• 제목/요약/키워드: anisotropic plates

검색결과 69건 처리시간 0.025초

비등방성 적층 캔틸레버 박판 및 후판의 해석연구 (Study on the Analysis of Anisotropic Laminated Cantilever Thin Plates and Anisotropic Laminated Cantilever Thick Plates)

  • 박원태
    • 복합신소재구조학회 논문집
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    • 제1권4호
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    • pp.1-5
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    • 2010
  • In this study, it is presented analysis results of bending problems in the anisotropic cantilever thick plates and the anisotropic laminated cantilever thin plates bending problems. Finite element method in this analysis was used. Both Kirchoff's assumptions and Mindlin assumptions are used as the basic governing equations of bending problems in the anisotropic laminated plates. The analysis results are compared between the anisotropic laminated cantilever thick plates and the anisotropic laminated cantilever thin plates for the variations of thickness-width ratios.

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전단변형을 고려한 이방성 적층판의 좌굴해석 (Buckling Analysis of Anisotropic Laminated Plates with Shear Deformation)

  • 최용희;권택진
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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    • pp.361-368
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    • 2001
  • This paper deals with the buckling load of antisymmetric angle-ply and cross-ply laminated rectangular plates. Buckling analysis is preformed for a simply supported, shear deformable laminated plate subjected to uniaxial compression and biaxial compression combined with uniform lateral pression. The shear deformation theory is considered to figure out a more exact behavior of laminated plates exactly. The purposes of this study are to formulate anisotropic laminated plates with shear deformation and to investigate the buckling load according to the various variables of laminated plates by using the exact solutions for anisotropic laminated plates having simply supported boundary.

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Free vibrations of anisotropic rectangular plates with holes and attached masses

  • Rossit, C.A.;Ciancio, P.M.
    • Structural Engineering and Mechanics
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    • 제28권1호
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    • pp.53-67
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    • 2008
  • Anisotropic materials are increasingly required in modern technological applications. Certainly, civil, mechanical and naval engineers frequently deal with the situation of analyzing the dynamical behaviour of structural elements being composed of such materials. For example, panels of anisotropic materials must sometimes support electromechanical engines, and besides, holes are performed in them for operational reasons e.g., conduits, ducts or electrical connections. This study is concerned with the natural frequencies and normal modes of vibration of rectangular anisotropic plates supported by different combinations of the classical boundary conditions: clamped, simply - supported and free, and with additional complexities such holes of free boundaries and attached concentrated masses. A variational approach (the well known Ritz method) is used, where the displacement amplitude is approximated by a set of beam functions in each coordinate direction corresponding to the sides of the rectangular plate. Consequently each coordinate function satisfies the essential boundary conditions at the outer edge of the plate. The influence of the position and magnitude of both hole and mass, on the natural frequencies and modal shapes of vibration are studied for a generic anisotropic material. The classical Ritz method with beam functions as spatial approximation proved to be a suitable procedure to solve a problem of such analytical complexity.

Investigation of wave propagation in anisotropic plates via quasi 3D HSDT

  • Bouanati, Soumia;Benrahou, Kouider Halim;Atmane, Hassen Ait;Yahia, Sihame Ait;Bernard, Fabrice;Tounsi, Abdelouahed;Bedia, E.A. Adda
    • Geomechanics and Engineering
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    • 제18권1호
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    • pp.85-96
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    • 2019
  • A free vibration analysis and wave propagation of triclinic and orthotropic plate has been presented in this work using an efficient quasi 3D shear deformation theory. The novelty of this paper is to introducing this theory to minimize the number of unknowns which is three; instead four in other researches, to studying bulk waves in anisotropic plates, other than it can model plates with great thickness ratio, also. Another advantage of this theory is to permits us to show the effect of both bending and shear components and this is carried out by dividing the transverse displacement into the bending and shear parts. Hamilton's equations are a very potent formulation of the equations of analytic mechanics; it is used for the development of wave propagation equations in the anisotropic plates. The analytical dispersion relationship of this type of plate is obtained by solving an eigenvalue problem. The accuracy of the present model is verified by confronting our results with those available in open literature for anisotropic plates. Moreover Numerical examples are given to show the effects of wave number and thickness on free vibration and wave propagation in anisotropic plates.

다적층 복합면재를 갖는 비등방성 샌드위치판의 휨해석 (Bending Analysis of Anisotropic Sandwich Plates with Multi-layered Laminated Composite faces)

  • 지효선
    • 복합신소재구조학회 논문집
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    • 제3권4호
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    • pp.17-26
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    • 2012
  • This study presents a governing equations of bending behavior of anisotropic sandwich plates with multi-layered laminated composite faces. Based on zig-zag models for through thickness deformations, the shear deformation of composite faces is included. All edges of plate are assumed to be simply supported. Results of the bending analysis under lateral loads are presented for the influence of various lay up sequences of antisymmetric angle-ply laminated faces. The accuracy of the approach is ascertained by comparing solutions from the sandwich plates theory with composite faces to the laminated plates theory. Since the present analysis considers the bending stiffness of the core and also the transverse shear deformations of the laminated faces, the proposed method showed higher than that calculated according to the general laminated plates theory. The information presented might be useful to design sandwich plates structure with polymer matrix composite faces.

