scholarly journals Study on bandgap vibration isolation of super-cell phononic crystals based on magnetorheological elastomers

AIP Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 125113
Author(s):  
Guo-Jun Yu ◽  
Xi-Xi Wen ◽  
Cheng-Bin Du ◽  
Ling-Yun Wang ◽  
Shao-Jie Zhu
Keyword(s):  
Vibration Isolation ◽  
Phononic Crystals ◽  
Magnetorheological Elastomers ◽  
Super Cell

scholarly journals Band gap and experimental study in phononic crystals with super-cell structure

2019 ◽  
Vol 13 ◽  
pp. 102200 ◽  
Author(s):  
Yingjian Sun ◽  
Yingjie Yu ◽  
Yayu Zuo ◽  
Lili Qiu ◽  
Mingming Dong ◽  
...  
Keyword(s):  
Experimental Study ◽  
Band Gap ◽  
Cell Structure ◽  
Phononic Crystals ◽  
Super Cell

Magnetorheological Elastomers With Increased Structural Integrity for Multifunction Applications

2007 ◽  
Author(s):  
Zelalem Aga ◽  
Dan Feimster ◽  
LeAnn Faidley
Keyword(s):  
Elastic Modulus ◽  
Vibration Isolation ◽  
Structural Integrity ◽  
Effective Elastic Modulus ◽  
Zero Field ◽  
Magnetorheological Elastomers ◽  
The Matrix ◽  
Cure Temperature ◽  
Vibration Tests ◽  
Novel Applications

Magnetorheological Elastomers (MREs) are composite materials formed of a soft elastomer matrix and a magnetic-powder filler. The interaction of the matrix and filler in a magnetic field causes the effective elastic modulus of the MRE to be controllable by an external field. In previous studies the applications of MREs have been severely limited by their lack of structural integrity, forcing them to be applied only as soft pads or as the filler in sandwich beams. This study represents initial steps towards improving the structural integrity of MREs while retaining some level of modulus variability. Specimens are made from Sylgard 184 Silicone with a variety of cure temperatures and filler volume percentages. Longitudinal swept-sine vibration tests are performed to measure the dependence of elastic modulus on applied fields of up to 40 kA/m. It is found that the softer specimen (ie: the lowest cure temperature) with 27% percent filler exhibits the largest percent change in effective modulus of almost 40%. The zero-field modulus for this specimen is 5.7 MPa giving it the structural integrity needed for multifunction applications in which the material is both active and load bearing. Many novel applications exist including active modulus control of sound radiating plates, novel design of vibration isolation tables, and more.

scholarly journals Optimization of a type of elastic metamaterial for broadband wave suppression

2021 ◽  
Vol 477 (2251) ◽  
pp. 20210337
Author(s):  
Kun Wu ◽  
Haiyan Hu ◽  
Lifeng Wang
Keyword(s):  
Vibration Isolation ◽  
Wave Attenuation ◽  
Low Frequency ◽  
Dispersion Analysis ◽  
Mass Unit ◽  
Super Cell ◽  
Unit Cells ◽  
Sequential Quadratic Programming Method ◽  
Continuous Frequency ◽  
Quadratic Programming Method

The optimal design is studied for a type of one-dimensional dissipative metamaterial to achieve broadband wave attenuation at low-frequency ranges. The complex dispersion analysis is made on a super-cell consisting of multiple mass-in-mass unit cells. An optimization algorithm based on the sequential quadratic programming method is used to design the wave suppression of target frequencies by coupling multiple separate narrow bandgaps into a broad bandgap. A new objective function is proposed in the optimization process for a continuous bandgap. Then, the continuous frequency range with low-wave transmissibility is optimized to achieve the maximal width of bandgap. The stiffness optimization of super-cell gives the broad bandgap from 10 Hz to 22.9 Hz at low-frequency ranges. In addition, numerical simulations are conducted for a type of dissipative metamaterial composed of a finite number of periodicities. The level of vibration isolation can be tuned by adjusting a critical value in the optimization scheme. The wave suppression in the numerical simulation well coincides with the obtained bandgaps and verifies the optimization results.

