• Title, Summary, Keyword: Higher order zig-zag theory

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HIGHER ORDER ZIG-ZAG PLATE THEORY FOR COUPLED THERMO-ELECTRIC-MECHANICAL SMART STRUCTURES (열-기계-전기 하중이 완전 연계된 지능 복합재 평판의 지그재그 고차이론)

  • 오진호;조맹효
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.114-117
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    • 2001
  • A higher order zig-zag plate theory is developed to refine accurately predict fully coupled of the mechanical, thermal, and electric behaviors. Both the displacement and temperature fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. Linear zig-zag form is adopted in the electric field. The layer-dependent degrees of freedom of displacement and temperature fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses and transverse heat flux The numerical examples of coupled and uncoupled analysis are demonstrated the accuracy and efficiency of the present theory. The present theory is suitable for the predictions of fully coupled behaviors of thick smart composite plate under mechanical, thermal, and electric loadings.

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Damping Analysis of Composite Plates with Zig-Zag Triangular Element (지그재그 삼각형 유한요소를 이용한 복합재료판의 Damping해석)

  • 이덕규
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.5-8
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    • 2001
  • A three node flat triangular element incorporating Layerwise Zig-Zag Theory(HZZT) is developed suitable for analyzing damped laminated composite structures. Using an interdependent kinematic relation, the higher order shear rotations are replaced by in-plane displacements, a transverse displacement and section rotations, which result in three translations and two rotations. Natural frequencies and modal loss factors of cantilevered laminated plates with embedded damping layers are calculated with the zig-zag triangular element and compared to the experimental results and MSC/NASTRAN results using a layered combination of plate and solid elements.

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HIGHER ORDER ZIG-ZAG SHELL THEORY FOR SMART COMPOSITE STRUCTURES UNDER THERMO-ELECTRIC-MECHANICAL LOADING (고차 지그재그 이론을 이용한 열_전기_기계 하중하의 스마트 복합재 쉘 구조물의 해석)

  • Oh, Jin-Ho;Cho, Maeng-Hyo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.1-4
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    • 2005
  • A higher order zig-zag shell theory is developed to refine accurately predict deformation and stress of smart shell structures under the mechanical, thermal, and electric loading. The displacement fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. The mechanical, thermal, and electric loading is applied in the sinusoidal distribution function in the in-surface direction. Thermal and electric loading is given in the linear variation through the thickness. Especially, in electric loading case, voltage is only applied in piezo-layer. The layer-dependent degrees of freedom of displacement fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses. In order to obtain accurate transverse shear and normal stresses, integration of equilibrium equation approach is used. The numerical examples of present theory demonstrate the accuracy and efficiency of the proposed theory. The present theory is suitable for the predictions of behaviors of thick smart composite shell under mechanical, thermal, and electric loadings combined.

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Higher Order Zig-Zag Theory for Composite Shell under Thermo-mechanical load (열, 기계 하중을 고려한 지그재그 고차 복합재 쉘 이론)

  • Oh Jin-Ho;Cho Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.217-224
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    • 2005
  • A higher order zig-zag shell theory is developed to refine the predictions of the mechanical and thermal behaviors partially coupled. The in-plane displacement fields are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field through the thickness. Smooth parabolic distribution through the thickness is assumed in the out-of-plane displacement in order to consider transverse normal deformation and stress. The layer-dependent degrees of freedom of displacement fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses. Thus the proposed theory has only seven primary unknowns and they do not depend upon the number of layers. In the description of geometry and deformation of shell surface, all rigorous exact expressions are used. Through the numerical examples of partially coupled analysis, the accuracy and efficiency of the present theory are demonstrated. The present theory is suitable in the predictions of deformation and stresses of thick composite shell under mechanical and thermal loads combined.

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Higher Order Zig-zag Piezoelectric Plate Theory Under Thermo-electric-mechanical Loads (열-전기-기계 하중 하에서의 고차 지그재그 판이론)

  • Cho, Maeng-Hyo;Oh, Jin-Ho
    • Proceedings of the KSME Conference
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    • pp.426-431
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    • 2000
  • A decoupled thermo-piezoelectric-mechanical model of composite laminates with surface bonded piezoelectric actuators, subjected to externally applied load, temperature change load, electric field load is developed. The governing differential equations are obtained by applying the principle of free energy and variational techniques. A higher order zigzag theory displacement field is employed to accurately capture the transverse shear and normal effects in laminated composite plates of arbitrary thickness.

