Journal of Aerospace System Engineering (항공우주시스템공학회지)

The Society for Aerospace System Engineering (항공우주시스템공학회)
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Optimal Design and Verification Studies on Orthogrid-Stiffened Cylinders Incorporating Improved Buckling Knockdown Factors

개선된 좌굴 설계 기준을 이용한 직교 격자 원통 구조의 최적 구조 설계 및 검증 연구

  • Chang-Hoon Sim (Department of Aerospace Engineering, Chungnam National University) ;
  • Jae-Sang Park (Department of Aerospace Engineering, Chungnam National University)
  • 심창훈 (충남대학교 항공우주공학과) ;
  • 박재상 (충남대학교 항공우주공학과)
  • Received : 2024.06.11
  • Accepted : 2024.08.14
  • Published : 2024.10.31
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Abstract

Optimal design and verification studies were performed on an orthogrid-stiffened cylinder for a propellant tank of a space launch vehicle. Hypersizer, an optimal design code for aerospace structures, was used in the present optimal design study. Design optimization was conducted to minimize structural weight of the orthogrid-stiffened cylinder. In this study, KDFs with different values (0.40, 0.83, and 0.92) were considered for the design optimization. Three optimal cylinders were designed. As the KDF increased from 0.40 to 0.83 and 0.92, structural weights of optimal design models decreased by 27.70% and 30.08%, respectively. Postbuckling analysis was conducted using ABAQUS. Results showed that global buckling loads of those optimally designed models were higher than the design load. Global buckling loads of those optimal design models with initial imperfection were derived to be at least 1.64% higher than the design load (2,860 kN). Results of this study demonstrated that the optimal design satisfying the design load was appropriately conducted.

우주 발사체의 추진제 탱크 구조인 직교 격자 원통 구조에 대한 최적 설계 및 검증 연구를 수행하였다. 항공우주 구조의 최적 설계 코드인 Hypersizer가 최적 설계 연구에 사용되었으며, 직교 격자 원통의 구조 중량 최소화를 위한 최적 설계가 수행되었다. 본 연구에서는 서로 다른 값의 KDF (0.40, 0.83, 및 0.92)를 최적 설계에 적용하였고, 이를 통해 3개의 최적 설계 모델이 각각 설계되었다. KDF가 0.40에서 0.83 및 0.92로 증가함에 따라, 직교 격자 원통 구조의 구조 중량이 각각 27.70% 및 30.08% 감소하였다. 이후, ABAQUS의 비선형 후좌굴 해석을 이용하여, 설계 하중 보다 높은 전역 좌굴 하중을 갖는 최적 설계 모델이 구축되었는지 확인하기 위한 검증 연구를 수행하였다. 기하학적 초기 결함은 갖는 최적 설계 모델의 전역 좌굴 하중이 설계 하중 (2,860 kN)에 비해 최소 1.64% 높게 도출되어, 설계 하중을 만족시키는 최적 설계가 적절히 수행됨을 확인하였다.

Keywords

Acknowledgement

본 논문의 일부는 2024년도 한국항공우주학회 우주학술대회에서 발표되었습니다. 이 연구는 충남대학교(교육·연구 및 학생지도비)에 의해 지원되었음.

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