• Title, Summary, Keyword: 정적 비선형해석

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Applicability of Nonlinear Static Procedures with Earthquake Property (지진특성에 따른 비선형 정적해석법의 적용성)

  • Shin, Dong-Kyu;Kwak, Hyo-Gyoung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.174-177
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    • 2011
  • 비선형 정적 해석법(NSPs)은 최근 구조물의 지진해석방법으로서 그 사용성을 인정받고 있다. 비선형 정적 해석법은 직관적으로 구조물의 지진해석을 수행할 수 있는 등의 장점으로 빌딩구조물의 지진해석법으로 널리 사용되고 있지만, 기본 진동모드에 의해서 구조물의 거동이 지배되지 않는 구조물의 경우에는 그 사용성에 대한 연구가 매우 제한적이다. 이를 개선하기 위한 고차모드의 기여분을 반영할 수 있는 비선형 정적 해석법들이 제시 되었지만, 교량 구조물에 사용함에 있어서는 여전히 지진의 특성에 따라 그 사용성 및 신뢰성이 크게 변화하는 문제가 발생한다. 이 논문에서는 지진의 특성을 고려할 수 있는 두가지 지수를 제시하고, 이를 이용하여 비선형정적 해석법의 적용성을 사용단계에서 알아 낼 수 있는지에 대한 연구를 진행하였다.

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Seismic Analysis of Cable-Stayed Bridges using Nonlinear Static Procedures (비선형 정적 해석법을 이용한 사장교의 지진해석)

  • Shin, Dong Kyu;Kwak, Hyo-Gyoung
    • Journal of The Korean Society of Civil Engineers
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    • v.31 no.2A
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    • pp.59-69
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    • 2011
  • Nonlinear static procedures (NSPs) basing on the concept of performance based seismic design have become one of the promising procedures for seismic evaluation of buildings. Although it needs much less computational cost compared to nonlinear time history analysis (NTHA), its usages are limited to simple structures by its inherent restriction to structures wherein the fundamental mode dominates the response. Several new nonlinear static procedures (Modal Pushover Analysis; MPA and Improved Modal Pushover Analysis; IMPA) which can consider higher modes effect were introduced. Nonetheless, its applicability for complex structures such as cable-stayed bridge has not studied yet. This paper focuses on applicability of nonlinear static procedures for the seismic analysis of cable-stayed bridges. Moreover, reliability indexes which can predict analysis procedure's accuracy are introduced.

Improved Distribution of Seismic Forces for Evaluation of Nonlinear Seismic Response of Building Structures (건축구조물의 비선형 지진응답 평가를 위한 개선된 지진하중 분배방법)

  • 이동근;최원호;안지희
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.2
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    • pp.33-47
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    • 2001
  • 성능에 기초한 내진설계에서는 구조물이 보유하고 있는 능력을 효과적으로 파악하기 위해서 비선형 정적 해석이 적용되고 있다. 그러나 비선형 정적해석은 고차모드에 대한 효과를 고려하지 못함으로써 고층구조물이나 비정형 구조물과 같은 경우에는 정확한 비선형 지진응답의 산정과 내진성능을 평가하는데 문제점을 가지고 있다. 본 연구에서는 건축구조물의 선형 및 비선형 지진응답 평가를 위하여 응답 스펙트럼해석을 통하여 얻어지는 층전단력으로부터 층하중을 산정하는 유사동적해석법이 적용되었다. 제안된 방법을 비선형 정적 해석에 적용하여 구조물의 비선형 자동응답을 비선형 시간이력해석의 결과와 비교하였다. 기존의 층분포하중에 의한 비선형 지진응답과 비교하였으며, 제안된 방법에 의한 지진 응답이 구조물의 비선형 거동특성을 가장 정확하게 표현하였다. 그러므로 본 연구에서 제안된 방법을 사용하여 비선형 정적 해석을 수행한다면 비교적 명확한 건축물의 비선형 거동특성과 내진성능을 평가할 수 있을 것으로 판단된다.

