• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.492-498
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• 2017

This study examined the bending performance of high strength and seismic purpose reinforcing bars experimentally with various parameters. For the experimental approach on the bending performance, the specimens were prepared with parameters, such as steel grades, diameters of reinforcing bars, and bending angles of reinforcing bars. Tensile strength tests on the reinforcing bars, the bending tests and re-bending tests, and the second tensile strength tests on the re-bended reinforcing bars were conducted. According to the test results on high strength and seismic purpose reinforcing bars, defects did not appear when the yield strength of the reinforcing bar was 500 MPa or less and the diameter was D13 or less, even when the first bending process was performed with a $135^{\circ}$ bending angle and a $2d_b$ inner radius. The bending performance decreased asthe strength and diameter of the reinforcing bars was increased. In addition, there was no significant difference between the general reinforcing bars and seismic purpose-reinforcing bars.

• Transactions of Materials Processing
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• v.25 no.1
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• pp.29-35
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• 2016

In the current study, finite element analysis was conducted for the press hemming of automotive panels in order to predict various hemming defects such as roll-in and turn down. The analysis used the exact punch movement based on the cam location and considered the sealer between the inner and outer panels with an artificial contact thickness. The analysis results quantify the hemming defects especially at the flange edge in the matching region of the head lamp. A design of experiments along with the parameter study was used to obtain the optimum process parameters for minimizing hemming defects. The optimization process selects the intake angle, bending angle of the hemming punch, and the flange height of the outer panel. The optimum design process determines an appropriate tool angle and flange height to reduce the roll-in and turn-down as compared to the initial design.

• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.5-12
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• 2011

In this paper, after studying structural performance for the representative corrugated steel plate used in Korea, we proposed the optimum shape for section of corrugated steel plate considering a width of steel plates that can be produced currently in the factory. Using AISI(1986) in examination for the performance of the corrugated steel plate, we determined the mechanical limit of the optimum sections considering shear force and bending moment of corrugated steel plate and also determined the geometric limit of them considering formability, shapes and ratio between width of steel plate before forming and that after forming. As a result of examination for performance of steel plate applying algorithm for searching optimal sections algorithm developed in this study to the existing representative corrugated steel plate, allowable force and moment of inertia indicated the maximum values at bending radius 76mm and internal bending angle $50^{\circ}$. And as an application result of the optimum design system that used SS490 with 1,550mm of width and 4,700mm of length considering current production situation in Korea, we developed the new section with more than 2 times of structural performance comparing with existing corrugated steel plate.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.1
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• pp.50-66
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• 2010

This Shanghai region study is a sample survey of female college students in their early 20s. This study collected and analyzed the information of shapes through a direct contact survey to understand the breast figures and the measurements of bodies to provide basic information to improve brassiere production for adult females in China. Data was analyzed through a SAS 9.0. The characteristic of the final brassiere pattern that had been corrected and complemented from the results of the $l^{st},\;2^{nd},\;3^{rd}$, and $4^{th}$ fitting tests is defined as a brassiere inserted with a round wire that has the 3/4cup to wrap the bust area by about 3/4. It consists of an upper and lower nonwoven fabric cup that has a flat-shaped wing of a circular dart. The drawing method of the pattern of this brassiere is applied with the conditions to cover the body naturally under the diverse and organic relations of the material factor of stretch material and wire, functional factor, and sewing factor. The final pattern is created as a bigger angle of wing pattern and a short inner side diameter because there are more Chinese women with a back of bending figure compared to Korean women.

• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.245-255
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• 2009

The purpose of this study is to analyzed the coordination of lower limb of elderly women who experienced a fall to present basic information for sports science and to deal with the factors that make elderly women fall more effectively. Twenty elderly women were divided into two groups of 10. The mechanisms of balancing lower limb during walk and differences were compared and analyzed using motion analysis and electromyography. The findings of this study are as follows. The first, walking patterns of these women were unstable as their hip joints did not provide sufficient support because of aging. Second, the left and right knee joints showed different walking patterns. The third, the motions of ankle joints became abnormal with increased age. As for the activation of major lower limb muscles, rectus fermois muscle and biceps fermois muscle contracted more to prevent the bending of knees and moved forward while anterior tibial muscle and inner gastrocnemius muscle were demanded highly during walk and the rate of plantar flexion was reduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.12
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• pp.1541-1546
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• 2013

The stress concentration of lock-claws, which are one of the important parts for pneumatic fitting for a flexible tube connection, was investigated by finite element simulation. In this study, the generation of the local plastic deformation was predicted when the tube was hooked up to a pneumatic fitting in order to disperse the stress concentration, and design optimization was carried out using the Taguchi method. For the optimization, the outer width, bending angle, and inner radius of the lock-claws are used as main variables. As a result, their respective contribution ratios are revealed as 81.3%, 10.9%, and 1.5%. The ratio of the total stress distribution was improved by 4% compared with the initial design of the lock-claws.