• Title/Summary/Keyword: Newmark 방법

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Seismic Effect of LRB Base Isolator on Bridges (LRB 기초분리장치의 교량 내진효과)

  • Hwang, Eui Seung
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.5
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    • pp.13-18
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    • 1993
  • The purpose of this study is to analyze the seismic effects of Lead Rubber Bearing base isolators on bridges. Base isolation is the tool to minimize the effect of earthquake before the seismic force is transfered to the structure. Currently, many structures including the buildings, power plants, and bridges, were built and planned with base isolation method. The simple model is developed for bridges with Lead Rubber Bearings. Equations of motion are solved by Newmark ${\beta}$ method. Springs representing the base isolators are assumed as bilinear springs and piers are modeled as nonlinear springs implementing Q-HYST model. Analysis is performed for the selected bridge. El Centro (N-S) earthquake(1940) is used. Deck displacement, pier ductility and pier shear force are calculated for the various Lead Rubber Bearings.

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Development of Fragility Curves for Seismic Stability Evaluation of Cut-slopes (지진에 대한 안전성 평가를 위한 깎기비탈면의 취약도 곡선 작성)

  • Park, Noh-Seok;Cho, Sung-Eun
    • Journal of the Korean Geotechnical Society
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    • v.33 no.7
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    • pp.29-41
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    • 2017
  • There are uncertainties about the seismic load caused by seismic waves, which cannot be predicted due to the characteristics of the earthquake occurrence. Therefore, it is necessary to consider these uncertainties by probabilistic analysis. In this paper, procedures to develop a fragility curve that is a representative method to evaluate the safety of a structure by stochastic analysis were proposed for cut slopes. Fragility curve that considers uncertainties of soil shear strength parameters was prepared by Monte Carlo Simulation using pseudo static analysis. The fragility curve considering the uncertainty of the input ground motion was developed by performing time-history seismic analysis using selected 30 real ground input motions and the Newmark type displacement evaluation analysis. Fragility curves are represented as the cumulative probability distribution function with lognormal distribution by using the maximum likelihood estimation method.

The Comparision of Analysis Methods in dynamic Design of Dam based on Shaking Table tests (진동대시험에 근거한 댐의 내진설계시 해석 방법의 비교)

  • Hwang, Seong-Choon;Oh, Byung-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.732-737
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    • 2005
  • This paper performed pseudo static analysis and dynamic analysis for CFRD and evaluated reliability with the results of Shaking Table Test. The Seismic coefficient method, modified seismic coefficient method, Newmark method of Pseudo static analysis and frequency domain response analysis, time domain history analysis of dynamic analysis were used. The analysis results were differ between analysis method, but the trends of acceleration and displacement were good agreement with the results of shaking table test.

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Hydroelastic Responses of a Very Large Floating Structure in Time Domain (시간영역에서 초대형 부유식 해양구조물에 대한 유탄성 운동해석)

  • 이호영;신현경
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.04a
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    • pp.18-22
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    • 2000
  • This paper is transient motions of a very large floating structure subjected to dynamic load induced by wave. A time domain method is applied to the hydroelasticity problems for this purpose. The method is based on source-dipole and FEM scheme and on Newmark $\beta$ method to pursuit time step process taking advantage of the memory effect. The present method is appied to hydroelastic response analysis in regular waves and impact responses due to dropping aircraft.

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Behaviour Analyses of Ocean Structure Due to Ship Collision (선박의 충돌로 인한 해양구조물의 거동 해석)

  • 이호영
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.103-107
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    • 2001
  • When ship claps against the ocean structure sited at shallow water, the time simulation of motion responses of dolphin-moored ocean structure is presented. The equatien of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The added mass and damping coefficients involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The impact forces due to ship collision are modeled as two method, and those are elastic and non-elastic collisions. The mooring forces for dolphin systems of scean structure are considered as linear spring system.

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Nonlinear Response Analyses for a Barge-Mounted Plant with Dolphin Mooring Systems in Irregular Waves (불규칙파 중에서 돌핀 계류된 바아지식 해상공장에 대한 비선형 응답 해석)

  • 이호영;신현경;염재선
    • Journal of Ocean Engineering and Technology
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    • v.14 no.4
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    • pp.1-8
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    • 2000
  • The time simulation of motion responses of dolphin-moored BMP in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The hydrodynamic coefficient and first order wave exciting forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The second order wave drift forces and mooring for dolphin system are taken into account. As for numerical example, time domain analysis are carried out for a BMP in irregular wave condition.

