• Proceedings of the Korean Fiber Society Conference
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• 1994.10a
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• pp.70-70
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• 1994

• The Korean Journal of Rheology
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• v.10 no.1
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• pp.14-23
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• 1998

비상용성 고분자 브렌드계인 PS/PP와 EPDM/PP의 유변학적 거동에 미치는 계면의 영향을 알아보았고 그실험 결과를 Park & Lee 모델과 비교하였다. PS/PP와 EPDM/PP 블 렌드계에서의 계면에 의한 전단응력과 법선 응력차에의 기여도는 $textsc{k}$와λ(1-$\mu$), 두 개의 변 수에 의해 잘설명되었다. 특히 계면의 탄성적인 효과와 관련있는 법선응력차 항이 전단 응 력 항보다 더 뚜렷하게 나타났다. 30PS/70PP 블렌드 조성에서는 블렌드의 유변학적 특성이 주로 연속상을 이루는 고분자의 의해 좌우된 반면에 50PS/50PP 블렌드조성에서는 계면에 의한 영향이 더두드러지게 나타났다. 이것은 50/50 블렌드 조성에서 계면의 넓이가 증가한 것과 관계 있다. 그러나 EPDM/PP 블렌드계에서 계면에 의한 응력 항들이 모두 PS/PP 블 렌드계의 그것보다 매우 큰 값을 가졌지만, 그 상대적인 비를 나타내는 $textsc{k}$값은 작았다. 이것 은 블렌드를 구성하고 있는 순수한 성분의 법선응력차 값의 차이가 크기 때문이다. 또한 PS/PP 블렌드계에 대한 동적 계면장력을 Park & Lee 모델을 이용하여 예측해 보았다.

• Magazine of the Korea Concrete Institute
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• v.9 no.3
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• pp.137-147
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• 1997

Interface shear strength of' concrete under static loading and deterioratiion of interface strength by fatigue loading in shear were experimentally investigated using composite beam test specimens. Thirteen beams were constructed. Five composite beams were tested statically until interface delaminations were observed in the static tests. Seven composite beam and one monolithically cast beam were subjected to two to three million cycles of fatigue load. Test variables were interface roughness, interface shear reinforcement, and presence of interface bond. The average interface shear strength of the composite beams with bonded-rough interface was 6, 060 kPa. No interface delamination was observed after cycling for the composite beams with bonded - rough interface and interface bond was not influenced by repeated application of the shear stress of 2.000 kPa(about 1/3 of the static interface shear strength). Smooth interface and unbonded-rough interface with shear reinforcement deteriorated under repeated shear loading.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.252-256
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• 2002

본 연구에서는 유리섬유/나일론 6 복합재료의 계면특성에 미치는 실란계 사이징제의 영향을 조사하기 위하여 microbonding test, short-beam shear test 그리고 dynamic mechanical analysis 방법을 사용하였다. 전자의 미시적인 방법과 후자의 두 가지 거시적인 접근 방법으로부터 얻은 유리섬유/나일론 6 복합재료의 계면특성에 대한 결과가 서로 일치하였다. 상업적으로 사이징 처리된 경우와 비교할 때, 본 연구에 적용된 네 종류의 실란계 사이징제는 유리섬유-나일론 6 수지의 계면결합력을 크게 향상시켰다. 특히, 3-chloropropyltrimethoxysilane (Z-6076)의 사용은 유리섬유/나일론 6 복합재료의 계면전단강도와 층간전단강도를 가장 두드러지게 증가시켰다.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.472-477
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• 2016

We studied the effects of anodic oxidation treatments of carbon fibers on interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites with various current densities. The surface of treated carbon fibers was characterized by atomic force microscope (AFM), field emission-scanning electron microscope (FE-SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). The interlaminar shear strength (ILSS) of the composites was determined by a short beam shear test. This result showed that both the roughness and oxygen group of the carbon fibers surface increased in proportion to the current density. After anodic-oxidation-treated, the ILSS also increased as a function of the current density. In addition, the proportional relationship between ILSS and phenolic hydroxyl group was confirmed. The ILSS of the CF-2.0 sample increased by 4% compared to that of the CF-AS sample, because the anodic oxidation treatment increased the oxygen group and roughness on the carbon fibers surface, which leading to the improvement of the interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites. Among these, the phenolic hydroxyl group which has the proportional relationship with ILSS is found to be the most important factor for improving the interfacial adhesion of the carbon fibers-reinforced epoxy matrix composites.