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Dynamic analysis for delaminated composites using DKQ concept based on higher-order zig-zag theory (고차 지그재그 모델을 이용한 다중 층간 분리부가 내재한 복합재 평판의 동적 해석)

  • 오진호;조맹효;김준식
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.71-74
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    • 2002
  • A higher-order zig-zag theory is developed to refine the predictions of natural frequency and mode shape of laminated composite plates with multiple delaminations. By imposing top and bottom surface transverse shear stress-free and interface continuity conditions of transverse shear stresses including delaminated interfaces, the displacement field with minimal degree-of-freedoms are obtained. This displacement field can systematically handle the number, shape, size, and locations of delaminations. Through the dynamic version of variational approach, the dynamic equilibriums and variationally consistent boundary conditions are obtained. Through the numerical example of natural frequency analysis, the accuracy and efficiency of present theory are demonstrated. The present theory is suitable as an efficient tool to analyze the static and dynamic behavior of the composite plates with multiple delaminations.

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The Analysis of Smart Plate Using Enhanced First Shear Deformation Theory (개선된 일차전단변형이론을 이용한 지능구조평판의 거동해석)

  • Oh, Jin-Ho;Kim, Heung-Su;Rhee, Seung-Yun;Cho, Maeng-Hyo
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.663-668
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    • 2007
  • An enhanced first shear deformation theory for composite plate is developed. The detailed process is as follows. Firstly, the theory is formulated by modifying higher order zigzag theory. That is, the higher order theory is separated into the warping function representing the higher order terms and lower order terms. Secondly, the relationships between higher order zig-zag field and averaged first shear deformation field based on the Reissner-Mindlin's plate theory are derived. Lastly, the effective shear modulus is calculated by minimizing error between higher order energy and first order energy. Then the governing equation of FSDT is solved by substituting shear modulus into effective shear modulus. The recovery processing with the nodal unknown obtained from governing equation is performed. The accuracy of the present proposed theory is demonstrated through numerical examples. The proposed method will serve as a powerful tool in the prediction of laminated composite plate.

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Higher order zig-zag plate theory for coupled thermo-electric-mechanical smart structures (열-기계-전기 하중 하에서의 지능 복합재 평판 고차이론)

  • Oh, Jin-Ho;Cho, Maeng-Hyo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.5
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    • pp.9-14
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    • 2002
  • A higher order zig-zag plate theory is developed to accurately predict fully coupled mechanical, thermal, and electric behaviors. Both the in-plane displacement and temperature fields through the thickness are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field. Smooth parabolic distribution through the thickness is assumed in the transverse deflection in order to consider transverse normal deformation. Linear zig-zag form is adopted in the electric field. The layer-dependent degrees of freedom of displacement and temperature fields are expressed in tern-is of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses and transverse heat flux. The numerical examples of coupled and uncoupled analysis demonstrate the accuracy and efficiency of the present theory. The present theory is suitable for the predictions of fully coupled behaviors of thick smart composite plate under mechanical, thermal, and electric loadings combined.

A Finite Element Analysis based on Higher-Order Zig-Zag Shell Theory for Laminated Composites with Multiple Delamination (다중 층간 분리부가 내재된 복합재 쉘 고차 지그재그 모델의 유한요소 해석)

  • 오진호;조맹효
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.229-236
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    • 2004
  • A new three-node triangular shell element based on higher order zig-zag theory is developed for laminated composite shells with multiple delaminations. The present higher order zig-zag shell theory is described in a general curvilinear coordinate system and in general tensor notation. All the complicated curvatures of surface including twisting curvatures can be described in an exact manner in the present shell element because this element is based on geometrically exact surface representation. The displacement field of the proposed finite element includes slope of deflection. which requires continuity between element interfaces. Thus the nonconforming shape function of Specht's three-node triangular plate bending element is employed to interpolate out-of-plane displacement. The present element passes the bending and twisting patch tests in flat surface configurations. The developed element is evaluated through the buckling problems of composite cylindrical shells with multiple delaminations. Through the numerical examples it is demonstrated that the proposed shell element is efficient because it has minimal degrees of freedom per node. The accuracy of the present element is demonstrated in the prediction of buckling loads and buckling modes of shells with multiple delaminations. The present shell element should serve as a powerful tool in the prediction of buckling loads and modes of multi-layered thick laminated shell structures with arbitrary-shaped multiple delaminations.

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