• Title/Summary/Keyword: nonlinear hypothesis-theory

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Three-point bending of beams with consideration of the shear effect

  • Magnucki, Krzysztof;Paczos, Piotr;Wichniarek, Radosław
    • Steel and Composite Structures
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    • v.37 no.6
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    • pp.733-740
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    • 2020
  • The subject of the paper pertains to simply supported beams with bisymmetrical cross sections under three-point bending with consideration of the shear effect. The deformation of a planar cross section of the beam is described taking into account the assumed nonlinear hypothesis-theory. Two differential equations of equilibrium are obtained based on the principle of stationary potential energy. This system is analytically solved and the shear coefficients and deflections of the beams are derived. Moreover, the Young's modules of the materials and deflections of the beams are experimentally determined on a test stand. The results of the studies are specified in tables and compared.

Structural Behavior Analysis of Two-way RC Slabs by p-Version Nonlinear Finite Element Model (p-Version 비선형 유한요소모텔에 의한 2방향 철근 콘크리트 슬래브의 역학적 거동해석)

  • Cho, Jin-Goo;Park, Jin-Hwan
    • Journal of The Korean Society of Agricultural Engineers
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    • v.47 no.4
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    • pp.15-24
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    • 2005
  • This study is focused on modeling to predict the behavior of two-way RC slabs. A new finite element model will be presented to analyze the nonlinear behavior of RC slabs. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on the Kuper's yield criterion, hardening rule, and crushing condition. The validity of the proposed p-version nonlinear RC finite element model is demonstrated through the load-deflection curves and the ultimate loads. It is shown that the proposed model is able to adequately predict the deflection and ultimate load of two-way slabs with respect to steel arrangements and steel ratios.

Ultimate Load of RC Structures Bonded with the Soffit Plate by p-Version Nonlinear Analysis (p-Version 비선형 해석에 의한 팻취보강된 RC구조물의 극한강도 산정)

  • 안재석;박진환;홍종현;우광성
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2004.04a
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    • pp.365-372
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    • 2004
  • A new finite element model will be presented to analyze the nonlinear behavior of not only RC beams and slabs, but also RC beams strengthened by a patch repair. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on hardening rule, crushing condition, plate-end debonding strength model and so on. The Gauss-Lobatto numerical quadrature is applied to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version finite element model is demonstrated through several numerical examples for the load-deflection curves, the ultimate loads, and the failure modes of reinforced connote slabs and RC beams bonded with steel plates or FRP plates compared with available experimental and numerical results.

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Axisymmetric Nonlinear Consolidation Analysis for Drainage-installed Deposit Considering Secondary Compression (배수재가 설치된 연약지반의 2차압축을 고려한 축대칭 비선형 압밀해석)

  • Kim Yun-Tae
    • Journal of the Korean Geotechnical Society
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    • v.21 no.3
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    • pp.133-140
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    • 2005
  • In order to accelerate the rate of consolidation settlement and gain a required shear strength for a given soft clay deposit, vertical drain method combined with a preloading technique has been widely applied. In this paper, a theory of axisymmetric nonlinear consolidation fer drainage-installed deposit, which considers secondary compression (or creep) during primary consolidation, as well as the variations of compressibility and permeability during the consolidation process, has been developed. A computer program named AXICON based on Hypothesis B fur the analysis of axisymmetric nonlinear consolidation was developed by adopting finite difference method. The results of AS(ICON were compared with Hansbo's solution based on Hypothesis A, as well as in-situ settlements and pore pressures measured in test embankment of Ska-Edeby. The results indicated that Hypothesis A usually underestimated the in-situ settlement and Hypothesis B was considered to be logically correct. It was also shown that one may able to appropriately predict the real in-situ behaviors using the proposed program.

p-Version Finite Element Analysis of Anisotropic Laminated Plates considering Material-Geometric Nonlinearities (재료-기하비선형을 고려한 이방성 적층평판의 p-Version 유한요소해석)

  • 홍종현;박진환;우광성
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.319-326
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    • 2002
  • A p-version finite element model based on degenerate shell element is proposed for the analysis of orthotropic laminated plates. In the nonlinear formulation of the model, the total Lagrangian formulation is adopted with large deflection and moderate rotation being accounted for in the sense of von Karman hypothesis. The material model Is based on the Huber-Mises yield criterion and Prandtl-Reuss flow rule in accordance with the theory of strain hardening yield function, which is generalized for anisotropic materials by introducing the parameters of anisotropy. The model is also based on extension of equivalent-single layer laminate theory(ESL theory) with shear deformation, leading to continuous shear strain at the interface of two layers. The Integrals of Legendre Polynomials we used for shape functions with p-level varying from 1 to 10. Gauss-Lobatto numerical quadrature is used to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version finite element model is demonstrated through several comparative points of view in terms of ultimate load, convergence characteristics, nonlinear effect, and shape of plastic zone

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Energy equivalent lumped damage model for reinforced concrete structures

