• 한국해양공학회지
• /
• 제10권4호
• /
• pp.38-50
• /
• 1996

Recently carbon fiber reinforced plastic (CFRP) has been used structural materials in corrosive environment such as for water, chemical tank and pipes. However, mechanical properties of such materials may be change when CFRP and exposed to corrosive environment for long periods of time. The degradation behavior of carbon fiber/epoxy resin composite material in distilled water is investigated using acoustic emission (AE) technique, Fracture toughness tests are performed on the compact tension specimens that are pilled by two types of $[O_2/9O_2]_{3s}$ and $[O/9O]_6s$. During the testes, AE test was carried out to monitor the damage of CFRP by moisture absorption. The data was treated by 2-parameter Weibull distribution and the fracture surface was observed by scanning electron microscope.

• 공업화학전망
• /
• 제24권2호
• /
• pp.31-37
• /
• 2021

일반적으로 cross-link된 열경화성 에폭시수지는 유기용매에 용해되지 않고 열에 용융되지 않는 특성이 있다. 따라서 에폭시수지가 사용된 물질, 특히 탄소섬유강화플라스틱(carbon fiber reinforced plastic, CFRP)은 재활용이 어렵고, 사용 후 폐기물 처리에 막대한 비용이 소비되고 있다. 본 원고는 열경화성 에폭시수지 응용물 중 CFRP의 재활용을 중심으로 한 친환경적 재활용 기술에 관하여 정리하였다. 특히, CFRP의 구성요소인 탄소섬유(CF)와 기지재인 에폭시수지를 모두 재활용 할 수 있는 화학적 방법에 관하여 보고한다. 더 나아가 열경화성 에폭시수지의 화학적 분해물의 재이용기술에 관한 예를 소개한다.

• Applied Microscopy
• /
• 제46권4호
• /
• pp.227-237
• /
• 2016

This investigation deals with the process of field electron emission from composite microemitters. Tested emitters consisted of a tungsten or carbon-fiber core, coated with a dielectric material. Two coating materials were used: (1) Clark Electromedical Instruments Epoxylite resin and (2) Epidian 6 Epoxy resin (based on bisphenol A). Various properties of these emitters were measured, including the current-voltage characteristics, which are presented as Fowler-Nordheim plots, and the corresponding electron emission images. A field electron microscope with a tip (cathode) to screen (anode) distance of 10 mm was used to electrically characterize the emitters. Measurements were carried out under ultra-high vacuum conditions with a base pressure of $10^{-6}$ Pascal ($10^{-8}$ mbar).

• Carbon letters
• /
• 제16권4호
• /
• pp.241-246
• /
• 2015

Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, −15°/+15°, −30°/+30°, −45°/+45°, and −90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.

• 한국표면공학회지
• /
• 제46권5호
• /
• pp.223-228
• /
• 2013

In this work, the grow of carbon nanotube (CNT) on carbon fiber was introduced on PAN-based carbon fibers for the enhancement of mechanical interfacial strength of carbon fibers-reinforced composites. The surface properties of carbon fibers were determined by scanning electron microscopy (SEM) and mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS). From the results, it was found that the mechanical interfacial properties of CNT-carbon fibers-reinforced composites (CNT-CFRPs) enhanced with decreasing the CNT content. The excessive CNT content can lead the failure due to the interfacial separation between fibers and matrices in this system. In conclusion, the optimum CNT content on carbon fiber surfaces can be a key factor to determine the mechanical interfacial properties of the CNT-CFRPs.

• 대한기계학회논문집
• /
• 제18권8호
• /
• pp.1930-1938
• /
• 1994

In this paper, the effects of temperature change on the impact of CFRP laminates was experimentally studied. Composite laminates used for this experiment are CFRP orthotropic laminated plates, which have two-interfaces$[0_6^{\circ}/90_7^{\circ}]_s$ and four-interfaces$[0_3^{\circ}/90_6^{\circ}/0_3^{\circ}]_s$. The interrelations between the impact energy vs. delamination area, the impact energy vs. residual bending strength, and the interlayer delamination area vs. the decrease of the residual flexural strength of carbon fiber epoxy composite laminates subjected to FOD(Foreign Object Damage) under high temperatures were experimentally observed.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 추계학술대회 논문집
• /
• pp.111-115
• /
• 2001

The stress and torque transmission capability of the tubular, hexagonal and elliptic single lap joints were analyzed by the finite element method (ANSYS 4.4A) and compared to those with the experimental results. The adherends of the joints were composed of the carbon fiber epoxy composite shafts and the steel shafts. In calculating the torque capability, the linear laminate (smeared) properties of the composite and the nonlinear shear properties of the adhesive were used. The experiments revealed that the torque capability calculation performed by this method gave accurate results.

• 비파괴검사학회지
• /
• 제17권3호
• /
• pp.151-155
• /
• 1997

본 연구에서는 방사성동위원소 $^{241}Am$의 감마선 감쇠를 이용하여 유리섬유 및 탄소섬유 복합적층판의 섬유체적분율을 비파괴적으로 측정하였다. NaI(Tl) detector에 의해 섬유와 기지의 방사선 감쇠계수를 측정하고, 시험체의 두께를 $2{\sim}20mm$로 변화시키면서 섬유체적분율을 측정하였으며, 적층판과 에폭시판을 겹쳐서 섬유체적분율을 변화시키면서 섬유체적분율을 측정하였다. 연구 결과 단면을 현미경으로 관찰하여 구해진 값과 비교 할 때 오차 ${\pm}1{\sim}2.5%$ 범위 이내로 측정이 가능하였으며, 방사선원의 energy, activity의 선택에 따라서 대부분의 복합재료에 적용이 가능할 것으로 판단된다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 추계학술대회 논문집
• /
• pp.1331-1334
• /
• 2004

The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties or from structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites), was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz～12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test showed little shielding effect.

• Corrosion Science and Technology
• /
• 제19권2호
• /
• pp.75-81
• /
• 2020

To reduce structural weight, light metals, including aluminum and magnesium alloys, have been widely used in various industries such as aircraft, transportation and automobiles. Recently, composite materials such as Carbon Fiber Reinforced Plastics (CFRP) and Graphite Epoxy Composite Material (GECM) have also been applied. However, aluminum and its alloys suffer corrosion from various factors, which include aggressive ions, pH, solution temperature and galvanic contact by potential difference. Moreover, carbon fiber in CFRP and GECM is a very efficient cathode, and very noble in the galvanic series. Galvanic contact between carbon fiber composites and metals in electrolytes such as rain or seawater, is highly undesirable. Notwithstanding the potentially dangerous effects of chloride and temperature, there is little research on galvanic corrosion according to chloride concentration and temperature. This work focused on the effects of chloride concentration and solution temperature on AA7075T6. The increased galvanic corrosion between CRFP and AA7075T6 was evaluated by electrochemical experiments, and these effects were elucidated.