• Journal of Korean Tunnelling and Underground Space Association
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• v.15 no.5
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• pp.537-546
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• 2013

Traffic congestion in existing tunnels has increased due to increased traffic volume and enlarged vehicles. Enlarging existing tunnels has advantages over constructing new tunnels by reducing land purchasing costs as well as minimizing natural environment destruction. In fact, many overseas projects for enlarging existing tunnels have been reported. Thus, it appears that the demand on enlarging existing tunnels continues to rise in Korea in near future. Nonetheless, the studies related to the enlarged tunnels have been relatively rare since there have been few tunnel enlargement projects in Korea. In the present study, the tunnel behavior and the stability of rock pillar when enlarging existing parallel tunnels were investigated by performing FE analysis and using existing theory and empirical relationships. Four different enlarging cases, depending on the enlargement types and directions, were examined in the study. According to the results, for the tunnels with the same pillar width after enlarged, the uni-laterally enlarged tunnel indicated 5 to 20% higher crown settlement compared to the bi-laterally enlarged tunnel, and for the tunnel with the narrowest pillar, the highest shotcrete stress was observed. Also, the strength/stress ratio for rock pillar was more than 1.0 for all four enlargement cases, and the Matsuda's method was found to give higher strength/stress ratio by about 50% compared to the Peck's method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.542-552
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• 2018

In this paper, the precast method of a concrete eco-pillar debris barrier was proposed to improve the construct ability and economic efficiency. The performance was validated by experimental and structural analysis. The steel debris barrier has a high construction cost and causes environmental damage with corrosion. The construction of a concrete eco-pillar debris barrier has been increased recently. On the other hand, there are no design standards regarding debris barriers in Korea, and debris barriers are being designed by the experience and sense of engineers. Therefore, in this study, a method to determine the design external forces was proposed and the design was performed by applying a hollow cross-section to the debris barrier. In addition, three types of connection methods of a concrete cantilever column with the maximum bending moment acts were proposed, and validation of the performance of each type was performed with a real-scale experiment. The experimental results showed that the type with loop reinforcement had the highest rigidity and the type with anchorage performance exceeded the maximum bending moment according to the ultimate load. In the manufacturing procedure of mock-up debris barriers, the type with an anchorage-bar was found to have superior construct ability.

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.106-112
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• 2014

Here, we demonstrated the optimum design of pillar microstructure for efficient microdroplet merging. The microfluidic device mainly consisted of programmable microvalves and pillar microstructures. Based on the system, aqueous droplets were continuously generated at T-junction using actuating of integrated programmable microvalaves under the immiscible continuous fluid (mineral oil containing 0.5 wt% Span 80). The principle of merging process depended on the competitive correlation of hydraulic pressure of continuous phase and Laplace pressure of the droplet. We found that the design of the micropillars controls above two pressures. Finally, it was demonstrated that the microfluidic system could be able to efficient biochemical reaction. We expect that the microfluidic system is useful analytical or reaction tools in fundamental science, biotechnology, and chemical engineering.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6366-6371
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• 2014

This study examined the structural elements of Korean-style houses (Hanok) and proposed formula accounting for their similar patterns and regular behavior. The design of modern apartment buildings adopts many aesthetic elements from Hanok but those are only for interior decoration. In this study, the projected Hanok eaves were examined in terms of the length of solar insolation. Leaning pillars toward the inside of the building were analyzed in detail not only for the front and back pillar, side pillar, but also the corner pillar. This study also suggested a design element from the Hanok structure, such as the elevated balcony, porch flooring, and inner garden in porch area. In addition, the new apartment plan improved air circulation, ventilation and natural lighting.

• Transactions of Materials Processing
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• v.8 no.1
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• pp.7-13
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• 1999

In this study, side panels were developed using the laser-welded tailored blank (T.B.) of both the same thickness and different thickness. At first, the formability of the same thickness T.B. was investigated to compare with one of the non-welded panel with respect to weldline movement and strain distribution in blank during the stamping process. Based on these results, we determined the weld line positions and the die step for T.B. forming of the blanks composed of different thickness combination. Then we made some stamping tryouts with selected types of blanks to investigate the formability of T.B. of the different thickness. During the tryouts, wrinkles were found in the a-pillar lower region which is under the deformation mode of the shrink flange. In the b-pillar region, fractures were also found. These defects have been reduced and corrected by controlling the blank design, the die faces and process parameters.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.1
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• pp.94-99
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• 2004

The global stiffnesses and vibration characteristics of vehicle structures are mainly influenced by local stiffnesses of the joint structures consisted of complicated thin-walled panels. In this paper, the parametric study for the stiffnesses of the center pillar-roof rail joint of vehicle structure is performed through the linear static analysis. The analysis result shows that the reinforcement panel much affects the joint stiffness of out-plane direction (i.e., z-direction). And also, the flange radius and width of the joint structure much affect the Joint stiffness of out-plane direction. The study shows that vehicle joint stiffnesses can be effectively determined in designing vehicle structure through the parametric study.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.102-109
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• 1998

In this study, the side panels were developed using the laser-welded Tailored Blanks (TB) with both the same thickness and the different thickness. At first, the formability of the same thickness T.B was investigated to be compared with one of the non welded panel with respect to weldline movements and strain distribution on blank during the stamping. Based on these results, we selected candidates of T.B with different thickness for stamping experiments. That is, we determined the weld line positions and the die step. Then we made some stamping tryouts with selected types of blank designs to investigate the formability of T.B with different thickness. During the tryouts, the wrinkles were found in the a-pillar lower region which is under the deformation mode of the shrink flange. In the b-pillar region, the fractures were found also, these defects have been reduced and corrected by controlling the blank design and the die faces and process pamameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.893-894
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• 2012

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2008.10a
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• pp.123-134
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• 2008

• Journal of the Korea Furniture Society
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• v.25 no.2
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• pp.79-86
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• 2014

Furniture can be a product of design and is considered a form of a decorative art. Architectural works are often perceived as cultural symbols and as works of art. Korean traditional architectural form and wooden furniture were improved by adding up an organic coordination in the interior space. Furniture adds beauty of life by being coordinated with the interior space with its particular characteristic in the form of architectural structure. Architecture and furniture are also being improved in a more natural and diverse way. Therefore, in this research, from the choice of the location, Korean traditional architecture is considered to be coordinated with the nature, and the technical skill is lessened to express its beauty. There is a presence of elegance yet robust combination of simplicity and beauty. In addition, the traditional architecture and wooden furniture are completely expressed structurally with coordination of the outstanding design and solid structure according to the thrifty living in the Confucian ideas which influenced the Korean traditional society. The representative of Korean traditional architecture, Baeheulrim pillar, has worked as motive because of its visual comfort caused by optical illusion and formative elements. The small portable dining table (Soban) which reflects the characteristic of Korean unique tradition and the sensitivity of Koreans has been reinterpreted through the motive in this research. As a result, it has shown the possibility as the design element to change the aesthetic structure. In the modern society, cultural identity plays a vital role. Therefore, this research can be used as reference for the new concept of furniture - making. It could be a combination of modern people, lifestyle and living space by creating the Korean image suitable for the modern society.