• Title, Summary, Keyword: 비선형 동적해석

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Finite element dynamic analysis of laminated composite shell structures considering geometric nonlinear effects (기하학적 비선형 효과를 고려한 복합재료 적층 쉘 구조의 유한요소 동적 해석)

  • Lee, Sang-Youl
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.11
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    • pp.5979-5986
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    • 2013
  • This study carried out a geometrical nonlinear dynamic analysis of laminated composite shell structures. Based on the first-order shear deformation shell theory and nonlinear formulation of Sanders, the Newmark method and Newton-Raphson iteration are used for dynamic solution considering nonlinear effects. The effects of radius, fiber angles, and layup 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, and the new results reported in this paper show the significant interactions between the radius, fiber angles and layup sequence in the laminate. Key observation points are discussed and a brief design guideline of laminated composite shells is given.

A Method for Vibration and Sensitivity Analysis of Structure Systems with Non-linear Characteristics (비선형 특성을 가진 구조시스템의 진동과 감도해석 방법)

  • Moon, Byung-Young;Kim, Sa-Soo;Iwatsubo, Takuzo
    • Journal of Ocean Engineering and Technology
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    • v.13 no.4
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    • pp.10-18
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    • 1999
  • 본 논문에서는 대형구조물의 해석에 있어서 부분구조합성법과 섭동법을 이용하여 복잡한 비선형시스템의 해석방법을 제안하였다. 해석방법은 전체시스템을 먼저 몇 개의 분계로 분할한다. 각 분계의 운동방정식에 비선형항이 존재하여도 전체시스템의 지배적 진동모드는 선형모드라는 가정하에 이 시스템의 각 분계를 모드좌표로 변환한다. 이때, 비선형항은 근사적으로 변환한다. 그리고 섭동법을 이용하여 각 분계의 모드좌표방정식은 섭동좌수별로 정식화되어 순차적으로 구해진다. 비선형의 감도는 비선형계수로 정의되고, 그에 상응하는 강성에 의해 구해진다. 제안된 해석방법으로 비선형회전체, 비선형 베어링-페데스탈로 구성된 대형시계구조물의 진동을 해석하였다. 해석방법의 유효성을 평가하기 위해 응답의 정도와 계산소요시간을 유한요소법의 결과와 비교 분석하였다.

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Simplified seismic analysis of underground rectangular structures (박스 지하 구조물의 간편 내전해석)

  • Park, Inn-Joon;Park, Seong-Yong;Kim, Soo-Il;Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.7 no.3
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    • pp.249-257
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    • 2005
  • There are basically two methods for the seismic design of underground structures ; analytical or pseudo-static, and dynamical method. In pseudo-static analysis approach, the ground deformations are imposed as a static load and soil-structure interaction does not include dynamic or wave propagation effects. However the behavior of soil structure interaction is nonlinear, it needs to consider nonlinear soil-structure interaction effects. In this study simplified seismic analysis method to consider soil-structure interaction by iterative procedure is proposed and the results are compared and analyzed by a finite difference computer program.

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Efficient Dynamic Analysis of High-rise Buildings Having Belt Walls Connected by a Sky-Bridge (스카이브릿지로 연결된 벨트월이 있는 고층건물의 효율적인 동적해석)

  • Lee, Dong-Guen;Kim, Hyun-Su;Yang, Ah-Ram;Ko, Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.3
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    • pp.231-242
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    • 2009
  • In the design of a sky-bridge, repetitive boundary nonlinear time history analyses are required to accurately predict dynamic behaviors of the connected buildings because the connection systems of a sky-bridge usually have high nonlinearity. If a conventional finite element model for entire high-rise buildings is used for repetitive boundary nonlinear time history analyses, computational efforts could be significant. In this study, an equivalent cantilever model considering the belt-wall effect has been proposed for an efficient dynamic analysis and a performance evaluation of vibration control of high-rise buildings connected by a sky-bridge. To verify the accuracy and efficiency of the proposed equivalent model, boundary nonlinear time history analyses of 49- and 42-story example buildings connected by a sky-bridge have been performed for wind excitation. Based on the analytical results, it has been verified that the proposed equivalent model can provide accurate dynamic responses of building structures connected by a sky-bridge with significantly reduced computational efforts.

