• Applied Science and Convergence Technology
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• v.26 no.1
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• pp.1-5
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• 2017

The spurt vacuum pump is widely used to transfer sludge and slurry, and to control flow rate in a variety of processing fields, such as the oil, chemical, and fiber industries. The efficiency of the pump depends on the design parameters of the impeller, such as the number of blades, and the blade angle. In this study, the effect of the configuration of the impeller discharge angle of a spurt vacuum pump, which influences total head, shaft power, and efficiency, was numerically investigated using the commercial code, ANSYS CFX ver. 16.1. In addition, the performance of the pump was evaluated on the basis of the correlations between the total head, pump efficiency, and pressure distribution.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1292-1294
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• 1994

With the contact angle of phase epoxy resin on the inorganic filler(glass plate) surface treated with air plasma, we have studied about the interface between epoxy resin and glass plate as simple model of a glass fiber reinforced composite materials. The contact angle on the inorganic filler surface varied with surface treatment conditions. The contact angle significantly depends on plasma treating time and environment temperature of the oven.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.6
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• pp.33-41
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• 2004

In this paper, a polarimetric fiber optic current sensor(P-FOCS) is experimented and fabricated, and then a possibility to the commercial utilization of the P-FOCS is also investigated. The P-FOCS measures an applied current by a Faraday rotation linearly proportional to a magnetic field generated by the applied current. The bending-induced linear birefringence in the sensing fiber is minimized by using the low birefringent fiber. Also, all fiber-optic components are used to avoid optical losses coming from the use of bulk components. A signal processing circuit is constructed and used to eliminate the effects of intensity variations in the output signal due to losses coming from misalignments of components such as fiber connectors. Using the optical source of 632.8nm wavelength, Faraday rotation is measured by passing through the sensing fiber within the solenoid of about 1500 turns which is equivalent to a current source of about 7500A. In the range of 1000A to 7500A, the measurement error for linearity is within about 1.5%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.2
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• pp.234-242
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• 2002

A shape optimal design of synthetic intervertebral disc prosthesis is performed using a three-dimensional finite element method. Geometric parameters are introduced to model the cross-sectional geometry of the intervertebral disc. It is assumed that the total strain energy in the intact intervertebral disc is minimized under the normal load conditions, as often cited in other references. To calculate the stain energy density, both the nonlinear material properties and the large deformations are taken into account. The design variables of the annulus fiber angle and the area ratio of the nucleus pulposus are calculated as 31°and 30%, respectively, which complies well with the intact disc. Thus, the same optimization procedure is applied to the design of the synthetic intervertebral disc prosthesis whose material properties are different from the intact disc. For the given synthetic material properties, the values of 67°and 24% for the fiber angle and the area ratio are obtained.

• Composites Research
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• v.14 no.6
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• pp.24-31
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• 2001

Filament wound structures such as pressure tanks, pipes and motor cases of rockets are widely used in the aerospace application. The determination of a proper winding angle and thickness is very important to decrease manufacturing difficulties and to increase structural efficiency. In this study, possible winding angles considering the slippage between a fiber and a mandrel surface are calculated using the semi-geodesic path equation. In addition, finite element analysis using ABAcUS are performed to predict the behavior of filament wound structures considering continuous change of winding angle along the dome part. The water-pressuring tests of 3rd stage motor case are performed to verify the analysis procedure. The strain gages are attached on the surface in the fiber direction. Progressive failure analysis is performed to predict the burst pressure and the weakest region of the motor case. The effect of reinforcement is also studied to increase its performance.

• Journal of the Korean Society of Safety
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• v.27 no.1
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• pp.55-62
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• 2012

Steel plate or FRP materials have been typically used for the seismic retrofit of civil infrastructures. In order to overcome the limitation of each retrofitting material, a composite material, which takes advantages from both metal and fiber polymer materials, has been developed. In the study herein, the composite retrofitting material consists of metal part(steel or aluminum) and FRP sheet part(glass or carbon fiber). The metal part can enhance the ductility and the FRP part the ultimate strength. As a preliminary study to investigate the fundamental mechanical characteristics of the metal-FRP laminated composite material this study performed the flexural fracture test with various experimental variables including the number, the angle and the combination of FRP laminates. From the aluminum-FRP composite tests no great increase in flexural strength and flexural toughness were observed. However, flexural toughness of steel-FRP laminate composite was increased so that its behavior can be considered in the retrofit design. In addition, the angle and the kind of fibers should be carefully considered in conjunction with the expected loading conditions.

