• Title/Summary/Keyword: 확장된 Galerkin 방법

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Free Vibration Responses of Composite Plates Subjected to Transverse Magnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 판의 자유진동응답)

  • Kim, Sung-Kyun;Choi, Jong-Woon;Kim, Young-June;Park, Sang-Yun;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.136-142
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    • 2011
  • The equations of motion for composite plates incorporating magneto-thermo-elastic effects have been derived via Hamilton's principle. In order to get the insight into the implications of a number of geometrical and physical features of the system, the vibrational responses of finite composite rectangular plates immersed in a transversal magnetic field are investigated by applying the extended Galerkin method. The vibration response characteristics of a composite plate are exploited in connection with the magnetic field intensity, thermal load, and electric conductivity of fibrous composite materials. Some pertinent conclusions, which highlight the various effects induced by the magneto-thermo-elastic couplings, are outlined.

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Development of Finite Element Method for the Extended Boussinesq Equations (확장형 Boussinesq 방정식의 유한요소모형 개발)

  • Woo, Seung-Buhm;Choi, Young-Kwang;Yoon, Byung-Il
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.3
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    • pp.133-141
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    • 2007
  • A finite element model is developed for the extended Boussinesq equations that is capable of simulating the dynamics of long and short waves. Galerkin weighted residual method and the introduction of auxiliary variables for 3rd spatial derivative terms in the governing equations are used for the model development. The Adams-Bashforth-Moulton Predictor Corrector scheme is used as a time integration scheme for the extended Boussinesq finite element model so that the truncation error would not produce any non-physical dispersion or dissipation. This developed model is applied to the problems of solitary wave propagation. Predicted results is compared to available analytical solutions and laboratory measurements. A good agreement is observed.

Hybrid Element Model for Wave Transformation Analysis (파랑 변형 해석을 위한 복합 요소 모형)

  • 정태화;박우선;서경덕
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.15 no.3
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    • pp.159-166
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    • 2003
  • In this study, we develop a finite element model to directly solve the Laplace equation while keeping the same computational efficiency as the models based on the extended mild-slope equation which has been widely used for calculation of wave transformation in shallow water. For this, the computational domain is discretized into finite elements with a single layer in the vertical direction. The velocity potential in the element is then expressed in terms of the potentials at the nodes located at water surface, and the Galerkin method is used to construct the numerical model. A common shape function is adopted in horizontal direction, and the cosine hyperbolic function in vertical direction, which describes the vertical behavior of progressive waves. The model was developed for vertical two-dimensional problems. In order to verify the developed model, it is applied to vertical two-dimensional problems of wave reflection and transmission. It is shown that the present finite element model is comparable to the models based on extended mild-slope equations in both computational efficiency and accuracy.

Vibration and Stability of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 원통셸의 진동 및 안정성해석)

  • Park, Sang-Yun;Kang, Sunghwan;Seo, Jung Seok;Song, Ohseop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.23 no.9
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    • pp.797-805
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    • 2013
  • In this paper vibration and stability analysis of laminated composite shells based on the first order shear deformation theory(FSDT) for two different boundary conditions(clamped-clamped, simply supported) are performed. Structural model of cross-ply symmetric laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations)and thermal equations which are involved in constitutive equations. Extended Galerkin method is adopted to obtain the discretized equations of motion. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, laminate thickness-ratio and radius ratio for two boundary conditions are investigated and pertinent conclusions are derived.

Vibration Analysis of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 원통셸의 진동해석)

  • Park, Sang-Yun;Kim, Sung-Kyun;Choi, Jong-Woon;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.8
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    • pp.791-799
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    • 2012
  • In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT was performed through discretization of equations of motion and boundary condition. Structural model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence are investigated and pertinent conclusions are derived.

Study on the Dynamic Characteristics of Composite Shells Subjected to an Electromagnetic Field (자기장을 받는 복합재료 원통쉘의 동적특성 연구)

  • Park, Sang-Yun;Kim, Sung-Kyun;Choi, Jong-Woon;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.04a
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    • pp.748-754
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    • 2012
  • In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT was performed through discretization of equations of motion and boundary condition. Model of laminated composite shells subjected to a combination of magnetic and thermal fields is developed. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Dynamic characteristic of composite shells for change of magnetic fields is investigated.

