• Title/Summary/Keyword: Winkler foundation

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The effect of parameters of visco-Pasternak foundation on the bending and vibration properties of a thick FG plate

  • Boulefrakh, Laid;Hebali, Habib;Chikh, Abdelbaki;Bousahla, Abdelmoumen Anis;Tounsi, Abdelouahed;Mahmoud, S.R.
    • Geomechanics and Engineering
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    • v.18 no.2
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    • pp.161-178
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    • 2019
  • In this research, a simple quasi 3D hyperbolic shear deformation model is employed for bending and dynamic behavior of functionally graded (FG) plates resting on visco-Pasternak foundations. The important feature of this theory is that, it includes the thickness stretching effect with considering only 4 unknowns, which less than what is used in the First Order Shear Deformation (FSDT) theory. The visco­Pasternak's foundation is taken into account by adding the influence of damping to the usual foundation model which characterized by the linear Winkler's modulus and Pasternak's foundation modulus. The equations of motion for thick FG plates are obtained in the Hamilton principle. Analytical solutions for the bending and dynamic analysis are determined for simply supported plates resting on visco-Pasternak foundations. Some numerical results are presented to indicate the effects of material index, elastic foundation type, and damping coefficient of the foundation, on the bending and dynamic behavior of rectangular FG plates.

Combined effects of material properties and boundary conditions on the large deflection bending analysis of circular plates on a nonlinear elastic foundation

  • Altekin, Murat
    • Computers and Concrete
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    • v.25 no.6
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    • pp.537-549
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    • 2020
  • Geometrically nonlinear axisymmetric bending analysis of shear deformable circular plates on a nonlinear three-parameter elastic foundation was made. Plates ranging from "thin" to "moderately thick" were investigated for three types of material: isotropic, transversely isotropic, and orthotropic. The differential equations were discretized by means of the finite difference method (FDM) and the differential quadrature method (DQM). The Newton-Raphson method was applied to find the solution. A parametric investigation using seven unknowns per node was presented. The novelty of the paper is that detailed numerical simulations were made to highlight the combined effects of the material properties and the boundary conditions on (i) the deflection, (ii) the stress resultants, and (iii) the external load. The formulation was verified through comparison studies. It was observed that the results are highly influenced from the boundary conditions, and from the material properties.

Effect of an Intermediate Support on the Stability of Elastic Material Subjected to Dry Friction Force (건성마찰력을 받는 탄성재료의 안정성에 미치는 중간 지지의 효과)

  • 류시웅;장탁순
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.8
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    • pp.129-135
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    • 2004
  • This paper discussed on the effect of an intermediate support on the stability of elastic material subjected to dry friction force. It is assumed in this paper that the dry frictional force between a tool stand and an elastic material can be modeled as a distributed follower force. The elastic material on the friction material is modeled for simplicity into an elastic beam on Winkler-type elastic foundation. The stability of beams on the elastic foundation subjected to distributed follower force is formulated by using finite element method to have a standard eigenvalue problem. The first two eigen-frequencies are obtained to investigate the dynamics of the beam. The eigen-frequencies yield the stability bound and the corresponding unstable mode. The considered beams lose its stability by flutter or divergence, depending on the location of intermediate support.

A Study on Structural reinforcement suggestions for improvement of Seismic Performance of Masonry Buildings in rural areas (농촌지역의 조적조 건축물의 내진성능 개선을 위한 구조적 보강법 제안에 관한 연구)

  • Lee, Deog-Yong;Kim, Il-Jung
    • Journal of the Korean Institute of Rural Architecture
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    • v.15 no.4
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    • pp.51-58
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    • 2013
  • This study Masonry Buildings in rural areas, due to the lateral load resistance for seismic reinforcement method is proposed. Some of the proposed methods for reinforcement directly through finite element analysis to evaluate the change in frequency. The results for the following: This paper has the object of investigating natural frequencies of opening thick plates on Pasternak foundation by means of finite element method and providing Kinematic design data for mat of building structures. In this paper, vibration analysis of rectangular opening thick plate is done by use of Serendipity finite element with 8 nodes by considering shearing strain of plate. It is shown that natrural frequencies depend on not only Winkler foundation parameter but also shear foundation parameter, opening position.

Thermomechanical postbuckling of imperfect moderately thick plates on two-parameter elastic foundations

  • Shen, Hui-Shen
    • Structural Engineering and Mechanics
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    • v.4 no.2
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    • pp.149-162
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    • 1996
  • A postbuckling analysis is presented for a simply supported, moderately thick rectangular plate subjected to combined axial compression and uniform temperature loading and resting on a two-parameter elastic foundation. The two cases of thermal postbuckling of initially compressed plates and of compressive postbuckling of initially heated plates are considered. The initial geometrical imperfection of the plate is taken into account. The formulations are based on the Reissner-Mindlin plate theory considering the first order shear deformation effect, and including the plate-foundation interaction and thermal effect. The analysis uses a deflection-type perturbation technique to determine the buckling loads and postbuckling equilibrium paths. Numerical examples cover the performances of perfect and imperfect, moderately thick plates resting on Winkler or Pasternak-type elastic foundations. Typical results are presented in dimensionless graphical form.

