• Journal of Korean Society of Steel Construction
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• v.21 no.1
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• pp.93-103
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• 2009

Two-girder bridge is composed of primary members such as deck slab and main girder, and secondary member such as cross beam, vertical and horizontal stiffeners etc,. Two-girder bridge is prescribed as a non-redundant load path structure in the ASSHTO and the Korean Highway Bridge Design Code. Such structure is that if one girder is damaged, problems of function and safety of the bridge are caused. From the reasons, fatigue cracks in two-girder bridge can affect safety of the bridge seriously. Therefore, in this paper, fatigue evaluation was performed at connection parts of vertical stiffener and web with radius of curvature of scallop of vertical stiffener and thickness of web as variables. Such joint is known as a detail which has high possibility of fatigue crack in the bridge. Based upon the analytical results, preferable joint detail in terms of fatigue and simple empirical formula for fatigue evaluation of the detail were suggested.

• Fashion & Textile Research Journal
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• v.20 no.6
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• pp.722-732
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• 2018

This study was to develop a dress form that is highly representative of the body shapes of senior men in their 50s and 60s. And this research was compared the measurements and forms of three different dress forms available in the market, in order to analyze the body type and suitability and provide a standard for developing and utilizing the dress forms. After extracting the body shapes of the senior men's 3D shape, the body type that is curvature on the back prevalent among senior men, was chosen. The dress form was created as follows: 3D modeling and rendering, printing with a FDM-type 3D printer. The dress forms were 3D-scanned and the 3D data was analyzed - classification drop value, area deviation, compared horizontal section and vertical section. The results were as follows: This suggested that the area deviation amount at the chest and hip circumference levels was larger in the commercial products than in the dress form in this study, while that at the waist circumference level was larger in the dress form in this study. The vertical length of the lateral shoulder point-waist circumference was smaller, the side shape showed severe curvature on the back, and the waist circumference was larger in the senior men dress form than the commercial products. The dress form developed in this study reflected the body type of senior men and, therefore, were suitable for fitting when creating clothes for senior men.

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.149-162
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• 2012

PURPOSES : The causes of traffic accidents can be classified into the factors of highway users, vehicles, and driving environments. Traffic accidents result from the deficiency in single or combination of these three factors. The objective of this study is to define the "potentially hazardous sections of highway" in terms of traffic safety considering these three factors. METHODS : The test drivers performed repeated driving on these highway sections. The drivers and passengers recorded the sections on which the driving was uncomfortable, and the speeds on the sections excluding the uncomfortable sections were used for the development of the model. RESULTS : The model is composed of three sub-models for each of the horizontal curve, tangent, and the section where the curve starts/ends. The safe driving behavior coefficients by the horizontal curvature were derived by comparing the maximum operating speeds at which the vehicle may slide or deviate and the speeds at which the drivers feel comfort. The safety speeds on tangent were derived by the length of tangent section considering the driver's desired speeds under the traffic condition on which the drivers hardly influenced by the other vehicles. For the sections where the curve starts/ends, the driving behaviors were classified by the distances between the curves, and the safe acceleration/deceleration speeds were derived on which the drivers enter/exit the curve sections safely. CONCLUSIONS : Safety speed could then be regarded that the model suggested in this study may be useful to define the potentially hazardous highway section and contribute the improvement of highway safety.

• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• The korean journal of orthodontics
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• v.21 no.2 s.34
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• pp.367-397
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• 1991

This study was aimed to investigate the occlusal plane inclination in relation to the skeletal and dental assessment measurements in order to provide a reference in orthodontic treatment planning as the occlusal plane should be reconstructed orthodontically or gnathologically. The sample consisted of 73 normal occlusions and 113 malocclusions of adults. The computerized statistical analysis of 38 occlusal plane's and 29 skeletal and dental measurements were carried out with SPSS. The conclusions were as follows; 1 In normal occlusion, COP-NaPog was average $83.63^{\circ}$ (2.44) and occlusal plane inclination had a strong negative correlation with SNB and FH-NaPog. 2. In normal occlusion, ArANS plane was nearly parallel to the occlusal plane. 3. In malocclusion, the larger the mandibular plane angle and the shorter the ramus height was, the more downward the occlusal plane had a tendency to tip anteriorly. 4. Occlusal plane was more horizontal in deep bite group, while it was steeper in openbite group. 5. The curve of Spee was severe in deep bite group but in openbite group mandibular occlusal plane showed average reverse curvature, where it was found that the configuration of the occlusal plane contributed to the excess or deficiency of anterior overbite.

