Research On Anti-icing And Seismic Performance Of Large Wind Turbines In Conduit Frame Based On Anti-buckling Support

The winter climate in the Bohai Sea is harsh,and the phenomenon of sea water freezing is more serious.Ice load is the main control load for large wind turbines on conduit frames,whose support structures are thin-walled hollow cylindrical steel structures with relatively large lengths,which are susceptible to compression buckling damage under extreme ice loads,thus causing the main structure to suffer greater ice vibration and greatly reducing the service life and safety of offshore wind turbines;To ensure the safety and durability of offshore wind turbine structures,effective vibration control of them is essential.Anti-buckling bracing(BRB)is widely used in building structures because of its full and stable hysteresis curve and its dual role as a general bracing and energy dissipating member.In order to solve the problem that the support bars are prone to buckling under pressure,improve the safety and durability of offshore wind turbines,and reduce the vibration response of the structure under ice loads and earthquakes,we propose a conduit frame wind turbine structure based on anti-buckling support and a new hollow sandwich steel pipe concrete(CFDST)combined conduit frame wind turbine structure based on anti-buckling support,and use ANSYS software to analyze the ice and vibration resistance of the conduit frame wind turbine structure under extreme ice loads and giant earthquakes.The main work conducted in this paper and the findings of the study are as follows:(1)Linear elastic buckling analysis and nonlinear buckling analysis of the conduit frame fan structure were carried out separately using ANSYS finite element software.The results show that when the sea ice interacts with the conduit legs,the second layer of the conduit frame has excessive pressure support deformation and is susceptible to buckling damage when subjected to extreme ice loads,which is the weak layer of the conduit frame fan structure.(2)In response to the problem that common supports are prone to buckling,a conduit frame fan structure based on anti-buckling supports is proposed,and two antibuckling supports are designed according to the support replacement principle.To study the damping effect of replacing different anti-buckling supports for duct frame wind turbine structures under the action of 3 extruded ice loads.The results showed that the highest damping effect of peak displacement and peak acceleration of the structure under extruded ice load reached 28.90% and 31.19%,respectively.(3)Seismic response analysis of the duct frame wind turbine structure based on the anti-buckling support under the action of Tianjin wave,Taft wave and El-Centro wave was conducted to compare and analyze the seismic reduction effect of replacing different anti-buckling supports on the duct frame wind turbine structure.The results show that the replacement of anti-buckling bracing can effectively control the interstory deformation of offshore wind turbines under seismic action.The best damping effect of the peak structural displacement and peak acceleration of the wind turbine structure under the effect of Tianjin,Taft and El-Centro waves were 20.00% and 7.35%,respectively.(4)CFDST replaced the hollow steel duct legs of the wind turbine to form CFDST combined duct frame wind turbine structure(referred to as combined structure),and combined with anti-buckling support to form a new CFDST combined duct frame wind turbine structure based on anti-buckling support(referred to as new combined structure),and used ANSYS software to analyze the vibration damping effect of the two combined structures and their ice resistance performance under extreme ice load.The results show that the new combined structure has the best damping effect under the extreme extruded ice load,and the peak displacement and peak acceleration of the structure are reduced by up to 47.38% and 55.22%,and the maximum equivalent force is reduced by up to more than 22%,and the problem of compression buckling of the support is solved,which greatly improves the safety and reliability of the conduit frame wind turbine structure.(5)Seismic performance analysis of Tianjin,Taft and El-Centro waves under the action of a giant earthquake(peak seismic acceleration of 1000 gal)was performed for the two combined structures.The results show that the maximum values of peak displacement and peak acceleration of the new combined structure are reduced by52.21% and 43.36%,respectively,and the maximum equivalent force is reduced by21.05% under the action of Tianjin wave mega-shock,Taft wave mega-shock and ElCentro wave mega-shock compared with the original duct-frame wind turbine structure,which indicates that the new combined structure can effectively resist the seismic action and can improve the seismic performance of the conduit frame wind turbine structure.