• Fashion & Textile Research Journal
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• v.16 no.3
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• pp.456-461
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• 2014

The objective of this study is to give PP(polypropylene) fabric a good affinity for water. Oxygen plasma was treated to PP fabrics in a commercial glow discharge reactor with different RF power, discharge pressure, and reaction time. The PP fiber surfaces were characterized by the measurement of contact angle and ESCA. A JEOL scanning electron microscope was used to observe the surface morphology of fibers. The spontaneous water uptake amount of PP fabrics was determined by the demand wettability test. To determine the effect of aging on the surface properties of $O_2$ plasma treated PP, all the above measurements of the samples were carried out after 1, 7, 30, 60, and 150 days. The results are as follows. The PP fiber surfaces treated by $O_2$ plasma treatment have a chemical composition that consisted of various oxygen containing polar groups. Consequently, the contact angles of the treated PP fibers decreased, which improved the water uptake rate of PP fabrics. Surface roughness of the treated PP affected the fabric wettabiity as well. Wettability of the treated PP decreased and leveled off with aging. The $O_2$ plasma treatment is a simple and effective method to increase the water uptake rate of PP fabrics.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.113-118
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• 2010

For a present study, woven type carbon fibers were surface-modified by oxygen plasma to improve adhesive strength between carbon fibers and epoxy. The change of hydrophilic properties by the plasma modification was investigated through the contact angle measurement and the calculation of surface energy of carbon fiber due to the oxygen plasma modification. FESEM and XPS analyses were performed to study the chemical and physical changes on the surface of carbon fibers due to the oxygen plasma modification. Pin-on-disk wear tests were conducted under dry condition using unmodified and plasma-modified carbon/epoxy composites to investigate the effect of plasma modification on the wear behavior of woven type carbon/epoxy composites. The results showed that the friction coefficient and the wear rate of plasma-modified carbon/epoxy composites were lower than those of unmodified carbon/epoxy composites, respectively. XPS analysis showed that new functional group of a carbonyl type was created on the carbon fibers by the $O_2$ plasma treatment, which enhanced adhesive strength between carbon fibers and epoxy, leading to improve wear properties

• Journal of the Korean Society of Safety
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• v.26 no.6
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• pp.54-63
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• 2011

Steel plate or FRP materials have been typically used for the seismic retrofit of civil infrastructures. In order to overcome the limitation of each retrofitting material, a composite material, which takes advantages from both metal and fiber polymer materials, has been developed. In the study herein, the composite retrofitting material consists of metal part(steel or aluminum) and FRP sheet part(glass or carbon fiber). The metal part can enhance the ductility and the FRP part the ultimate strength. As a preliminary study to investigate the fundamental mechanical characteristics of the metal-FRP laminated composite material this study performed the tensile test with various experimental variables including the number, the angle and the combination of FRP laminates. From the test results, both aluminum and steel-FRP laminate composite material showed increased fracture toughness. However, the angle and the kind of fibers should be carefully considered in conjunction with the expected loading conditions. In general, steel-FRP laminate composite showed better tensile performance in regards to the seismic retrofit purposes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.429-432
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• 2004

The demand for electric power keeps growing, and tends to be more effective. Polymer insulators have been manufactured for almost twenty years and the excellent insulation performance of polymer insulators is attractive. Polymeric materials are now widely used as a replacement for inorganic materials such as porcelain or glass for the outdoor insulation of high voltage insulation. GFRP has been used widely as a core materials for polymer insulators. This paper reports the mechanical properties of GFRP for insulators. The bending strength was simulated and evaluated according to the winding angle. The fiber orientation in GFRP has a great effect on the strength of GFRP because the strength of GFRP mainly depends on the strength of fiber. Results of simulated and evaluated strength of GFRP were compared each other. The simulated strength of GFRP rod was different from the evaluated strength. It was caused that the shear stress had a great effect on the strength of GFRP although the stress of parallel direction of GFRP was much higher.