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  • Title/Summary/Keyword: 수치진동

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강체거동을 하는 플로팅구조물의 진동제어

  • Hwang, Jae-Seung;Park, Seong-Cheol;Jeong, Gi-Beom;Choe, Jun-Seong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2012.06a
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    • pp.425-427
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    • 2012
  • 본 연구에서는 플로팅 구조물과 제진장치가 연계된 시스템에 대한 진동제어를 위하여 제어알고리듬에 의한 시뮬레이션을 수행하였다. 플로팅 구조물모형 2자유도, AMD 제진장치 2자유도가 연계된 4자유도 시스템에 대한 수학적 해석모형을 모델링하였으며, 모델링을 통하여 모형과 제진장치의 계측변수, 그에 따른 시스템의 입축력 관계에 따른 상태방정식을 제어 프로세서 과정에서 모듈화 하였으며 수치시뮬레이션을 통한 제어효과를 검증하였다. 향후 플로팅 모형 실험체를 제작하여 수조실험을 통한 실험적 검증을 수행할 예정이다.

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In-Plane Extensional Vibration Analysis of Curved Beams using DQM (미분구적법을 이용한 곡선보의 태평면 진동분석)

  • Kang, Ki-Jun;Kim, Byeong-Sam
    • Journal of the Korean Society of Safety
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    • v.17 no.1
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    • pp.99-104
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    • 2002
  • DQM(differential quadrature method) is applied to computation of eigenvalues of the equations of motion governing the free in-plane vibration for circular curved beams including mid-surface extension and the effects of rotatory inertia. Fundamental frequencies are calculated for the members with various end conditions and opening angles. The results are compared with numerical solutions by other methods for cases in which they are available. The differential quadrature method gives good accuracy even when only a limited number of grid points is used.

Estimation of Structural Damages by Inverse Modal Perturbation Method (구조물 손상의 추정을 위한 Inverse Modal Perturbation 기법)

  • Min, Jin Ki;Kim, Hyeong Ki;Hong, Kyu Seon;Yun, Chung Bang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.4
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    • pp.35-42
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    • 1990
  • A method for the damage assessment of a structure by an inverse modal perturbation technique is studied. The first few natural frequencies and mode shapes of the damaged structure are assumed to be known. Then, the perturbation equation is formulated for the changes of the modal properties due to the stiffness changes. The stiffness changes due to damages are evaluated, using optimization techniques. Example analyses are carried out for several cases of stick models and a truss model. Results indicate that the present method yields very reasonable estimates for the element stiffness changes.

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In-Plane Vibration Analysis of Asymmetric Curved Beams Using DQM (DQM을 이용한 비대칭 곡선보의 내평면 진동해석)

  • Kang, Ki-Jun;Kim, Young-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.8
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    • pp.2734-2740
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    • 2010
  • The free in-plane vibration of asymmetric circular curved beams with varying cross-section is analyzed by the differential quadrature method (DQM) neglecting transverse shearing deformation. Natural frequencies are calculated for the beams with various opening angles and boundary conditions. Results obtained by the DQM are compared with available results by other methods in the literature. It is found that the DQM gives the good accuracy even with a small number of grid points.

Research on a Reduction of Automotive Vibration using Impact Dampers (충돌 댐퍼를 이용한 자동차의 진동 저감 연구)

  • Yang, Wonseok
    • Journal of Institute of Convergence Technology
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    • v.9 no.1
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    • pp.21-24
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    • 2019
  • This research presents an development of impact damper for reduction of vehicle vibration from road excitation. The structural vibrations are transferred through the vehicle body. The impact damper for reducing structural vibration from road excitation were designed and derived by using simplified numerical model. To analyze the characteristics of the impact damper, the vibration of simplified beam attached to impact damper was simulated. The damping ratios for different mass ratios of the impact dampers were calculated. The numerical results can be utilized to reduce the radiated noise from the electric vehicle.

