Comparison of 2D and 3D carbon/carbon composites with respect to damage and fracture resistance

Aly-Hassan, Mohamed S.; Hatta, Hiroshi; Wakayama, Shuichi; Watanabe, Mitsuhiro; Miyagawa, Kiyoshi

doi:10.1016/s0008-6223(02)00442-6

Cited by 99 publications

(45 citation statements)

References 23 publications

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“…Medidas de módulo elástico obtidas por Hassan et al [14], mostram valores de 60-65 GPa, em compósitos CRFC 2D com 48%/volume de fibras de carbono. Como os compósitos CRFC uni-direcionais apresentam uma fração em volume de fibras de carbono de cerca de 60%/volume é necessário mensurar as frações volumétricas de fibras nas direções correspondentes das varetas nas preformas que serão objeto de avaliação no trabalho.…”

Section: Resultados Da Rigidez Média Para Compósitos 3d E 4dunclassified

Predição das propriedades elásticas de compósitos termoestruturais com reforço multidirecional

Ribeiro¹,

Gregori²,

Pardini³

2008

Matéria (Rio J.)

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RESUMOOs compósitos são uma classe de materiais que apresentam propriedades superlativas em relação aos materiais isotrópicos (metais, cerâmicos, polímeros), se considerarmos sua alta resistência aliada ao baixo peso. O reforço, a matriz e a interface entre ambos, definem o desempenho do componente em serviço e a temperatura de trabalho destes materiais. Particularmente, compósitos de uso a temperaturas superiores à 1000 o C são denominados de compósitos termoestruturais. Estes materiais suportam demandas termomecânicas significativas, sendo utilizados em gargantas de tubeira de foguetes, proteções térmicas reirradiativas e materiais de fricção. Via de regra, esses materiais são manufaturados mediante a utilização de preformas fibrosas, que nada mais são que um "esqueleto" de reforço que translada resistência e rigidez ao material. A utilização de preformas permite a concepção e obtenção de componentes com geometrias complexas e dimensões as mais diversas, permitindo assim uma flexibilidade no projeto do componente a ser obtido. Embora apresentem virtudes incontestáveis, o custo desses materiais ainda é proibitivo para aplicações rotineiras. Também o custo dos testes mecânicos que validem suas propriedades em relação aos materiais de uso convencional torna-se oneroso, além de demandar equipamentos especiais. O presente trabalho aborda a predição das propriedades elásticas de compósitos termoestruturais de Carbono Reforçado com Fibras de Carbono (CRFC), com configurações de reforço tri-direcional (3D) e tetra-direcional (4D). As propriedades foram calculadas à temperatura ambiente para efeito de comparação ao grafite sintético, ainda utilizado em gargantas de tubeira de motores foguete de pequeno porte. Os cálculos de predição de propriedades elásticas foram baseados no método de homogeneização considerando a hipótese de mechas de fibras retas pela rigidez média ponderada. Palavras chaves:Compósitos termoestruturais, compósitos carbono/carbono, propriedades elásticas, micromecânica de materiais ortotrópicos.Prediction of elastic properties of thermo structural composites with multidirectional reinforcement. ABSTRACTComposites are a class of materials which have superlative properties in relation to the isotropic materials (metals, ceramics and polymers) if one can look to a combination of high resistance and low weight. The reinforcement fibers, the matrix and the interface between them define the performance and the maximum temperature of the component in service. Composites designed to work under temperatures higher than 1000°C are called thermo-structural composites. Because of their high thermal shock resistance, these materials are used in critical applications such as kick motor nozzles, thermal protections for re-entry ablative and reradiative systems and aircraft brakes. They are usually made by using preforms, that are assembled rods forming a "skeleton" that translates rigidity and strength to the material. The use of preform technology allows an enormous variety of complex geometries and dimensions, wh...

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Section: Resultados Da Rigidez Média Para Compósitos 3d E 4dunclassified

Predição das propriedades elásticas de compósitos termoestruturais com reforço multidirecional

Ribeiro¹,

Gregori²,

Pardini³

2008

Matéria (Rio J.)

