• Title/Summary/Keyword: spurious

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Non-conforming Plate Bending Element with Variable-nodes (변절점을 가진 비적합 평판휨 요소)

  • 최창근;이태열
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.409-416
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    • 2001
  • The present work is concerned with the development of new variable-node Mindlin plate bending elements. The proposed variable-node elements pass the patch tests, do not show spurious zero-energy modes, and do not produce shear locking phenomena. It is also shown that the elements produce reliable solutions through numerical tests for standard benchmark problems.

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Triangular Plate-Bending Element by Combined node (절점 병합에 의한 삼각형 평판휨 요소)

  • 최창근;강윤숙;이태열
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.10a
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    • pp.104-111
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    • 2002
  • A new triangular element fur the finite element analysis of plate-bending problems is presented. For the purpose of sharing the program code of 4 node plate-bending element, two nodes of the 4-node element are combined to form a triangular element. Thus, the presented element would bring about great deal of efficiency of the computer program. The proposed variable-node elements pass the patch tests, do not show spurious zero-energy modes, and do not produce shear locking phenomena. It is also shown that the elements produce reliable solutions through numerical tests for standard benchmark problems.

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An Improved Quadratic Finite Element with Modified Integration Order (수정된 적분차수를 이용한 평면유한요소의 개선)

  • 김선훈;김주일;이창원;신재철
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.04a
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    • pp.42-49
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    • 2001
  • In this paper the efficient finite element for stress analysis of plane stress/strain problems is proposed. This element is achieved by adding the bubble-mode function to 8-node element. The stiffness matrix of the element is calculated by using modified numerical integration order to avoid spurious zero energy mode. In order to demonstrate the performance of this element numerical tests for various verification problems are carried out. The results of numerical tests show accuracy and reliability of the element presented in this paper.

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New Approach for Nonlinear Analysis of Reinforced Concrete Frames (철근콘크리트 골조 비선형해석의 새로운 기법)

  • 김진근;이태규;양주경
    • Proceedings of the Korea Concrete Institute Conference
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    • 1992.04a
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    • pp.47-52
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    • 1992
  • The entire nonlinear behavior of reinforced concrete frames up to collapse, is analyzed by the displacement control method and the combined layered and nonlayered method. All of the rigidities of section are calculated approximately by a sum over all the layers for the layered method, are used the integral values over the cross section area for the nonlayered method. The spurious sensitivity to the chosen element size in the result of analysis by finite element method for the materials with strain-softening can be overcome by modifying the strain distribution based on the concept of fracture energy at plastic hinge considering the applied axial load.

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The Kaiser Rocket Effect in Cosmology

  • Bahr-Kalus, Benedict
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.43.3-43.3
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    • 2021
  • The peculiar motion of the observer, if not (or only imperfectly) accounted for, is bound to induce a well-defined clustering signal in the distribution of galaxies. This spurious signal is related to the Kaiser rocket effect. We examined the amplitude of this effect and discuss possible implications for analysis and interpretation of future cosmological surveys. We found that it can in principle bias very significantly the inference of cosmological parameters, especially for primordial non-Gaussianity.

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Improvement of Enhanced Assumed Strain Four-node Finite Element Based on Reissner-Mindlin Plate Theory (개선된 추가변형률 4절점 평판휨 요소)

  • Chun, Kyoung Sik;Park, Dae Yong;Chang, Suk Yoon
    • Journal of Korean Society of Steel Construction
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    • v.16 no.3 s.70
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    • pp.295-303
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    • 2004
  • In this paper, an improved four-node Reissner-Mindlin plate-bending element with enhanced assumed strain field is presented for the analysis of isotropic and laminated composite plates. To avoid the shear locking and spurious zero energy modes, the transverse shear behavior is improved by the addition of a new enhanced shear strain based on the incompatible displacement mode approach and bubble function. The "standard" enhanced strain fields (Andelfinger and Ramm, 1993) are also employed to improve the in-plane behaviors of the plate elements. The four-node quadrilateral element derived using the first-order shear deformation theory is designated as "14EASP". Several applications are investigated to assess the features and the performances of the proposed element. The results are compared with other finite element solutions and analytical solutions. Numerical examples show that the element is stable, invariant, passes the patch test, and yields good results especially in highly distorted regimes.