  • Neto, Renerio Pereira;Teles, Daniel V.C.;Vieira, Camila S.;Amorim, David L.N.F.
    • Structural Engineering and Mechanics
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    • v.84 no.2
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    • pp.285-293
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    • 2022
  • Lumped damage mechanics (LDM) is a recent nonlinear theory with several applications to civil engineering structures, such as reinforced concrete and steel buildings. LDM apply key concepts of classic fracture and damage mechanics on plastic hinges. Therefore, the lumped damage models are quite successful in reproduce actual structural behaviour using concepts well-known by engineers in practice, such as ultimate moment and first cracking moment of reinforced concrete elements. So far, lumped damage models are based in the strain energy equivalence hypothesis, which is one of the fictitious states where the intact material behaviour depends on a damage variable. However, there are other possibilities, such as the energy equivalence hypothesis. Such possibilities should be explored, in order to pursue unique advantages as well as extend the LDM framework. Therewith, a lumped damage model based on the energy equivalence hypothesis is proposed in this paper. The proposed model was idealised for reinforced concrete structures, where a damage variable accounts for concrete cracking and the plastic rotation represents reinforcement yielding. The obtained results show that the proposed model is quite accurate compared to experimental responses.

TESTING FOR SMOOTH TRANSITION NONLINEARITY IN PARTIALLY NONSTATIONARY VECTOR AUTOREGRESSIONS

  • Seo, Byeong-Seon
    • Journal of the Korean Statistical Society
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    • v.36 no.2
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    • pp.257-274
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    • 2007
  • This paper considers the tests for the presence of smooth transition non-linearity in the partially nonstationary vector autoregressive model. The transition parameters cannot be identified under the null hypothesis of linearity, and therefore this paper develops the tests for smooth transition nonlinearity, the associated asymptotic theory and the bootstrap inference. The Monte Carlo simulation evidence shows that the bootstrap inference generates moderate size and power performances.

Nonthermal Radiation from Supernova Remnant Shocks

  • Kang, Hyesung
    • Journal of Astronomy and Space Sciences
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    • v.30 no.3
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    • pp.133-140
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    • 2013
  • Most of high energy cosmic rays (CRs) are thought to be produced by diffusive shock acceleration (DSA) at supernova remnants (SNRs) within the Galaxy. Fortunately, nonthermal emissions from CR protons and electrons can provide direct observational evidence for such a model and place strong constraints on the complex nonlinear plasma processes in DSA theory. In this study we calculate the energy spectra of CR protons and electrons in Type Ia SNRs, using time-dependent DSA simulations that incorporate phenomenological models for some wave-particle interactions. We demonstrate that the time-dependent evolution of the self-amplified magnetic fields, Alfv$\acute{e}$nic drift, and escape of the highest energy particles affect the energy spectra of accelerated protons and electrons, and so resulting nonthermal radiation spectrum. Especially, the spectral cutoffs in X-ray and ${\gamma}$-ray emission spectra are regulated by the evolution of the highest energy particles, which are injected at the early phase of SNRs. Thus detailed understandings of nonlinear wave-particle interactions and time-dependent DSA simulations of SNRs are crucial in testing the SNR hypothesis for the origin of Galactic cosmic rays.

Numerical Prediction of Ultimate Strength of RC Beams and Slabs with a Patch by p-Version Nonlinear Finite Element Modeling and Experimental Verification (p-Version 비선형 유한요소모델링과 실험적 검증에 의한 팻취 보강된 RC보와 슬래브의 극한강도 산정)

  • Ahn Jae-Seok;Park Jin-Hwan;Woo Kwang-Sung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.17 no.4
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    • pp.375-387
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    • 2004
  • A new finite element model will be presented to analyze the nonlinear behavior of RC beams and slabs strengthened by a patch repair. The numerical approach is based on the p-version degenerate shell element including theory of anisotropic laminated composites, theory of materially and geometrically nonlinear plates. In the nonlinear formulation of this model, the total Lagrangian formulation is adopted with large deflections and moderate rotations being accounted for in the sense of von Karman hypothesis. The material model is based on hardening rule, crushing condition, plate-end debonding strength model and so on. The Gauss-Lobatto numerical quadrature is applied to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed p-version nonlinear finite element model is demonstrated through the load-deflection curves, the ultimate loads, and the failure modes of RC beams or slabs bonded with steel plates or FRP plates compared with available result of experiment and other numerical methods.

p-Version Finite Element Analysis of Composite Laminated Plates with Geometric and Material Nonlinearities (기하 및 재료비선형을 갖는 적층평판의 p-Version 유한요소해석)

  • 홍종현;박진환;우광성
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.3
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    • pp.491-499
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    • 2002
  • A p-version finite element model based on degenerate shell element is proposed tot the analysis of orthotropic laminated plates. In the nonlinear formulation of the model, the total Lagrangian formulation is adopted with large deflection and moderate rotation being accounted tot in the sense of yon Karman hypothesis. The material model is based on the Huber-Mises yield criterion and Prandtl-Reuss flow rule in accordance with the theory of strain hardening yield function, which is generalized lot anisotropic materials by introducing the parameters of anisotropy. The model is also based on extension of equivalent-single layer laminate theory(ESL theory) with shear deformation, leading to continuous shear strain at the interface of two layers. The integrals of Legendre polynomials are used for shape functions with p-level varying from 1 to 10. Gauss-Lobatto numerical quadrature is used to calculate the stresses at the nodal points instead of Gauss points. The validity of the proposed P-version finite element model is demonstrated through several comparative points of iew in terms of ultimate load, convergence characteristics, nonlinear effect, and shape of plastic tone.