• Title/Summary/Keyword: 강성 모델

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Model Tests for The Behavior of Propped Retaining Walls in Sand (굴착모형실험을 통한 토류벽체 및 지반거동에 관한 연구)

  • 이봉열;김학문
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.259-279
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    • 1999
  • Model tests on propped retaining walls were performed for the investigation of wall displacement, distribution of earth pressure, surface settlement and underground movement at various excavation stage in sand. The result of model tests on the trough of surface settlement showed considerable difference depending on the characteristic of wall stiffness, wall friction and soil condition. The location of maximum underground movement were found to be at range of 0.15H to 0. 1H(H: Final excavation depth). Effect of arching by the redistribution of earth pressure were closely related to the stiffness of wall as well as the soil condition. The wall displacement and earth pressure distribution were simulated by elasto - plastic beam analysis program and finite element method with GDHM model respectively. The result of elasto-plastic analysis showed some discrepancy on the wall displacement and earth pressure, but result of underground movement by FEM with various wall stiffness were in good agreement with the model tests.

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Simplified 2D Analysis for Suspension Bridges Subject to Wind Excitation (현수교 풍진동에 관한 2D 간단해석 및 변수연구)

  • Kim, Woo Seok;Lee, Jaeha
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.6
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    • pp.463-470
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    • 2013
  • In this paper, 2D simple analyses were performed in order to predict the large torsional oscillations in a suspension bridge based on Makenna and Tuama model(2001). The existing model(Makenna and Tuama, 2001) has shown unrealistic results as the wind speed increases and frequency decreases. Furthermore, resonance could not be simulated by the existing model. Therefore, in this study, new model was proposed with a consideration of the torsional resistance. The vertical and rotational behaviors of the deck in the suspension bridge were analyzed. Analysis results showed that at first vertical oscillations were observed and it was gradually transformed to the rotation oscillations. With the consideration of the torsional resistance, it was shown that vertical behavior were stabilized as time passed. However, the rotational behavior was not stabilized and was kept until the end of analysis. Beat periods decreased while the wind speed increased. The resonance of the rotational mode was dependent to the rotational resistance. Obtained results could be applied for the design of the suspension bridge under the wind load.

Finite Element Model Updating of Simple Beam Considering Boundary Conditions (경계조건을 고려한 단순보의 유한요소모델개선)

  • Kim, Se-Hoon;Park, Young-Soo;Kim, Nam-Gyu;Lee, Jong-Jae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.2
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    • pp.76-82
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    • 2018
  • In this present study, in order to update the finite element model considering the boundary conditions, a method has been proposed. The conventional finite element model updating method, updates the finite element model by using the dynamic characteristics (natural frequency, mode shape) which can be estimated from the ambient vibration test. Therefore, prediction of the static response of an actual structure is difficult. Furthermore, accurate estimation of the physical properties is relatively hard. A novel method has been proposed to overcome the limitations of conventional method. Initially, the proposed method estimates the rotational spring constant of a finite element model using the deflection of structure and the rotational displacement of support measurements. The final updated finite element model is constructed by estimating the material properties of the structure using the finite element model with updated rotational spring constant and the dynamic characteristics of the structure. The proposed finite element model updating method is validated through numerical simulation and compared with the conventional finite element model updating method.

Nonlinear Modeling of RC Shear Walls Using Fiber and Shear Spring Elements (전단스프링과 섬유요소를 이용한 철근콘크리트 전단벽의 비선형 해석모델에 관한 연구)

  • Lee, Kwang-Ho;You, Tae-Sang;Kim, Tae-Wan;Jeong, Seong-Hoon
    • Journal of the Korea Concrete Institute
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    • v.24 no.5
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    • pp.559-566
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    • 2012
  • In this study, fiber elements and a spring are used to build a reinforced concrete shear wall model. The fiber elements and the spring reflect flexural and shear behaviors of the shear wall, respectively. The fiber elements are built by inputting section data and material properties. The spring parameters representing strength and stiffness degradation, pinching, and slip were determined by comparing behaviors of fiber element and VecTor2 results. 'Pinching4' model in OpenSees is used for shear spring. The parameter selecting process for shear spring is a complicated and time consuming process. To study the applicability of the fiber element, reinforced concrete buildings containing a shear wall are evaluated using nonlinear dynamic analysis with various wall aspect ratio (H/L), various beam heights, and stiffness and flexural strength of beam and wall ratios. The aspect ratio of the wall showed distinct difference in IDR (interstory drift ratio) of the models with and without spring. On the other hand, the height of beam and ratio of stiffness and flexural strength of beam and wall did not show clear relation.

CANFLEX 연료봉 다발의 진동특성

  • 박진석;정장환
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05d
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    • pp.306-311
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    • 1996
  • CANFLEX 연료봉 다발을 구성하는 우라늄 펠릿이 장전된 핵연료봉의 공기중 진동특성을 진동 실험과 유한요소 해석을 통하여 구하였다. 유한요소 해석 시에는 우라늄 펠릿의 강성은 무시하고 질량은 지르칼로이 튜브에 부가하며, 연료봉 양단의 용접부위를 단순 지지보로 처리하는 모델을 제시하였다. 이 모델로부터 얻은 해석결과를 진동실험에서 구한 측정값과 비교하였다.

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