All structures can not be perfect due to geometric or material initial imperfections. Initial imperfections are an important factor in determining the buckling mode and are known to be important factors in evaluating the actual buckling strength. The DNV-RP-C202 design standard limits the longitudinal stiffener spacing. However, the criteria for the stiffener spacing presented in DNV-RP-C202 is a guideline derived from the curved panel theory of perfect cross-sectional shape without initial imperfections. In this study, considering geometric initial imperfections, the transition point of stiffener spacing where longitudinal stiffeners affect the buckling strength of reinforced steel wind turbine tower is analyzed using finite element analysis program. The results of finite element analysis compared with theoretical results based on the perfect shape. As a result, a more reasonable stiffener spacing considering the initial imperfections was suggested.

ABSTRACT
 1. 서 론
 2. 탄성좌굴 방정식 및 DNV 설계기준 분석
  2.1 Equilibrium Equation for Cylindrical Shells
  2.2 DNV-RP-C202 Buckling Strength of Shells
 3. 유한요소 해석 및 분석
  2.1 Curved Panel
  3.2 Stiffened Cylinder
 4. 결 론
 References

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• 김승준(대전대학교 건설안전방재공학과) | Kim Seungjun
• 한상윤(고려대학교 초대형구조기술연구소) | Han Sang-Yun