• Journal of the Korea Furniture Society
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• v.21 no.1
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• pp.26-39
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• 2010

This is a leading study to replace the structural analysis methodology on the specific traditional joint by a numerical analysis. Tests were carried out to test the compressive methodologies with the numerical results. The Japanese larch was used as a sample. The Orthotropic property of wood was specifically considered for the finite element numerical analysis. Linear numerical analysis and non-linear numerical analysis for the BEAM element and the two SOLID elements of ANSYS were used to analyze the compressive performance. In addition, more finely divided elements were used to raise the accuracy of the numerical result. Finally, the statistically significant differences were tested between that of the analytical and numerical results. It could be concluded that the SOLID 64 element shows the most optimum result when the non-linear analysis with the more finely divided element was used. However, finely dividing of the element is a considerable time consuming process, and it is quite difficult to raise the accuracy of the non-linear numerical analysis. Therefore, if considering the vertical displacement to be of the only interest, the BEAM element is more efficient than the SOLID element because the BEAM element is reflected as a simple line, which is less time consuming and difficult in dividing the elements. But, the BEAM element cannot accurately model the knot as a strength defect factor which is an important property in the orthotropic property of wood. Therefore, the SOLID element should be used to model the strength defect factor, knot, as it can be efficiently applied on the structural size flexure member which could be more strongly effected by the knot. In addition, it is useful at times when the failure types of members are to be more closely investigated, as the SOLID element is able to examine the local stress distribution of the member. The conclusion drawn by this study is of the good concordance between analytical results and numerical results of compressive wood members, but how orthotropic properties should only be considered. The numerical analysis on the specific Korean traditional joints will be based on the current study results.

• The Journal of Natural Sciences
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• v.12 no.1
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• pp.11-21
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• 2002

This is for the cyber class of Numerical Analysis in which we can learn and practice by ourselves in Numerical Analysis through internet.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.138-141
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• 2008

The screen doors installed in the station of subway are subject to the train-wind pressure caused by the operation of trains. The train-wind pressure has to be correctly estimated for the design of safe structure of screen doors. As three-dimensional numerical flow analysis technology has been significantly developed, the analysis on the train-wind pressure with diverse variables such as train specifications, train speed, tunnel and station configurations, and blockage ratio can be effectively carried out with three-dimensional numerical method. In this study, computational analysis of train-induced wind in a subway tunnel employing the screen doors are carried out by using the three-dimensional numerical method with the model of the moving boundary for the run of trains. While the numerical analysis of train-wind pressure was applied on the one island-type station in the Seoul Subway Line 2, maximum pressure of 494 Pa was estimated on the screen door when two trains pass each other at the speed of 80km/h in the platform.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.85-94
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• 2007

This study, regarding curved channel, was performed to compare and analyze hydraulic characteristics and the speed of water and water level for left bank and right bank through hydraulic model experiments and numerical analysis. Real channels that had characteristics of curved channel were selected as objectives. In order to easily operate one and two dimensional numerical analysis and comparison for total 2.4Km model channel, measuring point was set up as 200m. HEC-RAS model was applied as one dimensional numerical analysis program and SMS model was used as two dimensional numerical analysis program. In respect of speed of water, the average speed of water for right bank recorded 8.33m/s in a model experiment and 3.08m/s, 8.57m/s were average speed of water for right bank in one dimensional and two dimensional numerical analysis. The average speed of water of two dimensional numerical analysis was quite similar to that of model experiments. Also, as for water level, maximum observational errors between one and two dimensional numerical analysis for right and left bank of model experiments were 0.66m, 0.84m and 0.28m, 0.48m for each. It was found that two dimensional numerical analysis had a similar result to hydraulic model experiments. Accordingly, from the result of this study, two dimensional numerical analysis should be used rather than one dimensional numerical analysis, when numerical analysis for curved channel is conducted.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.784-791
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• 2008

In this study, we recognized about application of the load distribution factor for design of tunnel in 3D numerical analysis. Generally, load distribution factor of tunnel is applied to describe 3D arching effect that can not describe when 2D numerical analysis. Through result of 3D numerical analysis, we used to apply in numerical analysis for the load distribution factor that ratio of finally displacement to displacement of construction step. But 3D numerical analysis need to apply to load distribution factor for convenience of numerical analysis. Therefore, we proposed load distribution factor that reduce time and coast. It corrected variable of advanced length in load distribution factor of 3D numerical analysis.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.487-496
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• 2020

