• Journal of Ocean Engineering and Technology
• /
• v.18 no.2
• /
• pp.52-57
• /
• 2004

Preflex beam is a method of construction designed to hold the pre-compressive stresses over the concrete pier by the preflexion load. During the fabrication of the girder, welding causes residual stresses. The welding residual stresses must be relieved in order to generate the accurate compressive pre-stresses. In this study, to determine the thermal distribution characteristics on the girder by welding, both three-dimensional finite element analysis and two-dimensional finite element analysis, in a quasi-steady state, is carried out. After comparing each result between the three-dimensional analysis and the two-dimensional analysis, finite element analysis is carried out against the actual girder, and the welding thermal distribution characteristic over the preflex beam is analyzed. It is possible to provide the input data for the analysis of the welding residual stresses.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.12
• /
• pp.57-68
• /
• 2020

In the case of two-dimensional analysis generally applied in the analysis of Earth Retaining Wall, mutual interference occurs due to earth pressure, when the excavation width is small, and in the section where the excavation width is small, and the resulting influence makes it difficult to secure reliability in the horizontal displacement of the retaining wall when performing 2-dimensional analysis in a section with a small excavation width. This study performed two-dimensional and three-dimensional finite element analyses on excavation depth (H) and excavation width (B) under various conditions for the H-pile earth wall, in the geological conditions of clayey soil, sandy soil, and weathered rock, and examined the relationship between excavation width and horizontal displacement according to each condition, to identify the boundary of the excavation width, which is the range of mutual interference caused by earth pressure. As a result, it was possible to clearly distinguish the analytical boundary according to the excavation width only in the clayey soils with relatively large horizontal displacement. It is concluded that it is reasonable to perform a 3D finite element analysis, which is similar to the actual behavior, if the excavation scale (B/H) is 2.0 or less, with the digging width less than 12 m at a digging depth of 10 m or less, and with the the one less than 24 m at a digging depth of 10 m or more, and that 2-dimensional finite element analysis may be used in cases where the excavation width is greater than 12 m when the excavation scale (B/H) is 2.0 or more and the excavation depth is 10 m or less, and the excavation width is greater than 24 m at an excavation depth of 10 m or more.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.23 no.2
• /
• pp.335-344
• /
• 1993

The purpose of this study was to clarify the spatial relationship of temporomandibular joint and to an aid in the diagnosis of temporomandibular disorder. For this study, three-dimensional images of normal temporomandibular joints were reconstructed by computer image analysis system and three-dimensional reconstructive program integrated in computed tomography. The obtained results were as follows: 1. Two-dimensional computed tomograms had the better resolution than three dimensional computed tomograms in the evaluation of bone structure and the disk of TMJ. 2. Direct sagittal computed tomograms and coronal computed tomograms had the better resolution in the evaluation of the disk of TMJ. 3. The positional relationship of the disk could be visualized, but the configuration of the disk could not be clearly visualized on three-dimensional reconstructive CT images. 4. Three-dimensional reconstructive CT images had the smoother margin than three-dimensional images reconstructed by computer image analysis system, but the images of the latter had the better perspective. 5. Three-dimensional reconstructive images had the better spatial relationship of the TMJ articulation, and the joint spaces were more clearly visualized on dissection images.

• Computational Structural Engineering
• /
• v.2 no.1
• /
• pp.47-53
• /
• 1989

An efficient model for three-dimensional analysis of multistory structures with flexible floor diaphrgms is proposed in this paper. Three-dimensional analysis of a building structure using a finite element model requires tedious input data preparation, longer computation time, and larger computer memory. The model proposed in this study is developed by assembling a series of two-dimensional resisting systems and is considered to overcome the shortcomings of a three-dimensional finite element model without deteriorating the accuracy of analysis results. Static and dynamic analysis results obtained using the proposed model are in excellent agreement with those obtained using three-dimensional finite element models in terms of displacement, periods, and mode shapes. Effects of floor diaphragm flexibility on seismic response of multistory building structures are investigated.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.2
• /
• pp.66-71
• /
• 2001

A sectional analysis of trunk-lid carried out by using the equilibrium approach based on the force balance together with geometric relations and plasticity theory. In computing a force balance equation, it is required to define a geometric curve approximating the shape of sheet metal at any step of deformation from the interaction between the die and the deformed sheet. The trunk-lid panel material is assumed to possess normal anisotropy and to obey Hill's new yield criterion. Deformation of each section of trunk-lid panel is simulated and composed to get the three-dimensional shape by using CAD technique. It was shown that the three-dimensional shape composition of the two-dimensional analysis.

