• KIEAE Journal
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• v.4 no.3
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• pp.113-119
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• 2004

As Building Integrated Photovoltaic(BIPV) system replaces the conventional building finishing materials with PV modules, two function of electricity generation and building envelope can be expected. Therefore BIPV can be a good alternative technology for the 21 century environment-friendly buildings. The objective of this paper is to develope BIPV modules for a commercial buildings of which structure is mainly light-weight, curtain wall system. Two types of module are developed for a opaque part and a transparent part of building envelope. Current technology level and market status of Korea determines the configuration of developed BIPV modules. Architectural considerations for the integration of PV module to building envelope such as building structure, construction type, safety, regulation, maintenance etc. have been carefully reflected from the early stage of BIPV module design. Especially the survey result of current building envelope materials determines the size of unit BIPV modules and a unique cladding method for PV module installation is developed. Trial product of BIPV modules and cladding hardwares are manufactured and sample construction details for a demonstration building are proposed.

• Journal of the Korean Professional Engineers Association
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• v.32 no.1
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• pp.67-73
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• 1999

• Journal of Korean Association for Spatial Structures
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• v.16 no.3
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• pp.89-97
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• 2016

With the recent trend to construct high-rise and large buildings, the steel structure system is widely used, but there are not enough studies on the vibration characteristics of the iFLASH system on the buildings. Therefore, in this study, we performed a vibration measurement of the natural frequency and damping ratio in the stage of iFLASH panel, composit, frame completion and cladding completion. The result findings suggest that the damping ratio after the cladding completion has a greater effect on the reduction of the damping ratio, than the stage after the frame completion.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.327-330
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• 2004

Laser aided direct metal deposition (LADMD) process offers the ability to make a metal component directly from 3-D CAD dimensions. A 3-D object can be formed by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using optical sensors is introduced to control laser power and powder mass flow rate. Using H13 tool steel and $CO_2$ laser system, comprehensive analysis are executed to test the efficiency of the system. In addition, the dimensional characteristics of directed deposited material are investigated with the parameters of deposition thickness, laser power, traverse speed and powder mass flow rate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.816-819
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• 2002

Accurate stress intensity factor analyses and crack growth rate of surface-cracked components in inhomogeneous materials are needed for reliable prediction of their fatigue lift and fracture strengths. This paper describes an automated system for analyzing the stress intensity factors of three-dimensional (3D) cracks in inhomogeneous materials. 3D finite element method (FEM) was used to obtain the stress intensity factor for subsurface cracks and surface cracks existing in inhomogeneous materials. To examine accuracy and efficiency of the present system, the stress intensity factor for a semi-elliptical surface crack in a plate subjected to uniform tension is calculated, and compared with Raju-Newman's solutions. Then the system is applied to analyze cladding effect of subsurface cracks in inhomogeneous materials. The results were compared with those surface cracks in homogeneous materials. It is clearly demonstrated from these analyses that the stress intensity factors for subsurface cracks are less than those of surface cracks.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1680-1690
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• 2006

As a promising and novel manufacturing technology, laser aided direct metal deposition (DMD) process produces near-net-shape functional metal parts directly from 3-D CAD models by repeating laser cladding layer by layer. The key of the build-up mechanism is the effective control of powder delivery and laser power to be irradiated into the melt-pool. A feedback control system using two sets of optical height sensors is designed for monitoring the melt-pool and real-time control of deposition dimension. With the feedback height control system, the dimensions of part can be controlled within designed tolerance maintaining real time control of each layer thickness. Clad nugget shapes reveal that the feedback control can affect the nugget size and morphology of microstructure. The pore/void level can be controlled by utilizing pulsed-mode laser and proper design of deposition tool-path. With the present configuration of the control system, it is believed that more innovation of the DMD process is possible to the deposition of layers in 3-D slice.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.3
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• pp.211-218
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• 2015

