• Title/Summary/Keyword: Winkler foundation

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Nonlinear electromechanical analysis of a functionally graded square plate integrated with smart layers resting on Winkler-Pasternak foundation

  • Arefi, Mohammad
    • Smart Structures and Systems
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    • v.16 no.1
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    • pp.195-211
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    • 2015
  • This paper presents nonlinear analysis of a functionally graded square plate integrated with two functionally graded piezoelectric layers resting on the Winkler-Pasternak foundation. Geometric nonlinearity was considered in the strain-displacement relation based on the Von-Karman assumption. All the mechanical and electrical properties except Poisson's ratio can vary continuously along the thickness of the plate based on a power function. Electric potential was assumed as a quadratic function along the thickness direction and trigonometric function along the planar coordinate. The effect of non homogeneous index was investigated on the responses of the system. Furthermore, a comprehensive investigation has been performed for studying the effect of two parameters of assumed foundation on the mechanical and electrical components. A comparison between linear and nonlinear responses of the system presents necessity of this study.

Multiphase material topology optimization of Mindlin-Reissner plate with nonlinear variable thickness and Winkler foundation

  • Banh, Thanh T.;Nguyen, Xuan Q.;Herrmann, Michael;Filippou, Filip C.;Lee, Dongkyu
    • Steel and Composite Structures
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    • v.35 no.1
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    • pp.129-145
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    • 2020
  • In typical, structural topology optimization plays a significant role to both increase stiffness and save mass of structures in the resulting design. This study contributes to a new numerical approach of topologically optimal design of Mindlin-Reissner plates considering Winkler foundation and mathematical formulations of multi-directional variable thickness of the plate by using multi-materials. While achieving optimal multi-material topologies of the plate with multi-directional variable thickness, the weight information of structures in terms of effective utilization of the material at the appropriate thickness location may be provided for engineers and designers of structures. Besides, numerical techniques of the well-established mixed interpolation of tensorial components 4 element (MITC4) is utilized to overcome a well-known shear locking problem occurring to thin plate models. The well-founded mathematical formulation of topology optimization problem with variable thickness Mindlin-Reissner plate structures by using multiple materials is derived in detail as one of main achievements of this article. Numerical examples verify that variable thickness Mindlin-Reissner plates on Winkler foundation have a significant effect on topologically optimal multi-material design results.

Dynamic behavior of a functionally graded plate resting on Winkler elastic foundation and in contact with fluid

  • Shafiee, Ali A.;Daneshmand, Farhang;Askari, Ehsan;Mahzoon, Mojtaba
    • Structural Engineering and Mechanics
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    • v.50 no.1
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    • pp.53-71
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    • 2014
  • A semi-analytical method is developed to consider free vibrations of a functionally graded elastic plate resting on Winkler elastic foundation and in contact with a quiescent fluid. Material properties are assumed to be graded distribution along the thickness direction according to a power-law in terms of the volume fractions of the constituents. The fluid is considered to be incompressible and inviscid. In the analysis, the effect of an in-plane force in the plate due to the weight of the fluid is taken into account. By satisfying the compatibility conditions along the interface of fluid and plate, the fluid-structure interaction is taken into account and natural frequencies and mode shapes of the coupled system are acquired by employing energy methods. The results obtained from the present approach are verified by those from a finite element analysis. Besides, the effects of volume fractions of functionally graded materials, Winkler foundation stiffness and in-plane forces on the dynamic of plate are elucidated.

Thermal buckling analysis of SWBNNT on Winkler foundation by non local FSDT

  • Semmah, Abdelwahed;Heireche, Houari;Bousahla, Abdelmoumen Anis;Tounsi, Abdelouahed
    • Advances in nano research
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    • v.7 no.2
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    • pp.89-98
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    • 2019
  • In this work, the thermal buckling characteristics of zigzag single-walled boron nitride (SWBNNT) embedded in a one-parameter elastic medium modeled as Winkler-type foundation are investigated using a nonlocal first-order shear deformation theory (NFSDT). This model can take into account the small scale effect as well as the transverse shear deformation effects of nanotubes. A closed-form solution for nondimensional critical buckling temperature is obtained in this investigation. Further the effect of nonlocal parameter, Winkler elastic foundation modulus, the ratio of the length to the diameter, the transverse shear deformation and rotary inertia on the critical buckling temperature are being investigated and discussed. The results presented in this paper can provide useful guidance for the study and design of the next generation of nanodevices that make use of the thermal buckling properties of boron nitride nanotubes.

Nonlinear shear-flexure-interaction RC frame element on Winkler-Pasternak foundation

  • Suchart Limkatanyu;Worathep Sae-Long;Nattapong Damrongwiriyanupap;Piti Sukontasukkul;Thanongsak Imjai;Thanakorn Chompoorat;Chayanon Hansapinyo
    • Geomechanics and Engineering
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    • v.32 no.1
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    • pp.69-84
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    • 2023
  • This paper proposes a novel frame element on Winkler-Pasternak foundation for analysis of a non-ductile reinforced concrete (RC) member resting on foundation. These structural members represent flexural-shear critical members, which are commonly found in existing buildings designed and constructed with the old seismic design standards (inadequately detailed transverse reinforcement). As a result, these structures always experience shear failure or flexure-shear failure under seismic loading. To predict the characteristics of these non-ductile structures, efficient numerical models are required. Therefore, the novel frame element on Winkler-Pasternak foundation with inclusion of the shear-flexure interaction effect is developed in this study. The proposed model is derived within the framework of a displacement-based formulation and fiber section model under Timoshenko beam theory. Uniaxial nonlinear material constitutive models are employed to represent the characteristics of non-ductile RC frame and the underlying foundation. The shear-flexure interaction effect is expressed within the shear constitutive model based on the UCSD shear-strength model as demonstrated in this paper. From several features of the presented model, the proposed model is simple but able to capture several salient characteristics of the non-ductile RC frame resting on foundation, such as failure behavior, soil-structure interaction, and shear-flexure interaction. This confirms through two numerical simulations.

