• Title, Summary, Keyword: geometric nonlinearity

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Geometric Nonlinear Analysis of Flexible Media Using $C^1$ Beam Element ($C^1$보요소를 이용한 유연매체의 기하비선형 해석)

  • Jee, Jung-Geun;Hong, Sung-Kwon;Jang, Yong-Hoon;Park, No-Cheol;Park, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.326-329
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    • 2005
  • In the development of sheet-handling .machinery, it is important to predict the static and dynamic behavior of the sheets with a high degree of reliability because the sheets are fed and stacked at suck a high speed flexible media behaves geometric nonlinearity of large displacement and small strain. In this paper, static analysis of flexible media are performed by FEM considering geometric nonlinearity. Linear stiffness matrix and geometric nonlinear stiffness matrix based m the updated Lagrangian approach are derived using $C^1$ beam element and numerical simulations are performed by Updated Newton-Raphson(UNR) method.

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Nonlinear Structural Analysis of High-Aspect-Ratio Structures using Large Deflection Beam Theory

  • Kim, Kyung-Seok;Yoo, Seung-Jae;Lee, In
    • International Journal of Aeronautical and Space Sciences
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    • v.9 no.2
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    • pp.41-47
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    • 2008
  • The nonlinear structural analyses of high-aspect-ratio structures were performed. For the high-aspect-ratio structures, it is important to understand geometric nonlinearity due to large deflections. To consider geometric nonlinearity, finite element analyses based on the large deflection beam theory were introduced. Comparing experimental data and the present nonlinear analysis results, the current results were proved to be very accurate for the static and dynamic behaviors for both isotropic and anisotropic beams.

Nonlinear Analysis of 3-D Steel Frames (3차원 강뼈대구조의 비선형 해석)

  • Kim, Seung Eock;Kim, Yo Suk;Choi, Se Hyu;Kim, Sung Mo;Choi, Joon Ho
    • Journal of Korean Society of Steel Construction
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    • v.11 no.4
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    • pp.417-424
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    • 1999
  • In this paper a nonlinear analysis of three-dimensional steel frames is developed. This analysis accounts for material and geometric nonlinearities. The material nonlinearity includes gradual yielding associated with flexural behaviors. The geometric nonlinearity includes the second-order effects associated with $P-{\delta}\;and\;P-{\Delta}$ effects. The material nonlinearity at the node is considered using the concept of P-M hinge consisting of many fibers. The geometric nonlinearity is considered by the use of stability function. The nonlinearity caused by shear and torsional interaction effects is neglected. The modified incremental displacement method is used as the solution technique. The load-displacements predicted by the proposed analysis compare well with those given by other approaches.

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Nonlinear Numerical Analysis and Experiment of Composite Laminated Plates (복합재 적층판재의 비선형 수치해석 및 실험)

  • 조원만;이영신;윤성기
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.12
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    • pp.2915-2925
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    • 1993
  • A finite element program using degenerated shell element was developed to solve the geometric, material and combined nonlinear behaviors of composite laminated plates. The total Lagrangian method was implemented for geometric nonlinear analysis. The material nonlinear behavior was analyzed by considering the matrix degradation due to the progressive failure in the matrix and matrix-fiber interface after initial failure. The results of the geometric nonlinear analyses showed good agreements with the other exact and numerical solutions. The results of the combined nonlinear analyses considered both geometric and material nonlinear behaviors were compared to the experiments in which a concentrated force was applied to the center of the square laminated plate with clamped four edges.

SIX SOLUTIONS FOR THE SEMILINEAR WAVE EQUATION WITH NONLINEARITY CROSSING THREE EIGENVALUES

  • Choi, Q-Heung;Jung, Tacksun
    • Korean Journal of Mathematics
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    • v.20 no.3
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    • pp.361-369
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    • 2012
  • We get a theorem which shows the existence of at least six solutions for the semilinear wave equation with nonlinearity crossing three eigenvalues. We obtain this result by the variational reduction method and the geometric mapping defined on the finite dimensional subspace. We use a contraction mapping principle to reduce the problem on the infinite dimensional space to that on the finite dimensional subspace. We construct a three-dimensional subspace with three axes spanned by three eigenvalues and a mapping from the finite dimensional subspace to the one-dimensional subspace.

Vibration Characteristics of a Curved Pipe Conveying Fluid with the Geometric Nonlinearity (기하학적 비선형성을 갖는 유체를 수송하는 곡선관의 진동 특성)

  • Jung, Du-Han;Chung, Jin-Tai
    • Proceedings of the KSME Conference
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    • pp.793-798
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    • 2004
  • The vibration of a curved pipe conveying fluid is studied when the pipe is clamped at both ends. To consider the geometric nonlinearity, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the extended Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigate the vibration characteristics of the system, the discretized equations of motion are derived from the Galerkin method. The natural frequencies varying with the flow velocity are computed from the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. From these results, we should consider the geometric nonlinearity to analyze the dynamics of a curved pipe conveying fluid more precisely.

