• Structural Engineering and Mechanics
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• 제51권4호
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• pp.601-625
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• 2014

Based on continuum mechanics and the principle of virtual displacements, incremental total Lagrangian formulation (T.L.) and incremental updated Lagrangian formulation (U.L.) were presented. Both T.L. and U.L. considered the large displacement stiffness matrix, which was modified to be symmetrical matrix. According to the incremental updated Lagrangian formulation, small strain, large displacement, finite rotation of three dimensional Timoshenko fiber beam element tangent stiffness matrix was developed. Considering large displacement and finite rotation, a new type of tangent stiffness matrix of the beam element was developed. According to the basic assumption of plane section, the displacement field of an arbitrary fiber was presented in terms of nodal displacement of centroid of cross-area. In addition, shear deformation effect was taken account. Furthermore, a nonlinear finite element method program has been developed and several examples were tested to demonstrate the accuracy and generality of the three dimensional beam element.

• 대한기계학회논문집A
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• 제21권11호
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• pp.1931-1942
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• 1997

A new load/displacement parameter method is developed for the cases that loads are applied to one or more points, and displacements of a structure are controlled at one or more points sinultaneously. The procedure exploits a generalized Riks method, which utilizes load/displacement parameters as scaling factors in order to analyze the post-buckling phenomena including snap-through or snap-back. A convergence characteristic is improved by employing new relaxation factors in incremental displacement parameter, particularly at the region where exhibits severe numerical instability. The improved performance is illustrated by means of numerical example.

• Structural Engineering and Mechanics
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• 제19권2호
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• pp.153-172
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• 2005

A new load/displacement parameter method is proposed for the simultaneous control of applied loads and structural displacements at one or more points. The procedure is based on a generalized Riks' method, which utilizes load/displacement parameters as scaling factors to analyze post-buckling phenomena including snap-through or snap-back. The convergence characteristics are improved by employing new relaxation factors through an incremental displacement parameter, particularly in a region that exhibits severe numerical instability. The improved performance is illustrated by means of a numerical example.

• 대한토목학회논문집
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• 제5권3호
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• pp.107-115
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• 1985

초기(初期)처짐을 가지는 평판(平板)이 일보면내압축하중(一輔面內壓縮荷重)을 받을 때의 거동을 살피기 위하여 새로운 변위함수(變位凾數)를 도입(導入)한 유한대판법(有限帶板法)을 정식화(正式化)하고, 이 이론(理論)에 따라 컴퓨터 프로그램을 편성(編成)하여 여러 경우에 대한 평판(平板)의 거동을 계산(計算)하고 이미 발표된 결과(結果)와 비교해 보았는데 그 요점은 다음과 같다. 1. Curvature effect를 고려하여 면외변위(面外變位)함수로부터 유도한 식을 참고로 하여 새로운 면내변위(面內變位) 함수를 가정하고 이것을 대판요소(帶板要素)의 변위(變位)함수로 사용한 유한대판법(有限帶板法)을 안식화(定式化)하였다. 2. 위에서 안식화(定式化)한 유한대판법(有限帶板法)에 따라 편성(編成)한 프로그램을 써서 수치해석한 결과 변위증분방식(變位增分方式)이 하중증분방식(荷重增分方式)보다 수렴이 빨랐다. 3. 일축압축(一軸壓縮)을 받는 평판(平板)을 여려 경우에 대해 위의방법으로 해석한 결과는 해석적(解析的) 방법(方法)이나 Crisfield(D)에 의(依)한 유한요소법(有限要素法)으로 얻어진 결과와 잘일치 하였다. 따라서 위의 방법은 평판의 비선형해석을 위한 하나의 유용한 방법으로 생각된다.

• 대한기계학회논문집A
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• 제23권7호
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• pp.1112-1119
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• 1999

Fracture resistance(J-R) curves, which are used for the elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to study the effect of reverse cyclic loading on J-R curves in CT specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio(R) and the other was the incremental plastic displacement(${\delta}_{cycle}/{\delta}_i$), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance test on CT specimens with varying load ratio and incremental plastic displacement were performed. For the SA 516 Gr. 70 steel, the results showed that the J-R curves were decreased with decreasing the load ratio and the incremental plastic displacement. When the load ratio was set to -1, the results of the J-R curves and the $J_i$ value were about $40{\sim}50$ percent of those for the monotonic loading condition. Also on condition that the incremental plastic displacement reached 1/40, the J-R curves and the $J_i$ value were about $50{\sim}60$ percent of those for the incremental plastic displacement of 1/10.

