항공기 인증을 위한 복합재 구조물 설계/해석

Design and Analysis on Composite Structure for Aircraft Certification

  • 투고 : 2008.12.19
  • 심사 : 2009.07.01
  • 발행 : 2009.07.01

초록

복합재 항공기의 경우 인증 시 여러 가지 요소를 고려해야한다. 금속과는 달리 복합재구조물의 감항성은 운용 및 제작 중 발생하는 손상 등에 의해 큰 영향을 받는다. 그러므로 예상 가능한 여러 가지 손상에 대해 정적강도, 강성, 플러터 및 손상허용강도 등을 입증하여 야한다. 복합재료의 기계적물성은 환경조건에 영향을 받는다. 특히 압축강도는 수지의 영향이 지배적이고 수지가 온도와 습도의 영향을 많이 받으므로 설계/해석 시 고려하여야한다. 복합재 항공기의 경우 육안으로 탐지가 어려운 손상에 대한 정적강도를 입증하여야하고, 육안으로 보이는 큰 손상에 대해서는 발견 즉시 수리하도록 규정되어있다. 본 논문에서는 복합재 구조물의 설계/해석에 필요한 규정을 분석하고 해석방법 등에 대해 검토하려한다.

There are a number of factors affecting the continued airworthiness of composite structure. Unlike metal structure, damages made in manufacturing processes or maintenance repair procedures need to be considered. The different levels of degradation and damage, which may occur, must be considered for structural substantiation of static strength, stiffness, flutter, and damage tolerance. This can start with an evaluation of environmental effects for the particular composite material. Matrix-dominated composite properties, such as compressive strength, are most sensitive to moisture absorption and temperatures. Static strength substantiation includes the smaller damages that will not be detected in production or maintenance inspection while damage tolerance addresses larger damages that need to be repaired once discovered. In this paper, we intend to list the airworthiness regulations and advisory circular that are deemed closely related to the certification of composite airplanes.

키워드

참고문헌

  1. FAR Part 23, Airworthiness Standards: normal, utility, acrobatic, and commuter
  2. FAR Part 25, Airworthiness Standards: Transport Category Airplanes
  3. AC20-107A, Composite Aircraft Structures, FAA, 1984
  4. MIL-HDBK-17H, Composite Materials Handbook
  5. AC 25.571, Damage Tolerance and Fatigue Evaluation of Structure
  6. Whitney, J. M. and Nuismer, R. J., "Stress fracture criteria for laminated composites containing stress concentrations," Journal of composite materials, Vol. 8, pp.253-265, 1974 https://doi.org/10.1177/002199837400800303
  7. MIL-A-8867, "Airplane Strength and Rigidity Ground Tests"
  8. Wu, E. M., " Application of fracture mechanics to anisotropic plates," Journal of applied mechanics, pp.967-974, 1967
  9. Poe, Jr., C. C., "A unifying strain criterion for fracture of fiberous composite laminates," Engineering Fracture Mechanics, Vol.17 1983, pp. 153-171. https://doi.org/10.1016/0013-7944(83)90166-2
  10. Mar, J. W. and Lin, K. Y.,"Fracture of boron/aluminum composites with discounties," Journal of Composite Materials, Vol. 11, Oct. 1977, pp
  11. Harris, C. E. and Morris D. H., "Fracture behavior of thick, laminated graphite/epoxy composites," NASA Contractor report 3784