• Structural Engineering and Mechanics
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• 제38권6호
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• pp.767-802
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• 2011

Developers of new finite elements or nonlinear solution techniques rely on discriminative benchmark tests drawn from the literature to assess the advantages and drawbacks of new formulations. Buckling benchmark tests provide a rigorous evaluation of finite elements applied to thin structures, and a complete and detailed set of reference results would therefore prove very useful in carrying out such evaluations. Results are usually presented in the form of load-deflection curves that developers must reconstruct by extracting the points, a procedure which is often tedious and inaccurate. Moreover the curves are usually given without accompanying information such as the calculation time or number of iterations it took for the model to converge, even though this type of data is equally important in practice. This paper presents ten different limit-point buckling benchmark tests, and provides for each one the reference load-deflection curve, all the points necessary to recreate the curve in tabulated form, analysis data such as calculation time, number of iterations and increments, and all of the inputs used to obtain these results.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.351-354
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• 2003

To inspect point-defect in LCD pannel, calculate period and eliminated pattern. And then find point-defect to compare block image with each period. First processing, Founded over point defects. To reduce wrong point defect. Next, label point-defects and eliminated not surpass fixed limit-size.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제5권1호
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• pp.13-16
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• 1998

For continuous maps f of the circle to itself, we show that (1) every $\omega$-limit point is recurrent (or almost periodic) if and only if every $\omega$-limit set is minimal, (2) every $\omega$-limit set is almost periodic, then every $\omega$-limit set contains only one minimal set.

• 대한수학회지
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• 제44권4호
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• pp.997-1012
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• 2007

We consider the nonrelativistic limit in the self-dual Abelian Chern-Simons model, and give a rigorous proof of the limit for the radial solutions to the self-dual equations with the nontopological boundary condition when there is only one-vortex point. By keeping the shooting constant of radial solutions to be fixed, we establish the convergence of radial solutions in the nonrelativistic limit.

• 대한수학회논문집
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• 제11권1호
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• pp.253-258
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• 1996

For a nonelementary discrete group $\Gamma$ of hyperbolic isometries acting on $B^m(m\geq2)$, we give a topological characterization of conical limit points using admissible pairs.

• Structural Engineering and Mechanics
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• 제36권5호
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• pp.529-544
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• 2010

Nonlinear equations of structures are generally solved numerically by the iterative solution of linear equations. However, this iterative procedure diverges when the tangent stiffness is ill-conditioned which occurs near limit points. In other words, a major challenge with simple iterative methods is failure caused by a singular or near singular Jacobian matrix. In this paper, using the Newton-Raphson algorithm based on Davidenko's equations, the iterations can traverse the limit point without difficulty. It is argued that the propose algorithm may be both more computationally efficient and more robust compared to the other algorithm when tracing path through severe nonlinearities such as those associated with structural collapse. Two frames are analyzed using the proposed algorithm and the results are compared with the previous methods. The ability of the proposed method, particularly for tracing the limit points, is demonstrated by those numerical examples.

• 한국안전학회지
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• 제23권3호
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• pp.36-41
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• 2008

For the safety design and operation of many chemical process, it is necessary to know certain explosion limit, flash point and autoignition temperature(AIT) of handling substances. Also it is necessary to know explosion limit at high temperature and pressure. For the safe handling of MEK(methyl ethyl ketone), explosion limit at $25^{\circ}C$ and the temperature dependence of the explosion limits were investigated. And flash point and AIT for MEK were experimented. By using the literatures data, the lower and upper explosion limits of MEK recommended 1.8 vol% and 11.0 vol%, respectively. In this study, measured the lower and upper flash points of MEK were $-5^{\circ}C$ and $22^{\circ}C$, respectively. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for MEK, and the experimental AIT of MEK was $507^{\circ}C$. The new equations for predicting the temperature dependence of the explosion limits of MEK is proposed. The values calculated by the proposed equations were a good agreement with the literature data.

