In this study, the capability of an existing analysis method for the fluid-structure-soil interaction of an offshore wind turbine is expanded to account for the geometric nonlinearity and sea water drag force. The geometric stiffness is derived to take care of the large displacement due to the deformation of the tower structure and the rotation of the footing foundation utilizing linearized stability analysis theory. Linearizing the term in Morison’s equation concerning the drag force, its effects are considered. The developed analysis method is applied to the earthquake response analysis of a 5 MW offshore wind turbine. Parameters which can influence dynamic behaviors of the system are identified and their significance are examined.

• 김재관(서울대학교 건설환경공학부) | Kim, Jae Kwan Corresponding author
• 진병무(대우건설 기술연구원 토목연구팀) | Jin, Byeong Moo
• 배경태(대우건설 기술연구원 토목연구팀) | Bae, Kyung Tae
• 이진호(한국철도기술연구원 초고속자기부상철도연구단) | Lee, Jin Ho