• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.367-372
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• 2003

Fiber Reinforced Cementitious Composite, DFRCC has strain hardening property with multiple crack in failed of compressive, tensile, bending force, concrete is not so that. But DFRCC could not use to the building element for which has not structural stiffness only has ductile property. DFRCC is used for repair only in recently. In that reason, we considered the concrete of light weight concrete, porous concrete, mortar complex with DFRCC. and DFRCC reinforced by fiber net, steel bar. In this study, results of experiment on complex method of concrete and DFRC were shown as follows; The complex methods of concrete lay on DFRCC, sandwich layer composition were effective for bending force depending on section size each layer, and reinforce DFRCC by fiber net, steel bar was effective method also.

• Fibers and Polymers
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• v.4 no.4
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• pp.151-155
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• 2003

The abrasion behavior of three kinds of warp knitted fabrics, which are normally used for upper sole of footwear, was evaluated. We measured the changes of mechanical and structural properties of each sample as abrasion cycle increased. Each sample showed similar trends in compression and surface properties but there were significant differences in abrasion rate among the samples. The mechanical properties showed remarkable differences with directions. The frictional coefficient (MIU) of fabric surface increased at the beginning of abrasion and decreased as abrasion cycles increased. The weight and thickness of the fabric linearly decreased with abrasion cycles. The surface roughness (SMD) and the compressional resilience (RC) decreased as abrasion cycles increased while compressional energy (WC) increased.

• Journal of the Korean Applied Science and Technology
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• v.28 no.3
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• pp.359-366
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• 2011

In this study we experimented that how polyurethane effect to acrylic-polyurethane resin in Full-Grain leather coatings. First of all, we consummated waterborne acrylic emulsion and waterborne polyurethane resin, Than we prepared F.G leathers which were coated by acrylic resin and acrylic-polyurethane resins. According to measured data for solvent resistance, acrylic resin and acrylic-polyurethane resins had good property. Sample a(WAC) had most low strength($2.10kg_f/mm^2$) and sample d(WAC 93 : WPU 7) had most high strength($3.41kg_f/mm^2$). Also we knew that most good property of abrasion is d(47.4 mg). In elongation case, a(WAC) had most good result(645 %) in this experiment.

• Fashion & Textile Research Journal
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• v.12 no.4
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• pp.494-499
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• 2010

Knitted fabrics are very popular for their numerous advantages such as greater comfort, attractive garment appearance, better fit on the body, etc. In this study, we investigated the mechanical properties and abrasion property of warp knitted fabrics for footwear which treated with several softeners to improve abrasion resistance. The antistatic softener among the various softeners showed high improvement in abrasion resistance. Among the mechanical properties with treating conditions, WT (tensile energy), G (shear stiffness), B (bending rigidity) increased as treating timeincreased. But the other mechanical properties were little changed with treating concentration.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.107-112
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• 1990

Chromatograms of asphalt cements were observed using high pressure - gel permeation chromatography (HP-GPC). The chromatogram characterzed profile of molecular size distribution of asphalt cements. Bituminous concretes using the asphalt cements were prepared in laboratory to measure mechanical properties, tensile strength (TS) and resilient modulus (MR), in dry and wet conditions. Three sources of AC-20 Asphalt cements and one aggregates were used for GPC test and strength test. Results of mechanical property tests and GPC tests were analyzed to evaluate correlation between those two results. Regression analysis showed strong correlation between a mechanical property and sliced percent areas of GPC profile. Mathematical models were developed for estimating mechanical properties of asphalt cement concrete based on HP-GPC data.

• Magazine of the Korea Concrete Institute
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• v.3 no.1
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• pp.71-78
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• 1991

Moleclar size distribution of three AC-20 asphalt cements were observed using high pressure - gel permeation chromatograph (HP-GPC). Bituminous concrete specimens were made using the asphalt cements and one aggre¬gate in laboratory to measure mechanical properties, tensile strength CIS) and resilient modulusCM,J. in dry and wet conditons. Results of mechanical property tests and profile of molecular size distribution of asphalt cements were analyzed to evaluate the relatonship of mechanical property with chromatogram. Regression analy¬sis showed a strong correlation between a mechanical property and sliced percent areas of chromatogram. Mathematical prediction models were developed based on the regression analysis. It was shown that characteris¬tics of asphalt cement chromatogram could be successfully used for estimation of selected mechanical property of asphalt concrete .

