• Title/Summary/Keyword: Dynamic response

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Dynamic reliability analysis of offshore wind turbine support structure under earthquake

  • Kim, Dong-Hyawn;Lee, Gee-Nam;Lee, Yongjei;Lee, Il-Keun
    • Wind and Structures
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    • v.21 no.6
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    • pp.609-623
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    • 2015
  • Seismic reliability analysis of a jacket-type support structure for an offshore wind turbine was performed. When defining the limit state function by using the dynamic response of the support structure, a number of dynamic calculations must be performed in a First-Order Reliability Method (FORM). That means analysis costs become too high. In this paper, a new reliability analysis approach using a static response is used. The dynamic effect of the response is considered by introducing a new parameter called the Peak Response Factor (PRF). The probability distribution of PRF can be estimated by using the peak value in the dynamic response. The probability distribution of the PRF was obtained by analyzing dynamic responses during a set of ground motions. A numerical example is presented to compare the proposed approach with the conventional static response-based approach.

Development of automatic measurement system for dynamic respose time of pneumatic solenoid valve (공압밸브의 동적응답 특성측정 자동화 시스템 개발)

  • 강보식;김형의
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.974-978
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    • 1991
  • Electro-pneumatic valve is an electro-mechanical device which converts electric signal into pneumatic flow mu or pressure. A measurement of dynamic response time is very important to evaluate valve performance. Dynamic response time of electro-pneumatic valve has a variation accordance with valve types, operating way and test standard. In this study, automatic measurement system of dynamic response time is composed based on test condition of dynamic response time test standard(CETOP, JIS). Also, in this study test pressure variation characteristics accordance with variation of solenoid excitation power, and we developed dynamic response measurement system enable to compare of and analyze these two characteristics.

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Analysis of the Reduction of the Dynamic Response for the CNC 5 Axles Machining Center (CNC 5축 공작기계의 동응답 저감 해석)

  • KIM, Gi Man;CHOI, Seong Dae
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.5
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    • pp.83-89
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    • 2010
  • In this paper, the dynamic response of a CNC 5 Axles machining center was analyzed and then controlled passively by using the dynamic absorber. For the simplification of the theoretical approach, the CNC 5 Axles machining center was modeled as a flexible beam(Bed) having a point mass(Column), two discrete systems(a Table-set and a dynamic absorber). Specifically by using the dynamic absorber, the dynamic response of a Table-set which be caused by the vibration of a flexible beam, was reduced down to the infinitesimal level. The optimal design factors of the dynamic absorber were obtained from the minimization of the cost function. It was found that the natural frequencies of a UT-380 machining center be varied due to the movement of the Table-set. In view of the dynamic response of a Table-set, the larger spring stiffness and mass of the dynamic absorber were found to give the greater reduction.

A Dynamic Calibration Technique for Piezoelectric Sensors Using Negative Going Dynamic Pressure (부방향 동압력을 이용한 압전형 압력센서의 교정기법)

  • Kim, Eung-Su
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.4
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    • pp.491-499
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    • 2009
  • The determination of response characteristics for pressure sensors is routinely limited to static calibration against a deadweight pressure standard. The strength of this method is that the deadweight device is a primary standard used to generate precise pressure. Its weakness lies in the assumption that the static and dynamic responses of the sensor in question are equivalent. Differences in sensor response to static and dynamic events, however, can lead to serious measurement errors. Dynamic techniques are required to calibrate pressure sensors measuring dynamic events in milliseconds. In this paper, a dynamic calibration using negative going dynamic pressure is proposed to determine dynamic pressure response for piezoelectric sensors. Sensitivity and linearity of sensor by the dynamic calibration were compared with those by the static calibration. The uncertainty of calibration results and the goodness of fit test of linear regression analysis were presented. The results show that the dynamic calibration is applicable to determine dynamic pressure response for piezoelectric sensors.

