• Title/Summary/Keyword: 진동저감효과

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An Experimental Study on the Reduction Effect of Reflected Sound and Diffraction Effect by Types of Noise Barrier (방음벽 종류별 반사음 저감효과 및 회절효과에 관한 실험적 연구)

  • 김흥식
    • Journal of KSNVE
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    • v.6 no.2
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    • pp.245-251
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    • 1996
  • This study is to suggest the improved noise barrier which is harmonized with surrounding landscape and maintained the similar reduction of reflected sound and diffraction effects in comparison with the aluminum noise barrier of absorbing type which is formed a great majority in Korea. In this study the two improved models of noise barrier(Diffuse and Disperse type) were designed and compared with the noise barriers of absorbing type in the acoustics performance (the reduction of reflected sound and diffraction effects) through the field and full-scale experimental measurement. As these two models have the same acoustic performance as the noise barrier of aluminum absorbing type, it is suggested that these models can be applied to the improved noise barrier as an alteration of aluminum absorbing type barrier.

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A Study on the Acoustic Resonator and Shutter for the In-door Substation (흡차음 셔터 및 공명기를 이용한 옥내변전소 소음저감연구)

  • Lee, Jun-Shin;Sohn, Seok-Man;Kim, Tae-Ryong;Kim, Ki-Hong;An, Kyeong-Duk
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1836-1841
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    • 2000
  • 옥내용 변전소의 셔터 및 공기풍도에 대한 흡차음 기술은 변전소의 민원소음 방지 측면에서 매우 중요한 기술이다. 변압기는 전원 주파수 60Hz의 2배 성분을 기저주파수로 하는 하모닉 성분의 소음을 발생시킨다. 본 연구에서는 실내 변압기에서 셔터를 투과하거나 공기풍도를 통해 실의로 방사되는 소음을 효과적으로 차단하는 방법론을 개발하는데 있다. 기존의 셔터의 흡/차음 성능을 개선하기 위하여 기존 셔터 앞에 흡/차음 셔터를 추가하는 장치를, 공기 풍도에는 변압기 소음주파수와 맞는 공명기를 적용하는 방법을 검토하였다. 또한, 이 장치들을 실제 현장에 적용하여 그 효과를 확인하였으며 실내변전소 변압기 소음제어용으로 유용하게 쓰일 수 있음을 확인하였다.

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A Study on Transferred Load Reduction effect of Low Elastic Pad through Dynamic Response Analysis (동적응답해석을 통한 저탄성패드의 전달하중 저감효과 연구)

  • Kim, Hyun-Ju;Lee, Il-Wha;Cho, Guk-Hwan
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.2464-2472
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    • 2011
  • Train runs on high speed and the concrete track is constructed. Rail fastening device needs to reduce elasticity, transferred load, noise, and vibration etc. Consequently, low elastic pad has a great impact of the durability and stability of the track. In this study, discussed in previous studies, static numerical analysis and real scale repeated loading test, followed by dynamic response analysis were implemented. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition track while load reduction effect of transfer on roadbed assessed by various low elastic pad.

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Shape Optimal Design of Anti-Vibration Rubber Assembly to Reduce the Vibration of a Tractor Cabin (트랙터 캐빈의 진동저감을 위한 방진고무의 형상최적설계)

  • Choi, Hyo-Joon;Lee, Sang-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.4
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    • pp.657-663
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    • 2018
  • In this study, shape optimization was performed to improve the vibration isolation capability of an anti-vibration rubber assembly, which is used in the field option cabin of agricultural tractors. A uniaxial tension test and biaxial tension test were performed to characterize the hyper-elastic material properties of rubber, and the data were used to calibrate the material model used in the finite element analyses. A field test was performed to quantify the input excitation from the tractor and the output response at the cabin frame. To account for the nonlinear behavior of rubber, static analyses were performed and the load-displacement curve of rubber was derived. The stiffness of the rubber was calculated from this curve and input to the harmonic analyses of the cabin. The results were verified using the test data. Taguchi's parameter design method was used to find the optimal shape of the anti-vibration rubber assembly, which indicated a shape with reduced stiffness. The vibration of the cabin frame was reduced by the optimization by as much as 35% compared to the initial design.

Vibration Reduction Evaluation of Jacket Structure by applying Precast Concrete Block and Suction pile (Precast Concrete Block 및 Suction pile을 적용한 Jacket 구조물의 진동저감 효과 평가)

  • Lee, Sung-Jin;Kyung, Kab-Soo;Ryu, Seong-Jin;Jeong, Ji-Young;Park, Jin-Eun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.4
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    • pp.375-384
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    • 2015
  • Recently, construction sites of offshore wind power tend to move from shallow water to deep water. From this tendency, the research on the support structure of offshore wind power in deep water will be a key issue. In this study, precast concrete block and suction pile are applied to existing jacket structure. In order to reduce the vibration of this structure, the tuned liquid damper is also applied in the precast concrete block. The applicability of the suggested jacket structure is evaluated by finite element analysis. And the vibration tends to decrease about 5%, when the tuned liquid damper is applied.