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Effect of Nonlinear Analysis Procedures for Seismic Responses of Reinforced Concrete Wall Structure (철근콘크리트 벽체구조물의 지진응답에 대한 비선형 해석기법의 영향)

  • Song, Jong-Keol;Jang, Dong-Hui;Chung, Yeong-Hwa
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.4A
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    • pp.659-675
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    • 2006
  • Recently, significant progress has been made in performance-based engineering methods that rely mainly on nonlinear static seismic analysis procedures. The Capacity Spectrum Method (CSM) and the Displacement Coefficient Method (DCM) are the representative nonlinear static seismic analysis procedures. In order to evaluate the applicability of the procedures to the seismic evaluation and design process of new and existing structures, the accuracy of both CSM and DCM should be evaluated in advance. The accuracy of seismic responses by the nonlinear static procedures is evaluated in comparison with the shaking table test results for the structural wall specimen subjected to the far field and near field earthquakes. Also conducted are comparative studies where the shaking table test results are compared with those from nonlinear dynamic analysis procedures, i.e., Single-Degree-of-Freedom (SDOF), equivalent SDOF and Multi-Degree-of-Freedom (MDOF) systems.

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Linear Analysis and Non-linear Analysis with Co-Rotational Formulation for a Cantilevered Beam under Static/Dynamic Tip Loads (정적 및 동적 하중을 받는 외팔보 거동에 관한 선형 및 CR 정식화 비선형 예측의 비교)

  • Ko, Jeong-Woo;Bin, Young-Bin;Eun, Won-Jong;Shin, Sang-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.5
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    • pp.467-475
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    • 2015
  • In this paper, the behaviour of a cantilevered beam was predicted to examine the difference between linear and non-linear static, dynamic analysis for a structure by using CR nonlinear formulation. Then, external transverse static and dynamic loads were applied at the free tip of the beam. Classical theories were used for the present linear analysis and co-rotational dynamic FEM program was used for the present nonlinear analysis. In the static analysis, effects of the load for the beam deflection were observed in both linear and nonlinear analysis. Then, normalized displacement at the tip of the beam was predicted for different frequency ratio and a significant difference was obtained in the vicinity of the resonant frequency. In addition, effects of frequency and time for the beam deflection were investigated to find the frequency delay.

Propose of Capacity Spectrum Method by Nonlinear Earthquake Response Analysis (질점계 비선형 지진응답해석에 의한 구조물의 역량스펙트럼 제안)

  • You, Jin-Sun;Yang, Won-Jik;Yi, Waon-Ho;Kim, Hyoung-Joon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.6
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    • pp.501-508
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    • 2014
  • In this paper, a method on deducing the capacity spectrum based on nonlinear earthquake response analysis will be introduced. Damage assessment of general building draws the capacity spectrum through the Push-over analysis and the intersection point of capacity spectrum and demand spectrum is seen as performance point. Push-over analysis is the way to perform static analysis by using the equivalent static load changed from the effect of earthquake and predict the behavior of structures by earthquake. But, this method can not be taken into account in the effects of higher mode and the dynamic characteristic. Therefore, in order to calculate the capacity spectrum under dynamic properties of building. A capacity spectrum from going ahead with the nonlinear earthquake response analysis is suggested.

Local Nonlinear Static Analysis via Static Condensation (강성응축기법을 이용한 국부 비선형 정적 해석)

  • Shin, Han-Seop;Oh, Min-Han;Boo, Seung-Hwan
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.27 no.1
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    • pp.193-200
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    • 2021
  • In this study, an analysis technique using static condensation is proposed for an efficient local nonlinear static analysis. The static condensation method is a model reduction method based on the degrees of freedom, and the analysis model is divided into a target part and a condensed part to be omitted. In this study, the nonlinear and linear parts were designated to the target and the omitted parts, respectively, and both the stiffness matrix and load vector corresponding to the linear part were condensed into the nonlinear part. After model condensation, the reduced model comprising the stiffness matrix and the load vector for the nonlinear part is constructed, and only this reduced model was updated through the Newton-Raphson iteration for an efficient nonlinear analysis. Finally, the efficiency and reliability of the proposed analysis technique were presented by applying it to various numerical examples.