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Vibration Analysis for the In-plane Motions of a Semi-Circular Pipe Conveying Fluid Considering the Geometric Nonlinearity (기하학적 비선형성을 고려한 유체를 수송하는 반원관의 면내운동에 대한 진동 해석)

  • 정진태;정두한
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.12
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    • pp.2012-2018
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    • 2004
  • The vibration of a semi-circular pipe conveying fluid is studied when the pipe is clamped at both ends. To consider the geometric nonlinearity, this study adopts the Lagrange strain theory for large deformation and the extensible dynamics based on the Euler-Bernoulli beam theory for slenderness assumption. By using the Hamilton principle, the non-linear partial differential equations are derived for the in-plane motions of the pipe, considering the fluid inertia forces as a kind of non-conservative forces. The linear and non-linear terms in the governing equations are compared with those in the previous study, and some significant differences are discussed. To investigate the dynamic characteristics of the system, the discretized equations of motion are derived from the Galerkin method. The natural frequencies varying with the flow velocity are computed from the two cases, which one is the linear problem and the other is the linearized problem in the neighborhood of the equilibrium position. Finally, the time responses at various flow velocities are directly computed by using the generalized-$\alpha$ method. From these results, we should consider the geometric nonlinearity to analyze dynamics of a semi-circular pipe conveying fluid more precisely.

Long-term structural analysis and stability assessment of three-pinned CFST arches accounting for geometric nonlinearity

  • Luo, Kai;Pi, Yong-Lin;Gao, Wei;Bradford, Mark A.
    • Steel and Composite Structures
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    • v.20 no.2
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    • pp.379-397
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    • 2016
  • Due to creep and shrinkage of the concrete core, concrete-filled steel tubular (CFST) arches continue to deform in the long-term under sustained loads. This paper presents analytical investigations of the effects of geometric nonlinearity on the long-term in-plane structural performance and stability of three-pinned CFST circular arches under a sustained uniform radial load. Non-linear long-term analysis is conducted and compared with its linear counterpart. It is found that the linear analysis predicts long-term increases of deformations of the CFST arches, but does not predict any long-term changes of the internal actions. However, non-linear analysis predicts not only more significant long-term increases of deformations, but also significant long-term increases of internal actions under the same sustained load. As a result, a three-pinned CFST arch satisfying the serviceability limit state predicted by the linear analysis may violate the serviceability requirement when its geometric nonlinearity is considered. It is also shown that the geometric nonlinearity greatly reduces the long-term in-plane stability of three-pinned CFST arches under the sustained load. A three-pinned CFST arch satisfying the stability limit state predicted by linear analysis in the long-term may lose its stability because of its geometric nonlinearity. Hence, non-linear analysis is needed for correctly predicting the long-term structural behaviour and stability of three-pinned CFST arches under the sustained load. The non-linear long-term behaviour and stability of three-pinned CFST arches are compared with those of two-pinned counterparts. The linear and non-linear analyses for the long-term behaviour and stability are validated by the finite element method.

Nonlinear spectral collocation analysis of imperfect functionally graded plates under end-shortening

  • Ghannadpour, S. Amir M.;Kiani, Payam
    • Structural Engineering and Mechanics
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    • v.66 no.5
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    • pp.557-568
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    • 2018
  • An investigation is made in the present work on the post-buckling and geometrically nonlinear behaviors of moderately thick perfect and imperfect rectangular plates made-up of functionally graded materials. Spectral collocation approach based on Legendre basis functions is developed to analyze the functionally graded plates while they are subjected to end-shortening strain. The material properties in this study are varied through the thickness according to the simple power law distribution. The fundamental equations for moderately thick rectangular plates are derived using first order shear deformation plate theory and taking into account both geometric nonlinearity and initial geometric imperfections. In the current study, the domain of interest is discretized with Legendre-Gauss-Lobatto nodes. The equilibrium equations will be obtained by discretizing the Von-Karman's equilibrium equations and also boundary conditions with finite Legendre basis functions that are substituted into the displacement fields. Due to effect of geometric nonlinearity, the final set of equilibrium equations is nonlinear and therefore the quadratic extrapolation technique is used to solve them. Since the number of equations in this approach will always be more than the number of unknown coefficients, the least squares technique will be used. Finally, the effects of boundary conditions, initial geometric imperfection and material properties are investigated and discussed to demonstrate the validity and capability of proposed method.

GEOMETRIC RESULT FOR THE ELLIPTIC PROBLEM WITH NONLINEARITY CROSSING THREE EIGENVALUES

  • Jung, Tacksun;Choi, Q-Heung
    • Korean Journal of Mathematics
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    • v.20 no.4
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    • pp.507-515
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    • 2012
  • We investigate the number of the solutions for the elliptic boundary value problem. We obtain a theorem which shows the existence of six weak solutions for the elliptic problem with jumping nonlinearity crossing three eigenvalues. We get this result by using the geometric mapping defined on the finite dimensional subspace. We use the contraction mapping principle to reduce the problem on the infinite dimensional space to that on the finite dimensional subspace. We construct a three dimensional subspace with three axis spanned by three eigenvalues and a mapping from the finite dimensional subspace to the one dimensional subspace.