AN EXPERIMENTAL INVESTIGATION OF SLOW GROUP VELOCITIES IN A PHONONIC CRYSTAL BEAM WITH A POINT DEFECT
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- 英文论文题名：AN EXPERIMENTAL INVESTIGATION OF SLOW GROUP VELOCITIES IN A PHONONIC CRYSTAL BEAM WITH A POINT DEFECT
- 论文作者：Kuo-chih CHUANG ; Zhi-qiang ZHANG ; Hua-xin WANG
- 英文论文作者：Kuo-chih CHUANG ; Zhi-qiang ZHANG ; Hua-xin WANG ; Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province ; School of Aeronautics and Astronautics ; Institute of Applied Mechanics ; Zhejiang University
- 年：2016
- 作者机构：Key Laboratory of Soft Machines and Smart Devices of Zhejiang Province, School of Aeronautics and Astronautics, Institute of Applied Mechanics, Zhejiang University;
- 英文论文关键词：Phononic crystal beam ; Group velocity ; Defect mode ; Fiber Bragg grating(FBGs)
- 会议召开时间：2016-10-21
- 会议录名称：2016年全国压电和声波理论及器件应用研讨会论文摘要集
- 英文会议录名称：Abstract Book of 2016 Symposium on Piezoelectricity, Acoustic Waves and Device Applications
- 语种：英文
- 分类号：O735;TP212
- 学会代码：AGLU
- 会议名称：2016年全国压电和声波理论及器件应用研讨会
- 会议地点：中国陕西西安
- 主办单位：中国力学学会、中国声学学会、IEEE UFFC分会
- 学会名称：中国力学学会
- 页数：2
- 文件大小：10k
- 原文格式：D
- 会议级别：全国
摘要
Background, Motivation and Objective Phononic crystals(PCs) have gained much attention for their potential applications in vibration suppression, sound insulation, filters, and so on. Apart from the phenomena of band gaps, existence of the crystal defects makes confinement of elastic waves in a localized mode possible. When the periodicity of the lattice is broken by the defects, localized resonance peaks can occur inside the band gaps. Various wave-manipulation devices can be designed through the introductions of the defect modes(e.g., frequency filters, couplers, focusing devices, etc). Here we experimentally investigate influences of the point defect modes on the propagations of flexural waves in a PC Timoshenko beam. Statement of Contribution/Methods In this work, the dispersion curves and the group velocities around the defect modes are theoretically obtained by the transfer matrix method with a supercell technique. In order to demonstrate the existence of the localized defect modes inside the band gaps, we set up a high-sensitivity fiber Bragg grating(FBG) sensing system and measure the displacement transmittance of the PC beam. Hanning windowed tone burst excitations are generated through a multilayered piezoelectric actuator and the transient elastic waves are then measured by the FBG sensing system. Results We show that the proposed FBG sensing system is able to obtain point-wise input and output displacements at the two ends of the PC beam for the obtainment of the displacement transmittance. In addition, we experimentally demonstrate that flexural waves propagate with slow group velocities around the defect modes. Discussion and Conclusions In conclusion, we have investigated the transmission properties of a PC Timoshenko beam with a point defect. The defect mode is existed inside the band gaps, validated theoretically by the transfer matrix theory with a supercell technique and experimentally by the proposed FBG displacement sensing system. The slow group velocity via the defect coupling is experimentally demonstrated with Hanning windowed tone burst excitations.
Background, Motivation and Objective Phononic crystals(PCs) have gained much attention for their potential applications in vibration suppression, sound insulation, filters, and so on. Apart from the phenomena of band gaps, existence of the crystal defects makes confinement of elastic waves in a localized mode possible. When the periodicity of the lattice is broken by the defects, localized resonance peaks can occur inside the band gaps. Various wave-manipulation devices can be designed through the introductions of the defect modes(e.g., frequency filters, couplers, focusing devices, etc). Here we experimentally investigate influences of the point defect modes on the propagations of flexural waves in a PC Timoshenko beam. Statement of Contribution/Methods In this work, the dispersion curves and the group velocities around the defect modes are theoretically obtained by the transfer matrix method with a supercell technique. In order to demonstrate the existence of the localized defect modes inside the band gaps, we set up a high-sensitivity fiber Bragg grating(FBG) sensing system and measure the displacement transmittance of the PC beam. Hanning windowed tone burst excitations are generated through a multilayered piezoelectric actuator and the transient elastic waves are then measured by the FBG sensing system. Results We show that the proposed FBG sensing system is able to obtain point-wise input and output displacements at the two ends of the PC beam for the obtainment of the displacement transmittance. In addition, we experimentally demonstrate that flexural waves propagate with slow group velocities around the defect modes. Discussion and Conclusions In conclusion, we have investigated the transmission properties of a PC Timoshenko beam with a point defect. The defect mode is existed inside the band gaps, validated theoretically by the transfer matrix theory with a supercell technique and experimentally by the proposed FBG displacement sensing system. The slow group velocity via the defect coupling is experimentally demonstrated with Hanning windowed tone burst excitations.
Background, Motivation and Objective Phononic crystals(PCs) have gained much attention for their potential applications in vibration suppression, sound insulation, filters, and so on. Apart from the phenomena of band gaps, existence of the crystal defects makes confinement of elastic waves in a localized mode possible. When the periodicity of the lattice is broken by the defects, localized resonance peaks can occur inside the band gaps. Various wave-manipulation devices can be designed through the introductions of the defect modes(e.g., frequency filters, couplers, focusing devices, etc). Here we experimentally investigate influences of the point defect modes on the propagations of flexural waves in a PC Timoshenko beam. Statement of Contribution/Methods In this work, the dispersion curves and the group velocities around the defect modes are theoretically obtained by the transfer matrix method with a supercell technique. In order to demonstrate the existence of the localized defect modes inside the band gaps, we set up a high-sensitivity fiber Bragg grating(FBG) sensing system and measure the displacement transmittance of the PC beam. Hanning windowed tone burst excitations are generated through a multilayered piezoelectric actuator and the transient elastic waves are then measured by the FBG sensing system. Results We show that the proposed FBG sensing system is able to obtain point-wise input and output displacements at the two ends of the PC beam for the obtainment of the displacement transmittance. In addition, we experimentally demonstrate that flexural waves propagate with slow group velocities around the defect modes. Discussion and Conclusions In conclusion, we have investigated the transmission properties of a PC Timoshenko beam with a point defect. The defect mode is existed inside the band gaps, validated theoretically by the transfer matrix theory with a supercell technique and experimentally by the proposed FBG displacement sensing system. The slow group velocity via the defect coupling is experimentally demonstrated with Hanning windowed tone burst excitations.
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