• Title/Summary/Keyword: 진동저감효과

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Vibration and Acoustic Noise characteristic on SRM with compensating winding by two stage commutation (2단계 소호전압방식을 적용한 보상권선형 SRM의 진동.소음특성)

  • 오석규;이종근;최태완
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.3
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    • pp.250-257
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    • 2001
  • SRM drives generate large vibration and acoustic noise because it is rotated by step pulse mmf and switching commutation mechanism. The main vibration source of SRM drive is generated by rapidly variation of radial force when phase winding current is extinguished for commutation action. So the rapidly variation of radial force is repressed firstly to reduce vibrating force of SRM drive. This paper suggests an SRM excitation scheme using unidirect-short compensation winding to reduce vibration of the motor. The motor is excited by a two stage commutation method during commutation period. This paper suggests an SRM excitation scheme using unidirect-short compensation winding to reduce vibration of the motor. The motor is excited by a tow stage commutation method during commutation period. This reduction effect of vibration is verified with the result obtained in the test of prototype machine.

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A Study on the Reduction of the Vibration in PKM Using a Propeller Damper (프로펠러 감쇄기를 이용한 고속정 진동 감소방안 연구)

  • Kim, Hye-Jin;Lee, Heun-Hwa;Seong, Woo-Jae;Pyo, Sang-Woo
    • The Journal of the Acoustical Society of Korea
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    • v.27 no.3
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    • pp.103-110
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    • 2008
  • Strategically, the Patrol Killer Medium (PKM) ought to run at high speed that produces largely vibration by propeller, in a consequence, the vibration gradually deterioratescrews' working condition and increases the possibility of SONAR detection. In this paper, we propose the propeller damper, which is one of waysto reduce the vibration induced by the propeller, and simulate the ability of the damper numerically. The propeller damper was designed to apply to an isolated plate at the bottom flat board of ship which is directly affected by the fluctuating pressure. The dynamic pressure for the stern part of the PKM is calculated by using the DnV rule and the numerical analysis when the propeller damper applied or not, is performed with ANSYS at the isolated plate that simplified. From the analysis, the damping effect of the proposed propeller damper is confirmed and the reduction ratio for each compartment is estimated based on the experimental data in the PKM.

An Analysis on the Effect of Application on Vibration Isolation Liner of Elevator Guide Rail Bracket (엘리베이터 가이드 레일 브라켓의 방진라이너 적용효과에 관한 분석)

  • Roh, Seung-Kwon;Kim, Eundo;Oh, Jong-Seok;Cho, Jae-Ung
    • Journal of the Korea Convergence Society
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    • v.10 no.8
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    • pp.145-151
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    • 2019
  • In this study, the effects were analyzed by applying the vibration absorption liner into the guide rail bracket as a part of method to reduce the vibration and noise on the high-rise apartment. As the result of vibration absorption liner performance, it was checked that the level of vibration and noise was reduced around 65.49% in the car side and around 90.05% in the counterweight side. Therefore, the vibration absorption effect by the vibration absorption liner of elevator guide rail bracket became fairly good. In case of the vibration absorption liner application, there was an effect on the reduction of 7.26 to 22.22% at hoistway section area, 3,840,000 to 9,780000 KRW at the cost of material and installation by comparing with the damping beam application. Also, in case of the vibration absorption liner application with light weight instead of damping beam with heavy weight, it was thought to become significant effect at preventing the safety from the accidents on installation site.

Evaluation of Functional and Structural Performance of Semi Rigid Overlay Pavements (반강성 덧씌우기 포장의 기능적 및 구조적 성능 평가)

  • Park, Kang Yong;Lee, Jae Jun;Kwon, Soo Ahn;Jeong, Jin Hoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.3D
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    • pp.271-278
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    • 2010
  • Semi rigid pavement is a pavement type using advantages of both flexibility of asphalt pavement and rigidity of concrete pavement by infiltrating cement paste into voids of open graded asphalt mixtures. The semi rigid pavement has better smoothness and smaller driving vibration or noise comparing to the concrete pavement, and has smaller permanent deformation and has temperature falling effect comparing to the asphalt pavement. The temperature falling effect were investigated at a semi rigid overlay pavement test section, and the temperature falling and water retaining effects were verified by measuring the temperature and weight of specimens at a housetop. Horizontal and vertical stresses and strains were compared by structural analysis of the semi rigid pavement and asphalt pavement using the Abaquser o, a commercial 3D finite element analysis program. The results were verified by Bisar 3.0, a multi-layered elastic analysis program. Performance of the semi rigid pavement and asphalt pavement were compared by predicting fatigue cracking based on the structural analysis results.

