• Title/Summary/Keyword: Structural intensity

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Damping patch placement on outdoor unit of air-conditioner by using structural intensity technique (구조 인텐서티 법을 이용한 에어컨 실외기의 제진재 적용)

  • Kim Kyu Sik;Kang Yeon June
    • Proceedings of the Acoustical Society of Korea Conference
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    • autumn
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    • pp.323-326
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    • 2004
  • 에어컨 실외기의 구조 방사 소음을 줄이기 위해 제진재를 적용함에 있어 구조 인텐서티(structural intensity)법을 사용할 수 있다. 에어컨 실외기 각 패널의 법선 방향의 속도는 레이져 스케닝 바이브로미터(laser scanning vibrometer)에 의해 측정되며, 측정된 데이터는 공간 주파수 영역(k-domain)으로 변환하여 구조 인텐서티 계산에 필요한 공간 미분값이 구해진다. 이러한 과정을 통하여 계산된 구조 인텐서티 중 반동 전단 구조인텐서티(reactive shearing structural intensity)값이 가장 높은 부분에 사각형 형상의 제진재를 적용한다. 본 논문은 패널에 비해 그 크기가 작은 제진재의 적용으로 에어컨 실외기의 구조 방사 소음을 줄일 수 있음을 보여준다.

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Numerical Analysis on the Affection of Lumped Attachments to the Vibration Power Flow in Cross-stiffened Plate (집중 부가물이 보강판의 진동파워 흐름에 미치는 영향에 대한 수치 해석적 고찰)

  • 조대승;정상민;김재홍
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.1
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    • pp.36-46
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    • 2003
  • To investigate the affection of lumped mass and spring on the vibration power flow of cross-stiffened plate experiencing bending vibration, structural intensity analysis is done using the modal analysis based on assumed mode method. The numerical analysis is carried out varying the mass and spring constant and their attached positions. The results show that both the spring and the mass may cause to large variation of not only vibratory displacement but also vibratory power flow patterns in case of little change of natural frequencies, and the attachments near to excitation location can effectively reduce the magnitude of maximum structural intensity.

An Experimental Study on Intensity property of High Strength Concrete Using Transparent Joint Separation Test Body (투명 접합분리 몰드를 사용한 고강도 콘크리트의 강도특성에 관한연구)

  • Ki, Jun-Do;Park, Hyun;Kim, Kwang-Ki;Paik, Min-Su;Lee, Young-Do;Jung, Sang-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2009.05a
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    • pp.411-412
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    • 2009
  • The techniques of testing and controlling intensity of structural concrete involve many problems and difficulties on the construction site. Hence this study aims at evaluating intensity of structural concrete in order to verify on-site application and structural efficiency assessment using joint separation test body.

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FTIR Spectroscopic Analysis of Structural Changes of Cellulosic Fibres During Papermaking Process

  • Kim, Hyoung-Jin
    • Journal of the Korean Wood Science and Technology
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    • v.26 no.2
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    • pp.51-58
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    • 1998
  • Structural changes of cellulosic fibres during the papermaking process were studied by analysis of FTIR spectra collected by the transmission method. The spectra were obtained from a carefully prepared handsheet, using a special infra-red (IR) cell suitable for evacuating the sample. The deconvolution technique was also applied for sharpening the FTIR spectra in the frequency range of the OH and CH stretching bands, which gave detailed information on the structural changes of cellulose. The intensity of some bands was decreased by predrying the sample as a result of the removal of adsorbed moisture. An increase in intensity of some bands in the frequency range of 3700 to $3200cm^{-1}$ was shown at a higher beating level. This increase in intensity was caused by changes in the crystal domain of cellulose resulting from the exposure of the crystalline area on the fibre surface.

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Deterministic structural and fracture mechanics analyses of reactor pressure vessel for pressurized thermal shock

  • Jhung, M.J.;Park, Y.W.
    • Structural Engineering and Mechanics
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    • v.8 no.1
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    • pp.103-118
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    • 1999
  • The structural integrity of the reactor pressure vessel under pressurized thermal shock (PTS) is evaluated in this study. For given material properties and transient histories such as temperature and pressure, the stress distribution is found and stress intensity factors are obtained for a wide range of crack sizes. The stress intensity factors are compared with the fracture toughness to check if cracking is expected to occur during the transient. A round robin problem of the PTS during a small break loss of coolant transient has been analyzed as a part of the international comparative assessment study, and the evaluation results are discussed. The maximum allowable nil-ductility transition temperatures are determined for various crack sizes.

