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Fatigue Life Evaluation of Fiber Reinforced Composite Rotor Blades Considering Impact Damages

충격손상을 고려한 섬유강화 복합재 로터 블레이드의 피로수명 평가

  • Kee, Young-Jung (Korea Aerospace Research Institute, Aeronautics Research Directorate) ;
  • Park, Jae-Hun (Korea Aerospace Research Institute, Aeronautics Research Directorate) ;
  • Kim, Sung-Man (Korea Aerospace Industries, LTD., LAH Program Division) ;
  • Kim, Gi-Hun (Korea Testing Laboratory, Aviation Technology Center)
  • 기영중 (한국항공우주연구원 항공연구소) ;
  • 박재훈 (한국항공우주연구원 항공연구소) ;
  • 김성만 (한국항공우주산업(주) 소형무장헬기 사업본부) ;
  • 김지훈 (한국산업기술시험원 항공기술센터)
  • Received : 2020.03.05
  • Accepted : 2020.03.27
  • Published : 2020.03.31

Abstract

Composite rotor blades for rotorcraft have an intrinsic vulnerability to foreign object impact from its inherent structural characteristics of insufficient strength in the thickness direction, which may easily lead to internal structure damage. Therefore, defects and strength reducing effects caused by foreign object impact should be considered in fatigue evaluation of composite blades. For this purpose, the flaw tolerant safe-life and fail-safe concepts were adopted in fatigue evaluation since 1980s, and recently those concepts have been replaced by the damage tolerance concept. In this paper, the relevant standards for fatigue evaluation are analyzed focusing on fiber reinforced composite rotor blades used in rotorcraft. In addition, fatigue evaluation procedure of composite blades considering impact damages is proposed by reviewing the practices implemented through domestic development projects.

복합재 헬리콥터 로터 블레이드는 두께방향으로의 강도가 부족한 구조적인 특성으로 인해 외부 물체의 충돌에 의해 내부 구조물에 손상이 발생하기 쉬운 단점을 지니고 있다. 따라서 복합재 블레이드의 피로 평가 시 외부 물체의 충돌에 의해 발생하는 결함과 강도저하 현상을 함께 고려해야 한다. 이를 위해 내결함 안전 수명(flaw tolerant safe-life) 및 파손안전(fail-safe) 개념을 이용한 피로평가 방안이 1980년대부터 적용되었으며, 최근에는 회전익 항공기의 감항기준에 위의 두 개념이 손상허용(damage tolerance) 평가 방안으로 대체되었다. 본 논문에서는 회전익 항공기에 사용되는 섬유강화 복합재 로터 블레이드를 중심으로 피로수명을 평가하기 위한 관련규정을 분석하고, 국내 헬기 개발사업 등을 통해 적용된 사례들을 검토함으로써 충격손상을 고려한 섬유강화 복합재 로터 블레이드의 피로 평가 방안을 제시하였다.

Keywords

References

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