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Dynamic Characteristics of Composite Plates Subjected to Electromagnetic Field (자기장을 받는 복합재료 판의 동적 특성 연구)

  • Kim, Sung-Kyun;Lee, Kune-Woo;Moon, Jei-Kwon;Choi, Jong-Woon;Kim, Young-Jun;Park, Sang-Yun;Song, Oh-Seop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.681-688
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    • 2011
  • Structural model of laminated composite plates based on the first order shear deformable plate theory and subjected to a combination of magnetic and thermal fields is developed. Coupled equations of motion are derived via Hamilton's principle on the basis of electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. In order to obtain the implications of a number of geometrical and physical features of the model, one special case is investigated, that is, free vibration of a composite plate immersed in a transversal magnetic field. Special coupling effects between the magnetic and elastic fields are revealed in this paper.

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Vibration Analysis of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields with Different Boundary Conditions (경계조건에 따른 자기장 및 열하중을 받는 복합재료 원통셸의 진동해석)

  • Park, Sang-Yun;Kim, Sung-Kyun;Choi, Jong-Woon;Song, Ohseop
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.653-660
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    • 2012
  • In this paper free vibration analysis of symmetric and cross-ply elastic laminated shells based on FSDT with two different boundary conditions(C-C, S-S) was performed through discretization of equations of motion and boundary condition. Model of laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations (Faraday, Ampere, Ohm, and Lorenz equations) and thermal equations which are involved in constitutive equations. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, and stacking sequence for each boundary conditions are investigated and pertinent conclusions are derived.

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Dynamic Characteristics of Composite Plates Subjected to Electromagnetic and Thermal Fields (자기장 및 열하중을 받는 복합재료 판의 동적 특성)

  • Kim, Sung-Kyun;Lee, Kune-Woo;Moon, Jei-Kwon;Choi, Jong-Woon;Kim, Young-Jun;Park, Sang-Yun;Song, Oh-Seop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.6
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    • pp.536-545
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    • 2011
  • Structural model of laminated composite plates based on the first order shear deformable plate theory and subjected to a combination of magnetic and thermal fields is developed. Coupled equations of motion are derived via Hamilton's principle on the basis of electromagnetic equations (Faraday, Ampere, Ohm, and Lorentz equations) and thermal ones which are involved in constitutive equations. In order to reveal the implications of a number of geometrical and physical features of the model, free vibration of a composite plate immersed in a transversal magnetic field and subjected to a temperature gradient is considered. Special coupling effects between the magnetic-thermal-elastic fields are revealed in this paper.

Analysis of RTM Process Using the Extended Finite Element Method (확장 유한 요소 법을 적용한 RTM 공정 해석)

  • Jung, Yeonhee;Kim, Seung Jo;Han, Woo-Suck
    • Composites Research
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    • v.26 no.6
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    • pp.363-372
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    • 2013
  • Numerical simulation for Resin Transfer Molding manufacturing process is attempted by using the eXtended Finite Element Method (XFEM) combined with the level set method. XFEM allows to obtaining a good numerical precision of the pressure near the resin flow front, where its gradient is discontinuous. The enriched shape functions of XFEM are derived by using the level set values so as to correctly describe the interpolation with the resin flow front. In addition, the level set method is used to transport the resin flow front at each time step during the mold filling. The level set values are calculated by an implicit characteristic Galerkin FEM. The multi-frontal solver of IPSAP is adopted to solve the system. This work is validated by comparing the obtained results with analytic solutions. Moreover, a localization method of XFEM and level set method is proposed to increase the computing efficiency. The computation domain is reduced to the small region near the resin flow front. Therefore, the total computing time is strongly reduced by it. The efficiency test is made with a simple channel flow model. Several application examples are analyzed to demonstrate ability of this method.