The reaction rates of ZIRLO cladding hulls with cross-section openings were investigated using a thermo-gravimetric analysis system in order to identify whether selective recovery of Zr from oxidized cladding hulls is possible. The experimental results showed that an oxidized ZIRLO cladding hull was not reactive with chlorine gas at 400℃. However, providing fresh cross-sections on one or both ends of the ZIRLO hulls enabled a chlorination reaction. This reaction was completed after 8 hours; a 14% increase on the 7 hours seen with a bare ZIRLO cladding hull. The Sharp-Hancock plot analysis results revealed that the contracting volume model is the best for describing the reaction between the cross-section opened ZIRLO hulls and chlorine gas under the condition of this work. It was concluded that the chlorination process can be employed for oxidized ZIRLO cladding hulls by providing cross-section openings.

• Journal of Welding and Joining
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• v.31 no.6
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• pp.90-95
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• 2013

Pipe inside clad welding is mainly used to the flow pipe of sub-sea or chemical plant. For the inside clad welding to the medium pipe with the diameter of about 12", TIG welding is frequently applied with filler metal. In this case, the clad welding has the very broad weld area over $10m^2$. And, the non-destructive test (NDT) such as ultrasonic test (UT) or radiographic testing (RT) should be conducted on the broad weld area, and it costs very high due to the time-consuming work. Therefore, the present study investigated the variation of arc voltage to develop the in-line quality monitoring system for the pipe inside TIG cladding. The 4 experimental parameters (current, arc length, wire feed position, and shield gas flow rate) varied to observe the change of arc voltage and to establish the model for the monitoring. The arc voltage was decreased when the wire was fed to the backward eccentric position(over 2mm), and the shield gas flow rate was insufficient under 10L/min. In the case of the backward eccentric position over 2mm, the bead appearance was not good and the dilution ratio was increased due to deep penetration. When the shield gas flow rate was lower than 10L/min, the bead surface was oxidized.

• Journal of the Korean housing association
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• v.23 no.6
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• pp.49-59
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• 2012

This study suggested a new model in consideration of long life and constructability of apartment house suggested in the former part. New model suggested the possibility of cost saving based on the idea that people trend to reject because of the recognition that the new model would cost a lot of expense which work as the barrier for the expansion and distribution at the local market so as to prepare the ground for its activation. The Study was aimed at verifying the possibility of cost saving through comparing it with the existing standard apartment house system centered on the skeleton and cladding system among the new structural design models suggested in the former part. Assuming that these existing standard both models should be changed structural design into new model system, the quantity volume, cost and construction period along with the alteration of finished materials between two models were compared altogether. Simultaneously BIM library was built for easy taking-off bill of quantity and consideration of working methodology for construction working cycle, which was translated into construction cost so as to derive the cost of the two subject systems to be counted. Through the analysis, it was concluded that new model would secure variability in the future and constructability along with shortening the construction period (29%) and achieve cost saving (13%) of construction against the those of existing model.

• Nuclear Engineering and Technology
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• v.49 no.7
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• pp.1472-1482
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• 2017

Zirconium alloy cladding tube specimens were irradiated at $380^{\circ}C$ up to a fast neutron fluence of $7.5{\times}10^{24}n/m^2$ in a research reactor to investigate the effect of neutron irradiation on hydride reorientation and mechanical property degradation. Cool-down tests from $400^{\circ}C$ to $200^{\circ}C$ under 150 MPa tensile hoop stress were performed. These tests indicate that the irradiated specimens generated a smaller radial hydride fraction than did the unirradiated specimens and that higher hydrogen content generated a smaller radial hydride fraction. The irradiated specimens of 500 ppm-H showed smaller ultimate tensile strength and plastic strain than those characteristics of the 250 ppm-H specimens. This mechanical property degradation caused by neutron irradiation can be explained by tensile hoop stress-induced microcrack formation on the hydrides in the irradiation-damaged matrix and subsequent microcrack propagation along the hydrides and/or through the matrix.