• Title/Summary/Keyword: RESPONSE 2000

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Dynamic response of a bridge deck with one torsional degree of freedom under turbulent wind

  • Foti, Dora;Monaco, Pietro
    • Wind and Structures
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    • v.3 no.2
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    • pp.117-132
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    • 2000
  • Under special conditions of turbulent wind, suspension and cable-stayed bridges could reach instability conditions. In various instances the bridge deck, as like a bluff body, could exhibit single-degree torsional instability. In the present study the turbulent component of flow has been considered as a solution of a differential stochastic linear equation. The input process is represented by a Gaussian zero-mean white noise. In this paper the analytical solution of the dynamic response of the bridge has been determined. The solution has been obtained with a technique of closing on the order of the moments.

Modal transformation tools in structural dynamics and wind engineering

  • Solari, Giovanni;Carassale, Luigi
    • Wind and Structures
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    • v.3 no.4
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    • pp.221-241
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    • 2000
  • Structural dynamics usually applies modal transformation rules aimed at de-coupling and/or minimizing the equations of motion. Proper orthogonal decomposition provides mathematical and conceptual tools to define suitable transformed spaces where a multi-variate and/or multi-dimensional random process is represented as a linear combination of one-variate and one-dimensional uncorrelated processes. Double modal transformation is the joint application of modal analysis and proper orthogonal decomposition applied to the loading process. By adopting this method the structural response is expressed as a double series expansion in which structural and loading mode contributions are superimposed. The simultaneous use of the structural modal truncation, the loading modal truncation and the cross-modal orthogonality property leads to efficient solutions that take into account only a few structural and loading modes. In addition the physical mechanisms of the dynamic response are clarified and interpreted.

Fabrication and Characteristics of Hot-Film Type Micro-flowsensors integrated with RTD (측온저항체 온도센서가 집적화된 발열저항체형 마이크로 유량센서의 제작 및 특성)

  • 정귀상;홍석우
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.7
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    • pp.612-616
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    • 2000
  • This paper describes on the fabrication and characteristics of hot-film type micro-flowsensors integrated with Pt-RTD(resistance thermometer device) and micro-heater on the Si membrane in which MgO thin-film was used as medium layer in order to improve adhesion of Pt thin-film to SiO$_2$layer. The MgO layer improved adhesion of Pt thin-film to SiO$_2$layer without any chemical reactions to Pt thin-film under high annealing temperatures. Output voltages increased due to increase of heat-loss from sensor to external. The output voltage was 82 mV at $N_2$flow rate of 2000 sccm/min heating power of 1.2 W. The response time($\tau$:63%) was about 50 msec when input flow was stepinput

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Performance Evaluation of Steel Moment Frame Buildings with Different Response Modification Factors (반응수정계수의 영향에 따른 철골조 빌딩의 내진 성능 평가)

  • Lee, Ki-Hak
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2006.03a
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    • pp.201-208
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    • 2006
  • This study lotuses on the seismic behavior of 3-, 9-, and 20-story steel moment resisting frame (MRF) structures designed in accordance with the 2000 International Building Code using different Response Modification factors (R factors) 8, 9, 10, 11, and 12. For a detailed case study, 30 different structures were evaluated for twenty ground motions representing the hazard level which is equal to a 2% probability exceeding in 50 years (2% in 50 years). The results showed that the current R factors provide conservative designs for the 3- and 9-story buildings for the Collapse Prevention performance objective. However, the 20-story buildings designed without using the minimum requirement of spectral acceleration CS prescribed in the IBC 2000 did not satisfy the seismic performance for Collapse Prevention performance.

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The Clinical Observation of Immune Response by Korean Bee Venom Therapy (봉약침요법의 면역반응에 관한 임상적 연구)

  • Kwon, Gi-Rok;Koh, Hyung-Kyun
    • Journal of Acupuncture Research
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    • v.17 no.1
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    • pp.169-174
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    • 2000
  • The immune response of Bee Venom Therapy is commonly appear in clinics. It is whole body delayed allergy type and generally like fatigue. Therefore, in order to analysis the clinical form, we have observed immune response of 100 patients who visited Sangji University Oriental Medical Hospital and treated Bee Venom Therapy over 10 times from November 1998 to October 1999. The results were summarized as follows. 1. The distribution of Sex was 60 females, 40 males, and the average of patients age was $50.6{\pm}1.5years$. 2. The distribution of disease was degenerative arthritis, HIVD of L-spine, RA, etc. 3. The total treated time is 2765 and is observed 361 immume responses. 4. The average of keeping time in immume response is $11.8{\pm}0.6(hr)$, and the cases of over 24hrs is occupied 24.0%. 5. In the correlation between treated times and immume response is generally in inverse proportion. 6. The general aspect of immume response is chilling, heating, powerless, headache, dizziness, etc. 7. $M{\ddot{u}}ller$ Grade II-III was observed only 1%.

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A Study on Comparison of Combination Rules for the Seismic Analysis on Curved Bridges with the Different Radiuses of Curvature (곡선교의 내진 해석 시 곡률에 따른 하중 조합 방법의 비교에 관한 연구)

  • Ryu, Dong-Hyeon;Shin, Myoung-Gyu;Park, Jin-Wan;Kim, Moon-Kyum
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.567-572
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    • 2008
  • This paper's purpose is to improve determining of the critical response of curved bridge to multi-component seismic motion. There are several methods to combine responses by multi-component excitation response, 30%, 40% rules and square-root-of-sum (SRSS). These combination rules determine same value of critical response in straight bridges. However, each method has critical response value of different magnitude in curved bridges. Thus a study about critical response of curved bridges is required. This paper presents comparison critical responses value as each combination rule, 30%, 40% rules and SRSS on curved bridges with the different radiuses of curvature. This study was carried out by response spectrum analysis of OO IC steel box girder bridge using SAP2000. It is concluded as follows: 1) In curved bridges, 30% and 40% rules tend to underestimate the critical response relatively to SRSS. 2) When bridges have smaller radiuses than 100m, difference between SRSS and 30% or 40% rules let run errors up as radiuses of curvature decreased.

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A Modified Travelling Wave Method for the Prediction of Vibration Response in One-dimensional Structures (일차원구조물에서의 진동응답예측을 위한 진행파기법)

  • Chae, Ki-Sang;Ih, Jeong-Guon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.06a
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    • pp.314-318
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    • 2000
  • For one-dimensional structures, a vibration response consists of direct and reflected waves from boundaries. Based on this concept of separable wave components, a modified travelling wave method (MTWM) is proposed in this paper: while all allowable waves are assumed and the boundary conditions are applied on by the conventional travealling wave method (TWM), in the proposed MTWM direct and reflected waves are assumed within the beam element, and the governing relations between direct and reflected waves are described in terms of the reflection or transmission coefficients. It is shown that the vibration response with considerable accuracy can be obtained compared to TWM for single and coupled beams. It is also shown that the band analysis to obtain quadratic response, or power flow response can be carried out by a slight change of the governing equations for one-dimensional structural systems. It is thought that the suggested MTWM can be used as a unified approach for predicting linear spectral response and/or quadratic band response involved in the one-dimensional structural vibration.

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