• Title, Summary, Keyword: Free vibration

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Free Vibration Analysis of the Cantilevered Circular Cylindrical Shells Combined with Circular Plates at Axial Positions (원판이 결합된 외팔 원통셸의 고유진동 특성)

  • 임정식;이영신;손동성
    • Journal of KSNVE
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    • v.7 no.2
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    • pp.331-345
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    • 1997
  • A theoretical formulation for the analysis of free vibration of clamped-free cylindrical shells with plates attached at arbitrary axial position(s) was completed and it was programed to get the numerical results which yield natural frequencies and mode shape of the combined system of the plate and the shells. The frequencies and mode shapes from theoretical calculation were compared with those of commercial finite element code, ANSYS. In order to validate the theory, modal test was also performed by impact test and FFT analysis. The results shows good agreement with those of ANSYS and test results in frequencies and mode shapes. The method developed herein is likely to be used for the analysis of the free vibration of the clamped-free circular cylindrical shells with any kinds of lids such as hollow circular plates, conical shells, spherical shells, or semi-spherical shells.

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Free Vibrations of Hinged-Hinged Arches with Constant Arc Length (일정한 곡선길이를 갖는 양단회전 아치의 자유진동)

  • Lee, Byoung-Koo;Lee, Tae-Eun;Kim, Gwon-Sik;Yoon, Hee-Min
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.46-49
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    • 2008
  • This paper deals with the free vibrations of elastica shaped arches with constant arc length. The elastica shaped arches are formed by the post-buckled column whose arc length is always constant. The equations governing free, in-plane vibration of general arch in open literature are modified for applying the free vibrations of elastica shaped arch and solved numerically to obtain frequencies and mode shapes for hinged-hinged end constraints. The effects of rotatory inertia, rise to span length ratio and slenderness ratio on natural frequencies are presented. The frequencies of elastica and parabolic shaped arches are compared. Also, typical mode shapes are presented in figures.

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Numerical analysis for free vibration of functionally graded beams using an original HSDBT

  • Sahouane, Abdelkader;Hadji, Lazreg;Bourada, Mohamed
    • Earthquakes and Structures
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    • v.17 no.1
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    • pp.31-37
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    • 2019
  • This work presents a free vibration analysis of functionally graded beams by employing an original high order shear deformation theory (HSDBT). This theory use only three unknowns, but it satisfies the stress free boundary conditions on the top and bottom surfaces of the beam without requiring any shear correction factors. The mechanical properties of the beam are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. In order to investigate the free vibration response, the equations of motion for the dynamic analysis are determined via the Hamilton's principle. The Navier solution technique is adopted to derive analytical solutions for simply supported beams. The accuracy and effectiveness of proposed model are verified by comparison with previous research.

Vibration Control of Tower Structure under Wind Load (풍하중에 의한 타원형 구조물의 진동 제어)

  • Hwang Jae-Seung;Kim Yun-Seok;Joo Seok-Jun
    • Proceedings of the KSME Conference
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    • pp.427-430
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    • 2002
  • The present parer outlines the system identification and vibration control performance of air traffic control tower of Yangyang international airport with tuned mass damper(TMD). From the free vibration test, natural frequency, damping ratio and mode shape of tower are obtained and these values are compared with the values from numerical analysis. In the vibration control test to evaluate the vibration control performance, equivalent damping ratio increased by tuned mass damper are obtained in case the TMD is operated as passive mode. Damping ratio of tower evaluated from free vibration test is about $1.0{\%}$. It is very low value than damping ratio recommended in general code. Damping ratio of passive mode is about $5{\%}$. These equivalent damping ratio increased by TMD is enough to enhance the serviceability of tower structure under wind load.

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A State of the Art on a Noise & Vibration - Free PHC Screw Pile Method (무소음.무진동 스크류 PHC 말뚝공법에 관한 기술적 수준 고찰)

  • Ha, Young-Min;Jung, Ho-Young;Kim, Young-Pil;Kim, Sung-Su;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.496-506
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    • 2009
  • Various the low noise & vibration pile methods were developed and used in many construction sites. Low noise & vibration pile methods must be used essentially from the sites where popular complints would be expected. In this paper, low noise & vibration pile methods and screw pile methods were investigated, noise & vibration-free screw PHC pile method, also, was studied and its constructibility and applicability were analyzed.

