• Title, Summary, Keyword: drilling rotational stiffness

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Development of Reinforced Concrete Shell Element with Drilling Rotational Stiffness (면내회전강성도를 갖는 철근콘크리트 쉘요소의 개발)

  • 김태훈;유영화;신현목
    • Journal of the Korea Concrete Institute
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    • v.11 no.6
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    • pp.47-56
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    • 1999
  • In this paper, a nonlinear finite element procedure is presented for the analysis of reinforced concrete shell structures. The 4-node quadrilateral flat shell finite element with drilling rotational stiffness is developed. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. The steel reinforcement is assumed to be in a uniaxial stress state and to be a smeared in a layer. The proposed numerical method for nonlinear analysis of reinforce concrete shells will be verified by comparison with reliable experimental results.

Nonlinear Analysis of Reinforced and Prestressed Concrete Shells Using Layered Elements with Drilling DOF

  • Kim Tae-Hoon;Choi Jung-Ho;Kim Woon-Hak;Shin Hyun Mock
    • Journal of the Korea Concrete Institute
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    • v.17 no.4
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    • pp.645-654
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    • 2005
  • This paper presents a nonlinear finite element procedure for the analysis of reinforced and prestressed concrete shells using the four-node quadrilateral flat shell element with drilling rotational stiffness. A layered approach is used to discretize, through the thickness, the behavior of concrete, reinforcing bars and tendons. Using the smeared-crack method, cracked concrete is treated as an orthotropic nonlinear material. The steel reinforcement and tendon are assumed to be in a uni-axial stress state and to be smeared in a layer. The constitutive models, which cover the loading, unloading, and reloading paths, and the developed finite element procedure predicts with reasonable accuracy the behavior of reinforced and prestressed concrete shells subjected to different types of loading. The proposed numerical method fur nonlinear analysis of reinforced and prestressed concrete shells is verified by comparison with reliable experimental results.

A Computational Platform for Nonlinear Analysis of Prestressed Concrete Shell Structures

  • Kim, Tae-Hoon;Shin, Hyun-Mock
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.6
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    • pp.593-606
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    • 2010
  • This paper presents a formulation to include the prestressing effects in available numerical models for the nonlinear material, instantaneous and long-term analysis of prestressed concrete shell structures, based on the displacement formulation of the finite element method. A four-node flat shell element is adopted for nonlinear analysis of prestressed concrete shells. This element was incorporated into an existing general-purpose finite element analysis program. A distinctive characteristic of the element is its capability to simulate the behavior of shells subjected to a variety of types of loading and drilling rotational stiffness. Consequently, the response of prestressed concrete shell structures can be predicted accurately using the proposed nonlinear finite element procedure.

Thrust Bearing Design for High-Speed Composite Air Spindles (고속 복합재료 공기 주축부를 위한 추력베어링 설계)

  • Bang, Kyung-Geun;Lee, Dai-Gil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.10
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    • pp.1997-2007
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    • 2002
  • Composite air spindles are appropriate for the high-speed and the high-precision machining as small hole drilling of printed circuit board (PCB) or wafer cutting for manufacturing semiconductors because of the low rotational inertia, the high damping ratio and the high fundamental natural frequency of composite shaft. The axial load and stiffness of composite air spindles fur drilling operation are determined by the thrust ben ring composed of the air supply part mounted on the housing and the rotating part mounted on the rotating shaft. At high-speed rotation, the rotating part of the thrust bearing should be designed considering the stresses induced by centrifugal force as well as the axial stiffness and the natural frequency of the rotating shaft to void the shaft from failure due to the centrifugal force and resonant vibration. In this work, the air supply part of the thrust bearing was designed considering the bending stiffness of the bearing and the applied load. The rotating part of the thrust bearing was designed through finite element analysis considering the cutting forces during manufacturing as well as the static and dynamic characteristics under both the axial and con trifugal forces during high-speed rotation.

A Four-node General Shell Element with Drilling DOFs (면내회전자유도를 갖는 4절점 곡면 쉘요소)

  • Chung, Keun-Young;Kim, Jae-Min;Lee, Eun-Haeng
    • Journal of the Earthquake Engineering Society of Korea
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    • v.16 no.4
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    • pp.37-52
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    • 2012
  • In this study, a new 4-node general shell element with 6 DOFs per node is presented. Drilling rotational degrees of freedom are introduced by the variational principle with an independent rotation field. In formulation of the element, substitute transverse shear strain fields are used to avoid shear locking, while four nonconforming modes are applied in the in-plane displacement fields as a remedy for membrane locking. In addition, a direct modification method for nonconforming modes is employed in the numerical implementation of nonconforming modes to represent constant strain states. A 9-points integration rule is adopted for volume integration in the computation of the element stiffness matrix. With the combined use of these techniques, the developed shell element has no spurious zero energy modes, and can represent a constant strain state. Several numerical tests are carried out to evaluate the performance of the new element developed. The test results show that the behavior of the elements is satisfactory.