scholarly journals Elastic Wave Propagation of Two-Dimensional Metamaterials Composed of Auxetic Star-Shaped Honeycomb Structures

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 121 ◽  
Author(s):  
Shu-Yeh Chang ◽  
Chung-De Chen ◽  
Jia-Yi Yeh ◽  
Lien-Wen Chen
Keyword(s):  
Wave Propagation ◽  
Cross Sections ◽  
Vibration Isolation ◽  
Negative Refraction ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
The Self ◽  
The Finite Element Method ◽  
Elastic Waveguide ◽  
Potential Applications

In this paper, the wave propagation in phononic crystal composed of auxetic star-shaped honeycomb matrix with negative Poisson’s ratio is presented. Two types of inclusions with circular and rectangular cross sections are considered and the band structures of the phononic crystals are also obtained by the finite element method. The band structure of the phononic crystal is affected significantly by the auxeticity of the star-shaped honeycomb. Some other interesting findings are also presented, such as the negative refraction and the self-collimation. The present study demonstrates the potential applications of the star-shaped honeycomb in phononic crystals, such as vibration isolation and the elastic waveguide.

Thermal Tuning of Band Structures in a One-Dimensional Phononic Crystal

2013 ◽  
Vol 81 (4) ◽  
Author(s):  
Zuguang Bian ◽  
Wei Peng ◽  
Jizhou Song
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Vibration Isolation ◽  
Phononic Crystal ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Polybutylene Terephthalate ◽  
Band Structures ◽  
One Dimensional ◽  
Thermal Tuning

Phononic crystals make the realization of complete acoustic band gaps possible, which suggests many applications such as vibration isolation, noise suppression, acoustic barriers, filters, wave guides, and transducers. In this paper, an analytic model, based on the transfer matrix method, is developed to study the band structures of bulk acoustic waves including SH-, P-, and SV-waves in a one-dimensional phononic crystal, which is formed by alternating strips of two different materials. The analysis is demonstrated by the phononic crystal of Ba0.7Sr0.3TiO3 (BST) and polybutylene terephthalate (PBT), whose elastic properties depend strongly on the temperature. The results show that some band gaps are very sensitive to the temperature. Depending on the wave mode, the center frequency of the first band gap may decrease over 25% and band gap width may decrease over 60% as the temperature increases from 30 °C to 50 °C. The transmission of acoustic waves in a finite phononic crystal is also studied through the coefficient of transmission power. These results are very useful for the design and optimization of thermal tuning of phononic crystals.

scholarly journals Study on Tunable Band Gap of Flexural Vibration in a Phononic Crystals Beam with PBT

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1346
Author(s):  
Peng Zhao ◽  
Lili Yuan ◽  
Tingfeng Ma ◽  
Hanxing Wei
Keyword(s):  
Band Gap ◽  
Elastic Foundation ◽  
Vibration Isolation ◽  
Axial Stress ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Phononic Crystals ◽  
Band Gaps ◽  
Response Curves ◽  
Element Method

Low-frequency flexural vibration plays a significant role in beam vibration control. To efficiently attenuate the propagation of flexural vibration at a low-frequency range, this paper proposes a new type of a phononic crystals beam with an adjustable band gap. The governing equations of flexural vibration in a periodic beam are established based on the Euler theory and Timoshenko theory. The band structures are calculated by the plane wave expansion method, the attenuation properties and transmission response curves with a finite periodic beam are calculated by the spectral element method and finite element method. The effects of the elastic foundation and axial stress on band gaps are discussed in detail, and the regulation of the temperature field on the band gap is emphatically studied. The theoretical and numerical results show that the elastic foundation and axial stress have significant influence on the band gap, and the location and width of the band gaps can be adjusted effectively when the Young’s modulus of PBT is changed by a varying temperature. The results are very useful for understanding and optimizing the design for composite vibration isolation beams.

Sign in / Sign up

Export Citation Format

Share Document