A study on the Dynamic Behavior Enhancement of the Korean High-speed Train (고속열차의 주행동특성 개선에 관한 연구)

  • Jeon, Chang-Sung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.10
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    • pp.81-87
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    • 2017
  • This paper describes the dynamic behavior and enhancement of Korean high-speed trains. The tail vibration reduction method of the yaw damper installation method change, which was derived from previous research, was applied to the running test of high-speed train. In addition, the vibration reduction method for the entire vehicle was derived by a numerical method and its effect was confirmed by a running test. The improved design was applied to the double-deck high-speed train coaches and the commissioning proceeded without problems in dynamic behavior. Sensitivity analysis of the suspension parameters affecting the critical speed of Korean next-generation high-speed trains was performed and four design variables that greatly affected the critical speed were derived. These were in the order of the primary elastic joint x-directional stiffness, the secondary yaw damper series stiffness, the secondary lateral damper damping coefficient, and the carbody damper damping coefficient. By optimizing the design variables, the suspension parameter that improves the critical speed by 23.3% can be used in the commercial designs of Korean next-generation high-speed trains.

Behaviour of Embankment using Bottom Ash-Tire Shred Mixture (저회(Bottom Ash)와 폐타이어를 활용한 성토구조물 거동에 관한 연구)

  • Lee, Sung Jin;Shin, Min ho;Koh, Tae hoon;Hwang, Seon Keun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.1C
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    • pp.21-31
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    • 2009
  • Based on the proven feasibility of bottom ash and tire shred-soil mixtures as lightweight fill materials, tire shred-bottom ash mixtures were suggested as a new lightweight fill material to replace the conventional construction material (soil) with bottom ash. Therefore, we carried out the field compaction test and performance test of large scale embankment in order to evaluate their suitability for the use of lightweight fill materials. In these tests, we could assess the settlement, earth pressure, stress-strain relation, vibration of large scale embankment which were made with tire shred-bottom ash mixture and the conventional fill material(weathered soil) respectively. The earthpressure and vibration transmission was decreased and the settlement behaviour of the 2 materials (tire shred mixture and weathered soil) was measured similarly under static/cyclic loading condition.

A Study on the Effects of Absorptive Treatments for the Highway Noise Barriers (도로교통소음의 방음벽 흡음효과에 관한 연구)

  • 김재석;루이스칸;김갑수
    • Journal of KSNVE
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    • v.8 no.1
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    • pp.146-156
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    • 1998
  • To mitigate excessive noise from highways, and high speed rail road, it is often necessary to construct a noise barrier. Absorptive barroer attenuation solution is obtained for the problem of diffration of a plane wave sound source by a semi-infinite plane. A finite region in the vicinity of the edge has an highly absorbing boundary condition ; the remaining portion of the half plane is rigid. The problem which is solved is a mathematical model for a hard barrier with an absorbing edge. If the wavelength of the sound is much smaller than the length scale associated with the barrier, the diffraction process is governed to all intents and purpose by the solution to a standard problem of diffraction by a semi-infinite hard plane with an absorbent edge. It is concluded that the absorbing material that comprises the edge need only be of the order of a wavelength long to have approximately the same effect, on the sound attenuation in the shadow side of the barrier. Traffic noise is composed of thousands of sources with varying frequency content. To simplify noise predictions when barriers are present, an effective frequency of 550Hz may be used to represent all vehicles. The wavelength of sound at f=550Hz for traffic noise is about 2 feet. According to the above conclusion, an absorptive highway noise barrier is only needed to cover to cover approximately a 2 foot length of absorbing material. It would be more economical to cover only the region in the immediate vicinity of the edge with highly sound obsorbent material.

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An Experimental Study on the Development of a Cabin Noise Reduction System for Improving Ship Habitability (선박 거주성 향상을 위한 선실 소음 저감 시스템 개발에 관한 실험적 연구)

  • Young-Choul Seo;Deug-Bong Kim;Chol-Seong Kim
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.6
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    • pp.620-627
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    • 2023
  • Ship noise is one of the important factors for the living and health of seafarers, and ef orts to reduce ship noise are actively underway. There are two methods of noise reduction: passive noise Control (PNC) and active noise control (ANC). Unlike cars and airplanes, ANC is not widely used for noise reduction on ships. This study aimed to reduce the noise generated in the engine room by using soundproof panels and high-frequency vibration generators, as well as active noise control (ANC). For this purpose, an experimental model was made using an acrylic box, and the noise reduction effect was measured under four conditions. The experimental results are as follows: First, the soundproof panel had a noise reduction effect in all ranges from 55 dB to 85 dB. In the case of using a high-frequency vibration generator, there was no ef ect in the low noise range such as 55 dB(A), but there was a noise reduction effect in the high noise range such as 70.8 dB(A) and 85 dB(A).Second, when the soundproof panel and the high-frequency vibration generator were used simultaneously, the noise reduction ef ect was up to -2.2 dB(A). The results of this experiment were obtained from an experimental model made of acrylic, and they may be different from actual ships made of steel plate. In future studies, we plan to experiment using iron plate (considering the material, thickness, and structure) used in actual ships. We hope that this study will help to improve the living environment and health of seafarers on ships.

Vibration Analysis and Mitigable Countermeasures of Semi High-speed Subway Electric Trains (준고속 도시철도의 진동분석 및 저감대책)

  • Park, Ki-Soo;Choi, Yeon-Sun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.10
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    • pp.1014-1023
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    • 2008
  • Subway electric trains need to be faster for accommodation of long distance passengers. The faster run of the existing trains results in deterioration of ride quality due to noise and vibration. To reduce the noise and vibration of the electric train, a running test of the electric train was performed and an ADAMS/Rail model was set up to verify the running test results. The experimental results show that the sources of the cabin noise and vibration basically comes from the irregularity of the railroad track and the deterioration of the connection part between cabin and bogie. Consequently for mitigation of noise and vibration of the electric train, the redesign of the center pivot with softer stiffness and the minimization of rail irregularity are necessary. the frequent maintenance of the train will lead to better comport.