• Journal of the Korean Society of Visualization
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• v.1 no.2
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• pp.29-37
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• 2003

During the past five decades or so, the characteristics of turbulent swirling flow have been studied extensively because of its great technological and scientific importance. It is well known that the swirling flow improves heat transfer in duct flow. The reason for this is due to the effect of streamline curvature associated with the tangential velocity component. Although many studies have been carried out to investigate the characteristics of the swirling flow in a circular tube. The experimental methods for measuring the velocity components are by hot-wire or LDV (Laser-Doppler-Velocimetry) measuring single point velocity so far. The present study was aimed to analyse the flow characteristics of swirling flow such as time-mean velocity vector, local velocity turbulence intensity and turbulence kinetic energy by using PIV(Particle-Image Velocimetry). The experiment was carried out for four Reynold numbers $1.0\times10^{4}$, $1.5\times10^{4}$, $2.0\times10^{4}$ and $2.5\times10^{4}$ of the measuring area.

• Architectural research
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• v.7 no.1
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• pp.39-48
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• 2005

Main objective of this research is to evaluate performance of high-strength concrete (HSC) columns for ductility and strength. Eight one-third scale columns with compressive strength of 69 MPa were subjected to a constant axial load corresponding to 30 % of the column axial load capacity and a cyclic horizontal load-inducing reversed bending moment. The variables studied in this research are the volumetric ratio of transverse reinforcement (${\rho}_s=1.58$, 2.25 %), tie configuration (Type H, Type C and Type D) and tie yield strength ($f_{yh}=549$ and 779 MPa). Test results show that the flexural strength of every column exceeds the calculated flexural capacity based on the equivalent concrete stress block used in the current design code. Columns with 42 % higher amounts of transverse reinforcement than that required by seismic provisions of ACI 318-02 showed ductile behaviour, showing a displacement ductility factor (${\mu}_{{\Delta}u}$) of 3.69 to 4.85, and a curvature ductility factor (${\mu}_{{\varphi}u}$) of over 10.0. With an axial load of 30 % of the axial load capacity, it is recommended that the yield strength of transverse reinforcement be held equal to or below 549 MPa.

• The korean journal of orthodontics
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• v.50 no.4
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• pp.249-257
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• 2020

Objective: To evaluate the changes in the nose in three dimensions after Le Fort I osteotomy in patients with skeletal Class III malocclusion. Methods: The subjects were 40 adult patients (20 females and 20 males; mean age, 20.3 ± 3.0 years; range, 17.0 to 31.1 years) who underwent one-piece Le Fort I osteotomy with maxillary advancement and impaction treatment for maxillary hypoplasia. The mean maxillary advancement was 4.56 ± 1.34 mm, and the mean maxillary impaction was 2.03 ± 1.04 mm. Stereophotogrammetry was used to acquire three-dimensional images before and at least 6 months after surgery. Results: Alare (Al) and alare curvature (Ac) points had moved vertically and anterolaterally postoperatively. A significant increase was observed in the nasal ala width and alar base width, and no changes were noted in the columellar length, nasolabial angle, and nasal area. There was a significant relationship between maxillary impaction and nasal ala width and horizontal and sagittal positions of the bilateral Al and Ac. The only relationship found was between maxillary advancement and postoperative sagittal location of the subnasale and pronasale. Conclusions: Nasal soft tissues were highly affected by the vertical movement of the maxilla; however, the soft tissue responses were individual-dependent.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.407-412
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• 2000

In this study, a research for process design in bending of structural frame of AA6061-T6 with rubber pad was conducted. In this process, the conventional lower die made of metal is replaced with a polyurethane pad, resulting in high flexibility during bending. Vulcanized polyurethane rubber with shore A hardness of 60 was used for the pad. Experiments on a newly developed bending machine were carried out by controlling the stroke of the roller and horizontal movement of roller pad lower die. From this, the relation between roller path and geometry of the materials bent was obtained for the process design of producing roof rail part of a passenger car and the experimental result was compared with the target profile. For more accurate process design, it is required to control the roller path interactively. Based on the experience in developing the prototype bending machine, it is construed that a fully automated bending system with rubber pad to produce various light-weight components for automotive body frames can be successfully developed.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.488-493
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• 2009

The very big springback of advanced high strength steel(AHSS) sheets invokes undesired shape defects, which can be generally eliminated by die correction or process parameter control. The springback reduction by controlling the forming process parameters is easy for the application, but limited for the bulky achievement. In this study, the effective die correction method, which obtains the modification of tool shape from the relationship between die design variable and springback, is introduced and is applied to the TWB tool of automotive side rail to show the validity and usefulness. Among the die correction trials repeatedly performed, the first trial is carried out by correcting the tool shape to the opposite direction to the springbacks of several tool sections. Next trials are done by extrapolating the springbacks of among the original tool uncorrected and the tools corrected negative amounts of the springback and by finding tool shapes without springbacks. After the angle of side wall and radius of curvature of horizontal bottom floor are chosen as design variables in the tool design of side rail, the tool shape is corrected 3 times. The accuracy of final shape within the assembly limit of 1mm and the springback reduction of 75.8% compared to the uncorrected tool are achieved.