• Composites Research
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• v.28 no.3
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• pp.94-98
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• 2015

This paper reports the effects of nickel film interleaves on the interlaminar shear strength(ILSS) of carbon fiber reinforced epoxy composites(CFRPs). A nickel thin film was deposited onto the prepreg by radio frequency(RF) sputtering at room temperature. The ILSS of the nickel film interleaved hybrid composites was increased compared to that of the composites without interleaves. To understand the mechanism of enhancement of the ILSS, the fracture surface of the tested specimens was examined by scanning electron microscopy(SEM). The metal interleaves were acted as a reinforcement for the matrix rich interface and the shear property of their composites improved by enhancing the resistance to matrix cracking.

• Composites Research
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• v.13 no.4
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• pp.67-74
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• 2000

The general solution of the anti-plane shear problem for the curved interfacial crack between viscoelastic foam and composites was investigated with the complex variable displacement function. Kelvin-Maxwell three parameter model is used to present viscoelasticity and the Laplace transform was applied to treat the viscoelastic characteristics of foam in the analysis. The stress intensity factor near the interfacial crack tip was predicted by considering both anisotropic and viscoelastic properties of two different materials. The results showed that the stress intensity factor increased with increasing the curvature of the curved interfacial crack and it also increased and eventually converged to a specific value with increasing time. The stress intensity factor increased with increasing the ratio of stiffness coefficients between foam and composites and the effect of fiber orientation on the stress intensity factor decreased with increasing the ratio of stiffness coefficients between foam and composites.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.6
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• pp.791-796
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• 2013

In this study, the mechanical properties of a carbon fiber/polypropylene composite were evaluated according to the carbon fiber surface treatment. Carbon fiber surface treatments such as silane coupling agents and plasma treatment were performed to enhance the interfacial strength between carbon fibers and polypropylene. The treated carbon fiber surface was characterized by XPS, SEM, and single-filament tensile test. The interlaminar shear strength (ILSS) of the composite with respect to the surface treatment was determined by a short beam shear test. The test results showed that the ILSS of the plasma-treated specimen increased with the treatment time. The ILSS of the specimen treated with a silane coupling agent after plasma treatment increased by 48.7% compared to that of the untreated specimen.

• The Journal of the Korea Contents Association
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• v.10 no.11
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• pp.228-234
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• 2010

Ni-Cr and Co-Cr alloy uncontained Be element for using as dental porcelain alloy were analyzed the mechanical properties through bonding strength and fracture test after the bonding with porcelain. The bonding strengths between alloy and ceramic were measured through the shear bond strength test. Consequently, the T-3 group contained Be element that had shear strength of 41.13(${\pm}5.11$)MPa was showed the highest shear strength than the other groups. The second highest group was a verabond contained Be element that had shear strength of 40.72(${\pm}5.98$)MPa. The results of the other groups according to the shear strength were Wirobond(38.40(${\pm}9.66$)MPa) belonged to Co-Cr alloy, and Verabond 2V(32.77(${\pm}4.31$)MPa), Bellabond N(28.63(${\pm}6.39$)MPa), Bellabond plus(24.97(${\pm}6.13$)MPa), Argeloy N.P. Star(22.69(${\pm}3.41$)MPa) uncontained Be element, respectively. The morphological aspects of the fracture surface between alloys and ceramic were observed that all groups were caused mixed failure as conformation attached ceramic fragments to metallic surface by fracture process.

• Journal of the Korean Geosynthetics Society
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• v.5 no.4
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• pp.27-33
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• 2006

Frictional properties between geostrip and sand paper interface were estimated considering soil particle size also the friction coefficients and angles were determined with normal stress. Three kinds of geostrips of design strength 50, 70, 100 KN/m were used and 5 sandpapers of P100, P220, P320, P400, P600 were used also. Shear strength between geostrip and sand paper interface with design strength showed big difference and this is due to the uniform surface pattern of each geostrip when contact to sandpaper without regard to design strength. Shear strength of geostrip was increased with design strength and geostrips/P100 sandpaper interface showed the biggest value. Finally, all of geostrips showed the decrease phenomena of post-peak strength and this is due to the abrasion of geostrip surface by shear test.