• Title/Summary/Keyword: Composite Noise

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Thermally Induced Vibration Control of Flexible Spacecraft Appendages Using by Piezoelectric Material (압전재료를 이용한 위성체 구조물의 열 진동 제어)

  • 윤일성;송오섭;김규선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.303-310
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    • 2002
  • The bending vibration and thermal flutter instability of spacecraft booms modeled as circular thin-walled beams of closed cross-section and subjected to thermal radiation loading is investigated in this paper. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferantially uniform system(CUS) configuration are exploited in connection with the structural flapwise bending-lagwise bending coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. The numerical simulations display deflection time-history as a function of the ply-angle of fibers of the composite materials, damping factor, incident angle of solar heat flux, as well as the boundary of the thermal flutter instability domain. The adaptive control are provided by a system of piezoelectric devices whose sensing and actuating functions are combined and that an bonded or embedded into the host structure.

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Forced Vibration Analysis of Damped Composite Beam (복합단면 감쇠보의 강제진동해석)

  • Won, Sung-Gyu;Jung, Weui-Bong;Bae, Soo-Ryong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.411-414
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    • 2006
  • In this paper, the forced vibration of damped composite beam with arbitrary section was analyzed. The damping material was assumed to have either complex shear modulus or complex Young???smodulus. Damped composite beam could be modeled using beam elements with less D.O.F. rather than solid elements. Finite element method for these methods was formulated and programmed using complex values. The results of frequency responses revealed good agreement with those of NASTRAN in several beam structures.

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A Numerical Analysis on the Vibration Characteristics of Rotating Composite Blades (회전하는 복합재료 블레이드의 진동특성에 대한 수치해석)

  • Kee, Young-Jung;Song, Keun-Woong;Kim, Deog-Kwan;Shim, Jeong-Wook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.300-303
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    • 2006
  • The rotor blade of a helicopter is the key structural units and provides three components such as vertical lifting force, horizontal propulsive force and control force. With advancements in aerospace technology, composite materials have been widely used in lightweight structures. In addition, composites show great potential on the design of rotor blades due to the advantages of strength, durability and weight of the materials. In the operational condition of a helicopter, it is required the vibration characteristics of the rotating blades for avoiding resonance and analysis of efficient performance prediction et al. In this study, the CAMRAD-II is used for analyzing the vibration characteristics of rotating composite blades. The effects of rotating speed and collective angles are investigated. Also, the numerical results are compared with experimental data.

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Vibration Analysis of Rotating Laminated Composite Disks (복합적층 회전원판의 진동 해석)

  • Koo, Kyo-Nam
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.854-857
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    • 2006
  • The centrifugal terce acting on a rotating disk creates the in-plane loads in radial and circumferential directions. Application of fiber reinforced composite materials to the relating disk can satisfy the demand for the increment of its rotating speed. However, the existing researches have been confined to lamina disks. This paper deals with the vibration analysis of rotating composite laminate disks. Dynamic equation is formulated in order to calculate the natural frequency and critical speed for rotating laminated disks. Galerkin's method is applied to obtain the series solution. The numerical results are given for the CFRP laminate disks with stacking sequence [0/90]s and [90/0]s.

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Vibration Analysis of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields with Different Boundary Conditions (경계조건에 따른 자기장 및 열하중을 받는 복합재료 원통셸의 진동해석)

  • Park, Sang-Yun;Kim, Sung-Kyun;Choi, Jong-Woon;Song, Ohseop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.653-660
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    • 2012
  • In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT with two different boundary conditions(C-C, S-S) was performed through discretization of equations of motion and boundary condition. Model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence for each boundary conditions are investigated and pertinent conclusions are derived.

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The Effect of Pyro Shock on Canister with Composite Sandwich Panel (복합재 샌드위치 패널 발사관의 폭발충격 영향도 분석)

  • Choi, Wonhong
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.6_spc
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    • pp.667-673
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    • 2016
  • Canister with composite sandwich panel has been suggested owing to its higher stiffness and strength over a weight for square shaped canisters. The pyro shock induced by a short time explosion inside a canister is generally considered to be the most severe source of load affecting on the entire structure. Therefore, in this study, the approach and modeling method to identify the effect of pyro shock on canister with composite sandwich panel in a numerical way were mainly discussed. Moreover, the verification was implemented through comparison with test results.

Optimal Ply Design of Laminated Composite Plate with a Hole Considering Vibration (진동을 고려한 원공복합적층판의 최적적층설계)

  • 홍도관;김동영;최경호;안찬우
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.6
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    • pp.423-429
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    • 2003
  • On this study. we improved the efficiency applying algorithm that is repeatedly using table of orthogonal array in discrete design space and filling a defect of gradient method in continuous design space. we showed optimal ply angle that maximized 1st natural frequency of CFRP laminated composite plate without a hole and with a hole by each aspect ratio. In the case of CFRP laminated composite plate without a hole, we confirmed the reliance and efficiency of algorithm in comparison with the result of optimization achievement repeatedly using statistical table of orthogonal array of experimental design and the BFGS optimal design method.

Vibration Analysis and Critical Speeds of Rotating Polar Orthoropic Disks (극직교 이방성 회전원판의 진동특성 및 임계속도)

  • Koo, Kyo-Nam;Han, Jae-Heung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.337-340
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    • 2005
  • Rotating annular disks are widely used in data storage devices such as CDs, DVDs(digital versatile disks), and HDs(hard disks). Higher data transfer rate in data storage disks could not be achieved by polycarbonate disks in the present market. The problem can be solved by applying the fiber-reinforce composite materials to the disks. In this paper, an application of composite materials to rotating disks is proposed to increase the critical speed. Dynamic equation is formulated in order to calculate the natural frequency and critical speed for rotating composite by the Galerkin method. The results show that the radially reinforced disk is more effective in increasing critical speed than the circumferentially reinforced disk.

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Active Control of Forced Vibrations in Smart Laminated Composite Plates Using Piezoceramics (압전세라믹을 이용한 지능 복합적층판의 강제진동의 능동제어)

  • 강영규;구근회;박현철
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.11 no.6
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    • pp.193-199
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    • 2001
  • Active control of forced vibration of the cantilevered laminated composite plates using collocated piezoceramic sensor/actuator is analyzed numerically and verified experimentally for various fiber orientations. Impact on the stiffness and the damping properties is studied by varying stacking sequence of [$\theta$$_{4}$O$_{2}$90$_{2}$]s for the laminated composite plate. For the forced vibration control, the plate is excited by one pair of collocated PZT exciters in resonance and its vibrational response is suppressed by the other collocated PZT sensor/actuator using direct negative velocity feedback. It is shown that the active control of forced vibration is more effective for the smart laminated plate with higher modal damped stiffness(2ζ$\omega$/aup 2/) .

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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.