• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.809-810
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• 2013

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.326-330
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• 2007

Bumper back beam is one of the essential structural components of front-end module. It should be designed to withstand a minor bump in low-speed collision, 2.5 mph crash test for example. And weight reduction is always important problem in the design of almost all the parts in car for energy saving. So, the key issues in shape design of a bumper are weight reduction and the performance in 2.5mph crash test. In this study, a light weight and high performance bumper back beam model was developed using analytical approach based on mechanics and FE simulation together.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.49-54
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• 2011

Carbody bolster must be a strong structural member of the underframe because it is in the direct line of weight transmission. On the other hand, carbody bolster is a heavy member that occupied about 20~25% in the weight of underframe. In order to reduce the weight of carbody bolster, we study the design factors such as bending stiffness, bending strength and deformation according to the change of carbody bolster's second moment of area. And we investigate the design factors of a total of 10 species of existing rail vehicles. The results of this study can be used as practicable method in designing carbody bolster in the future.

• Journal of Power System Engineering
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• v.21 no.1
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• pp.5-10
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• 2017

Pitch drive system in wind turbine is composed by the planetary gear system to satisfied its required performance such as long life and light weight for gear train. When the planetary gear system can reduce its volume and weight, the power consumption of the wind turbine can be reduced. In this study, the planetary gear system of the pitch drive system in medium-sized wind turbine is obtained for weight reduction by shape optimization method. And the planetary gear system is verified for their strength by the structural analysis.

• Textile Coloration and Finishing
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• v.5 no.3
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• pp.206-215
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• 1993

In the prior study, wool gabardines were treated with alkaline proteases which were some kinds of enzyme to decompose protein, and their tensile strengths were determined, and the surface of the fibers were also observed using a scanning electron microscope. Enzylon ASN 30 and Alkalase 2.5L DX did not show much effect on the weight loss of wool, however, the weight loss of wool increased considerably with treating Esperase 8.0L. Pretreatment of wool with dichloloisocyanuric acid before protease-treatment increased the weight loss of wool to a great extent. In this study, the enzyme treated wools dyeing behaviors with acid dye, Milling Cyanine 5R, were mainly investigated. The protease-treatment remarkably increased not only the rate of dyeing but also the saturation dye uptake. From these results, it seemed likely that the structural relaxation of adhesive filler of interscale or intercellular cement facilitated the dye penetration into the fibers, at the same time, the change in the inner structure of the wool fibers by the protease made the fixation of the dyes more efficient.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.124-130
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• 2003

Many structural evaluation procedures of road and airfield pavements use the Falling Weight Deflectometer (FWD) as a critical element of non-destructive deflection testing. FWD is a trailer mounted device that provides accurate data on pavement response to dynamic wheel loads. A dynamic load is generated by dropping a mass from a variable height onto a loading plate. The magnitude of the load and the pavement deflection are measured by a load celt and geophones. And database concerning pavement damage should be enhanced to analyze loss of thickness asphalt layer caused from the plastic deformation of pavement structure, such as cracking or rutting. The prototype FWD is developed, which consists of chassis system, hydraulic loading system, data acquisition and analysis system. This system subsequently merged to from automation management system and is then validated and updated to produce a working FWD which can actually be used in the field.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.651-661
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• 2017

This paper presents an experimental study of bond-slip behavior of reinforced lightweight aggregate concrete (LC) and normal weight concrete (NC) with embedded steel bar. Tests were conducted on tension-pull specimens that had cross-sectional dimension with a reinforcing bar embedded in the center section. The experimental variables include concrete strength (20, 40, and 60 MPa) and coarse aggregate type (normal-weight aggregate and reservoir sludge lightweight aggregate). The test results show that as concrete compressive strength increased, the magnitudes of the slip of the LC specimens were greater than those of the NC specimens. Moreover, the bond strength and stiffness approaches zero at the loaded end, or close to the central anchored point of the specimen. In addition, the proposed bond stress-slip equation can effectively estimate the behavior of bond stress and steel bar slipping.

• Structural Engineering and Mechanics
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• v.10 no.3
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• pp.197-209
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• 2000

The effects of weight and axial inertia of a beam are taken into account for studying the nonlinear vibration of the Timoshenko beam due to external loads. The combination of Galerkins method and Runge-Kutta method are employed to obtain the dynamic responses of the beam. A concentrated force and a two-axle vehicle traversing on the beam are taken as two examples to investigate the response characteristics of the beam. Results show that the effect of axial inertia of the beam increases the fundamental period of the beam. Further, both the dynamic deflection and the dynamic moment of the beam obtained with including the effect of axial inertia of the beam are greater than those of the beam without including that effect of the beam.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.749-752
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• 2005

Normally, the degradation of concrete member exposed to fire is largely dependent on the fire scale and fire condition. With all ensuring the fire resistance structure as a method of setting the required cover thickness to fire, the RC is significantly affected from the standpoint of its structural stability that the compressive strength and elastic modulus is reduced by fire. Thus, this study is concerned with experimentally investigating fire resistance of high strength-light weight concrete. From the test result, high strength-light weight concrete is happened explosive spalling. The decrease of cross section caused by explosive spalling made sharp increasing gradient of inner temperature.

• Journal of the Korean Home Economics Association
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• v.27 no.1
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• pp.1-8
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• 1989

In order to investigate the mechanical properties such as tensile, bending, shearing, thickness and weight of the wool fabrics were measured by KES-F system. Samples were classified into blend ratio, weave type, fabric count. Blend ratio was classified into two groups, which are P/W blended fabric (p=63~65%, w=35~37%) and all wool fabric. Weave type was classified into four groups, which are plain, 3 harness twill, 4harness twill, satin. Cloth count was classified into three groups, which are loose, medium, tight. Statistical analysis was performed using T-test, F-test. The results were as follows; 1. There was significant difference in the thickness, tensile, bending, shearing according to the blend ratio. 2. According the weave, there was significant difference in the bending, weight and thickness in the P/W blended fabrics. There was significant difference in the tensile, weight, thickness, bending, shearing, shearing hysterisis (2HG) in the all wool fabrics. 3. There was significant difference in the shearing properties according to the fabric count.