
The One

The low-frequency vibration and radiation performance of a locally resonant (LR) plate with periodic multiple resonators is studied in this paper, with both infinite and finite structure properties examined. For the finite cases, taking the LR plate attached with two periodic arrays of resonators as an example, the forced vibration response and the radiation efficiency are theoretically derived by adopting a general model with elastic boundary conditions. Through a comparison with the band structures calculated by the plane-wave-expansion method, it shows that the band gaps in the infinite LR plate are in good agreement with the vibration-attenuation bands in the finite LR plate, no matter what boundary conditions are applied to the latter. In contrast to the vibration reduction in the band gaps, the radiation efficiency of the finite LR plate is sharply increased in the band-gap frequency ranges. Furthermore, the acoustic power radiated from the finite LR plate can be seriously affected by its boundary conditions. For the LR plate with greater constraints, the acoustic power is reduced in the band-gap frequency ranges, while that from the one with fully free boundary conditions is increased. When further considering the damping loss factors of the resonators, the attenuation performance can be improved for both the vibration and radiation of the LR plate.

Sign in / Sign up

Export Citation Format

Share Document