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Number of results: 5
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Wave Propagation in a LRPC Composite Double Panel Structure with Periodically Attached Pillars and Etched Holes

Denghui Qian
Archives of Acoustics | 2018 | vol. 43 | No 4 | 717–725 | DOI: 10.24425/aoa.2018.125165
Keywords locally resonant phononic crystal composite double panel structure band structure displacement field transmission power spectrum “base-spring-mass” simplified model
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Abstract

The locally resonant phononic crystal (LRPC) composite double panel structure (DPS) made of a twodimensional periodic array of a two-component cylindrical LR pillar connected between the upper and lower composite plates is proposed. The plates are composed of two kinds of materials and periodically etched holes. In order to reveal the bandgap properties of structure theoretically, the band structures, displacement fields of eigenmodes and transmission power spectrums of corresponding 8 × 8 finite structure are calculated and displayed by using finite element method (FEM). Numerical results and further analysis demonstrate that if the excitation and response points are picked on different sides of the structure, a wide band gap with low starting frequency is opened, which can be treated as the coupling between dominant vibrations of pillars and plate modes. In addition, the influences of filled-in rubber, etched hole and viscidity of soft material on band gap are studied and understood with the help of “base-spring-mass” simplified model.

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Authors and Affiliations

Denghui Qian

A Honeycomb Based Graded Metamaterial Muffler with Broadband Sound Attenuation and Load Bearing Performances

Gen Li Yan Chen Huan He
Archives of Acoustics | 2022 | vol. 47 | No 2 | 213-221 | DOI: 10.24425/aoa.2022.141651
Keywords acoustic metamaterials honeycomb structure phononic crystal local resonance
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Abstract

A challenge for developing acoustic metamaterials (AMMs) is considering the application of broadband muffling and load bearing capacity simultaneously. In this paper, a honeycomb based graded AMM muffler is proposed, which can widen the attenuation band and improve the structural stiffness without any external device by means of integrated design. Firstly, the acoustic and mechanical characteristics of the muffler unit cell are theoretically and numerically studied, and the graded muffler is designed based on these characteristics. The numerical results show that the graded muffler widens the attenuation bandwidth of the unit cell, and the simulation also shows that the graded muffler has greater stiffness than the uniform one. The stiffness driven muffler provides new possibilities for the design of advanced metamaterial with simultaneous sound insulation and load bearing performances.
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Authors and Affiliations

Gen Li
1 2
Yan Chen
1 2
Huan He
1 3 4
  1. State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  2. Institute of Vibration Engineering Research, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
  3. MIIT Key Laboratory of Multi-Functional Lightweight Materials and Structures, Nanjing 210016, China
  4. Laboratory of Aerospace Entry, Descent and Landing Technology, Beijing 100094, China

Optimization of a Bandgap in the Ultrasonic Phononic Coating

S. Garus W. Sochacki J. Garus A.V. Sandu
Archives of Metallurgy and Materials | 2021 | vol. 66 | No 2 | 537-542 | DOI: 10.24425/amm.2021.135890
Keywords reflectance coating mechanical waves phononic crystal band gap optimization
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Abstract

This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. Increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure.
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Authors and Affiliations

S. Garus
1
ORCID: ORCID
W. Sochacki
1
ORCID: ORCID
J. Garus
1
ORCID: ORCID
A.V. Sandu
2
ORCID: ORCID
  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland
  2. Gheorghe Asachi Technical University of Iasi, Faculty of Materials Science and Engineering, Blv d. D. Mangeron 71, 700050 lasi, Romania

The Effect of Layer Thickness on the Reflectance of a Quasi One-Dimensional Composite Built with Zr55Cu30Ni5Al10 Amorphous Alloy and Epoxy Resin

S. Garus W. Sochacki
Archives of Metallurgy and Materials | 2021 | vol. 66 | No 2 | 503-510 | DOI: 10.24425/amm.2021.135885
Keywords amorphous alloy aperiodic multilayer mechanical waves phononic crystal bandgap
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Abstract

The study examined the impact of the angle of incidence of mechanical waves on various types of quasi one-dimensional superlattice. Binary periodic structure, quasi-periodic distribution of Thue-Morse layers and Severin’s aperiodic multilayer were used. Using the concatenation and recursive rules, the distribution of layers was determined for individual structure types for generation numbers equal to 3, 4 and 5. The structures were selected so that the thickness of the composite was the same for each type of distribution for a given generation number value. Transfer Matrix Method algorithm was used to determine reflectance. The band structure of reflectance has been demonstrated for incidence angles up to 90 degrees at mechanical wave frequencies up to 50 kHz. The existence of wide bands of high reflectance above the acoustic frequencies was demonstrated for the analyzed structures. Increasing the layer thickness caused an inhomogeneous shifts of transmission peaks towards lower frequencies.
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Authors and Affiliations

S. Garus
1
ORCID: ORCID
W. Sochacki
1
ORCID: ORCID
  1. Czestochowa University of Technology, Department of Mechanics and Fundamentals of Machinery Design, Faculty of Mechanical Engineering and Computer Science, 73 Dąbrowskiego Str., 42-201 Częstochowa, Poland

Influence of spatial distribution and the type of material on the occurrence of bandgaps in phononic crystals

Sebastian Garus Wojciech Sochacki Paweł Kwiatoń Marcin Nabiałek Jana Petrů Mariusz Kubanek
Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 3 | e144609 | DOI: 10.24425/bpasts.2023.144609
Keywords finite difference time domain band gap phononic crystal mechanical waves propagation
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Abstract

The study investigated the effect of the fill factor, lattice constant, and the shape and type of meta-atom material on the reduction of mechanical wave transmission in quasi-two-dimensional phononic structures. A finite difference algorithm in the time domain was used for the analysis, and the obtained time series were converted into the frequency domain using the discrete Fourier transform. The use of materials with large differences in acoustic impedance allowed to determine the influence of the meta-atom material on the propagation of the mechanical wave.
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Authors and Affiliations

Sebastian Garus
1
ORCID: ORCID
Wojciech Sochacki
1
ORCID: ORCID
Paweł Kwiatoń
1
ORCID: ORCID
Marcin Nabiałek
2
ORCID: ORCID
Jana Petrů
3
ORCID: ORCID
Mariusz Kubanek
4
ORCID: ORCID
  1. Faculty of Mechanical Engineering and Computer Science, Department of Mechanics and Fundamentals of Machinery Design, Czestochowa University of Technology, Dąbrowskiego 73, 42-201 Częstochowa, Poland
  2. Faculty of Production Engineering and Materials Technology, Department of Physics, Czestochowa University of Technology, Armii Krajowej 19, 42-201 Częstochowa, Poland
  3. Department of Machining, Assembly and Engineering Metrology, Faculty of Mechanical Engineering, VSB-Technical University of Ostrava,70833 Ostrava, Czech Republic
  4. Faculty of Mechanical Engineering and Computer Science, Department of Computer Science, Czestochowa University of Technology, Dąbrowskiego 73, 42-201 Częstochowa, Poland

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