• 한국농공학회논문집
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• 제51권5호
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• pp.59-68
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• 2009

In this study, it was developed that the software could be used to estimate consolidation settlement by curve fitting method according to Terzaghi's consolidation theory on the condition of gradual incremental loading, and the method of estimating settlement caused by lateral displacement was suggested, in which the settlement was calculated from the difference between the settlement calculated with the developed software using the early part of measured data and the settlement measured for the short duration from the beginning of embankment in the field. The verification of the suggested method of estimating settlement caused by lateral displacement showed good results.

• 대한기계학회논문집
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• 제14권3호
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• pp.503-512
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• 1990

본 연구에서는 하중작용점(혹은 변위제어점)이 일점이고 스탭 백 현상이 없는 문제에 유용한 페널티 방법(penalty method)을 제안하고, 스냅 백 현상이 수반되는 경 우에는 페널티 방법과 Riks 방법을 선택적으로 취할 수 있도록 한다. 그리고 하중 작용점이 일점 혹은 그 이상의 점일 경우에 대해서는 Riks 방법을 기준으로 하되 일정 조건하에서는 새로운 증분하중 파라미터를 선택할 수 있게 하여, 순수한 Riks 방법으 로만 계산할 때에 일어날 수 있는 발산을 없앨 수 있게 한다. 끝으로 변위제어점이 일점 혹은 그 이상의 점인 경우에 대해 'Riks형 방법(Riks' type method)'을 제안하고, 이때에도 Riks형 방법을 기준으로 게산하되 일정한 조건하에서는 새로운 증분변위 파 라미터를 선택적으로 취할 수 있게 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1638-1642
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• 2003

Piezoactuator using a flexure hinge mechanism is often used in the precision stages. When the total size of the hinge mechanism become small compared with the deformation of the hinge mechanism, the geometrical nonlinearity makes a considerable error in the output displacement. In this research, the incremental method based on the matrix method is developed to model the effect of the geometrical nonlinearity. Developed modeling method is applied to derive the error of output displacement of the bridge-type hinge mechanism and its results are derived with respect to the design parameters. This method can be easily used to the design optimization of the hinge mechanism and analysis results show that the geometrical nonlinearity error should be considered to achieve a high accuracy to the piezoactuators.

• 대한토목학회논문집
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• 제10권2호
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• pp.11-22
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• 1990

본(本) 논문(論文)에서는 보존력(保存力) 및 비보존력(非保存力)을 받는 구조물(構造物)의 비선형(非線形) 유한요소해석(有限要素解析)을 수행(遂行)하기 위하여 기존의 하중증분법(荷重增分法)과 변위증분법(變位增分法)을 효율적(效率的)으로 결합(結合)시킨 수치적(數値的)인 해석(解析)알고리즘을 제시(提示)하였다. 제안(提案)한 알고리즘은 하중증분(荷重增分)과 변위증분(變位增分)이 자동(自動) 생성되도록 하므로써 Snap-Through, Turning-Back과 같은 비선형(非線形) 거동(擧動)을 포함(包含)하는 다양(多樣)한 평형경로(平衡經路)들을 추적(追跡)할 수 있었다.

• 한국항만학회지
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• 제14권1호
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• pp.115-124
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• 2000

This study is a suggest a measurement method of lateral displacement, which can be used to judge the stability of bridge abutment on soil undergoing lateral movement. The abutment of bridge on soft foundation makes lateral movement due to the settlement of back fill and lateral flow. To measure the displacement of such a abutment, there are a lot of indirect method for measurement such as survey of leveling or inclinometer gauge around the abutment. But all of them are not sufficient to confirm the ground behavior and measure the exact lateral behavior of structure. As making the structure and pile cooperatively by measuring the movement of lateral displacement, for measuring the abutment displacement precisely by using the inclinometer. In this work, we try to suggest efficient measuring method of abutment displacement and its application.