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Subject: search.filters.subject.C/C composites

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    Microstructure Characterization and Effective Elastic Properties of Carbon/Carbon Composites
    (Springer Science and Business Media Deutschland GmbH, 2024) Vishnu, O.S.; Pavan, G.S.
    In this research, the effective elastic properties of C/C composites are evaluated using FEA-based homogenization technique. The FEA-based homogenization procedure is carried out by generating a Representative Volume Element (RVE). The features in the microstructure are observed with the help of Scanning Electron Microscopy (SEM) images. A detailed study on the SEM images of C/C composites is carried out. The microstructure of C/C composite consists of carbon fibers and carbon matrix. The details obtained from the microstructure are used to generate the RVE of the C/C composite. Random Sequential Adsorption (RSA) algorithm is employed to insert the carbon fibers inside the RVE model. Periodic boundary conditions are imposed on the RVE model, and six different far-field strains are applied on the RVE. For each case of far-field strains, the effective response of the RVE model is evaluated. The effective elastic properties of C/C composites are obtained by combining the volume-averaged stresses of the RVE for each case of far-field strains. The results from the numerical study are compared with those from the Mori–Tanaka method. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.
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    Micromechanical Analysis of Carbon/Carbon Composites with Pore Characterization
    (Springer Science and Business Media Deutschland GmbH, 2025) Vishnu, O.S.; Paul, J.; Pavan, G.S.
    In this study, the elastic properties of carbon/carbon (C/C) composite are computed by incorporating the presence of pores. Microstructure of C/C composites is analysed using scanning electron microscope (SEM) images. The pores inside the C/C composite are characterized based on area, shape and dimensions. Thirty-six SEM images are analysed. Based on this analysis, a three-dimensional RVE of C/C composite is constructed. The number of pores, their size and spatial distribution in the RVE is given by the analysis. Carbon fibres inside the representative volume element (RVE) are generated using the random sequential adsorption algorithm (RSA). Once the model is generated, periodic boundary conditions are imposed on the RVE model using Python script in Abaqus CAE. Effective elastic properties of C/C composites are computed using the finite element analysis (FEA)-based homogenization method. The effect of pore size distribution on the elastic properties of C/C composite can be understood from this study. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.
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    Effect of fiber weight fraction on mechanical properties of carbon-carbon composites
    (2012) Naik, P.S.; Orangalu, S.A.; Londhe, N.V.
    This article presents the synthesis of carbon-carbon (C/C) composites by preformed yarn (PY) method, by varying the percentage of carbon fiber weight fraction. The PY used was carbon fiber bundle surrounded by coke and pitch which was enclosed in nylon-6. Three types of samples with fiber weight fractions of 30, 40, and 50%, respectively, are fabricated and mechanical properties were studied. In each case, the PY was chopped and filled into a die of required shape and hot pressed at 500°C to get the preform composite. To obtain the carbonized and graphitic structure, the specimen was heat treated at 2500°C followed by soaking for 10 to 12 hrs. Further, two cycles pitch impregnation was done by hot isostatic pressing, to eliminate the voids and to increase the density hence to obtain good mechanical properties. The characteristics such as hardness, flexural strength, and impact strengths were studied. It is observed that, as the carbon fiber percentage increases, the properties also get improved, provided sintering is done at fairly higher temperatures such as 2700°C. The superiority of the new class of C/C composites made by the proposed PY technique over those obtained by the conventional methods is also demonstrated. Copyright © 2012 Society of Plastics Engineers.