• KCI Concrete Journal
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• v.14 no.1
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• pp.1-7
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• 2002

This paper reports the experimental and analytical investigations for evaluating the flexural strength of a RC slab strengthened with carbon fiber sheet (CFS). The evaluation of the ultimate flexural strength of a slab is tried under the assumption that the failure occurs when the shear stress mobilized at the interface between the concrete bottom and the glued CFS reaches its bond strength. The shear stress is evaluated theoretically and the bond strength is obtained by a laboratory test. The ultimate flexural strength is obtained by flexural static test of the slab specimen, which corresponds to the part of a real slab. From the results, the new approach based on the bond strength between concrete and CFS looks feasible to evaluate the flexural strength of the CFS and RC composite slab.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.583-584
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.903-904
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.473-474
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1583-1584
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• 2011

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.613-617
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• 1998

This study deals with the effect on adhesive strength properties of fiber sheet layer and maintenance position of coccrete structure reinforced using epoxy resin carbon and aramit fiber sheet. Properties of epoxy resin adhesive strength of the concrete bridge slab, tunnel and wall etc. reinforced using fiber sheet under many different environment change according to condition of concrete substrate, temperature, moisture, curing, cleaning, and chemical effects and so on. The purpose of this study is that it makes the estimation value of adhesive strength of concrete substrate and fiber sheet reinforcing layer penetrated epoxy resin under high temperature(9$0^{\circ}C$), chemical attack and condition of curing.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.53-56
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• 2004

The mechanical properties and optical micrographs are studied for rolled magnesium alloy sheet with hexagonal close packed structure(HCP) at room and elevated temperatures. Tensile properties such as tensile strength, elongation, R-value and n-value are also measured for AZ31 magnesium alloy. Magnesium with strong texture of basal plane parallel to the rolling direction usually has high R-value and plastic anisotropy at room temperature. As temperature increases, the R-value for AZ31 magnesium sheet decreases. In addition, the AZ31 sheet becomes isotropy and recrystallization above $200^{\circ}C$. Formability of magnesium alloy sheets remarkably poor at room temperature is improved by increasing temperature. Sheet forming of magnesium alloy is practically possible only at high temperature range where plastic anisotropy disappears.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.91-100
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• 2001

A sectional FEA program is developed lot analyzing forming processes of sandwich sheets, which are intensively used recently as a lightweight material of an automobile body. The aluminum sandwich sheet consists of two aluminum skins and a polyprophylen core in between. The aluminum sandwich sheet is dominantly effected by the bending effects in small radius of curvature, so that an appropriate description of bending effects is required to analyze the forming processes. For the evaluation of bending effects, the bending equivalent forces are calculated from the bending moment computed using the curvature of the tool and are added to the membrane stretch forces. To verify the validity of the developed program the sectional FEA results in stretch/draw forming Processes of a square cup and draw forming Processes of an outer hood panel were compared with the measurements.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.6-7
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• 2019

In order to solve problems such as scattered dust, dust and chemicals harmful to the human body, workability in a confined space, quality performance, and the like generated during the field construction of the conventional waterproof sheet construction method, a waterproof sheet is used as a PC formwork, Which is produced by pouring concrete after PC installation, and evaluating the applicability of the development method in comparison with the construction method of polypropylene waterproof sheet construction method and the construction period, safety, quality, construction cost.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.104-114
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• 1996

For the improvement of productivity, the reduction of cost and time for manufacturing is mandatory, especially in the field of electromic industry. The study is concerned with a practical means of systematic assistance to formability estimation and selection of reliable design specification for electronic sheet metal parts. The objective of this research work is to develop a simulation system which hops to analyze the target processes with the finite element method and to acquire available design data quickly and exactly. The simulation system developed in the study consists of design verification, selection of optimal combination of parameters, knowledge acquisition and graphical user interface(GUI). Design verification is automatically carried out by using the finite element method. A data base management system and nomograms are utilized for knowledge acquisition. The developed system has been applied to some major sheet metal forming operations such as flanging, embossing, bending and blanking. According to the simulated results, the validation of the target processes has been confirmend. Analysis data, estimation rules of formability and graphical representation of the analysis have been employed for the designer's understanding and evaluation, thus providing a practical means of robust design and evaluation of forma- bility for producing electronic sheet metal parts.