• Proceedings of the Computational Structural Engineering Institute Conference
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• 1993.04a
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• pp.19-26
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• 1993

The p-version crack model based on integrals of Legendre polynomial and virtual crack extension method is proposed with its potential for application to stress intensity factor computations in linear elastic fracture mechanics. The main advantage of this model is that the data preparation effort is minimal because only a small number of elements are used and the high accuracy and the rapid rate of convergence can be achieved in the vicinity of crack tip. There are two important findings from this study. Firstly, the limit value, the strain energy of the exact solution can be estimated with successive three p-version approximations by ascertaining the approximations is entered the asymptotic range. Secondly, the rate of convergence of p-version model is almost twice that of h-version model on the basis of uniform or quasiuniform mesh refinement for the cracked panel problem subjected tension.

• Structural Engineering and Mechanics
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• v.23 no.5
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• pp.487-504
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• 2006

Several new versatile two-dimensional p-version finite elements are developed. The element matrices are integrated analytically to guarantee the accuracy and monotonic convergence of the predicted solutions of the proposed p-version elements. The analysis results show that the convergence rate of the present elements is very fast with respect to the number of additional Fourier or polynomial terms in shape functions, and their solutions are much more accurate than those of the linear finite elements for the same number of degrees of freedom. Additionally, the new p-version plate elements without the reduced integration can overcome the shear locking problem over the conventional h-version elements. Using the proposed p-version elements with fast convergent characteristic, the elasto-plastic impact of the structure attached with the absorber is simulated. Good agreement between the simulated and experimental results verifies the present p-version finite elements for the analyses of structural dynamic responses and the structural elasto-plastic impact. Further, using the elasto-plastic impact model and the p-version finite element method, the absorber of the T structure on the Qiantang River is designed for its collision protection.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.57-62
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• 2000

저전송률 영상통신을 위한 H.263 Version 2에 포함된 Advanced Intra Coding(AIC) 모드는 INTRA 매크로블록별로, DCT 계수의 예측을 위하여 세가지 Submode를 선택한 후, 선택된 submode에 따라 DCT계수 주사 방향과 양자화 방법, VLC 테이블을 달리 적용한다. 이 기술을 비디오 압축에 적용함으로써 기존의 H.263 baseline에 비해 더 높은 압축율과 객관적 화질의 향상을 얻을 수 있다. Advanced Intra Coding 모드에서 최적화된 방향 선택은 압축율을 최대로 얻을 수 있으나, 방향 선택을 위한 추가적인 메모리를 요구하고 계산량도 많아지게 된다. 본 논문은 ITU-T의 H.263 Version 2에서 제안하는 Advanced Intra Coding 모드를 사용할 때 필요한 DCT 계수의 예측 방향 선택을 위한 간략화 된 방법을 제안한다. 기존의 방법과 비교하여 성능이 비슷하면서 계산량이 간단하고, 메모리도 절약할 수 있는 방법을 제안함으로써, 최적화된 H.263 시스템을 구현하는 것이 목적이다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.69-76
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• 1998

Due to the drastic improvement of computer hardware and operating system, it is easy to break through the main defects of limited computer memory and processing time, etc. To keep up with this situation, this paper is focused on developing the preprocessor program with the input method based on vector graphic editor and the preprocessing technique including automatic node generation algorithm for the $\rho$-version finite element program. To develop this preprocessor program, the special data structure and the OOP(Object Oriented Programming) have been used by the Visual Basic 4.0. The Special data structure is proposed to describe the geometric data of node numberings and coordinates suitable for the $\rho$-version finite element program, which are quite different from the comvential h-version finite element program.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.04a
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• pp.33-40
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• 1998

Although a structural analysis based on e linear elastic theory yields good results for deformations and stresses produced by working loads, it fails to assess the teal load-carrying of the plates on the verge of yielding. In case of a limit analysis of plates, the yield line theory is widely used on the basis of the upper bound theorem and theoretically it overestimates the strength of the plate. There is, therefore, a general need for analytical methods of predicting the inelastic behavior and load-carrying capacities of plate subjected to arbitrary loadings and boundary conditions. The $\rho$-version of finite element method has been presented for determining the accurate limit load of plates. The numerical results by $\rho$-version model compares with the results obtained by the h-version software ADINA as well as with the available analytical solutions in literatures.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3039-3042
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• 2012

Pressure tensors at the planar surface of liquid-vapor argon are evaluated from the virial theorem, Irving-Kirkwood, and Harasima versions using a test-area molecular dynamics simulation method through a Lennard-Jones intermolecular potential at two temperatures. We found that the normal and transverse components of the pressure tensor, $p_N(z)$ and $p_T(z)$, obtained from the virial theorem and Harasima version are essentially the same. The normal component of the pressure tensor from Irving-Kirkwood version, $p_N^{IK}(z)$, is shown to be a nearly constant at the lower temperature, independent of z, as agreed in a previous study, but not for $p_N^H$(z), while the transverse components, $p_T^{IK}(z)$ and $p_T^H(z)$, are almost the same. The values of surface tension for both versions computed from $p_N(z)-p_T(z)$ are also the same and are fully consistent with the experimental data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.04a
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• pp.30-35
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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 must fully account for fatigue of critical components. Due to the sensitivity of the Paris law, it is very important to calculate the ΔK numerically to minimize the error of predicted fatigue life in cycles. 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 problem of box car body bolster assembly and a crack problem emanating Iron a circular hole in finite strip have been solved.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.04a
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• pp.65-69
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• 1990

The elastic analysis of floor slabs using the p-version of finite element method encounters stress singularities at certain types of reentrant corners, openings and cut-outs. Results obtained using the computer code based on C$\^$o/-hierarchic plate element formulated by Reissner-Mindlin theory are compared with theoretical predictions and with computational results reported in the literature. The convergence rate of h-, p- and hp-version can be estimated on the basis of the energy norm in global sense. If accuracy in terns of the number of degrees-of-freedom is used as a criterion, the solutions presented here are the most efficient that have been published up to date. Examples are the rhombic plate with the obtuse angle of 150o and the square plate with cut-outs.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.62-69
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• 1996

In this study, an equivalent domain integral (EDI) method is presented to estimate the track-till integral parameter, J-value, for two dimensional cracked elastic bodies which may quantify the severity of the crack-tit) stress fields. The conventional J-integral method based on line integral has been converted to equivalent area or domain integrals by using the divergence theorem. It is noted that the EDI method is very attractive because all the quantities necessary for computation of the domain integrals are readily available in a finite element analysis. The details and its implementation are extened to both h-version finite element model with 8-node isoparametric element and p-version finite element model with high order hierarchic element using Legendre type shape fuctions. The variations with respect to the different path of domain integrals from the crack-tip front and the choice of 5-function have been tested by several examples.

• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.50-55
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• 2002

In this numerical study, characteristics of swirl generation by the fan and selection of the location of the fan was studied theoretically by the modified TEACH code. The governing equations for the system are solved by means of the k dimensional version of the SIMPLE method and STAGGERED grid. From the present results, the optimal position of the fm is 0.625(h/H).