• Carbon letters
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• v.5 no.1
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• pp.18-22
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• 2004

The failure behaviours of unidirectional pultruded carbon fiber reinforced polymer (CFRP) composites were monitored by the electrical resistance measurement during tensile loading, three-point-bending, interlaminar shear loading. The tensile failure behaviour of carbon fiber tows was also investigated by the electrical resistance measurement. Infrared thermography non-destructive evaluation was performed in real time during tensile test of CFRP composites to validate the change of microdamage in the materials. Experiment results demonstrated that the CFRP composites and carbon fiber tows were damaged by different damage mechinsms during tensile loading, for the CFRP composites, mainly being in the forms of matrix damage and the debonding between matrix and fibers, while for the carbon fiber tows, mainly being in the forms of fiber fracture. The correlation between the infrared thermographs and the change in the electrical resistance could be regarded as an evidence of the damage mechanisms of the CFRP composites. During three-point-bending loading, the main damage forms were the simultaneity fracture of matrix and fibers firstly, then matrix cracking and the debonding between matrix and fiber were carried out. This results can be shown in Fig. 9(a) and (b). During interlaminar shear loading, the change in the electrical resistance was related to the damage degree of interlaminar structure. Electrical resistance measurement was more sensitive to the damage behaviour of the CFRP composites than the stress/time curve.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.25-25
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• 2023

빅데이터, AI, 인공지능 등 기술이 발전함에 있어서 자율운항도입에 따른 VTS 체계변화에 대한 인식이 필요한 실정이다. 이 연구에서는 자율운항선박이 상용화함에 따라 요구되는 적합성을 제고하기 위해 영향을 미치는 내외적인 환경요인들을 전문가집단의 브레인스토밍, 설문조사, 인터뷰 등 다방면으로 조사하고, 해당 요소를 기반으로 TOWS분석을 통해 강점(Strength), 약점(Weakness), 기회(Opportunities), 위협(Threats)의 각 요소를 상호 결합해 전략주제 도출 및 새로운 관제절차와 관련 기술, 자율운항 교육프로그램, 사이버 보안조치, 자율운항 관련 알고리즘 구성 요소 등 구체적 실행계획을 제시함으로써 예측되는 변화 대응에 기여하고자 한다.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.528-532
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• 2013

Well-dispersed slurries of submicron-sized alumina powders were pressure-infiltrated in 3D preforms of mullite fibers and the effects of the particle size and infiltration pressure on the particle packing characteristics were investigated. Infiltration without pressure showed that the packing density increased as the particle size decreased due to the reduction of the friction between the particles and the fibers. The infiltrated preforms contained large pores in the large voids between the fiber tows and small pores in the narrow voids between the individual fibers. Pressure infiltration resulted in a packing density of 77% regardless of the particle size or the infiltration pressure(210 ~ 620 kPa). Pressure infiltration shortened the infiltration time and eliminated the large pores in preforms infiltrated with the slurries of smaller particles. The slurry pressure-infiltration process is thus an efficient method for the packing of matrix materials in various preforms.