• Title, Summary, Keyword: Pasternak 지반

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Stability Analysis of Thin Plates on Inhomogeneous Pasternak foundation (비균질 Pasternak지반에 의해 지지된 박판의 안정 해석)

  • 이용수;김광서
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.14 no.3
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    • pp.401-411
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    • 2001
  • This paper deals with the vibration analysis of the rectangular plates which are subjected to uniform in-plane stresses and supported on In-homogeneous Pasternak foundation. Two parametric foundation which Winkler foundation parameter and shear foundation parameter considered, is called by the Pasternak foundation. The values of Winkler foundation parameter of central and border zone of plate are chosen as k₁and k₂respectively, and the value of shear foundation is chosen as constant about all zone of plate. After composing global flexural stiffeness matrix, geometrical stiffeness matrix, mass matrix, and the stiffeness matrix of the Pasternak foundation, eigenvalue problems which are composed of these matrices are solved. The result shows that the shear foundation parameter must not be ignore when considering the stiffeness of foundation.

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The Stability Analysis of Timoshenko Beam-Column on Pasternak Foundation (Pasternak지반 위에 놓인 Timoshenko보-기둥의 안정해석)

  • Lee, Yong-Soo;Lee, Byoung Koo;Kim, Sun Gyun
    • Journal of Korean Society of Steel Construction
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    • v.13 no.1
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    • pp.91-100
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    • 2001
  • This paper is to analyze the stability of Timoshenko beam-column on Pasternak foundation, with the extensional and the rotational spring at center point of span by Finite Element Method. To verify this Finite Element Method, the results by the proposed method are compared with the existing solutionsof Timoshenko beam-column without the extensional and the rotational spring and the shear foundation. The dynamic stability regions are decided by the dynamic stability analysis of Timoshenko beam-column on Pasternak foundation with the extensional and the rotation spring at center point of span.

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Eigenvalue Analysis of Stiffened Plates on Pasternak Foundations (Pasternak지반위에 놓인 보강판의 고유치해석)

  • Lee, Byoung-Koo;Kim, Il-Jung;Oh, Soog-Kyoung;Lee, Yong-Soo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.2
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    • pp.151-158
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    • 2005
  • This research analyzes eigenvalue analysis of stiffened plates on the Pasternak foundations using the finite clement method. For analyzing the stiffened plates, both the Mindlin plate theory and Timoshenko beam-column theory were applied. In application of the finite element method, 8-nodes serendipity clement system and 3-nodes finite element system were used for plate and beam elements, respectively. Elastic foundations were modeled as the Pasternak foundations in which the continuity effect of foundations is considered. In order to verify the theory of this study, solutions obtained by this analysis were compared with the classical solutions in reference, experimental solutions and solutions obtained by SAP 2000. The natural frequency of stiffened plates on Pasternak foundations were determined according to changes or foundation parameters and dimensions of stiffener.

Free Vibration Analysis of Thick Plate Subjected to In-plane Force on Inhomogeneous Pasternak Foundation (비균질 Pasternak지반 위에 놓인 면내력을 받는 후판의 진동해석)

  • Lee, Yong Soo;Kim, Il Jung;Oh, Soog Kyoung
    • Journal of Korean Society of Steel Construction
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    • v.15 no.3
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    • pp.291-298
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    • 2003
  • Recently, as the size of buildings structure becomes large increases, their mat area of building structure is supported or by an inhomogeneous foundation. This paper presents a vibration analysis on thick plates subjected to in-plane force is presented in this paper. The rectangular plate is isotropic, homogeneous, and composed of a linearly elastic material. A vibration analysis of the rectangular thick plate iwas done by useing ofarectangular finite element with 8 nodes and 9 nodes. In this study, the foundation was idealized as a Pasternak foundation model. A Pasternak foundation haves a shear layer on Winkler's model, which idealizes the foundation as a vertical spring. In order tTo analysze the vibration of a plate supported on by an inhomogeneous Pasternak foundation, the value of the Winkler foundation parameter of the central and border zones of the plate awere chosen as WFP1 and WFP2. (fFigure 4.). The Winkler foundation parameter of WFP1 and WFP2 is varied from 0 to 10, $10^2$, and $10^3$ and the shear foundation parameters is were 0, 5, and 10. The ratio of the in-plane force to the critical load iwas applied as 0.4 to 0.8

Flexural-Torsional Free Vibrations of Circular Strip Foundation with Variable Breadth on Pasternak Soil (Pasternak지반으로 지지된 변화폭 원호형 띠기초의 휨-비틀림 자유진동)

  • Lee, Byoung Koo;Park, Kwang Kyou;Kang, Hee Jong;Yoon, Hee Min
    • Journal of Korean Society of Steel Construction
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    • v.19 no.5
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    • pp.539-548
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    • 2007
  • This paper deals with flexural-torsional free vibrations of the circular strip foundation with the variable breadth on Pasternak soil. The cross-section of the strip foundation is chosen as the rectangular one with the constant thickness and variable breadth, which is symmetrical about the mid-arc. Also, the foundation that supports the circular strip is modeled as the Pasternak soil with the shear layer. Ordinary differential equations accompanying the boundary conditions are derived. In the governing equations, the transverse, rotatory and torsional inertias are included. These equations are solved numerically and four lowest frequencies are obtained. In the numerical results, the effects of foundation parameters on frequencies are extensively investigated. It is expected that the theories and numerical results of this study can be used in the dynamic design of strip foundations.