Effect of Aerodynamic Nonlinearity on Drive-Train of Wind Turbine (공기역학적 비선형성이 풍력발전기 드라이버-트레인에 미치는 영향)

  • Lim, Chae-Wook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.235-235
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    • 2010
  • 풍력발전기의 공기역학적 비선형성은 풍력발전기 전체 시스템의 동적특성에 영향을 미친다. 풍력발전기의 드라이버-트레인의 감쇠가 매우 작으므로 풍력발전기를 제어함에 있어 드라이버-트레인의 동적특성은 중요하게 고려되어야 한다. 본 논문에서는 풍속에 따른 공기역학적 비선형성이 드라이버-트레인의 동적특성에 미치는 영향을 해석적으로 살펴보고자 한다.

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A New Methodology for Seismic Capacity Evaluation of Low-rise R/C Buildings (비선형요구내력스펙트럼을 이용한 저층 R/C 건물의 내진성능 평가법)

  • Lee, Kang Seok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.3
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    • pp.106-115
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    • 2011
  • This study proposed a new methodology for seismic capacity evaluation of low-rise reinforced concrete (RC) buildings based on non-linear required spectrum. In order to verify the reliability of the proposed method, relationships between results obtained using the proposed method and the non-linear dynamic analyses were investigated. Compared with the seismic protection index (Es=0.6) defined in the Japanese Standard, the applicability of the method was also estimated. Research results indicate that the method proposed in this study compares reasonably well with the detailed evaluation methods. Using the seismic evaluation method developed in this study, the seismic capacity category and earthquake damage degree of low-rise RC buildings corresponding to a specific earthquake level can be effectively estimated.

A Modification Technique of Finite Element Model for Dynamic Analysis under Multiple Support Excitations (다지지점 가진에 대한 동적해석을 위한 유한요소모형의 수정기법)

  • 김재민
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.3
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    • pp.437-445
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    • 1999
  • This paper presents a simple modification technique of finite element model for dynamic analysis of linear/nonlinear structural system subjected to multiple support excitation. For the sake of verification of the proposed method, dynamic responses obtained by the present technique for a couple of linear and nonlinear structural systems were compared with those by a general-purpose structural analysis software which can deal with the multi-support analysis. The method presented in this paper is expected to be used for multiple support excitation analysis by means of a computer code without the capability of modeling the non-synchronous support motion.

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The Dynamic Post-Buckling Analysis of the Non-Conservative System including Damping Effects (감쇠효과(減衰效果)를 고려한 비보존력계(非保存力系)의 동적(動的) 후좌굴(後挫屈) 해석(解析))

  • Kim, Moon Young;Chang, Sung Pil
    • Journal of The Korean Society of Civil Engineers
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    • v.10 no.3
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    • pp.67-75
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    • 1990
  • A geometrically nonlinear analysis procedure including the damping effects is presented for the investigation of the dynamic post-divergence and post-flutter behavior of a non-conservative system. The dynamic nonlinear analysis of plane frame structure subjected to conservative and non-conservative forces is carried out by solving the equations of motion using Newmark method. Numerical results are presented to demonstrate the effects of the internal and external damping forces in the conservative and non-conservative systems.

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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.

Energy Dissipation Demand of Braces Using Non-linear Dynamic Analyses of X-Braced Frame (비선형 동적 해석을 통한 X형 가새골조 내 가새 부재의 에너지 소산)

  • Lee, Kangmin
    • Journal of Korean Society of Steel Construction
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    • v.15 no.4
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    • pp.379-388
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    • 2003
  • The response of single story buildings and other case studies were investigated to observe trends and develop a better understanding of the impact of some design parameters on the seismic response of Concentrically Braced Frames (CBF). While many parameters are known to influence the behavior of braced frames, the focus of this study was mostly on quantifying energy dissipation in compression and its effectiveness on seismic performance. Based on dynamic analyses of single story braced frame and case studies, a bracing member designed with bigger R and larger KL/r was found to result in lower normalized cumulative energy ratio in both cases.