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Compressive Fracture Behavior of ATJ Graphite for Rocket Nozzle

로켓 노즐목에 이용되는 ATJ 그라파이트 압축거동 평가

  • Choi, Hoon Seok (Dept. of Mechanical Design Engineering, Chungnam Nat'l Univ.) ;
  • Seo, Bo Hwi (Dept. of Mechanical Design Engineering, Chungnam Nat'l Univ.) ;
  • Kim, Jae Hoon (Dept. of Mechanical Design Engineering, Chungnam Nat'l Univ.) ;
  • Moon, Soon Il (Propulsive group, Agency for Defense Development)
  • 최훈석 (충남대학교 기계설계공학과) ;
  • 서보휘 (충남대학교 기계설계공학과) ;
  • 김재훈 (충남대학교 기계설계공학과) ;
  • 문순일 (국방과학연구소)
  • Received : 2014.04.01
  • Accepted : 2014.09.10
  • Published : 2014.12.01

Abstract

The effects of the specimen size and temperature on the compressive strength of ATJ graphite were investigated. Compressive tests were conducted in accordance with ASTM C 965 at room temperature, $700^{\circ}C$ and $900^{\circ}C$. Three types of cylindrical specimen at room temperature were used in uniaxial tests, where the diameter-to - length ratios were one to two for the ASTM standard specimen, one to one for the Type I specimen, and one to 0.5 for the Type II specimen. Two kinds of cylindrical specimens, with and without antioxidant coating, were tested at elevated temperature. The Compressive strength of the expanded specimens(Type I, II) were slightly higher than that of standard specimen at room temperature. The compressive strength of a specimen with antioxidant coating increased as the temperature increased to $900^{\circ}C$. In contrast, that of the non-coated specimen decreases sharply due to the oxidation of the specimen.

Keywords

ATJ Graphite;Uniaxial Compression;Compressive Strength;Size Effect;Antioxidant

References

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