• Journal of Fashion Business
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• v.13 no.1
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• pp.82-90
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• 2009

This research was made to manufacture the fabric for interior uses by spinning a low melting mono 4 denier PET staple fiber with a soluble 1.4 denier fine PET fiber. The blended yarn has a thickness ranging from 10's to 14's, and the soluble PET fine fiber was dissolved to make a pore in the polymer. Thereby a snap property was decreased and a resilience property was improved to be suitable for a functional synthetic leather. In order to attain the optimum condition, a mechanical property according to fineness, and mixing ratio of low melting polymer, warp density, weft density and blending ratio, and a heat contraction ratio according to blending ratio were experimented. The warp density, 220 T/inch of fine denier PET and the weft density, 64 T/inch of thick denier PET were generated to 4/4 both twill weave fabric having constant tensile property and thickness.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.1
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• pp.47-57
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• 1986

The purpose of this study is to investigate fatigue phenomema of woven fabric. In order to obtain the basic data which is available for predicting the fabric fatigue phenomena, the change of mechanical properties of woven fabrics caused by the wearing and the changes of mechanical properties of woven fabrics which were subjected to repeated tensile-shearing deformation using fabric testing machine has been investigated and compared. The fatigue of woven fabrics was examined with the value of basic mechanical properties of specimens measured by the KES-F fabric testing system and their hand value and wearing ability. The results were as follows. 1) The fatigue phenomena of woven fabrics by the wearing for 800 hours are different on the position of the body: On the portion of hip, the change of surface property was the greatest, bending hysterisis was greatly increased, thickness weight, stiffness, fullness shearing hysterisis were more increased than original fabric and T.H.V. was decreased. On the portion of knee, decreasing of tensile resilience and increasing of bending, shearing hysterisis were observed greater than any other part, and increasing of stiffness, crispness was more than original fabric. On the bottom area, the changes of mechanical property was comparatively small, H.V. and T.H.V. showed near the value of the original fabric. 2) By drycleaning most of mechanical properties showed the tendency to recover the value of the original fabric, but bending hysterisis and thickess were increased, tensile and com-pression resilience were decreased more than original fabric in all parts. 3) The fatigue phenomena caused by fabric fatigue testing machine were as follows. The decreasing of hystersis in the repeated deformation such as bending, shearing was appeared at the $10^2$ deformation, but with the increasing cycle, the tendency was slightly regained. Handle value was also appeared the lowest value at the $10^2$ deformation.

• Composites Research
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• v.24 no.4
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• pp.11-16
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• 2011

Retention of interfacial shear strength (IFSS) of polymer composites at cryogenic temperature application is very important. In this work, single carbon tiber reinforced epoxy compositc was used to evaluate IFSS and apparent modulus under room and cryogenic temperatures. The property change of carbon and selected epoxy for particularly cryogenic temperature application were tested in tension and compression. Tensile strength and elongation of carbon fiber decreased at cryogenic temperature, whereas tensile modulus was almost same. On the other hand, epoxy matrix showed the increased tensile strength but decreased elongation. It can be due to maximum thermal contraction existing free volume in cryogenic temperature. IFSS increased up to $-10^{\circ}C$ and then decreased steadily. However, IFSS at cryogenic temperature was still similar to that at room temperature. This result is very useful to cryogenic application since selected epoxy toughness and interfacial adhesion can keep at such low temperature.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.1
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• pp.42-48
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• 2020

The effect of improving the tensile and J-R fracture toughness properties of SA508 Gr.1a on the LBB margin for the main steam pipe is investigated. The material properties and microstructure images of the existing main steam piping material SA106 Gr.C used in domestic nuclear power plants and the newly selected material SA508 Gr.1a were compared. For each material, LBB margins were calculated and compared through finite element analysis and crack instability evaluation. The LBB margin of the improved SA508 Gr.1a is found to be greatly improved compared to that of the existing SA106 Gr.C and SA508 Gr.1a. This is because of the increased material's strength and J-R fracture toughness compared to the previous materials. In order to analyze the effect of physical property change on the LBB margin, the sensitivity of each LBB margin according to the variation of tensile strength and J-R fracture toughness was analyzed. The effect of the change in tensile strength was found to be greater than that of the change in fracture toughness. Therefore, an increase in strength significantly influenced the improvement of the LBB margin of the improved SA508 Gr.1a.