• Title/Summary/Keyword: p Version

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Fatigue Crack Propagation Analysis by P-Version of Finite Element Method (P-version 유한요소법에 의한 피로균열해석)

  • 우광성;이채규
    • Computational Structural Engineering
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    • v.5 no.3
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    • pp.97-103
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    • 1992
  • Since many design problems in the railroad, aerospace and machine structures involve considerations of the effect of cyclic loading, manufacturing and quality control processes much fully account for fatigue of critical components. Due to the sensitivity of the Paris law, it is very important to calculate .DELTA.K numerically to minimize the error of predicted fatigue life in cycles. However, it is shown that the p-version of FEM based on LEFM analysis is far better suited for computing the stress intensity factors than the conventional h-version. To demonstrate the proficiency of the proposed scheme, the welded T-joint with crack problems of box car body bolster assembly and a crack problem emanating from a circular hole in finite strip have been solved.

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hp-Version of the Finite Element Analysis for Reissner-Mindlin Plates (Reissner-Mindlin 평판의 hp-Version 유한요소해석)

  • Woo, Kwang Sung;Lee, Gee Doug;Ko, Man Gi
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.2
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    • pp.151-160
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    • 1993
  • This paper is concerned with formulations of the hierarchical $C^{\circ}$-plate element on the basis of Reissner-Mindlin plate theory. On reason for the development of the aforementioned element based on Integrals of Legendre shape functions is that it is still difficult to construct elements based on h-version concepts which are accurate and stable against the shear locking effects. An adaptive mesh refinement and selective p-distribution of the polynomial degree using hp-version of the finite element method are proposed to verify the superior convergence and algorithmic efficiency with the help of the simply supported L-shaped plate problems.

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Ρ-Version Finite Element Analysis for Material Nonlinearity (재료적 비선형을 고려한 Ρ-Version 유한요소해석)

  • 정우성;홍종현;우광성;신영식
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.04a
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    • pp.71-78
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    • 1997
  • The high precision analysis by the p-version of the finite element method are fairly well established as highly efficient method for linear elastic problems, especially in the presence of stress singularity. It has been noted that the merits of p-version are accuracy, modeling simplicity, robustness, and savings in user's and CPU time. However, little has been done to exploit their benefits in elasto-plastic analysis. In this paper, the p-version finite element model is proposed for the materially nonlinear analysis that is based on the incremental theory of plasticity, the associated flow rule, and von-Mises yield criteria. To obtain the solution of nonlinear equation, the Newton-Raphson method and initial stiffness method, etc are used. Several numerical examples are tested with the help of the square plates with cutout, the thick-walled cylinder under internal pressure, and the center cracked plate under tensile loading. Those results are compared with the there cal solutions and the numerical solutions of ADINA software.

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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.

ERROR ANALYSIS OF THE hp-VERSION UNDER NUMERICAL INTEGRATIONS FOR NON-CONSTANT COEFFICIENTS

  • KIM, IK-SUNG
    • Honam Mathematical Journal
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    • v.27 no.2
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    • pp.317-332
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    • 2005
  • In this paper we consider the hp-version to solve non-constant coefficients elliptic equations on a bounded, convex polygonal domain ${\Omega}$ in $R^2$. A family $G_p=\{I_m\}$ of numerical quadrature rules satisfying certain properties can be used for calculating the integrals. When the numerical quadrature rules $I_m{\in}G_p$ are used for computing the integrals in the stiffness matrix of the variational form we will give its variational form and derive an error estimate of ${\parallel}u-{\widetilde{u}}^h_p{\parallel}_{1,{\Omega}$.

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An Analysis of the Reliability of Group Assessment of Logical Thinking (GALT) using Generalizability Theory (일반화가능도 이론을 이용한 집단논리적사고력검사(GALT)의 신뢰도 분석)

  • Ryu, Chun-Ryol;Lee, Yong-Geun
    • Journal of the Korean earth science society
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    • v.31 no.1
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    • pp.95-105
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    • 2010
  • The purpose of this study lies in applying generalizability theory depending on the aim of the usage of GALT to analyze the sources of error of single-facet considering item and person only and to analyze the sources of error of multi-facet considering item, person and domain. The study was conducted with 1016 students of local elementary, middle, and high schools. The 21 items of a full version were answered for 40 minute and then the 12 items of short version were sampled to analyze reliability using generalizability theory. Both the full version and the short version of the items were analyzed using Cronbach's alpha for data analysis, and we applied generalizability theory and separate $p{\times}i$ design and $p{\times}(i:h)$ design, G study and D study were performed. Results of analysis are as follows: First, the result of D study after $p{\times}I$ design both on the full version and the short version showed that in the case of the full version, the generalizability coefficient was 0.87 exceeding a normal level of 0.80, and the normal level of generalizability coefficient was achieved in 13 items as well. In case of short version, when 12 items were evaluated, generalizability coefficient was 0.77 not reaching the normal level, and the normal level was achieved in case of more than 15 items. Second, the result of D study after $p{\times}(I:H)$ design on the short version showed that once one domain consists of 2 items in 6 domains, generalizability coefficient was 0.71 which is lower than the normal level of 0.80, the normal level was achieved in more than 5 item cases.

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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Stress intensity factors for 3-D axisymmetric bodies containing cracks by p-version of F.E.M.

  • Woo, Kwang S.;Jung, Woo S.
    • Structural Engineering and Mechanics
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    • v.2 no.3
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    • pp.245-256
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    • 1994
  • A new axisymmetric crack model is proposed on the basis of p-version of the finite element method limited to theory of small scale yielding. To this end, axisymmetric stress element is formulated by integrals of Legendre polynomial which has hierarchical nature and orthogonality relationship. The virtual crack extension method has been adopted to calculate the stress intensity factors for 3-D axisymmetric cracked bodies where the potential energy change as a function of position along the crack front is calculated. The sensitivity with respect to the aspect ratio and Poisson locking has been tested to ascertain the robustness of p-version axisymmetric element. Also, the limit value that is an exact solution obtained by FEM when degree of freedom is infinite can be estimated using the extrapolation equation based on error prediction in energy norm. Numerical examples of thick-walled cylinder, axisymmetric crack in a round bar and internal part-thorough cracked pipes are tested with high precision.

THE HP-VERSION OF THE FINITE ELEMENT METHOD UNDER NUMERICAL QUADRATURE RULES

  • Kim, Ik-Sung
    • East Asian mathematical journal
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    • v.14 no.1
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    • pp.63-76
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    • 1998
  • we consider the hp-version to solve non-constant coefficients elliptic equations $-div(a{\nabla}u)=f$ with Dirichlet boundary conditions on a bounded polygonal domain $\Omega$ in $R^2$. In [6], M. Suri obtained an optimal error-estimate for the hp-version: ${\parallel}u-u^h_p{\parallel}_{1,\Omega}{\leq}Cp^{(\sigma-1)}h^{min(p,\sigma-1)}{\parallel}u{\parallel}_{\sigma,\Omega}$. This optimal result follows under the assumption that all integrations are performed exactly. In practice, the integrals are seldom computed exactly. The numerical quadrature rule scheme is needed to compute the integrals in the variational formulation of the discrete problem. In this paper we consider a family $G_p=\{I_m\}$ of numerical quadrature rules satisfying certain properties, which can be used for calculating the integrals. Under the numerical quadrature rules we will give the variational form of our non-constant coefficients elliptic problem and derive an error estimate of ${\parallel}u-\tilde{u}^h_p{\parallel}_{1,\Omega}$.

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