• Title/Summary/Keyword: Low Frequency Vibration

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The natural frequency measurement for a suction pile about the intrusion depth (관입깊이에 따른 석션파일 고유진동수 측정 및 분석)

  • Lee, Jong-Hwa;Kim, Min-Su;Seo, Yoon-Ho;Kim, Bong-Ki;Lee, Ju-Shin;Yu, Mu-Sung;Kwak, Dae-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.495-496
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    • 2014

  • The suction method is the substructure installation using the water pressure difference generated by discharging water inside the pile by the pumping operation, after the intrusion by the self-weights of a large hollow steel pipe or a concrete structure. It is known as the low-noise and low-vibration method against the general pile driven method and eco-friendly, also. Most current design and safety assessment of the support structure and considering only the static load, however, the importance of dynamic behavior becomes magnified as the size of wind power generator increases. This study measures the natural frequency of the suction pile prototype about the penetration depth as a part of basic research and analyzed the interaction between the soil and the structure.

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Design and Evaluation of Piezoelectric Ultrasonic Scaler Produced by a Simulation (시뮬레이션을 통한 압전형 초음파 스케일러 개발 및 평가)

  • Kim, Chul-Min;Lee, Young-Jin;Paik, Jong-Hoo;Jeong, Young-Hun;Kang, Kook-Jin;Lee, Jeong-Bae;Lee, Seung-Dae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.10
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    • pp.832-836
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    • 2009

  • A piezoelectric ultrasonic scaler, usually used to remove the tartar out of teeth and to amputate the pubis, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power, precision and low-cost. It has typically two parts of a tip and vibration system, which is also composed of head, piezoelectric elements and tail-mass. The scaler concentrates its displacement on tip and has commonly a resonance frequency at 25~30 kHz, and in order to improve the performance of the scaler, it is important to standardize the size of the vibration system without tip for high performance because scaler in quality differs according to several tips. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic scaler in the vibration system. Consequently, this study revealed that influence of several tips on property were minimized and scaler showed good property at the resonance frequency of 28 kHz.

  • https://doi.org/10.4313/JKEM.2009.22.10.832 인용 PDF KSCI