Dynamic Stability Analysis of Thick Plates with Varying Thickness and Concentrated Mass on Inhomogeneous Pasternak Foundation (비균질 Pasternak 지반에 놓인 집중질량을 갖는 변단면 후판의 동적안정해석)

  • Lee, Yong-Soo;Kim, Il-Jung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.8
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    • pp.698-707
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    • 2011
  • This paper is to analyze the stability of the thick plate on inhomogeneous Pasternak foundation, with linearly varying thickness and concentrated mass by finite element method. To verify this finite element method, the results of natural frequencies and buckling stresses by the proposed method are compared with the existing solutions. The dynamic instability regions are decided by the dynamic stability analysis of the thick plate on inhomogeneous Pasternak foundation, with linearly varying thickness and concentrated mass. The non-dimensional Winkler foundation parameter is applied as 100, 1000 and non-dimensional shear foundation parameter is applied as 5. The tapered ratios are applied as 0.25 and 1.0, the ratios of concentrated mass to plate mass as 0.25 and 1.0, and the ratio of in-plane force to critical load as 0.4. As the result of numerical analysis of the thick plate on inhomogeneous Pasternak foundation for $u{\times}v=300cm{\times}300cm$ and $a{\times}b=600cm{\times}600cm$, instability areas of the thick plate which has the larger rigidity of inner area are farther from ${\beta}$-axis and narrower than those which has the larger rigidity of outer area.

Parametric Studies of Flexural Free Vibrations of Circular Strip Foundations with Various End Constraints Resting on Pasternak Soil (경계조건 변화에 따른 Pasternak 지반으로 지지된 원호형 띠기초의 휨 자유진동에 관한 변수연구)

  • Lee, Byoung-Koo;Li, Guang-Fan;Kang, Hee-Jong;Yoon, Hee-Min
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.9
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    • pp.835-846
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    • 2007
  • This paper deals with the flexural free vibrations of circular strip foundation with the variable breadth on Pasternak soil. The breadth of strip varies with the linear functional fashion, which is symmetric about the mid-arc. Differential equations governing flexural free vibrations of such strip foundation are derived, in which the elastic soil with the shear layer, i.e. Pasternak soil, is considered. Effects of the rotatory and shear deformation are included in the governing equations. Differential equations are numerically solved to calculate the natural frequencies and mode shapes. In the numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. Four lowest frequency parameters accompanied with their corresponding mode shapes are reported and parametric studies between frequency parameters and various system parameters are investigated.

Free Vibration Analysis of Thick Plates on Inhomogeneous Pasternak Foundation (비균질 Pasternak지반 위에 놓여진 후판의 자유진동해석)

  • 김일중;오숙경;이효진;이용수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.852-857
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    • 2003
  • This paper has the object of investigating natural frequencies of thick plates on inhomogeneous Pasternak foundation by means of finite element method and providing kinematic design data lot mat of building structures. This analysis was applied for design of substructure on elastic foundation. Mat of building structure may be consisdered as a thick plate on elastic foundation. Recently, as size of building structure becomes larger, mat area of building structure also tend to become target and building structure is supported on inhomogeneous foundation. In this paper, vibration analysis or rectangular thick plate is done by use or serendipity finite element with 8 nodes by considering shearing strain of plate. The solutions of this paper are compared with existing solutions and finite element solutions with 4${\times}$4 meshes of this analysis are shown the error of maximum 0.083% about the existing solutions. It is shown that natrural frequencies depend on not only Winkler foundation parameter but also shear foundation parameter.

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Lowest Symmetrical and Antisymmetrical Natural Frequencies of Shallow Arches on Two-Parameter Elastic Foundations (두 개의 매개변수로 표현되는 탄성지반 위에 놓인 낮은 아치의 최저차 대칭 및 역대칭 고유진동수)

  • 오상진;서종원;이병구
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.2
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    • pp.367-377
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    • 2002
  • This paper deals with the free vibrations of shallow arches resting on elastic foundations. Foundations we assumed to follow the hypothesis proposed by Pasternak. The governing differential equation is derived for the in-plane free vibration of linearly elastic arches of uniform stiffness and constant mass per unit length. Two arch shapes with hinged-hinged and clamped-clamped end constraints we considered in analysis. The frequency equations (lowest symmetrical and antisymmetrical frequency equations) we obtained by Galerkin's method. The effects of arch rise, Winkler foundation parameter and shear foundation parameter on the lowest two natural frequencies are investigated. The effect of initial arch shapes on frequencies is also studied.

Dynamic Stability Analysis of Stiffened Tapered Thick Plate with Concentrated Mass on Pasternak Foundations (Pasternak지반에 지지된 집중질량을 갖는 보강된 변단면 후판의 동적안정해석)

  • Lee, Yong-Soo;Kim, Il-Jung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.12
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    • pp.1296-1305
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    • 2009
  • This paper has the object of investigating dynamic stability of stiffened tapered thick plate with concentrated mass on Pasternak foundation by means of finite element method and providing kinematic design data for mat of building structures. Finite element analysis of stiffened tapered thick 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 foundation parameter is varied with 10, 100, 1000 and the shear foundation parameter is 5, 10, concentrated mass is $0.25m_c$, $1.0m_c$, tapered ratio is 0.25, 0.5. The ratio of In-plane force to critical load is applied as $0.4\sigma_{cr},\;0.6\sigma_{cr},\;0.8\sigma_{cr}$ respectively. This paper analyzed varying tapered ratio.