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Development of a Framework for Improving Efficiency of Ship Vibration Analysis (선박 전선 진동해석 효율성 향상을 위한 프레임워크 개발)

  • Cho, Dae-Seung;Kim, Jin-Hyeong;Choi, Tae-Muk;Kim, Kyung-Soo;Choi, Sung-Won;Jung, Tae-Seok;Lee, Do-Kyung;Seok, Ho-Il
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.779-784
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    • 2011
  • Free and forced vibration analysis of the global ship structure using the 3-dimensional finite element(FE) method requires not only the specialized knowledge such as ship structure interacted with fluid, damping and various excitations due to propulsion system but also time-consuming manual tasks in FE modeling, analysis and response evaluation. As a result, the quality of the vibration analysis highly depends on engineer's expertise and experience. In this study, a framework system to improve the efficiency of global ship vibration analysis is introduced. The system promising the utilization of MSC/Patran and MSC/Nastran consists of various modules to support data management, FE modeling of ship structure and loading, input deck generation for free and forced vibration analysis, data extraction and evaluation of analysis results, and databases for FE models of marine diesel engines and vibration criteria. The system may be useful for pursuing standardization of uncertain analysis factors as well as reducing time, cost and human dependency in ship vibration analysis.

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A Study on the Cutting and Vibration Characteristic of Ultrasonic Vibration Cutting (초음파 진동선삭에서의 절삭 및 진동특성에 관한 연구)

  • 이규배;임영호;이계철
    • Journal of KSNVE
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    • v.4 no.2
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    • pp.147-154
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    • 1994
  • In this study, ultransonic vibration cutting system was contructed by installing throw-away-tool tip (KT 350) by screw lock on the bending vibration mode in free-free beam. During the conventional cutting and ultransonic conventional cutting of SM45C, variations of cutting force, roughness and acceleration were measured. The results were compared and analyzed in detail, and it was found that the ultransonic vibration cutting was more effective in reducing cutting force compareed with the conventional cutting .

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Free Vibration Analysis of Simply-Supported Rectangular Plate with a Circular Cutout by Independent Coordinate Coupling Method (독립좌표연성법을 이용한 원형 구멍을 갖는 단순지지 직사각형 평판의 자유진동해석)

  • Kwak, Moon-K.;Han, Sang-Bo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1177-1182
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    • 2006
  • This paper is concerned with the vibration analysis of a simply-supported rectangular plate with a circular cutout. Even though there have be en many methods developed for the free vibration of the rectangular plate with a rectangular cutout., very few research has been carried out for the rectangular plate with a circular cutout. In this paper, a new methodology called independent coordinate coupling method, which was developed to save the computational effort for the free vibration analysis of rectangular plate with a rectangular cutout, is applied to the case of circular cutout. The independent coordinate coupling method employs the global coordinate system for the plate and the local coordinate system for the cutout. In the case of the rectangular plate with a circular cutout, the global coordinate system is the Cartesian co ordinate system and the local coordinate system is the polar coordinate system. By imposing the compatibility condition, the relationship between the global coordinates and the local coordinates is derived. This equation is then used for the calculation of the mass and stiffness matrices resulting in eigenvalue problem. The numerical results show the efficacy of the proposed method.

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Free Vibration Analysis of Simply-supported Rectangular Plate with a Circular Cutout by Independent Coordinate Coupling Method (독립좌표연성법을 이용한 원형 구멍을 갖는 단순지지 직사각형 평판의 자유진동해석)

  • Kwak, Moon-K.;Han, Sang-Bo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.6
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    • pp.643-650
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    • 2006
  • This paper is concerned with the vibration analysis of a simply-supported rectangular plate with a circular cutout. Even though there have been many methods developed for the free vibration of the rectangular plate with a rectangular cutout, very few research has been carried out for the rectangular plate with a circular cutout. In this paper, a new methodology called independent coordinate coupling method, which was developed to save the computational effort for the free vibration analysis of rectangular plate with a rectangular cutout, is applied to the case of circular cutout. The independent coordinate coupling method employs the global coordinate system for the plate and the local coordinate system for the cutout. In the case of the rectangular plate with a circular cutout, the global coordinate system is the Cartesian coordinate system and the local coordinate system is the polar coordinate system. By imposing the compatibility condition, the relationship between the global coordinates and the local coordinates is derived. This equation is then used for the calculation of the mass and stiffness matrices resulting in eigenvalue problem. The numerical results show the efficacy of the proposed method.

Model Updating of Plate with Shape Change Using Parameter Modification (진동 파라미터 수정을 사용한 형상변화가 있는 판의 모델개선)

  • 최유근;김옥구;윤병옥;장인식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1260-1265
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    • 2001
  • It is important to model the mechanical structure precisely and reasonably in predicting the dynamic characteristics, controlling the vibration, and designing the structural dynamics. In the finite element modeling, the errors can be contained from the physical parameters, the approximation of the boundary conditions, and the element modeling, From the dynamic test. more precise dynamic characteristics can be obtained. Model updating using parameter modification is appropriate when the design parameter is used to analyze the input parameter like finite element method. Finite element analysis for free-free-free-free(FFFF) and clamped-free-free-free(CFFF) plate with uniform area and shape change are carried out as model updating examples, Mass and stiffness matrices are updated by comparing test and analytical modal frequencies. The result shows that the updated frequencies become closer to the test frequencies.

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