Electromagnetothermoelastic behavior of a rotating imperfect hybrid functionally graded hollow cylinder

  • Saadatfar, M.;Aghaie-Khafri, M.
    • Smart Structures and Systems
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    • v.15 no.6
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    • pp.1411-1437
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    • 2015
  • The electro-magneto- thermo-elastic behavior of a rotating functionally graded long hollow cylinder with functionally graded piezoelectric (FGPM) layers is analytically analyzed. The layers are imperfectly bonded to its inner and outer surfaces. The hybrid cylinder is placed in a constant magnetic field subjected to a thermo-electro-mechanical loading and could be rested on a Winkler-type elastic foundation. The material properties of the FGM cylinder and radially polarized FGPM layers are assumed to be graded in the radial direction according to the power law. The hybrid cylinder is rotating about its axis at a constant angular velocity. The governing equations are solved analytically and then stresses, displacement and electric potential distribution are calculated. Numerical examples are given to illustrate the effects of material in-homogeneity, magnetic field, elastic foundation, applied voltage, imperfect interface and thermo-mechanical boundary condition on the static behavior of a FG smart cylinder.

Research on the Applicability of Conventional p-y curve for Lateral Behavior of Pile Foundation based on Inverse Analysis (역해석기법에 의한 기존의 p-y곡선 적용성에 관한 고찰)

  • Kim, Hyun-Uk;Goh, Jae-Sin;Kim, Nam-Ho;Kim, Yeon-Jung
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.390-400
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    • 2010
  • BNWF(Beam on Nonlinear Winkler Foundation) method has long been adopted for lateral behavior analysis of pile foundation and widely recognized for its simplicity and accuracy up until now. However, due to lateral load tests which were done in limited conditions and theory-based input Parameter estimation, the applicbility of p-y curve has not been fully examined. Accordingly, we researched on the applicability of conventional input parameter estimation and the p-y curve to be determined by the estimation through inverse analysis based on lateral load tests.

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Vibration Analysis of Tapered Thick Plates on Position of Concentated Mass (집중질량 위치변화에 따른 변단면 후판의 진동해석)

  • Oh Soog-Kyoung;Lee Yong-Soo;Kim Il-Jung
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.681-688
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    • 2006
  • This paper has the object of investigating natural frequencies of tapered thick plate on pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. In order to analysis plate which is supported on pasternak foundation. the Winkler parameter is varied with 10, $10^2,\;10^3$ and the shear foundation parameter is 5, 10. This paper is analyzed varying thickness by taper ratio. The taper ratio is applied as 0.0, 0.25, 0.5, 0.75, 1.0 respectively.

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Vibration Analysis of Tapered Thick Plate Subjected to Static In-plane Stress on Pasternak Foundation (Pasternak지반 위에 놓인 면내력을 받는 변단면 후판의 진동해석)

  • Cheong, Jin-Taek;Lee, Yong-Soo;Oh, Soog-Kyoung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.4 s.97
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    • pp.388-394
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    • 2005
  • This paper has the object of investigating natural frequencies of tapered thick plate on Pasternak foundation by means of finite element method and providing kinetic design data for mat of building structures. Vibration analysis for tapered thick plate subjected to in-plane stress is presented in this paper. Finite element analysis of rectangular plate is done by use of rectangular finite element with 8-nodes. Analysis conditions of tapered thick plate are as follows each. The ratio of in-plane stress to critical load is varied with $0.2\sigma_{cr}$, $0.4\sigma_{cr}$, $0.6\sigma_{cr}$. The Winkler parameter is 0, 10, 100, 1000, the shear foundation parameter is 0, 10 and the taper ratio is 0.0, 0.2, 0.4, 0.6, 0.8.

An Analysis of Hemisphere-cylindrical Shell Structure by Transfer Matrix Method (전달행렬법에 의한 반구 원통형 쉘구조의 해석)

  • 김용희;이윤영
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.4
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    • pp.115-125
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    • 2003
  • Shell structures are widely used in a variety of engineering application, and mathematical solution of shell structures are available only for a few special cases. The solution of shell structure is more complicated when it has such condition as winkler foundation, other problems. In this study many simplified methods (analogy of beam on elastic foudation, finite element method and transfer matrix method) are applied to analyze a hemisphere-cylindrical shell structures on elastic foundation. And the transfer matrix method is extensively used for the structural analysis because of its merit in the theoretical backgroud and applicability. Therefore, this paper presents the analysis of hemisphere-cylindrical shell structure base on the transfer matrix method. The technique is attractive for implementation on a numerical solution by means of a computer program coded in FORTRAN language with a few elements. To demonstrate this fact, it gives good results which compare well with finite element method.