• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.32-37
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• 2021

To realize a zero-energy building, a technology that minimizes the energy loss due to thermal bridges by preventing their formation is emerging as an important design factor. In this study, we develop a thermal bridge breaker to prevent thermal bridging in a metal panel roof and attempt to analyze the effects of its application. To this end, we fabricated a thermal bridge breaker and analyzed it in terms of its strength and heat-transfer characteristics, in addition to conducting a load simulation. The thermal bridge prevention effect of the developed thermal bridge breaker improved the insulation performance of the metal panel roof, and the results of a cooling/heating peak load simulation performed by applying the heat transmission resistance test results to a building proved the existence of this effect.

• Advances in environmental research
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• v.3 no.4
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• pp.367-377
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• 2014

In this study, we investigated a life cycle assessment (LCA) of six roof-waterproofing systems [asphalt (C1), synthetic polymer-based sheet (C2), improved asphalt (C3), liquid applied membrane (C4), Metal sheet with asphalt sheet (N1), and liquid applied membrane with asphalt sheet (N2)]for reinforced concrete building using an architectural model. To acquire accurate and realistic LCA results, minimum units of material compositions for life cycle inventory and real data for compositions of waterproofing materials were used. Considering only materials and energy demands for waterproofing systems per square meter, higher greenhouse gas (GHG) emissions could be generated in the order of C1 > N2 > C4 > N1 > C2 > C3 during construction phase. However, the order was changed to C1 > C4 > C3 > N2 > N1 > C2, when the actual architecture model was applied to the roof based on each specifications. When an entire life cycle including construction, maintenance, and deconstruction were considered, the amount of GHG emission was in the order of C4 > C1 > C3 > N2 > C2 > N1. Consequently, N1 was the most environmental-friendly waterproofing system producing the lowest GHG emission. GHG emissions from maintenance phase accounted for 71.4%~78.3% among whole life cycle.

• Steel and Composite Structures
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• v.47 no.2
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• pp.239-251
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• 2023

The stiffness evaluation of cracked base metal is of great guidance to fatigue crack reinforcement. By carrying out fatigue tests and numerical simulation of typical cracking details in steel box girder, the strain-degradation law of cracked base metal was analyzed and the relationship between base metal stress and its displacement (stiffness) was explored. The feasibility of evaluating the stress of cracked base metal based on the stress field at the crack tip was verified. The results demonstrate that the stiffness of cracked base metal shows the fast-to-slow degradation trend with fatigue cracking and the base metal at 50mm or more behind the crack tip basically lose its bearing capacity. Drilling will further accelerate stiffness degradation with the increase of hole diameters. The base metal stress has a negative linear relation with its displacement (stiffness), The stress of cracked base metal is also related to stress intensity factor and its relative position (distance, included angle) to the crack tip, through which the local stiffness can be effectively evaluated. Since the stiffness is not uniformly distributed along the cracked base metal, the reinforcement patch is suggested to be designed according to the stiffness to avoid excessive reinforcement for the areas incompletely unloaded.

• KIEAE Journal
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• v.16 no.1
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• pp.73-79
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• 2016

This study aimed to investigate the flood prevention effect expected from the afforestation of a large area metal roof of an industrial complex located in an area prone to floods in the rainwater outflow reduction aspect through computer simulation based on soil, which is a key element of the system. In order to conduct a more realistic simulation, the properties of the surveyed soil were generated through substantive analysis, soil texture analysis, and saxton method. A comparative performance evaluation was conducted by using soil depth and ponding depth, which are key elements of the system, as variables. The study result showed that during the heavy rainfall period, the bottom ash artificial soil had 61% rainwater outflow reduction effect, which was 11% higher than the SWMM standard sand.

