• Title, Summary, Keyword: Flexural Vibration Damping

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Vibration Control of Laminated Composite Beams using Active Constrained Layer Damping Treatment (능동구속감쇠 기법을 이용한 복합적층보의 진동제어)

  • Kang, Young-Kyu;Kim, Jae-Hwan;Choi, Seung-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1333-1337
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    • 2000
  • The flexural vibration of laminated composite beams with active and passive constrained-layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations with active control.

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Vibration Characteristics of Laminated Composite Beams with Passive Constrained Layer Damping (수동 구속감쇠층을 갖는 복합적층보의 진동특성)

  • Kang, Young-Kyu
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.12
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    • pp.964-969
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    • 2002
  • The flexural vibration of laminated composite beams with passive constrained layer damping has been investigated to design structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, multi-layer laminated beams. The damping ratio and modal damping of the first bending mode are calculated by means of Iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations.

Vibration Control of Laminated Composite Beams Using Active Constrained Layer Damping Treatment (능동구속감쇠 기법을 이용한 복합적층보의 진동 제어)

  • 강영규;최승복
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.7
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    • pp.261-266
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    • 2001
  • The flexural vibration of laminated composite beams with active and passive constrained layer damping has been investigated to design a structure with maximum possible damping capacity. The equations of motion are derived fro flexural vibrations of symmetrical,. multi-layer laminated beams. The damping ratio and model damping of the first bending mode are calculated by means of iterative complex eigensolution method. The direct negative velocity feedback control is used for the active constrained layer damping. It is shown that the flexible laminated beam is more effective in the vibration control for both active and passive constrained layer damping. and this paper addresses a design strategy of laminated composite under flexural vibrations with constrained layer damping.

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A Study on the Characteristics of Vibration Damping of a Beam with Inserted Viscoelastic Layer (점탄성층을 삽입한 3층 적층보의 진동감쇠특성에 관한 연구)

  • 박응순;박세만;박명균;박상규
    • Journal of KSNVE
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    • v.7 no.3
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    • pp.511-519
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    • 1997
  • For a number of years it has been known that flexural vibration in a beam and plate can be damped by the application of layer of damping (viscoelastic) material that is in turn constrained by a backing layer or foil. In this study, a quantitative analysis of damping of the sandwich beam has been performed by using impact test. The damping is characterized by the loss factor .etha. in which the damping is normalized by imaginary part of the complex bending stiffiness of the beam. Results show that the relative thickness of the sandwich beam gives more effect on the riatural-frequencies and loss factor than the variation of width does. It is also shown that the Ross-Kerwin-Ungar equation and impact test can be effectively used to identify the damping characteristic of the sandwich beam and viscoelastic material.

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Modal Damping of the Flexural Vibration of a Sandwich Beam with Partially Inserted Viscoelastic Layer (점탄성층이 부분적으로 삽입된 샌드위치보의 횡진동모드별 감쇠특성)

  • 박진택;최낙삼
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.224-227
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    • 2000
  • Modal damping characteristics of the flexural vibration of a sandwich beam with paaially inserted viscoelastic layer have been quantitatively studied using the finite element analysis in combination with an experiment. Antisymmetric mode shapes of the flexural vibration were visualized by the holographic interferometry and agreed with those calculated by the finite element simulation. Effects of the length and thickness of partial viscoelastic layers on the system loss factor($\mu$) and resonant frequency($\omega$) were considerably latge at both symmetric and antisymmetric modes of the sandwich beam.

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Hybrid Vibration Control of Smart Laminated Composite Beams using Piezoelectric and Viscoelastic Material

  • Kang, Young-Kyu
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.1
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    • pp.37-42
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    • 2003
  • Active control of flexural vibrations of smart laminated composite beams has been carried out using piezoceramic sensor/actuator and viscoelastic material. The beams with passive constrained layer damping have been analyzed by formulating the equations of motion through the use of extended Hamilton's principle. The dynamic characteristics such as damping ratio and modal damping of the beam are calculated for various fiber orientations by means of iterative complex eigensolution method. This paper addresses a design strategy of laminated composite under flexural vibrations to design structure with maximum possible damping capacity.

