• Title/Summary/Keyword: successive approximations technique

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Buckling Load of Columns with Same Volume and Length but Variable Cross-section along the Length (부피와 길이가 같은 변단면 기둥의 좌굴하중)

  • Lee, Hong-Kyu;Yoo, Jong-Ho;Lee, Seung-Won;Kim, Sun-Hee;Won, Yong-Suk;Yoon, Soon-Jong
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.3
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    • pp.77-85
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    • 2015
  • In this paper, we present the result of investigations pertaining to the elastic buckling of simply supported columns with various cross-sectional dimensions but the same length and volume. In the investigations the accuracy of the analysis methods is studied and it was found that the result obtained by the successive approximations technique is the most accurate. In addition, the elastic buckling loads of columns with variable cross-section dimensions are obtained by the theoretical and numerical methods. From the results, it was found that the buckling loads obtained by the numerical methods are close to the buckling loads obtained by the successive approximations technique for the practical standpoints. Moreover, the buckling load of column with convexity in its middle is the highest while the buckling load of the tapered column is the lowest as expected.

Buckling Strength of Wooden Column with Entasis at the Muryangsugeon in Buseoksa-Temple (부석사 무량수전 배흘림 목재 기둥의 좌굴강도)

  • Yoon, Soon-Jong;Kim, Hee-Soo;Yoo, Hyung-Joo;Han, Min-Hyuck;Kim, Jin-Kyung;Ji, Hye-In
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.1
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    • pp.6-13
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    • 2015
  • In this paper we present the result of investigations pertaining to the buckling strength of Zelkova Serrata (Elm-like) tree column with entasis at the Muryangsujeon in Buseoksa-Temple, Korea. Wooden columns with entasis had been used in the construction of ancient architectural buildings in Korea. It was not known why did they design columns with entasis of the buildings. It is just presumed that the reason may be the compensation of optical illusion, aesthetics, and/or structural safety. The question is not answered even today and it may not be possible to answer clearly and easily. In the paper, the buckling analyses are conducted on both of the wooden column with entasis and the prismatic wooden column by the successive approximations technique and the finite element methods, respectively. The results of analyses are compared and discussed.

The influence of different support movements and heights of piers on the dynamic behavior of bridges -Part II: earthquake acting along the bridge axis

  • Raftoyiannis, I.G.;Konstantakopoulos, T.G.;Michaltsos, G.T.
    • Interaction and multiscale mechanics
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    • v.3 no.1
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    • pp.39-54
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    • 2010
  • In this paper, a simple approach is presented for studying the dynamic response of multi-span steel bridges supported by pylons of different heights, subjected to earthquake motions acting along the axis of the bridge with spatial variations. The analysis is carried out using the modal analysis technique, while the solution of the integral-differential equations derived is obtained using the successive approximations technique. It was found that the height of piers and the quality of the foundation soil can affect significantly the dynamical behavior of the bridges studied. Illustrative examples are presented to highlight the points of concern and useful conclusions are gathered.

In-Plane Buckling of Prime and Quadratic Parabolic Arches with Fixed Ends (양단고정 Prime과 Quadratic 포물선 아치의 면내좌굴에 관한 연구)

  • 이병구;김종만
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.29 no.3
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    • pp.153-162
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    • 1987
  • A numerical procedure for the analysis of slender arch buckling problems for uniform dead weight is presented in this paper. Such loading changes in the arch profile. The problem is nonlinear. The numerical procedure is limited to an inextensible analysis and to elastic behavior. Based upon a numerical integration technique developed by Newmark for straight beams, a large deflection bending analysis is combined with small deflection buckling routines to formulate the numerical procedure. The numerical procedure is composed of a combination of the numerical integration and successive approximations procedure. The results obtained in this study are as follows : 1.The critical loads obtained in this study coincide with the results by Austin so that the algorithm developed in this study is verified. 2.The numerical results are converged with good precision when the half arch is divided into 10 segments in both Prime and Quadratic section. 3.The critical loads are decreased as the ratios of rise versus span are increased. 4.The critical loads are increased as the moments of inertia at the ends are increased. 5.The critical loads of Prime section are larger than that of Quadratic section under the same profile conditions.

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Structural Optimization by Global-Local Approximations Structural Reanalysis based on Substructuring (부구조화 기반 전역-부분 근사화 구조재해석에 의한 구조최적화)

  • 김태봉;서상구;김창운
    • Journal of the Korean Society of Safety
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    • v.12 no.3
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    • pp.120-131
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    • 1997
  • This paper presents an approximate reanalysis methods of structures based on substructuring for an effective optimization of large-scale structural systems. In most optimal design procedures the analysis of the structure must be repeated many times. In particular, one of the main obstacles in the optimization of structural systems are involved high computational cost and expended long time in the optimization of large-scale structures. The purpose of this paper is to evaluate efficiently the structural behavior of new designs using information from previous ones, without solving basic equations for successive modification in the optimal design. The proposed reanalysis procedure is combined Taylor series expansions which is a local approximation and reduced basis method which is a global approximation based on substructuring. This technique is to choose each of the terms of Taylor series expansions as the basis vector of reduced basis method in substructuring system which is one of the most effective analysis of large -scale structures. Several numerical examples illustrate the effectiveness of the solution process.

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Application of the Unstructured Finite Element to Longitudinal Vibration Analysis (종방향 진동해석에 비구조적 유한요소 적용)

  • Kim Chi-Kyung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.1 s.71
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    • pp.39-46
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    • 2006
  • This paper analyzes the continuous Galerkin method for the space-time discretization of wave equation. The method of space-time finite elements enables the simple solution than the usual finite element analysis with discretization in space only. We present a discretization technique in which finite element approximations are used in time and space simultaneously for a relatively large time period called a time slab. The weighted residual process is used to formulate a finite element method for a space-time domain. Instability is caused by a too large time step in successive time steps. A stability problem is described and some investigations for chosen types of rectangular space-time finite elements are carried out. Some numerical examples prove the efficiency of the described method under determined limitations.

An Application of Space and Time Finite Element Method for Two-Dimensional Transient Vibration (2차원 동적 진동문제의 공간-시간 유한요소법 적용)

  • Kim, Chi-Kyung
    • Journal of the Korean Society of Safety
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    • v.21 no.2 s.74
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    • pp.143-149
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    • 2006
  • This paper deals with the space-time finite element analysis of two-dimensional vibration problem with a single variable. The method of space-time finite elements enables the simpler solution than the usual finite element analysis with discretization in space only. We present a discretization technique in which finite element approximations are used in time and space simultaneously for a relatively large time period. The weighted residual process is used to formulate a finite element method for a space-time domain. A stability problem is described and some investigations for chosen type of rectangular space-time finite elements are carried out. Instability is caused by a too large time step of successive time steps in the traditional time-dependent problems. It has been shown that the numerical stability of time-stepping on the larger time steps is quite good. The unstructured space-time finite element not only overcomes the shortcomings of the stability in the traditional numerical methods, but it is also endowed with the features of an effective computational technique. Some numerical examples have been presented to illustrate the efficiency of the described method.