Development of Special Purpose Computer Program for the Analysis of Car Interior Noise (자동차 차실소음 해석을 위한 전용 프로그램의 개발)

  • 박동철;강연준;이장무;김석현;김중희
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1991.04a
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    • pp.57-61
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    • 1991
  • 최근 차량의 고급화에 따라 차실 소음 저감에 대한 연구가 많이 수행되고 있다. 차실의 소음은 주로 엔진 또는 동력전달 장치의 진동과 도로의 요철로 생기는 차체의 진동으로부터 발생된다. 차실에서 20-200Hz의 저주파수대의 소음은 주로 차체 진동과의 연성 효과로 기인한다. 따라서 이 주파수영역에 있어서 소음의 특성을 파악하기 위해서는 차실의 음향 모우드 해석과 차체 구조물의 진동과 차실 음향 모우드의 상호관계를 고려한 구조-음향 연성 해 석이 필요하다. 차실의 음향 모우드 해석을 위해서는 실험적 방법과 유한 요 소법을 이용하는 방법이 있다. 유한 요소법을 이용하여 음향 특성을 결정하 는 경우, 큰 어려움은 없으나 밀폐된 공동에서 경계면을 이루는 구조물의 진 동에 의해 음이 발생되는 경우 단순히 공간의 음향 특성만으로는 음향 응답 을 예측할 수 없게 된다. 즉, 경계면에서 반사되는 반사파는 경계면의 탄성 변위에 의해 운동 특성이 변화되어 반사되므로 입사파와 다른 특성을 가지 게 된다. 따라서 이러한 구조 진동 특성과 음향 특성을 모두 고려한 연성 해 석을 수행하여야 하며, 음향 모우드와 구조 진동 모우드와의 연성에 의한 음 향 응답 특성을 결정하기 위한 수치 해석 프로그램을 개발하게 되었다. 본 연구에서는 전.후 처리 및 사용자 편의성을 염두에 두고 차실소음해석 전용 프로그램(ACSTAP: Acoustical and structural, coupling analysis program) 을 작성하고 이를 실차에 적용하여 유용성을 보였다.

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A Cogging Torque Reduction Method for Interior Permanent Magnet Synchronous Motor Considering Radial Flux Density (Radial Flux Density를 고려한 매입형 영구자석 동기전동기 코깅토크 저감 방법)

  • Park, Kyung-Soo;Lee, Jin hwan;Han, Wonseok;Kim, Yong-Jae;Jung, Sang-Yong
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.790-791
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    • 2015
  • 본 논문에서는 Radial flux density($B_r$)를 고려하여 매입형 영구자석 동기 전동기(Interior Permanent Magnet Synchronous Motor, IPMSM)에서 진동, 소음 발생의 원인이 되는 코깅토크를 최적화하는 방법을 제시한다. Maxwell Stress Method에 의하면 토크는 $B_r$에 비례한다. 따라서 $B_r$과 토크의 상관관계를 이용하여 코깅토크를 저감시켰다. 코깅토크가 가장 큰 회전자의 위치에서 회전자 표면의 $B_r$을 확인한 후 에 노치(Notch)를 적용할 위치를 선정하였다. 그리고 제안한 방법이 매입형 영구자석 동기 전동기 모델에서 효과적으로 코깅토크를 저감시키는 것을 유한요소법을 통해 검증하였다.

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A Study on the Design of PLHBM (선대구경 수평보링 발파공법(PLHBM)의 설계 연구)

  • Beak, Jong-Hyun;Beak, Sang-Hyun;Han, Dong-Hun;Won, Ah-Ram;Kim, Chang-Seop
    • Explosives and Blasting
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    • v.30 no.2
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    • pp.66-76
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    • 2012
  • Blasting technology aims to maximize digging efficiency as well as minimize vibration and noise. So, it is key point of blasting technology to raise blasting effect as much as possible and reduce vibration and noise and the design of PLHBM that is the tunnel blasting method having such merit was studied in this paper. PLHBM has the excellent blasting efficiency as it drills the empty hole with high caliber of 250~1,000mm at centre cut, contributes to blasting vibration reduction effect much and can be usefully applied to tunnel blasting sites. So it is judged that it enables the development of tunnel blasting method to be advanced one more step by studying and suggesting the design method of PLHBM.