Boundary Element Evaluation of Stress Intensity Factor for Interface Crack in Elastic and Viscoelastic Composite Materials (경계요소법에 의한 탄성-점탄성 복합구조체의 계면균열 해석)

  • 이상순;김정규;황종근
    • Computational Structural Engineering
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    • v.9 no.1
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    • pp.85-91
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    • 1996
  • The focus of the present work is on the computation of the stress intensity factor for the crack at the elastic-viscoelastic bimaterial interface. First, the stress intensity factor for an interface crack in dissimilar elastic and viscoelastic materials is dervied by applying the correspondence principle to associated elastic expression. Then the time-domain boundary element analysis is performed to calculate the stress intensity factor. Numerical results show that the proposed method is very useful for the analysis of the interface crack in elastic and viscoelastic materials.

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Measurement of Vibration Intensity of a Semi-Infinite Beam Using the Principle of Reciprocity (가역성 원리를 이용한 반무한보의 진동 인텐시티 측정)

  • 양귀봉;길현권;홍석윤
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1073-1077
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    • 2001
  • The objective of this paper is to apply an experimental method based on the principle of reciprocity to measuring the structural intensity. Since only one accelerometer is used in this method it has the advantages of shortening measurement time. reducing accelerometer phase error. overcoming the limitation that the situation should be stationary during the experiment. It has been used to measure the vibration intensity of an infinite beam (beam with damped ends) and a semi-infinite beam (beam with simply supported and damped ends). Results showed that the experiment method based on the principle of reciprocity can be effectively used to measure the structural intensity.

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Parameters affecting the seismic response of buildings under bi-directional excitation

  • Fontara, Ioanna-Kleoniki M.;Kostinakis, Konstantinos G.;Manoukas, Grigorios E.;Athanatopoulou, Asimina M.
    • Structural Engineering and Mechanics
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    • v.53 no.5
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    • pp.957-979
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    • 2015
  • The present paper investigates the influence of the orientation of the ground-motion reference axes, the seismic incident angle and the seismic intensity level on the inelastic response of asymmetric reinforced concrete buildings. A single storey asymmetric building is analyzed by nonlinear dynamic analyses under twenty bi-directional ground motions. The analyses are performed for many angles of incidence and four seismic intensity levels. Moreover three different pairs of the horizontal accelerograms corresponding to the input seismic motion are considered: a) the recorded accelerograms, b) the corresponding uncorrelated accelerograms, and c) the completely correlated accelerograms. The nonlinear response is evaluated by the overall structural damage index. The results of this study demonstrate that the inelastic seismic response depends on the orientation of the ground-motion reference axes, since the three individual pairs of accelerograms corresponding to the same ground motion (recorded, uncorrelated and completely correlated) can cause different structural damage level for the same incident angle. Furthermore, the use of the recorded accelerograms as seismic input does not always lead to the critical case of study. It is also shown that there is not a particular seismic incident angle or range of angles that leads to the maximum values of damage index regardless of the seismic intensity level or the ground-motion reference axes.

Compressive Strength Control of High Strength Concrete Using Transparent Joint Separation Test Body (투명접합분리 시험체를 활용한 고강도 콘크리트의 강도관리에 관한연구)

  • Ki, Jun-Do;Jung, Kwang-Sik;Kim, Hak-Young;Kim, Kwang-Ki;Lee, Young-Do;Jung, Sang-Jin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2009.05b
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    • pp.49-52
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    • 2009
  • This paper aims to evaluate hydration and intensity property of different kind of members and intensity in order to evaluate compressive strength of structural concrete using Joint Separation Test Body(JSTB). In fact it is difficult to test and evaluate already have constructed member. In this case, common method used by construction engineer is that ; Schmidt rebound hammer test, Ultrasonic pulse test, Method of using test specimen previously cast. However, these method to control the structural intensity involve many problem and impossibility to adapt construction. 80, this paper proposes advance an opinion which have proper to examine intensity. has also aims to examine its validity and the plan to make similar environment with structural concrete and joint separation test body in order to verify efficiency assessment and on-site application.

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Fracture analysis and remaining life prediction of aluminium alloy 2014A plate panels with concentric stiffeners under fatigue loading

  • Murthy, A. Ramachandra;Mathew, Rakhi Sara;Palani, G.S.;Gopinath, Smitha;Iyer, Nagesh R.
    • Structural Engineering and Mechanics
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    • v.53 no.4
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    • pp.681-702
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    • 2015
  • Fracture analysis and remaining life prediction has been carried out for aluminium alloy (Al 2014A) plate panels with concentric stiffener by varying sizes and positions under fatigue loading. Tension coupon tests and compact tension tests on 2014A have been carried out to evaluate mechanical properties and crack growth constants. Domain integral technique has been used to compute the Stress intensity factor (SIF) for various cases. Generalized empirical expressions for SIF have been derived for various positions of stiffener and size. From the study, it can be concluded that the remaining life for stiffened panel for particular size and position can be estimated by knowing the remaining life of corresponding unstiffened panel.