• Title/Summary/Keyword: winkler foundation

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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.

A unified formulation for modeling of inhomogeneous nonlocal beams

  • Ebrahimi, Farzad;Barati, Mohammad Reza
    • Structural Engineering and Mechanics
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    • v.66 no.3
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    • pp.369-377
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    • 2018
  • In this article, buckling and free vibration of functionally graded (FG) nanobeams resting on elastic foundation are investigated by developing various higher order beam theories which capture shear deformation influences through the thickness of the beam without the need for shear correction factors. The elastic foundation is modeled as linear Winkler springs as well as Pasternak shear layer. The material properties of FG nanobeam are supposed to change gradually along the thickness through the Mori-Tanaka model. The small scale effect is taken into consideration based on nonlocal elasticity theory of Eringen. From Hamilton's principle, the nonlocal governing equations of motion are derived and then solved applying analytical solution. To verify the validity of the developed theories, the results of the present work are compared with those available in literature. The effects of shear deformation, elastic foundation, gradient index, nonlocal parameter and slenderness ratio on the buckling and free vibration behavior of FG nanobeams are studied.

Study on the Stability of Elastic Material Subjected to Dry Friction Force (건성마찰력을 받는 탄성재료의 안정성에 관한 연구)

  • Ko, Jun-Bin;Jang, Tag-Soon;Ryu, Si-Ung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.2
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    • pp.143-148
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    • 2004
  • This paper discussed on the stability of elastic material subjected to dry friction force for low boundary conditions: clamped free, clamped-simply supported, simply supported-simply supported, clamped-clamped. 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 friction material is modeled for simplicity into a Winkler-type elastic foundation. The stability of beams on the elastic foundation subjected to distribute follower force is formulated by using finite element method to have a standard eigenvalue problem. It is found that the clamped-free beam loses its stability in the flutter type instability, the simply supported-simply supported beam loses its stability in the divergence type instability and the other two boundary conditions the beams lose their stability in the divergence-flutter type instability.

Vibration Analysis of Tapered Thick Plate Subjected to Static In-plane Stress (면내력을 받는 변단면 후판의 진동해석)

  • Cheong, Jin-Taek;Oh, Soog-Kyoung;Lee, Yong-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.521-525
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    • 2004
  • 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 that 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. In order to analysis tapered plate which is supported on pasternak foundation. The ratio of In-plane stress to critical load is varied with $0.2\sigma_{cr},\;0.4\sigma_{cr},\;0.6\sigma_{cr}$, and the Winkler parameter is 0, 10, 100, 1000 the shear foundation parameter 0, 10. The taper ratio is applied as 0.0, 0.2, 0.4, 0.6, 0.8 respectively. This paper is analyzed varying thickness by taper ratio with In-plane stress.

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Frequency response analysis of curved embedded magneto-electro-viscoelastic functionally graded nanobeams

  • Ebrahimi, Farzad;Fardshad, Ramin Ebrahimi;Mahesh, Vinyas
    • Advances in nano research
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    • v.7 no.6
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    • pp.391-403
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    • 2019
  • In this article the frequency response analysis of curved magneto-electro-viscoelastic functionally graded (CMEV-FG) nanobeams resting on viscoelastic foundation has been carried out. To this end, the study incorporates the Euler-Bernoulli beam model in association with Eringen's nonlocal theory to incorporate the size effects. The viscoelastic foundation in the current investigation is assumed to be the combination of Winkler-Pasternak layer and viscous layer of infinite parallel dashpots. The equations of motion are derived with the aid of Hamilton's principle and the solution to vibration problem of CMEV-FG nanobeams are obtained analytically. The material gradation is considered to follow Power-law rule. This study thoroughly investigates the influence of prominent parameters such as linear, shear and viscous layers of foundation, structural damping coefficient, opening angle, magneto-electrical field, nonlocal parameter, power-law exponent and slenderness ratio on the frequencies of FG nanobeams.