Development of Walk-down Performance Procedures for Fire Modeling of Nuclear Power Plants based on Deterministic Fire Protection Requirements (결정론적 화재방호요건을 기반으로 한 원자력발전소 화재모델링 현장실사 수행절차 개발)

  • Moon, Jongseol;Lee, Jaiho
    • Fire Science and Engineering
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    • v.33 no.6
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    • pp.43-52
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    • 2019
  • A walk-down procedure for fire modeling of nuclear power plants, based on deterministic fire protection requirements, was developed. The walk-down procedure includes checking the locations of safety shutdown equipment and cables that are not correctly indicated on drawings and identifying the existence and location of combustibles and ignition sources. In order to verify the performance of the walk-down procedure developed in this study, a sample of important equipment and cables were selected for hypothetical multiple spurious operation (MSO) scenarios. In addition, the hypothetical fire modeling scenarios were derived from the selected safe shutdown equipment and cables and an actual walk-down was conducted. The plant information collected through the walk-down was compared to the information obtained from the drawings, so that the collected information may be used as input values for the fire modeling.

Behavior of Poisson Bracket Mapping Equation in Studying Excitation Energy Transfer Dynamics of Cryptophyte Phycocyanin 645 Complex

  • Lee, Weon-Gyu;Kelly, Aaron;Rhee, Young-Min
    • Bulletin of the Korean Chemical Society
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    • v.33 no.3
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    • pp.933-940
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    • 2012
  • Recently, it has been shown that quantum coherence appears in energy transfers of various photosynthetic lightharvesting complexes at from cryogenic to even room temperatures. Because the photosynthetic systems are inherently complex, these findings have subsequently interested many researchers in the field of both experiment and theory. From the theoretical part, simplified dynamics or semiclassical approaches have been widely used. In these approaches, the quantum-classical Liouville equation (QCLE) is the fundamental starting point. Toward the semiclassical scheme, approximations are needed to simplify the equations of motion of various degrees of freedom. Here, we have adopted the Poisson bracket mapping equation (PBME) as an approximate form of QCLE and applied it to find the time evolution of the excitation in a photosynthetic complex from marine algae. The benefit of using PBME is its similarity to conventional Hamiltonian dynamics. Through this, we confirmed the coherent population transfer behaviors in short time domain as previously reported with a more accurate but more time-consuming iterative linearized density matrix approach. However, we find that the site populations do not behave according to the Boltzmann law in the long time limit. We also test the effect of adding spurious high frequency vibrations to the spectral density of the bath, and find that their existence does not alter the dynamics to any significant extent as long as the associated reorganization energy is changed not too drastically. This suggests that adopting classical trajectory based ensembles in semiclassical simulations should not influence the coherence dynamics in any practical manner, even though the classical trajectories often yield spurious high frequency vibrational features in the spectral density.

Performance Analysis of RF Transformation in DS/CDMA Receiver (DS/CDMA수신기에서 RF변환부의 성능분석)

  • Pyeon, Suk-Bum;Ju, Jae-Han
    • Journal of the Korean Institute of Telematics and Electronics T
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    • v.35T no.2
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    • pp.86-92
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    • 1998
  • In this paper, it is derived the system design parameters for the J-STD-018 of the PCS mobile station(MS) minimum performance using DS/CDMA analyzed the system performance due to the receiver components. The simulation shows the selectivity is -70.96dB at 1.25MHz frequency offset from the carrier frequency while the MS noise figure to satisfy J-STD-018 is 10dB and the input 3rd harmonics intercept point of the MS class I and MS class II-V is -9.5dBm and -14dBm respectively. When the interference power level at the receiver is small, the receiver has better performance as we increase the gain of LNA. However, when the interference level at the receiver is large, the receiver performance is decreased by the effect of the spurious. Thus, the effectiveness of LNA On/Off switching technique is proved as to reduce the effect of the spurious.

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