Dynamic response of integrated vehicle-bridge-foundation system under train loads and oblique incident seismic P waves

  • Xinjun Gao;Huijie Wang;Fei Feng;Jianbo Wang
    • Earthquakes and Structures
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    • v.26 no.2
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    • pp.149-162
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    • 2024
  • Aiming at the current research on the dynamic response analysis of the vehicle-bridge system under earthquake, which fails to comprehensively consider the impact of seismic wave incidence angles, terrain effects and soil-structure dynamic interaction on the bridge structure, this paper proposes a multi-point excitation input method that can consider the oblique incidence seismic P Waves based on the viscous-spring artificial boundary theory, and verifies the accuracy and feasibility of the input method. An overall numerical model of vehicle-bridge-soil foundation system in valley terrain during oblique incidence of seismic P-wave is established, and the effects of seismic wave incidence characteristics, terrain effects, soil-structure dynamic interactions, and vehicle speeds on the dynamic response of the bridge are analyzed. The research results indicate that with an increase in P wave incident angle, the vertical dynamic response of the bridge structure decreased while the horizontal dynamic response increased significantly. Traditional design methods which neglect multi-point excitation would lead to an unsafe structure. The dynamic response of the bridge structure significantly increases at the ridge while weakening at the valley. The dynamic response of bridge structures under earthquake action does not always increase with increasing train speed, but reaches a maximum value at a certain speed. Ignoring soil-structure dynamic interaction would reduce the vertical dynamic response of the bridge piers. The research results can provide a theoretical basis for the seismic design of vehicle-bridge systems in complex mountainous terrain under earthquake excitation.

Dynamic bending response of SWCNT reinforced composite plates subjected to hygro-thermo-mechanical loading

  • Chavan, Shivaji G.;Lal, Achchhe
    • Computers and Concrete
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    • v.20 no.2
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    • pp.229-246
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    • 2017
  • The dynamic bending response of single walled carbon nanotube reinforced composite (SWCNTRC) plates subjected to hygro-thermo-mechanical loading are investigated in this paper. The mechanical load is considered as wind pressure for dynamic bending responses of SWCNTRC plate. The dynamic version of the High Order shear deformation Theory (HSDT) for a composite plate with Matrix and SWCNTRC plate is first formulated. Distribution of fibers through the thickness of the SWCNTRC plate could be uniform or functionally graded (FG). The dynamic displacement response is predicted by using Nemarck integration method. The effective material properties of SWCNTRC are estimated by using micromechanics based modeling approach. The effect of different environmental condition, volume fraction of SWCNT, Width-to-thickness ratio, wind pressure, different SWCNTRC-FG plates, boundary condition, E1/E2 ratio, different temperature on dynamic displacement response is investigated. The dynamic displacement response is compared with the available literature and it shows good agreement.

A new metric for LCD temporal response;Dynamic gamma

  • Pan, Hao;Feng, Xiaofan;Daly, Scott
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.419-422
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    • 2004
  • In this paper, we propose a new metric called "dynamic gamma" to quantitatively evaluate the dynamic temporal response of an LC display device. The widely-used response time and corresponding 3-D bar graphs cannot fully describe the dynamic characteristics of an LC panel [1], and using response time to compare different LC panels and assessing the dynamic features of LC panels is difficult. On the other hand, the new metric MPRT mixes an LC panel's slow temporal response with its hold-type display effect. The proposed new metric, dynamic gamma, and corresponding 2-D plots, are arguably more suitable for quantitatively characterizing the dynamic characteristics of an LC panel, so comparing two LC panels becomes easy. Furthermore, dynamic gamma has the unique property that it can be used to quantify the limitations/capabilities and to assess the effectiveness of an overdrive mechanism for a particular LCD. In the paper, two LC panels using different technology are analyzed and compared using this new metric.

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Study on Implementing Dynamic Pricing to Demand Response System (변동요금제 기반의 DR 프로그램 운영 방안 연구)

  • Yu, In-Hyeob
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.541_542
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    • 2009
  • This paper reviews the definition and background of dynamic pricing which is the essential element of demand response system. Also, economic efficiency and related issues on dynamic pricing are studied. Several issues on design and operation of demand response system, which can implement the dynamic pricing, are described. Therefore the results will be helpful for developing the demand response system with dynamic pricing.

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Dynamic Response of Non-Uniform Beams under a Moving Mass (이동질량에 의한 불균일 단면보의 동적응답)

  • 김인우;이영신;이규섭;류봉조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.553-556
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    • 2000
  • The paper deals with the dynamic response of non-uniform beams subjected to a moving mass. In the dynamic analysis, the effects of inertia force, elastic force, centrifugal force, Coriolis force and self weight due to moving mass are taken into account. Galerkin's mode summation method is applied for the discretized equations of notion. Numerical results for the dynamic response of the non-uniform beam under a moving mass having various magnitudes and velocities are investigated. Experimental results have a good agrement with predictions

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