On exact wave propagation analysis of triclinic material using three-dimensional bi-Helmholtz gradient plate model

  • Karami, Behrouz;Janghorban, Maziar;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • 제69권5호
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    • pp.487-497
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    • 2019
  • Rapid advances in the engineering applications can bring further areas to provide the opportunity to manipulate anisotropic structures for direct productivity in design of micro/nano-structures. For the first time, magnetic affected wave characteristics of nanosize plates made of anisotropic material is investigated via the three-dimensional bi-Helmholtz nonlocal strain gradient theory. Three small scale parameters are used to predict the size-dependent behavior of the nanoplates more accurately. After owing governing equations of wave motion, an analytical approach based harmonic series is utilized to fine the wave frequency as well as phase velocity. It is observed that the small scale parameters, magnetic field and wave number have considerable influence on the wave characteristics of anisotropic nanoplates. Due to the lack of any study on the mechanics of three-dimensional bi-Helmholtz gradient plates made of anisotropic materials, it is hoped that the present exact model may be used as a benchmark for future works of such nanostructures.

Assessment of Equivalent Elastic Modulus of Perforated Spherical Plates

  • JUMA, Collins;NAMGUNG, Ihn
    • 한국압력기기공학회 논문집
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    • 제15권1호
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    • pp.8-17
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    • 2019
  • Perforated plates are used for the steam generator tube-sheet and the Reactor Vessel Closure Head in the Nuclear Power Plant. The ASME code, Section III Appendix A-8000, addresses the analysis of perforated plates, however, this analysis is only limited to the flat plate with a triangular perforation pattern. Based on the concept of the effective elastic constants, simulation of flat and spherical perforated plates and their equivalent solid plates were carried out using Finite Element Analysis (FEA). The isotropic material properties of the perforated plate were replaced with anisotropic material properties of the equivalent solid plate and subjected to the same loading conditions. The generated curves of effective elastic constants vs ligament efficiency for the flat perforated plate were in agreement with the design curve provided by ASME code. With this result, a plate with spherical curvature having perforations can be conveniently analyzed with equivalent elastic modulus and equivalent Poisson's ratio.

자유경계를 갖는 비등방성 판의 유한차분 안정성 해석 (Finite Difference Stability Analysis of Anisotropic Plates with Free Edge)

  • 유용민;이상열;장석윤
    • 한국강구조학회 논문집
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    • 제12권2호통권45호
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    • pp.221-230
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    • 2000
  • 자유단이 있는 비등방성 판의 안정성을 검토할 때, 기존의 해석적인 방법으로는 다양한 하중 조건 및 경계조건에 대해 좌굴하중 및 좌굴모드를 구할 수 없다. 이러한 단점을 해결하기 위해 수치해석 기법인 유한차분법을 사용하였다. 유한차분법을 적용할 때, 자유경계의 가상점 처리가 가장 난해하게 되므로 1변이 자유이고 3변이 고정인 경우와 마주보는 2변이 자유이고 다른 2변이 고정인 경우를 해석 모델로 삼아 좌굴해석을 수행하였다. 본 논문에서는 자유경계를 갖는 비등방성 판의 해석 기법으로 유한차분법을 제시하였으며, 다양한 수치해석을 통하여 자유경계의 좌굴하중 및 모드 특성을 규명하였다.

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등가 이방성 복합재 평판에 대한 파손 특성에 관한 연구 (A Study on the Failure Characteristics of Equivalent Anisotropic Composite Plates)

  • 윤재호;김한준;김용하
    • 항공우주시스템공학회지
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    • 제16권5호
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    • pp.35-42
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    • 2022
  • 본 논문에서는 효율적인 파손해석을 위해 등가 이방성 복합재 평판으로 가정된 복잡한 적층 패턴을 가진 복합재 적층판의 기계적 등가 물성을 예측하였다. 등가 이방성 복합재 평판의 강성은 고전적층판 이론을 기반으로 정의하였으며, 미시역학적 파손이론이 적용된 복합재 적층판의 파손 거동을 묘사할 수 있는 등가 파손방정식을 새롭게 정의하였다. 최종적으로 유한요소해석 결과와 비교하여 제안된 이론을 검증하였으며, 제안된 이론은 높은 계산 효율성과 단순성이라는 이점 때문에 항공우주분야 복합재 적층판의 파손 특성 분석에 적합하다고 판단된다.

Vibration and stability analyses of thick anisotropic composite plates by finite strip method

  • Akhras, G.;Cheung, M.S.;Li, W.
    • Structural Engineering and Mechanics
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    • 제3권1호
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    • pp.49-60
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    • 1995
  • In the present study, a finite strip method for the vibration and stability analyses of anisotropic laminated composite plates is developed according to the higher-order shear deformation theory. This theory accounts for the parabolic distribution of the transverse shear strains through the thickness of the plate and for zero transverse shear stresses on the plate surfaces. In comparison with the finite strip method based on the first-order shear deformation theory, the present method gives improved results for very thick plates while using approximately the same number of degrees of freedom. It also eliminates the need for shear correction factors in calculating the transverse shear stiffness. A number of numerical examples are presented to show the effect of aspect ratio, length-to-thickness ratio, number of plies, fibre orientation and stacking sequence on the natural frequencies and critical buckling loads of simply supported rectangular cross-ply and arbitrary angle-ply composite laminates.