Seismic Response of MDOF Structure with Shallow Foundation Using Winkler Model (Winkler Model을 적용한 얕은 기초 다자유도 구조물의 지진응답)

  • Kim, Dong Kwan;Kim, Ho Soo;Min, Ji Hee;Park, Jin Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.28 no.4
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    • pp.165-170
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    • 2024
  • This study investigated the impact of soil-structure interaction on multi-degree-of-freedom structures using the shallow-foundation Winkler model, known as the BNWF model. The model's period was determined through eigenvalue analysis and compared to results obtained from FEMA's formula. Results indicated that considering the soil, the structure's period increased by up to 8.7% compared to the fixed-base model, aligning with FEMA's calculations. Furthermore, with adequate ground acceleration, roof displacement increased by 3.4% to 3.8%, while base shear decreased by 4% to 10%. However, roof displacement and base shear increased in some earthquake scenarios due to spectral shape effects in regions with extended structural periods. Foundation damping effects, determined through the foundation's moment-rotation history, grew with higher ground acceleration. This suggests that accounting for period elongation and foundation damping can enhance the seismic design of multi-degree-of-freedom structures.

Vibration Analysis of Rectangular Thick Hate with Concentrated Mass (집중질량을 갖는 후판의 진동해석)

  • Kim, Il-Jung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.711-714
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    • 2005
  • This paper is for the vibration analysis of thick plate with concentrated mass on a inhomogeneous pasternak foundation. the thick rectangular plate resting on a inhomogeneous pasternak foundation is isotropic, homogeneous and composite with linearly elastic material. In order to analyize plat which is supported on inhomogeneous pasternak foundation, the value of winkler foundation parameter(WFP) of centural and border zone of plate are chosen as Kw1 and Kw2 respectively. The value of Kw1 and Kw2 can be changed as 0, 10, $10^2,\;10^3$ and the value of SFP(shear foundation parameter) also be changed 0, 5, 10, 15 respectively. Finally, In this paper, vibration of retangular plate on the inhomogeneous pasternak foundation, natural frequency of this plate with Concentrated Mass are calculated

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Stability Analysis of Rectangular Plate with Concentrated Mass (집중질량을 갖는 장방형판의 안정해석)

  • 김일중;오숙경;이용수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.05a
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    • pp.805-809
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    • 2004
  • This paper is for the vibration analysis of thick plate with concentrated mass on a inhomogeneous pasternak foundation. The vibration of rectangular plate on the inhomogeneous pasternak foundation, natural frequency of this plate with Concentrated Mass are calculated A thick rectangular plate resting on a inhomogeneous pasternak foundation is isotropic, homogeneous and composite with linearly elastic material. In order to analysis plate which is supported on inhomogeneous pasternak foundation, the value of winkler foundation parameter(WFP) of centural and border zone of plate are chosen as WFP1 and WFP2 respectively. The value of WFP1 and WFP2 can be changed as 10, 10$^3$ and the value of SFP(shear foundation parameter) also be changed 5, 15 respectively.

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Free vibration of an axially functionally graded pile with pinned ends embedded in Winkler-Pasternak elastic medium

  • Cetin, Dogan;Simsek, Mesut
    • Structural Engineering and Mechanics
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    • v.40 no.4
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    • pp.583-594
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    • 2011
  • In the present study, free vibration of an axially functionally graded (AFG) pile embedded in Winkler-Pasternak elastic foundation is analyzed within the framework of the Euler-Bernoulli beam theory. The material properties of the pile vary continuously in the axial direction according to the power-law form. The frequency equation is obtained by using Lagrange's equations. The unknown functions denoting the transverse deflections of the AFG pile is expressed in modal form. In this study, the effects of material variations, the parameters of the elastic foundation on the fundamental frequencies are examined. It is believed that the tabulated results will be a reference with which other researchers can compare their results.

Free Vibrations of Horizontally Curved Beams Resting on Winkler-Type Foundations (Winkler형 지반위에 놓인 수평 곡선보의 자유진동)

  • 오상진;이병구;이인원
    • Journal of KSNVE
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    • v.8 no.3
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    • pp.524-532
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    • 1998
  • The purpose of this paper is to investigate the free vibrations of horizontally curved beams resting on Winkler-type foundations. Based on the classical Bernoulli-Euler beam theory, the governing differential equations for circular curved beams are derived and solved numerically. Hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered in numerical examples. The free vibration frequencies calculated using the present analysis have been compared with the finite element's results computed by the software ADINA. Numerical results are presented to show the effects on the natural frequencies of curved beams of the horizontal rise to span length ratio, the foundation parameter, and the width ratio of contact area between the beam and foundation.

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