• Journal of Korean Society of Steel Construction
• /
• v.30 no.1
• /
• pp.59-66
• /
• 2018

In this study, the parametric analysis for the buckling behavior of plates stiffened with the new type(${\Box}$ type) ribs was performed. Changes of the buckling capacity according to dimensions of ${\Box}$ type ribs show certain behaviors, so that the system to find the section of ${\Box}$ type ribs under the specific buckling capacity can be proposed. Applying this system to the steel deck of existing bridges, more economic sections of ${\Box}$ type ribs rather than that of closed ribs can be obtained. Therefore, the economic section of steel deck having the required buckling capacity can be designed by using the proposed system of ${\Box}$ type ribs.

• Journal of Korean Society of Steel Construction
• /
• v.14 no.1
• /
• pp.41-49
• /
• 2002

An efficient algorithm automatically determining cross sectional properties of thin-walled beams is developed using the minimum information about geometry of the cross section. This scheme is applied to automatic calculation of normal and shear stress distribution corresponding to stress resultants as well as sectional constants for complex open and closed thin-walled sections. Numerical examples evaluating section constants and stress distributions is presented and compared with the available reference's results.

• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.2
• /
• pp.105-113
• /
• 1999

This paper resents a prediction method of natural frequencies of coupled horizontal and torsional vibration of hull girder based on design sensitivity analysis in case of the changes of system parameters. The sensitivity analysis is formulated applying the direct differentiation method and transfer matrix method. In the analysis, warping, shear deformation due to torsion and the continuity condition at the connected part of open and closed hull section are considered. Using the presented method. The affection for natural frequencies by the change of system parameters, especially cargo and added mass and their centers, is numerically investigated for a real large container carrier.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.25 no.1
• /
• pp.74-81
• /
• 2017

The door impact beam of the side-impacted vehicle plays a key role in securing occupant safety by preventing intrusion from the impacting vehicle. Despite the low production cost, the press door impact beam has been adopted sparingly because of the strength inferiority. In this study, the design technologies of the press beam aimed at improving bending strength were investigated. First, the effect of the section shape and size was examined. Next, thickness and material strength were increased. Also, the TRB beam application was simulated by varying combined thickness. Some TRB beams with reduced weight exhibited bending strength over the strength of the pipe beam. Then, the beam with a closed center section also showed remarkably enhanced maximum bending strength.

• Journal of Chest Surgery
• /
• v.23 no.2
• /
• pp.231-235
• /
• 1990

Segmental resection or wedge resection of the lung and direct cutting across of bronchi frequently results in postoperative airleaks or bronchopleural fistula in some cases. Many methods have been devised to handle air leak problems by oversuturing the raw edges, the application of pleural onlay flaps, the use of cautery or tissue adhesives, but these still has not solved the problem of air leaking from raw surfaces of the lung with only partial successful we have tried the use of histoacryl to closure the raw surface of the resected lung and compared it’s results with of the closure with chromic catgut sutures in cats from May 1989 to Jan. 1990 at the department of the thoracic and cardiovascular surgery, Yonsei University, College of Medicine. Ninety lobe of the lungs were used in this study and forty nine of which have been divided segmentally and closed with histoacryl on the raw surfaces. Forty one of which have been divided segmentally and closed with sutures using chromic catgut for control. There were air leakages in twelve cases among 49 cases with applying histoacryl and airleak were in two cases among 12 cases with reapply histoacryl, But there were air leak in two cases among 41 cases with sutures using chromic catgut and airleak were in one case among with resutures using chromic catgut.

• Journal of Korean Society of Steel Construction
• /
• v.14 no.2
• /
• pp.357-364
• /
• 2002

The study performed a series of flexural tests on Closed Cold-Formed Steel Sections for stud, joist, and roof truss. Results were compared with analytical values. Each 2.4-m long and 0.9-m wide specimen consisted of two steel beams set at 0.46 m interval. The steel beams were attached to the specimens using either plaster board or ply wood. Another specimens did not use any attachment material. Positive and negative bending tests were conducted to investigate the composite behavior, including the effects of plaster board or ply wood on the buckling behavior of steel beam. Full-scale roof truss tests were also performed to study the buckling behavior and failure mode of the truss members.

• Journal of Korean Society of Steel Construction
• /
• v.27 no.3
• /
• pp.299-310
• /
• 2015

CFT(Concrete-Filled Tube) structures have problems at processing cause closed section and concrete filling problems. In this study, a CFT structure that uses different types of diaphragms in its upper and lower connections to improve the concrete filling was tested and analyzed via the FEM program. Implementation of variable analysis of EP-T type to find out the reason that effect on the resistance force of the connection. As a result, through experiments and analysis investigated the structural characteristics of circular CFT beam-to-column connection.

• Journal of Korean Society of Steel Construction
• /
• v.15 no.3
• /
• pp.281-290
• /
• 2003

A series of connection tests of portal frames which were composed of cold-formed steel studs and rafters was carried out to study the moment-rotation relation, the rotational rigidity, and the yield and the ultimate moment of the connections. The main factors of the tests were the thickness, the shape of the connecting members which were made of mild steel, and the torsional restraints of the test specimens. The test results were compared with those obtained through the non-linear analysis, for verification. The secant stiffness estimated from the experimental moment-rotation curve was proposed for the rotational rigidity of semi-rigid connections, and its validity was verified in the structural frame analysis.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.4 no.2
• /
• pp.39-44
• /
• 2013

This study is aimed to examine the influence of the rotational stiffness of U-shaped ribs on the local buckling behaviors of laminated composite plates. Applying the orthotropic plates with eight layers of the layup $[(0^{\circ})4]s$ and $[(0^{\circ}/90^{\circ})2]s$, 3-dimensional finite element models for the U-rib stiffened plates were setup by using ABAQUS and then a series of eigenvalue analyses were conducted. There is a need to develope a simple design equation to establish the rotational stiffness effect, which could be easily quantified by comparing the theoretical critical stress equation for laminated composite plates with elastic restraints based on the Classical laminated plate theory. Through the parametric numerical studies, it is confirmed that there should clearly exist an increasing effect of local plate buckling strength due to the rotational stiffness by closed-section ribs. An applicable coefficient for practical design should be verified and proposed for future study. This study will contribute to the future study for establishing an increasing coefficient for the design strength and optimum design of U-rib stiffened plates.

• Journal of Korean Society of Steel Construction
• /
• v.11 no.1 s.38
• /
• pp.43-54
• /
• 1999

The divergence connection between steel circular tubes is widely used in such structures as factory facilities, steel circular hollow section truss, and off-shore tower. Steel circular hollow section (SCHS) have close section, and it makes their per-unit production expense higher than open sectioned products like L-shape, H-shape steels, but the sectional resistance of SCHS against vertical compression and torsion is very high. Despite the structural merits of SCHS, however, many engineers dislike to use them in their design because of uncertainty regarding the stress distribution and deformation behavior at their connections. Therefore, this thesis dealt with X-type connections, the most common forms of connection, and studied their load-deformation relationship. It observed how to show the load-deformation relationship at steel circular tube connections according to the diameter-thickness ratio (D/T) of the chord and diameter of branch-diameter of chord ratio (d/D) and suggested prediction yield load using by ring analysis method.