Most of the previous works on numerical analysis of galloping of transmission lines are generally based on the quasisteady theory. However, some wind tunnel tests of the rectangular section or hangers of suspension bridges have shown that the galloping phenomenon has a strong unsteady characteristic and the test results are quite different from the quasi-steady calculation results. Therefore, it is necessary to check the applicability of the quasi-static theory in galloping analysis of the ice-covered transmission line. Although some limited unsteady simulation researches have been conducted on the variation of parameters such as aerodynamic damping, aerodynamic coefficients with wind speed or wind attack angle, there is a need to investigate the numerical simulation of unsteady galloping of two-dimensional iced transmission line with comparison to wind tunnel test results. In this paper, it is proposed to conduct a two dimensional (2-D) unsteady numerical analysis of ice-covered transmission line galloping. First, wind tunnel tests of a typical crescent-shapes iced conductor are conducted firstly to check the subsequent quasisteady and unsteady numerical analysis results. Then, a numerical simulation model consistent with the aeroelastic model in the wind tunnel test is established. The weak coupling methodology is used to consider the fluid-structure interaction in investigating a two-dimension numerical simulation of unsteady galloping of the iced conductor. First, the flow field is simulated to obtain the pressure and velocity distribution of the flow field. The fluid action on the iced conduct at the coupling interface is treated as an external load to the conductor. Then, the movement of the conduct is analyzed separately. The software ANSYS FLUENT is employed and redeveloped to numerically analyze the model responses based on fluid-structure interaction theory. The numerical simulation results of unsteady galloping of the iced conduct are compared with the measured responses of wind tunnel tests and the numerical results by the conventional quasi-steady theory, respectively.

• Journal of Industrial Technology
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• v.27 no.B
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• pp.229-233
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• 2007

This research investigated the way of generating the flowing of water in case of artificial fluctuation of river width by the unidimensional numerical analysis in order to reconstruct vertical and expanse features of flowing, and the problem of existing numerical analysis in accordance with local enlargement and reduction of river through hydraulic model experiments with results of numerical analysis. The result revealed that when the local section change in the same river is exist, it showed 0.93m in the case of no change of local section in the hydraulic model experiments and numerical analysis, however, it presented 1.645m on the occasion of local section changes in the hydraulic model experiments and numerical analysis. In other words, there was a significant difference in the existing numerical analysis, when there was a local section change. As a result of the experimental section for the enlargement and reduction of local river width, due to the sensitive change for fluctuation of flood discharge, there was a significant difference between numerical analysis and hydraulic model experiments. In addition, the result of comparison between the enlargement and reduction of local river width confirmed that the result of numerical analysis with hydraulic model experiments showed larger generation of deviation in case of enlargement of section than in case of reduction of section.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.28-35
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• 2012

This study is on SCR reactor, NOx reduction system in Marine that has been an issue nowadays. Especially design data was obtained by numerical on flow uniformity that is one of the design factor in SCR reactor. Also pressure drop on catalyst size inserted into SCR reactor was compared by experiment and numerical analysis. S/W, numerical analysis used for this study was confirmed that the result of numerical analysis used STAR-CCM+, common use CFD code, pressure drop on catalyst is not big different from the result of numerical analysis. In addition, degree of uniformity of liquid on SCR reactor was over 0.9. Whereas it was assured that degree of uniformity of liquid was changed depends on the shape of pipe at the entrance of SCR.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.5-9
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• 2010

A numerical wind tunnel simulation is performed in order to predict wind loads acting on a building. The aim of the present study is to suggest a guideline for the numerical wind tunnel analysis, which could provide more detail wind load distributions compared to the wind code and expensive wind tunnel experiments. To validate the present numerical simulation, wind-induced loads on a 6 m cube model is predicted. Atmospheric boundary layer is used as a inlet boundary condition. Various effect of numerical methods are investigated such as size of computational domain, grid density, turbulence model and discretization scheme. The appropriate procedure for the numerical wind tunnel analysis is suggested through the present study.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.197-204
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• 2002

In this study, multivariate analysis based on domestic data(958 EA) of road tunnel, and suggest the easy prediction equation of Q-system. We generate applicable Q-value to numerical analysis method with using the equation and investigate the behavior as variable Q-value of rock mass induced excavation with discontinuum numerical analysis method, UDEC. In the result of the experiment, we research the application range of Q-value to apply the continuum model to discontinuous rock mass is below 0.7 and we testify the applicability of continuum model as researched Q-value with continuum numerical analysis method, FLAC.