• Transactions of Materials Processing
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• v.8 no.1
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• pp.22-28
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• 1999

The explicit and implicit time integration methods are applied effectively to analyze sheet metal stamping processes, which include the forming stage and the springback stage consecutively. The explicit time integration method has better merits in the forming stage including highly complicated three-dimensional contact conditions. By contrary, the implicit time integration method is better for analyzing springback since the complicated contact conditions are removed and the computing time to get the final static state is short. In this work, brief descriptions of the formulation and the factor study for springack simulations are presented. Further, the simulated results for the S-rail and the roof panel stamping processes are shown and discussed.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.3
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• pp.395-405
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• 2020

Compartment fire tests were performed using kerosene and Jet A-1 as fire sources to evaluate the relationship between flame temperature and opening size. The tests were performed for a fire caused by the release of kerosene owing to vehicle impact, and for a fire caused by the release of Jet-A-1 owing to airplane collision. The compartment fire tests were performed using a 1/3-scale model of a metal storage cask when the flame temperature was deemed to be the highest. We found the combustion time of Jet-A-1 to be shorter than that of kerosene, and consequently, the flame temperature of Jet-A-1 was measured to be higher than that of kerosene. When the opening was installed on the compartment roof, even though the area of the opening was small, the ventilation factor was large, resulting in a high flame temperature and long combustion. Therefore, the position of the opening is a crucial factor that affects the flame temperature. When the metal storage cask was stored in the compartment, the flame temperature decreased proportionally with the energy that the metal storage cask received from the flame.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.197-202
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• 2005

This study started to confirm and prove for the applicability of the dry-process waterproofing system to cover the defects of the wet-process waterproofing system according to weather circumstance, foundation condition and maintenance, etc. This process has triple combined waterproofing system using asphalt sheet, metal sheet, engineering plastic film. It is not influenced by the concrete's crack as the foundation of the roof according to the movement of the building because the waterproofing system is designed for maintaining good quality by absorbing the stress of contraction and expansion that is occurred by the variation of temperature. Ali components used in this process can be recycled environmentally. The superiority of this process proved and reconfirmed through with the investigation of about 130 fields, around 30,000nf for two years.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.06a
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• pp.1-8
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• 1998

The explicit and implicit time integration methods are applied effectively to analyze sheet metal stamping processes, which include the forming stage and the springback stage consecutively. The explicit time integration method has better merits in the forming stage including highly complicated three-dimensional contact conditions. By contrary, the implicit time integration method is better for analyzing springback since the complicated contact conditions are removd and the computing time to get the final static state is short. In this work, brief descriptions of the formulation and the factor study for springback simulations are presented. Further, the simulated results for the S-rail and the roof pannel stamping processes are shown and discussed.

• 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.

• 보존과학연구
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• s.24
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• pp.215-227
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• 2003

The gilt-bronze Sarira Reliquary was discovered when repairing three-stories east stone pagoda (Treasure No. 395) at Seungju-eup in Suncheon city in Jeollanam-do Province in August, 1986. Then it was appointed as Treasure in 1988. The Sarira Reliquary had been held in Seonamsa temple, but deterioration on the surface and corrosion had appeared affecting its surface detail. Consequently, the conservation treatment was carried out from November 2002 to March 2003.The corrosion and dirt on the surface of the Sarira Reliquary were cleaned with ethyl alcohol and Benzotriazole was applied to prevent further corrosion. Finally, NAD-10(Paraloid NAD-10), acrylic resin, was used to consolidate the structure. Moreover, after non-destructive analysis to confirm element of alloy, copper, gold, silver and mercury were discovered and this result tells us that it was plated with gold by amalgam. Fibers at the pedestal were examined under the microscope and identified as silk. The total height of this Sarira Reliquary is 6.0cm, the height of lotus pedestal and the roof is 2.7cm and 1.8cm, respectively. The roof and body are joined together, and the lotus pedestal can be separated, on which the octagonal reliquary is impaled. The pedestal consists of 3layers of petals and the surface is decorated with flower pattern. The reliquary is presumed to be created in the 14th century, and it becomes valuable historical material to reveal the secret of metal work in the late Goryeo Dynasty.