• Journal of Korea Water Resources Association
• /
• v.51 no.11
• /
• pp.971-976
• /
• 2018

An accurate analysis of pipeline transient is important for proper management and operation of a water distribution systems. The computational accuracy and its cost are two distinct components for unsteady flow analysis model, which can be strength and weakness of three-dimensional model and one-dimensional model, respectively. In this study, we used two-dimensional unsteady flow model with Five-Region Turbulence model (FRTM) with the implementation of interaction between liquid and air Since FRTM has an empirical component to be determined, we explored the response feature of two-dimensional flow model. The relationship between friction behaviour and the variation of undetermined parameter was configured through the comparison between numerical simulations and experimental results.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.21 no.1
• /
• pp.53-60
• /
• 2003

Generally, feature of real world as 2-dimensional information of point, line and polygon achieve a GIS function from 2-dimensional GIS. But at enduring the geography elements which exist when it is composed of 3-dimensional spatial information it is abstracted with 2-dimensional which will reach, the loss of many information and 2-dimensional GIS of existing the basic limit exists md, Accordingly, 3-dimensional geography elements of the real world even at the computer controlling with 3-dimensional geography element original it will be able to minimize the loss of information which it keeps, for 3-dimensional expression and the analysis against the natural facility and the artificial facility of the real world it is the actual condition whose 3-dimensional GIS of ultimate form are necessary. This study was 2-dimensional feature a point the line and polygon and 3-dimensional spatial data information as the method for to use the VRML(Virtual Reality Modeling Language), 3-dimensional virtual worlds for 3-dimensional GIS applications to create and hereafter various decision making of at connection web more efficient and the possibility of doing in vision in order to be, it drew up a spatial database.

• Journal of Technologic Dentistry
• /
• v.23 no.1
• /
• pp.95-106
• /
• 2001

The purpose of this study was to show the method of three-dimensional morphometry developed recently and to compare the accuracy of three-dimensional morphometry with those of PA cephalometry, The three-dimensional morphometry analysis program and device were developed. Steel balls (1.2mm in diameter) were attached in twenty five landmarks of artificial human skull. This artificial human skull was used as experimental materials. From three-dimensional morphometry and PA cephalometry of artificial human skull. eleven linear measurements were acquired and made into asymmetry index. Right-left differences of measurements were used as asymmetry index. These measurements and asymmetry index were compared respectively with those of actual. The results were as follows: 1. Mean difference between three-dimensional morphometry and actual artificial human skull in linear measurements was $1.99{\pm}0.37mm$, and mean difference between PA cephalometry and actual was $21.12{\pm}0.45mm$. Both of all were reduced more than those of actual. 2. Mean difference between three-dimensional morphometry and actual artificial human skull in asymmetry index was $0.07{\pm}0.42$, and mean difference between PA cephalometry and actual was $3.63{\pm}0.60$. Three-dimensional morphometry was reduced while PA cephalometry was magnified more than that of actual. 3. Each eleven asymmetry index of three-dimensional morphometry was the same negative sign as those of actuals while only N-Z, ANS-J, Tr-Go, Tr-ANS asymmetry index were the same in PA cephalometry. These results suggest that the method of three-dimensional morphometry is more accurate than those of PA cephalometry in asymmetry analysis.

• Analytical Science and Technology
• /
• v.14 no.6
• /
• pp.535-539
• /
• 2001

One-dimensional coordination polymer of cadmium(II) complex, $[Cd(SCN)_2(C_4H_6N_2]_n$, has been prepared and characterized by X-ray single crystallography. Structure analysis reveals that each cadmium(II) atom is six-coordinated in distorted octahedral fashion with $CdS_2N_4$ composition. $CdS_2N_4$ composition contains two S and two N atoms from four thiocyanates and tow N atoms from two 4-methylimidazole ligands. Central cadmium(II) atoms are run in parallel to the a-axis and are doubly bridged with neighboring cadmium(II) atoms by the thiocyanate and isothiocyanate ligands. Thus, this complex has a one-dimensional polymer structure in which the 4-methylimidazole is in the trans conformation.

• Journal of Welding and Joining
• /
• v.17 no.1
• /
• pp.104-115
• /
• 1999

There have been many studies on the two dimensional thermo-elasto-plastic analysis in welding process, mostly from viewpoint of residual stresses. In this study, the temperature distribution, transient thermal stress, and angular distortion during bead-on-plate gas metal arc welding of rectangular plates were analyzed by using the finite element method. A nonlinear heat transfer analysis was first performed by taking account of the temperature-dependent material properties and convection heat losses on the surface. This was followed by a thermo-elasto-plastic stresses and distortion analysis that incorporates the constrained boundary condition of the two dimensional solution domain to get the three dimensional size effect of the plate. The constrained boundary conditions adopted in this study were the constant displacement condition over the whole two dimensional section for axial movement in the welding direction, and the force boundary condition for rotational movementof the domain around the axis of the welding direction. It could be revealed that the theoretical predictions of the angular distortion have an improved agreement with the experimentally obtained data presented in the previous study.