Numerical Analysis for Nonlinear Static and Dynamic Responses of Floating Crane with Elastic Boom (붐(Boom)의 탄성을 고려한 해상크레인의 비선형 정적/동적 거동을 위한 수치 해석)

  • Cha, Ju-Hwan;Park, Kwang-Phil;Lee, Kyu-Yeul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.4
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    • pp.501-509
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    • 2010
  • A floating crane is a crane-mounted ship and is used to assemble or to transport heavy blocks in shipyards. In this paper, the static and dynamic response of a floating crane and a heavy block that are connected using elastic booms and wire ropes are described. The static and dynamic equations of surge, pitch, and heave for the system are derived on the basis of flexible multibody system dynamics. The equations of motion are fully coupled and highly nonlinear since they involve nonlinear mass matrices, elastic stiffness matrices, quadratic velocity vectors, and generalized external forces. A floating frame of reference and nodal coordinates are employed to model the boom as a flexible body. The nonlinear hydrostatic force, linear hydrodynamic force, wire-rope force, and mooring force are considered as the external forces. For numerical analysis, the Hilber-Hughes-Taylor method for implicit integration is used. The dynamic responses of the cargo are analyzed with respect to the results obtained by static and numerical analyses.

Earthquake Response Analysis of Bridges Using Fiber Element Method (섬유요소를 이용한 교량의 비선형 지진응답해석)

  • Byun, Soon-Joo;Im, Jung-Soon
    • Journal of the Korean Society of Hazard Mitigation
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    • v.6 no.3
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    • pp.29-35
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    • 2006
  • Fiber element method in earthquake response analysis of bridges is used to represents a realistic flexural deformation according to nonlinear behavior of beam-column section. Nonlinear pseudo-static analysis of two column bent using fiber element is accomplished and failure mechanism of the plastic hinge region is studied. Load-displacement curve obtained by nonlinear pseudo-static analysis can be applicable to earthquake response analysis by capacity spectrum method. The nonlinear time history analysis of a full bridge model using fiber element experienced by the ground motion corresponding to the target response spectrum is accomplished. The result of time history analysis is similar to that of capacity spectrum method.

The Properties of a Nonlinear Direct Spectrum Method for Estimating the Seismic Performance (내진성능평가를 위한 비선형 직접스펙트럼법의 특성)

  • 강병두;김재웅
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.4
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    • pp.65-73
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    • 2002
  • It has been recognized that the damage control must become a more explicit design consideration. In an effort to develop design methods based on performance it is clear that the evaluation of the nonlinear response is required. The methods available to the design engineer today are nonlinear time history analyses, monotonic static nonlinear analyses, or equivalent static analyses with simulated nonlinear influences. Some building codes propose the capacity spectrum method based on the nonlinear static analysis(pushover analysis) to determine the earthquake-induced demand given by the structure pushover curve. These procedures are conceptually simple but iterative and time consuming with some errors. This paper presents a nonlinear direct spectrum method(NDSM) to evaluate seismic performance of structures, without iterative computations, given by the structural initial elastic period and yield strength from the pushover analysis, especially for MDF(multi degree of freedom) systems. The purpose of this paper is to investigate the accuracy and confidence of this method from a point of view of various earthquakes and unloading stiffness degradation parameters. The conclusions of this study are as follows; 1) NDSM is considered as practical method because the peak deformations of nonlinear system of MDF by NDSM are almost equal to the results of nonlinear time history analysis(NTHA) for various ground motions. 2) When the results of NDSM are compared with those of NTHA. mean of errors is the smallest in case of post-yielding stiffness factor 0.1, static force by MAD(modal adaptive distribution) and unloading stiffness degradation factor 0.2~0.3.