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Development of Permanent Displacement Model for Seismic Mountain Slope (지진 시 산사면의 영구변위 추정식 개발)

  • Lee, Jong-Hoo;Park, Duhee;Ahn, Jae-Kwang;Park, Inn-Joon
    • Journal of the Korean Geotechnical Society
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    • v.31 no.4
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    • pp.57-66
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    • 2015
  • Empirical seismic displacement equations based on the Newmark sliding block method are widely used to develop seismic landslide hazard map. Most proposed equations have been developed for embankments and landfills, and do not consider the dynamic response of sliding block. Therefore, they cannot be applied to Korean mountain slopes composed of thin, uniform soil-layer underlain by an inclined bedrock parallel to the slope. In this paper, a series of two-dimensional dynamic nonlinear finite difference analyses were performed to estimate the permanent seismic slope displacement. The seismic displacement of mountain slopes was calculated using the Newmark method and the equivalent acceleration time history. The calculated seismic displacements of the mountain slopes were compared to a widely used empirical displacement model. We show that the displacement prediction is significantly enhanced if the slope is modeled as a flexible sliding mass and the amplification characteristics are accounted for. Regression equation, which uses PGA, PGV, Arias intensity of the ground motion and the fundamental period of soil layer, is shown to provide a reliable estimate of the sliding displacement. Furthermore, the empirical equation is shown to reliably predict the hazard category.

Bridge-Vehicle interaction Analysis of Suspension Bridges Considering the Effects of the Shear Deformation (전단변형효과를 고려한 현수교의 교량-차량 상호작용 해석)

  • Kim, Moon-Young;Lim, Myoung-Hun;Kwon, Soon-Duck;Kim, Ho-Kyung
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.6 s.40
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    • pp.1-11
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    • 2004
  • In the previous study(1), the finite element method was used for the vertical vibration analysis of suspension bridge considering the effects of the shear deformation and the rotary inertia under moving load. This study firstly performs the eigenvalue analysis for the free vertical vibration of suspension bridge using FEM analysis. Next the equations of motion considering interaction between suspension bridge and vehicles/train are derived using mode superposition method. And dynamic analysis was performed using the Newmark $\beta$ Method. Finally through the numerical examples, the dynamic responses of bridges by this study are investigated.

Linear and Nonlinear Analysis of Initially Stressed Elastic Solid (초기응력이 있는 탄성체의 선형 및 비선형해석 -플레이트 스트립을 중심으로)

  • 권영두;최진민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.4
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    • pp.642-651
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    • 1988
  • The present paper develops finite element procedures to calculate displacements, strains and stresses in initially stressed elastic solids subjected to static or time-dependent loading conditions. As a point of departure, we employ Hamilton's principle to obtain nonlinear equations of motion characterizing the displacement in a solid. The equations of motion reduce to linear equations of motion if incremental stresses are assumed to be infinitesimal. In the case of linear problem, finite element solutions are obtained by Newmark's direct integration method and by modal analysis. An analytic solution is referred to compare with the linear finite element solution. In the case of nonlinear problem, finite element solutions are obtained by Newton-Raphson iteration method and compared with the linear solution. Finally, the effect of the order of Gauss-Legendre numerical integration on the nonlinear finite element solution, has been investigated.

Parametric effects on geometrical nonlinear dynamic behaviors of laminated composite skew plates (적층된 복합소재 경사판의 기하학적 비선형 동적 거동에 미치는 매개변수 영향)

  • Lee, Sang-Youl
    • Composites Research
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    • v.25 no.6
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    • pp.217-223
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    • 2012
  • This study investigates a geometrical nonlinear dynamic behaviors of laminated skew plates made of advanced composite materials (ACM). Based on the first-order shear deformation plate theory (FSDT), the Newmark method and Newton-Raphson iteration are used for the nonlinear dynamic solution. The effects of cutout sizes, skew angles and lay up sequences on the nonlinear dynamic response for various parameters are studied using a nonlinear dynamic finite element program developed for this study. The several numerical results were in good agreement with those reported by other investigators for square composite plates with or without central cutouts, and the new results reported in this paper show the significant interactions between the cutout, skew angles and layup sequence in the laminate. Key observation points are discussed and a brief design guideline of skew laminates is given.