TY - JOUR T1 - Numerical investigation of structural behavior of fixed offshore wind turbines with CFDST sections based on hybrid monopile-footing foundation TT - مطالعه عددی بررسی رفتار سازه‌ای توربین‌های بادی ثابت فراساحلی دارای مقاطع مرکب فولاد و بتن متکی بر فونداسیون هایبریدی مونوپایل-پی سطحی JF - Marine-Engineering JO - Marine-Engineering VL - 18 IS - 35 UR - http://marine-eng.ir/article-1-933-en.html Y1 - 2022 SP - 47 EP - 59 KW - Offshore wind turbine KW - Hybrid foundation KW - CFDST sections KW - Finite element analysis N2 - Offshore wind energy is one of the main sources of renewable energy, which has led to the increasing expansion of offshore wind farms worldwide.One of the major challenges for offshore wind projects is the cost of construction of the foundation, which, depending on the location and type of wind turbine, accounts for about 16 to 34% of the total cost.Therefore, proper design of foundations is very important to ensure the performance of offshore wind turbines.The foundation proposed in this research includes a hybrid monopile-footing foundation in which CFDST sections have been used in monopile instead of conventional steel sections.Dynamic analysis of the foundation under environmental loads has been performed using finite element method by ABAQUS software. The results show that the use of CFDST sections, in addition to being able to reduce the diameter of the monopile, add a circular footing to the monopile, creates more lateral stiffness for the monopile at mud level and also reduces its lateral displacement.Also, by comparing the natural frequencies of wind turbines based on the proposed foundation, it was found that these structures are within the allowable frequency range and do not pose a risk of resonance. M3 ER -