Seismic Analysis of Reinforced Concrete Shear Wall (철근콘크리트 전단벽의 지진해석)

  • 김태훈;박지홍;박재근;최강룡;신현목
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.180-187
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    • 2003
  • The purpose of this study is to investigate the seismic behavior of reinforced concrete shear wall subjected to earthquake motions. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), was used for the analysis of reinforced concrete structures. A 4-node flat shell element with drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Solution of the equations of motion is obtained by numerical integration using Hither-Hughes-Taylor(HHT) algorithm. The proposed numerical method for the seismic analysis of reinforced concrete shear wall is verified by comparison of analysis results with reliable experimental results.

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Nonlinear Dynamic Analysis of Reinforced Concrete Containment Panel (철근콘크리트 격납 패널의 비선형 동적해석)

  • 박재근;김태훈;신현목
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.591-598
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    • 2003
  • The purpose of this study is to investigate the seismic behavior of reinforced concrete Containment Panel subjected to earthquake motions. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), was used for the analysis of reinforced concrete structures. A 4-node flat shell element with drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Solution of the equations of motion is obtained by numerical integration using Hither-Hughes-Taylor(HHT) algorithm. The proposed numerical method for the seismic analysis of reinforced concrete Containment panel is verified by comparison of analysis results with reliable experimental results.

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Nonlinear Dynamic Analysis of Reinforced Concrete Shells Using Layered Elements with Drilling DOF (회전자유도를 갖는 층상화 요소를 이용한 철근콘크리트 쉘구조의 비선형 동적해석)

  • 김태훈;이상국;신현목
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.6
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    • pp.21-27
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    • 2001
  • In this paper, a nonlinear finite element procedure is presented for the dynamic analysis of reinforced concrete shells. A computer program, named RCAHEST(reinforced concrete analysis in higher evaluation system technology), for the analysis of reinforced concrete structures was used. A 4-node flat shell element will drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Solution of the equations of motion is obtained by numerical integration using Hilber-Hughes-Taylor(HHT) algorithm. The proposed numerical method for the nonlinear dynamic analysis of reinforced concrete shells is verified by comparison with reliable analytical results.

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Nonlinear dynamic analysis of reinforced concrete shell structures

  • Kim, T.H.;Park, J.G.;Choi, J.H.;Shin, H.M.
    • Structural Engineering and Mechanics
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    • v.34 no.6
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    • pp.685-702
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    • 2010
  • In this paper, a nonlinear finite element procedure is presented for the dynamic analysis of reinforced concrete shell structures. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), was used. A 4-node flat shell element with drilling rotational stiffness was used for spatial discretization. The layered approach was used to discretize the behavior of concrete and reinforcement in the thickness direction. Material nonlinearity was taken into account by using tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach was incorporated. The low-cycle fatigue of both concrete and reinforcing bars was also considered to predict a reliable dynamic behavior. The solution to the dynamic response of reinforced concrete shell structures was obtained by numerical integration of the nonlinear equations of motion using Hilber-Hughes-Taylor (HHT) algorithm. The proposed numerical method for the nonlinear dynamic analysis of reinforced concrete shell structures was verified by comparison of its results with reliable experimental and analytical results.

Seismic Performance Assessment of RC Pier Walls under Cyclic Out-of-plane Loading (면외방향으로 반복하중을 받는 철근콘크리트 벽식 교각의 내진성능평가)

  • Kim, Tae-Hoon;Kim, Young-Jin;Shin, Hyun-Mock
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.5
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    • pp.73-83
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    • 2006
  • The purpose of this study is to investigate the seismic behavior of reinforced concrete pier walls under cyclic out-of-plane loading and to develop improved seismic design criteria. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. A 4-node flat shell element with drilling rotational stiffness is used for spatial discretization. The layered approach is used to discretize the behavior of concrete and reinforcement through the thickness. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The method is verified a useful tool to assess the seismic performance of reinforced concrete pier walls subjected to cyclic out-of-plane load through comparing with reliable experimental results.