• Earthquakes and Structures
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• 제19권3호
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• pp.189-196
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• 2020

The near-collapse performance limit is defined as the deformation at the 20% drop of maximum base shear in the decreasing region of the pushover curve for ductile framed buildings. Although monotonic pushover analysis is preferred due to the simple application procedure, this analysis gives rise to overestimated results by neglecting the cumulative damage effects. In the present study, the acceptabilities of monotonic and cyclic pushover analysis results for the near-collapse performance limit state are determined by comparing with Incremental Dynamic Analysis (IDA) results for a 5-story Reinforced Concrete framed building. IDA is performed to obtain the collapse point, and the near-collapse drift ratios for monotonic and cyclic pushover analysis methods are obtained separately. These two alternative drift ratios are compared with the collapse drift ratio. The correlations of the maximum tensile and compression strain at the base columns and beam plastic rotations with interstory drift ratios are acquired using the nonlinear time history analysis results by the simple linear regression analyses. It is seen that these parameters are highly correlated with the interstory drift ratios, and the results reveal that the near-collapse point acquired by monotonic pushover analysis causes unacceptably high tensile and compression strains at the base columns, as well as large plastic rotations at the beams. However, it is shown that the results of cyclic pushover analysis are acceptable for the near-collapse performance limit state.

• 지질공학
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• 제16권4호
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• pp.393-402
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• 2006

본 논문에서는 점오염원 형태의 유류누출이 발생되었던 실트질 토양층에서 BTEX와 TPH 성분의 오염특성이 연구되었다. TPH 성분의 토양오염기준별 초과율은 BTEX 성분에 비해 $1.5{\sim}1.7$ 배정도 높았다. BTEX와 TPH 성분의 채취지점별 평균과 최대값은 B-zone>A-zone>C-zone의 순이며, 두 성분 모두 지표면하 $1{\sim}2m$구간에서 오염농도가 가장 높게 나타났다. 오염원에서 수리경사 하부 방향으로 120m와 80m 이내인 지역에서는 BTEX와 TPH 농도가 이격거리에 따라 증가하였으며, 120 m 이상 이격된 지역에서는 토양오염기순 이하인 것으로 나타났다. BTEX와 TPH 성분에 대한 지시크리깅의 제한값으로는 토양오염 확인기준, 우려기준 및 대책기준 값이 적용되었다. 지시변환된 자료의 베리오그램 분석에 의하면, BTEX와 TPH성분 모두 선형모델이 가장 적합한 것으로 나타났다. 선형모델을 적용한 BTEX와 TPH 성분의 확률도에서 토양오염 확인기준과 우려기준의 오염 범위는 유사하게 나타났으나, 대책기준의 오염 범위는 매우 축소되었다. 토양오염 확인기준, 우려기준 및 대책기준에 의해 작성된 확률도에서 BTEX와 TPH 성분의 최대 오염 확률은 BTEX성분이 26%, 26% 및 13%, TPH 성분은 44%, 38% 및 26%인 것으로 추정되었다.

• 대한기계학회논문집A
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• 제25권11호
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• pp.1777-1784
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• 2001

This paper provides d simplified engineering J estimation method fur semi-e1liptical surface cracked plates in tension, based on the reference stress approach. Note that the essential element of the reference stress approach is the plastic limit lead in the definition of the reference stress. However, for surface cracks, the definition of the limit load is ambiguous ("local" or "global"limit lead), and thus the most relevant limit load (and thus reference stress) for the J estimation should be determined. In the present work, such limit load solution is found by comparing reference stress bated J results with those from extensive 3-D finite element analyses. Validation of the proposed equation against FF J results based on tactual experimental tensile data of a 304 stainless steel shows excellent agreements not only far the J values at the deepest point but also for those at an arbitrary paint along the crack front, including at the surface point. Thus the present results provide a good engineering tool for elastic-plastic fracture analyses of surface cracked plates in tension.