A Study on Traffic-Induced Vibration of Steel Girder-Bridge by Three-Dimensional Vehicle Model on Random Road Profile (불규칙 노면을 고려한 3차원 자동차 모델에 의한 강교의 동적 응답에 관한 연구)

  • Kim, Chul Woo;Kawatani, Mitsuo;Lee, Woo Hyun
    • Journal of Korean Society of Steel Construction
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    • v.9 no.1 s.30
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    • pp.23-36
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    • 1997
  • 교량(橋梁)의 동적응답(動的應答)을 파악하기 위해서는 노면(路面)조도에 의해 영향을 받는 차량의 거동 파악이 중요하게 된다. 최근, 교량의 상판(床版)등에서 발생되는 피로(疲勞)의 영향에 대한 관심이 고조되어 서서히 교통진동의 3차원 모델링에 대한 중요성이 대두되고 있다. 이에 본 연구에서는 교량에 발생되는 교통진동(交通振動)의 영향을 좀더 정확히 표현하기 위하여 3차원 해석 방법을 제시한다. 해석방법으로 유한 요소법이 이용되었고, 차량 모델링은 하나의 전축(煎軸)과 두 개의 후축(後軸)을 갖는 8자유도계(自由度系) 차량 모델을 이용하여 수치 시뮬레이션을 수행하였다. 동적(動的) 연립미분방정식(聯立微分方程式)의 해법에서는 Newmark-β법(法)을 이용하였고, 가상 노면요철(凹凸)모델링에서는 정상불규칙과정(定常不規則過程)으로 가정하여 노면 요철(凹凸)을 생성하여 시뮬레이션에 사용하였다. 또한 실제 차량 및 교량에서의 실측치와 비교하여 모델의 검증을 수행하였다.

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Natural Frequency Analysis of Arch by Galerkin's Method (갤러킨법을 이용한 아치의 고유진동해석)

  • Jung, Chan-Woo;Seok, Keun-Yung;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.4
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    • pp.55-61
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    • 2007
  • Recently, with the development of computer, FEM has became the most frequently used numerical analysis method. FEM shows great ability in structures analysis, however, Galerkin's Method is more useful in grasping influence or the tendency of parameter which forms the structure. This paper perform the eigenvalue analysis using Galerkin's Method which is advantageous in grasping the influence and the tendency of parameter which forms the structure and study on the influence of parameter that forms arch on natural frequency response.

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Using Numerical Solutions of the Vibration Measurement Accelerometers attached Vibration Isolator (수치 해법을 이용하여 제진대에 부착된 가속도 센서의 진동 측정)

  • Shin, Dong-Ho;Lee, Jung-Woo;Lee, Jong-Won;Oh, Jae-Eung;Lee, Jung-Youn
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.875-880
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    • 2012
  • According to the fixation detailed drawing and lightweight anger tendency of the product the vibration control of precision equipments is essential and establishes under the equipments. so It is important to know vibration characteristics of vibration isolator. For this reason the accelerometer attaches in vibration isolator and measures an acceleration response. The acceleration response which is measured will lead double integral and will be able to predict a displacement of vibration isolator. However, in compliance with the effect of the accelerometer can not be accurately. From this paper, mass, damping ratio and natural frequency of the accelerometers by changing the vibration isolator to predict the acceleration response and the results were compared.

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An Analysis of Forced Vibration Response of a Cantilever Beam with a Dry Friction Damper (건마찰 감쇠기가 부착된 외팔보의 강제진동 응답 해석)

  • Go, Young-Jun;Kang, Byoung-Yong;Chang, Ho-Gyeong;Kim, Ye-Hyun
    • The Journal of the Acoustical Society of Korea
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    • v.15 no.2
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    • pp.33-39
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    • 1996
  • A theoretical study of the forced vibration response of a cantilevered beam with non-linear dry friction damping is analyzed by various slip displacements and force levels for the position coordinates of spring-mass-damper and external exciting force. A component mode analysis is carried out based on the constraint conditions and Lagrange multipliers to treat physical systems with non-linear damping. The analysis has shown that the basic phenomena observed for a simply supported beam with a dry friction damper attached are also observed for cantilevered beam.

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Numerical Analysis of Hydrodynamic mass for various Tube Arrays in a circular cylindrical shell (원통 내부의 전열관 배열에 따른 유체부가질량특성 수치해석)

  • Yang, Keum-Hee;Ryu, Ki-Wahn;Park, Chi-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.693-699
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    • 2011
  • The outermost SG tubes have more structural problems than inside tubes. Many studies have used a uniform added mass coefficient for all of the SG tubes during the FIV analysis. The purpose of this study is to find out the added mass coefficients for each tube in a cylindrical shell. When a number of tubes are increased, added mass coefficients are also increased. And added mass coefficients at outermost tubes are less than those of inside tubes. According to gap changes between outermost tube and cylindrical shell, added mass coefficients are decreased with increasing the gap. When the gap has very large value, it shows that the added mass coefficient is asymptotically converged to the value of the tube array in a free fluid field.

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