• Title/Summary/Keyword: Composite Noise

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Thermally Induced Vibration Analysis of Flexible Spacecraft Appendages (위성체 유연구조물의 진동 해석)

  • Yoon, Il-Soung;Kim, Gu-Sun;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.1216-1221
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    • 2000
  • Thermally induced vibration response of composite thin walled beams is investigated. The thin-walled beam model incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, 'rotary inertia' and anisotropy of constituent materials. Thermally induced vibration response characteristics of a composite thin walled beam exhibiting the circumferentially uniform system(CUS) configuration are exploited in connection with the structural coupling resulting from directional properties of fiber reinforced composite materials and from ply stacking sequence. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated.

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Bearingless Rotor Hub Composite Component Fatigue Analysis of Utility Helicopter to perform the Basic Mission (기본임무를 수행하는 기동헬기에 적용될 무베어링 허브 복합재 구성품 피로수명 해석)

  • Kim, Taejoo;Kee, Youngjoong;Kim, Deog-kwan;Kim, Seung-ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.04a
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    • pp.383-389
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    • 2013
  • Rotor system is a very important part which produces lift, thrust and control force in helicopter. Component of rotor system must endure various flight load for the required life. In helicopter rotor system, bearingless rotor system is the highest technology rotor system compare with articulated and hingeless rotor system. Baaringless rotor system is not include mechanical flap hinge, lag hinge and pitch bearing. Bearingless rotor component flexbeam which made by composite material has conduct hinge and bearing role instead of mechanical flap hinge, lag hinge and pitch bearing. These characteristics has less part number and lass weight than others. In this paper, conduct safe life analysis of bearingless composite component flexbeam and torque tube applying to utility helicopter load condition.

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Vibration Analysis and Critical Speeds of Rotating Polar Orthotropic Disks, Part I : Formulation and Solution Method (극직교 이방성 회전원판의 진동해석 및 임계속도 I : 정식화 및 해법)

  • Koo, Kyo-Nam
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.2 s.107
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    • pp.169-175
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    • 2006
  • 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 disks by the Galerkin method. The orthogonal functions are used in series solution. A companion paper(Part II) presents and discusses the numerical results of vibration analysis and critical speed for rotating polar orthotropic disk using the formulation and solution method given in this paper (Part I).

Optimum Design of a Flexible Matrix Composite Driveshaft Using Genetic Algorithms (유전자 알고리즘을 이용한 유연 복합재 구동축의 최적 설계)

  • 홍을표;신응수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.109-115
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    • 2003
  • This study intends to provide an optimum design of flexible matrix composite driveshafts using a genetic algorithm. An objective function is defined as a combination of shaft flexibility, whirling stability and torsional buckling and the design variables are selected as ply angles and the shaft thickness. Results show that the genetic algorithm can successfully find an optimum solution at which the overall performance of the FMC shafts is significantly enhanced

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Dynamic Charateristics of Composite Plates Based On a Higher Order Theory Under Low-Velocity Impact (저속 충격시 고차이론을 이용한 복합재료 판의 동적 특성)

  • 심동진;김지환
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.42-48
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    • 1997
  • The dynamic response of symmetric cross-ply and angle-ply composite laminated plates under impact loads is investigated using a higher order shear deformation theory. A modified Hertz law is used to predict the impact loads and a four node finite element is used to model the plate. By using a higher order shear deformation theory, the out-of-plane shear stresses, which can be a crucial factor in the failure of composite plates, are determined with significant accuracy. The results compared with previous investigations showed good agreement. The effect of ply sequence and ply angle on the contact force is also studied.

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The Frequency Characteristics of Elastic Wave by Crack Propagation of SiC/SiC Composites

  • Kim, J.W.;Nam, K.W.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.110-114
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    • 2012
  • We studied on the nondestructive evaluation of the elastic wave signal of SiC ceramics and SiC/SiC composite ceramics under monotonic tensile loading. The elastic wave signal of cross and unidirectional SiC/SiC composite ceramics were obtained by pencil lead method and bending test. It was applied for the time-frequency method which used by the discrete wavelet analysis algorithm. The time-frequency analysis provides time variation of each frequency component involved in a waveform, which makes it possible to evaluate the contribution of SiC fiber frequency. The results were compared with the characteristic of frequency group from SiC slurry and fiber. Based on the results, if it is possible to shift up and design as a higher frequency group, we will can make the superior material better than those of exiting SiC/SiC composites.

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Characterization of a Misaligned Supercritical Shaft of Flexible Matrix Composite (축어긋남이 있는 유연복합재 고속구동축의 특성 분석)

  • 홍을표;신응수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.107-113
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    • 2003
  • This research is to investigate the performance of a flexible matrix composite driveshaft with respect to shaft design parameters such as the number of layers, ply orientations, and material properties. A finite element formulation is utilized to estimate the allowable misalignment under given driving torque, the maximum temperature at steady states, and external damping for ensuring whirling stability under supercritical speed. Results indicate that the system performance can be greatly affected by the shaft laminate parameters, especially the ply orientations. Several sets of shaft parameters that will provide satisfactory overall system performance are derived.

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A Study on the Sound Insulation Performance of the Composite Panel for Railroad Vehicle (철도차량용 복합 내장 패널의 차음성능에 관한 연구)

  • 김봉기;김재승;황병선;이상진
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.182-187
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    • 2002
  • Since most of main noise sources of the railroad vehicle are transmitted to the passenger's ear through the vibration of the panel, the insulation performance of the panels should be high enough to protect the passengers from the noisy environment. Specifically, the composite materials which are generally used for reducing the weight of the vehicle compartment have the low insulation performance, noise control actions should be taken appropriately by considering the insulation performance of the panels. In this study, the insulation performances of the inner/outer panels were evaluated and the contribution of the aluminum door was estimated compared to the composite panels. The results can furnish an indepth understanding of the insulation characteristics of the panel of railroad vehicle.

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Delamination detection in composite laminates using tapping test and wavelet transform (태핑시험과 웨이블릿 변환을 이용한 복합적층판의 층간분리 검출)

  • Kim, Sung Joon;Hwang, In Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.214-215
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    • 2013
  • The tapping test has simplicity of procedure for detection of the damage in aircraft structure. However, the result of tapping test depends on the subjective experience of inspector. In this paper, more objective tapping test has proposed. The impact force histories and tapping sounds are used as reference data to evaluate the delamination. The WT(wavelet transform) is used to decompose the test data. From the results, we could know that high frequency components of force and sound are reduced due to delamination in composite laminate. On these results, the tapping force and sound caused by tapping could be used for the reference data to evaluate the delamination in composite structure.

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Experimental Investigation into the Dynamic Characteristics of Flexible Matrix Composite Driveshafts (유연복합재 구동축의 동특성에 관한 실험 분석)

  • Shin, Eung-Soo;Lim, Byung-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.123-126
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    • 2005
  • This study provides a comprehensive experimental study on the dynamic characteristics of a flexible matrix composite(FMC) driveshaft. A primary objective is to verify the analytic results of the FMC drivetrain based on the equivalent complex modulus approach and the classical lamination theory. A testrig has been constructed, which consists of a FMC shaft, a foundation beam, bearings, external dampers and a driving motor. The frequency response functions and transient responses are obtained from the external excitation and the spinup testings. It turns out that the analytic results are in good agreement with the experimental ones.

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