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Author: search.filters.author.Sunil Kumar, B.V.S.Subject: search.filters.subject.(a/w) ratio

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    Experimental investigation on Mode-I fracture toughness of Carbon-Carbon composites fabricated by preformed yarn method
    (Elsevier Ltd, 2021) Sunil Kumar, B.V.S.; Neelakantha Londe, V.; Lokesha, M.; Anilas, M.; Surendranathan, A.O.
    Carbon-Carbon composites are one such material that gives designers significant importance for advanced applications over conventional materials. They are applied in applications at very high temperatures (up to 3000°C), and under extreme conditions. They have a density which is much less than metals and ceramics and thus, make low part weight a significant factor for aerospace applications. Fracturing toughness is a measurable way to express a substance's resistance to fracture in the case of a break. This paper describes the experimental studies done to investigate the Mode-1 fracture toughness of carbon-carbon composites which was fabricated via the preformed yarn method. Fracture toughness was determined for four different (a/w) ratios i.e. 0.45, 0.47, 0.50 and 0.52 respectively. The results showed that with only two cycles of pitch impregnation, HIP and graphitizing, carbon-carbon composites were successfully produced. The specimen having an (a/w) ratio of 0.45 had a higher fracture toughness value in comparison with all values. As the (a/w) ratio was increasing, the fracture toughness value decreased and the fractured surface clearly shows a brittle fracture behavior. © 2021 Elsevier Ltd. All rights reserved.
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    Influence of Precracking Techniques on Fracture Toughness of Carbon-Carbon Composites
    (Penerbit UTHM, 2021) Sunil Kumar, B.V.S.; Neelakantha, N.V.; Lokesha, M.; Surendranathan, A.O.
    Abstract: Carbon-Carbon composites are one such material which give designers significant importance for advanced applications over conventional materials. The remarkable characteristics of carbon-carbon composites had made these products initially extremely useful in the field of aerospace and defense applications. Now, they are presently used in many applications such as biomedical implants, glass, and high temperature glass, etc. In material science, fracture toughness is a trait that depicts the ability of a material to withstand fractures and is one of the most important features in many design applications of any material. A precracked specimen is a sample that is used to accurately assess the distribution of cracks and it is a favored method. This paper describes a comparison of four precracking techniques for carbon-carbon composites using SENB specimen. The potential implications of these techniques on fracture toughness values have been evaluated. The outcome of this work indicates that precracking with a jewel saw is recommended over the other techniques. © 2021. UTHM Publisher. All rights reserved.