Vibration Control Characteristics of Laminated Composite ER Beams with Electric Field Dependence (전기장에 따른 복합재 ER Beam의 진동제어 특성)

  • 김재환;강영규;최승복
    • Journal of KSNVE
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    • v.11 no.3
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    • pp.416-421
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    • 2001
  • The flexural vibration of laminated composite beams with an electro-rheological(ER) fluid has been investigated to design a structure with maximum possible damping capacity. The equations of motion are derived for flexural vibrations of symmetrical, mu1ti-layer laminated beams. The damping radio and modal damping of the first bending mode are calculated by means of iterative complex eigensolution method. Finite element method is used for the analysis of dynamic characteristics of the laminated composite beams with an ER fluid. For the validation of modeling methodology using viscoelastic theory the predicted dynamic properties are compared to the measured ones by author's previous work. They are in good agreement. This paper addresses a design strategy of laminated composite under flexural vibrations with an ER fluid.

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Behavior of the Flexural Vibration Damping of a Sandwich Beam System with a Partially Inserted Viscoelastic Layer (점탄성층이 부분적으로 삽입된 샌드위치보의 횡진동 감쇠특성)

  • Park, Jin-Taek;Yu, Hyeong-Won;Jang, Seok-Won;Choe, Nak-Sam
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.2
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    • pp.225-233
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    • 2002
  • The flexural vibration characteristics of a sandwich beam system with a partially inserted viscoelastic layer have been quantitatively studied using a finite element analysis in combination with a sine-sweep test. Antisymmetric mode shapes of the flexural vibration were visualized by the holographic interferometry and agreed with those calculated by the finite element simulation. Effects of the beam thickness as well as the length and thickness of partial viscoelastic layers on the system loss factor(η$\_$s/) and resonant frequency($\omega$$\_$r/) were significantly large fur the symmetric and antisymmetric modes of the beam system.

Impact Echo Test for the Dynamic Characteristics of a Vibration-Mitigated Concrete Structure

  • Chung, Young-Soo;Park, Young-Goo
    • KCI Concrete Journal
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    • v.14 no.1
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    • pp.23-29
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    • 2002
  • Recent construction activities have given rise to civil petitions associated with vibration-induced damages or nuisances. To mitigate unfavorable effects of construction activities, the measures to reduce or isolate from vibration need to be adopted. In this research, a vibration-mitigated concrete, which is one of the active measures for reducing vibration in concrete structures, was investigated. Concrete was mixed with vibration-reducing materials (i.e. latex, rubber power, plastic resin, and polystyrofoam) to reduce vibration and tested to evaluate dynamic material properties and structural characteristics. Normal and high strength concrete specimens with a certain level of damage were also tested for comparisons. In addition, recycling tires and plastic materials were added to produce a vibration-reducing concrete. A total of 32 concrete bars and eight concrete beams were tested to investigate the dynamic material properties and structural characteristics. Wave measurements on concrete bars showed that vibration-mitigated concrete has larger material damping ratio than normal or high strength concrete. Styrofoam turned out to be the most effective vibration-reducing mixture. Flexural vibration tests on eight flexural concrete beams also revealed that material damping ratio of the concrete beams is much smaller than structural damping ratio for all the cases.

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Placement of Passive Constrained Layer Damping for Vibration Control of Smart Plate (지능판의 진동제어를 위한 수동구속감쇠의 위치 설정)

  • Kang, Young-Kyu;Kim, Chan-Mook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.310.1-310
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    • 2002
  • Dynamic characteristics of smart laminated composite plates with passive constrained layer damping have been investigated to design structure with maximum possible damping capacity. The equations of motion are derived fur flexural vibrations of symmetrical, multi-layer laminated plates. The damping ratio and modal damping of the first bending and torsional modes are calculated by means of iterative complex eigensolution method. (omitted)

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