• Title/Summary/Keyword: 유한요소모델갱신

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Forced Vibration Test of a Real-Scale Structure and Design of HMD Controllers for Simulating Earthquake Response (실물 크기 구조물의 강제진동실험 및 지진응답 모사를 위한 HMD제어기 설계)

  • Lee, Sang-Hyun;Park, Eun-Churn;Youn, Kyung-Jo;Lee, Sung-Kyung;Yu, Eun-Jong;Min, Kyung-Won;Chung, Lan;Min, Jeong-Ki;Kim, Young-Chan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.6 s.52
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    • pp.103-114
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    • 2006
  • Forced vibration testing is important for correlating the mathematical model of a structure with the real one and for evaluating the performance of the real structure. There exist various techniques available for evaluating the seismic performance using dynamic and static measurements. In this paper, full scale forced vibration tests simulating earthquake response are implemented by using a hybrid mass damper. The finite element (FE) model of the structure was analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. Pseudo-earthquake excitation tests showed that HMD induced floor responses coincided with the earthquake induced ones which were numerically calculated based on the updated FE model.

Computational Efficiency on Frequency Domain Analysis of Large-scale Finite Element Model by Combination of Iterative and Direct Sparse Solver (반복-직접 희소 솔버 조합에 의한 대규모 유한요소 모델의 주파수 영역 해석의 계산 효율)

  • Cho, Jeong-Rae;Cho, Keunhee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.2
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    • pp.117-124
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    • 2019
  • Parallel sparse solvers are essential for solving large-scale finite element models. This paper introduces the combination of iterative and direct solver that can be applied efficiently to problems that require continuous solution for a subtly changing sequence of systems of equations. The iterative-direct sparse solver combination technique, proposed and implemented in the parallel sparse solver package, PARDISO, means that iterative sparse solver is applied for the newly updated linear system, but it uses the direct sparse solver's factorization of previous system matrix as a preconditioner. If the solution does not converge until the preset iterations, the solution will be sought by the direct sparse solver, and the last factorization results will be used as a preconditioner for subsequent updated system of equations. In this study, an improved method that sets the maximum number of iterations dynamically at the first Krylov iteration step is proposed and verified thereby enhancing calculation efficiency by the frequency domain analysis.

Compressive and failure behaviour of composite egg-box panel using non-orthogonal constitutive model (비 직교 물성 모델을 이용한 복합재료 계란판의 압축거동 및 파손)

  • Hahn, Young-Won;Chang, Seung-Hwan;Ryu, Yong-Mun;Cheon, Seong-Sik
    • Composites Research
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    • v.22 no.4
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    • pp.20-26
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    • 2009
  • In the current study, thermoforming and compression analysis were carried out for the woven composite egg-box panel with the non-orthogonal constitutive material model, which is proposed by Xue et al. The material model is implemented in commercial engineering software, LS-DYNA, with a user subroutine. Directional properties in non-orthogonal coordinates are determinedusing the deformation gradient tensor and the material modulus matrix in local coordinate is updated at eaeh corresponding time step. After the implemented non-orthogonal constitutive model is verified by the bias extension test, the egg-box panel simulations are performed. The egg-box panel simulations are divided into two categories: thermoforming (draping) and crushing. The finite element model for crushing analysiscan be obtained using the displacement result of thermoforming process.

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.

System Identification of Real-Scale Structures Using Forced Vibration Test (실물크기 구조물의 강제진동 실험을 통한 시스템 식별)

  • Youn, Kyung-Jo;Lee, Sang-Hyun;Park, Eun-Churn;Yu, Eun-Jong;Min, Kyung-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.195-200
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    • 2007
  • System identification of real-scale structure is performed using forced vibration test. There exist various techniques available for identifying the dynamic characteristis of structures using dynamic and static measurements. In this study, The finite element(FE) model of the structure is analytically constructed using ANSYS and the model was updated using the results experimentally measured by the forced vibration test. forced vibration tests showed that Hybrid Mass Damper induced floor responses coincided with the earthquake induced ones which was numerically calculated based on the updated FE model.

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Interior Eigenvalue Computation Using Algebraic Substructuring (대수학 부구조법을 이용한 내부 고유치 계산)

  • Ko, Jin-Hwan;Byun, Do-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.6
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    • pp.743-749
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    • 2007
  • Algebraic substructuring (AS) is a state-of-the-art method in eigenvalue computations, especially for large size problems, but, originally, it was designed to calculate only the smallest eigenvalues. In this paper, an updated version of AS is proposed to calculate the interior eigenvalues over a specified range by using a shift value, which is referred to as the shifted AS. Numerical experiments demonstrate that the proposed method has better efficiency to compute numerous interior eigenvalues for the finite element models of structural problems than a Lanczos-type method.