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“…The transverse crack is defined as a thin gap in fiber bundles and is generated by separating bundles during manufacturing due to the difference in the shrinkage rate between fibers and matrixes. 24,25) Table 3 also gives the number of transverse cracks of directions perpendicular and parallel to the lamina from the image analysis of Fig. 3.…”

Section: Microstructural Observation By X-ray Tomographymentioning

confidence: 99%

Investigation of Microstructural Change by X-ray Tomography and Anisotropic Effect on Thermal Property of Thermally Oxidized 2D-C/C Composite for Very High Temperature Reactor

Sumita

Shibata

Kunimoto³

et al. 2010

Journal of Nuclear Science and Technology

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Two-dimensional carbon fiber reinforced carbon composite (2D-C/C composite) is one of the candidate materials for reactor internals, e.g., control rod element, of Very High Temperature Reactor (VHTR) because of its high strength at high temperature and thermal stability. From the viewpoint of its application to the reactor internals of the VHTR, it is important to investigate the anisotropic effect on its properties for the design and safety analysis of the VHTR. Since the properties of the 2D-C/C composite are strongly dependent on its microstructure, it is necessary to observe its microstructural variations to correlate to the changes in its properties. This study has shown that X-ray tomography can be applied to observe the internal microstructural change of the thermally oxidized 2D-C/C composite. The relationship between the change in properties, including the thermal conductivity, coefficient of thermal expansion (CTE), and burn-off of the thermally oxidized 2D-C/C composite, can be expressed using the empirical exponential decay formula in both directions perpendicular and parallel to the lamina. The direction of the hexagonal graphite crystal structure from the carbon atoms and the microstructure of the 2D-C/C composite can explain not only the relationship between changes in the thermal conductivity, CTE, and burn-off but also the difference in the changes in the thermal conductivity and CTE between fiber directions.

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“…(Schmidt et al 1998;Blanco et al 2000). However, the conventional techniques of preparing C-C composites are complicated, expensive and time-consuming, such as liquid phase impregnation and chemical vapour deposition, which are indispensable for obtaining high-performance C-C composite materials (Aly-Hasan et al 2003). In these techniques, carbon matrices are derived from either pitches, polymeric resin, or chemical vapour infiltration (Li 2001); both processes take long fabrication time and have high production costs.…”

Section: Introductionmentioning

confidence: 99%

Strengthening of semicoke based carbon composites through multi-wall carbon nanotubes

2013

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The present investigation explored the possibility of developing carbon composites using semicoke as matrix precursor and multi-walled carbon nanotubes (MWCNTs) as reinforcement. The different weight fraction of MWCNTs was incorporated in semicoke-based composites, and these composites were heat treated at 1,000, 1,400 and 2,500°C. The MWCNTs carbon composite was characterized for electrical, thermal and mechanical properties. It was observed that the bulk density of composites with 1 wt% of MWCNTs was 1.92 g/cc, whereas without nanotubes it was 1.87 g/cc. The bending strength of carbonized composites was increased by 78 % and that of graphitized ones by 69 % at 1 wt% of MWCNTs. This value of bending strength was three times higher than that of conventional graphite. The electrical and thermal conductivity increased by 12 and 33 %, respectively. The Raman spectroscopic studies showed that intensity ratio of D and G band (ID)/(IG) ratio minimum deflects the lower level of defects and higher degree of graphitization in carbon composites at 1 wt% of MWCNTs. This demonstrates that in case of MWCNTs, semicoke-based carbon composites with 1 wt% of MWCNTs were sufficient for strengthening carbon composites, if MWCNTs were well dispersed in semicoke.

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Comparison of 2D and 3D carbon/carbon composites with respect to damage and fracture resistance

Cited by 99 publications

References 23 publications

Predição das propriedades elásticas de compósitos termoestruturais com reforço multidirecional

Predição das propriedades elásticas de compósitos termoestruturais com reforço multidirecional

Investigation of Microstructural Change by X-ray Tomography and Anisotropic Effect on Thermal Property of Thermally Oxidized 2D-C/C Composite for Very High Temperature Reactor

Strengthening of semicoke based carbon composites through multi-wall carbon nanotubes

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