Real-time Feedback Vibration Control of Structures Using Wireless Acceleration Sensor System - System Design and Basic Performance Evaluation - (무선 가속도센서 시스템을 이용한 건축물의 실시간 피드백 진동제어 - 시스템 구축 및 기초성능 평가 -)

  • Jeon, Joon Ryong;Park, Ki Tae;Lee, Chin Ok;Heo, Gwang Hee;Lee, Woo Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.21-32
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    • 2013
  • This is a preliminary study for the real-time feedback vibration control of building structures. The study developed a wireless acceleration sensor system based on authentic technology capacities, to integrate with the Prototype AMD system and ultimately construct the feedback vibration control system. These systems were used to evaluate the basic performance levels of the control systems within model building structures. For this purpose, the study first developed a wireless acceleration sensor unit that integrates an MEMS sensor device and bluetooth communication module. Also, the study developed an operating program that enables control output based on real-time acceleration response measurement and control law. Furthermore, the Prototype AMD and motor driver system were constructed to be maneuvered by the AC servo-motor. Eventually, all these compositions were used to evaluate the real-time feedback vibration control system of a 2-story model building, and qualitatively measure the extent of vibrational reduction of the target structure within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within the laboratory validation tests. As a result of the tests, there was a definite vibrational reduction effect within 1st and 2nd resonance frequency as well as the random frequency of the model building structure. Ultimately, this study confirmed the potential of its wireless acceleration sensor system and AMD system as an effective tool that can be applied to the active vibration control of other structures.

Performance Evaluation of Vibration Control According to Installation Location of a Sky-bridge (스카이브릿지 설치위치에 따른 고층건물의 진동제어 성능평가)

  • Kim, Hyun-Su;Park, Yong-Koo;Ko, Hyun;Lee, Ui-Hyun;Lee, Dong-Guen
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.3
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    • pp.65-74
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    • 2010
  • In this study, the vibration control effect according to the installation location of the sky-bridge and the difference of natural periods of the connected buildings has been investigated. To this end, 40-story and 50-story building structures connected by a sky-bridge were used as example structures and the equivalent modeling method was used. Boundary nonlinear time history analyses were performed using El Centro and Taft earthquakes to investigate the dynamic behavior of the example structures and vibration control effect of the sky-bridge. Based on numerical results, it has been shown that displacement responses can be effectively controlled as the installation floor of the sky-bridge increases and acceleration responses can be effectively reduced when the sky-bridge is installed on the mid-stories of the example building.

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A Study on the Noise and Vibration Damping Performance of RC Hollow Core Slab (중공형 RC 슬래브의 소음 및 진동 감쇠성능에 대한 연구)

  • Kim, Dong Baek;Kim, In Bae;Kim, Jong Hoon;Lee, Jae Won
    • Journal of the Society of Disaster Information
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    • v.15 no.2
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    • pp.292-300
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    • 2019
  • Purpose: To reduce the noise and vibration of reinforced concrete slab structures, the damping performance is to be performed experimentally after installing hollow core or filling it with liquid. Method: Using the hollow rate as an experimental variable, the damping ratio and stiffness of each test specimen at impact load are obtained to determine the difference between the damping ratio and stiffness of the numerical analysis. In addition, the damping effects are reviewed by comparing the difference in the damping ratio and stiffness of a test specimen filled with liquid 50% of the study. Results: Since the difference in resistance between a specimen with or without hollow core is 5%, it is judged that there is no structural problem, and the injection of liquid into the hollow core can increase the damping ratio, which can reduce noise or vibration. Conclusion: At less than 20% of hollow rate, there was little damping effect, and at 30%, damping effect was found. However, if liquid is injected into the hollow core of the specimen, damping rate is shown to increase, and the injection of liquid into the hollow part is believed to reduce noise or vibration.