| China has a wide sea area,and there is abundant wind energy that can be developed and utilized in the offshore waters.However,the seas close to the north will be freeze in winter due to the influence of cold air,such as the Bohai Sea,and sea ice will drift under the influence of environmental factors such as wind and currents.The upper equipment such as the tower,blades and nacelle of the wind turbine will be subjected to wind load,and the supporting structure will be scoured by sea ice,so it is very important to evaluate the fatigue life of the wind turbine foundation support structure.This paper takes a2.5MW offshore wind turbine in the Bohai Sea as an example,and uses the time-domain fatigue calculation method and the damage combination method to calculate the fatigue damage of the support structure.The main research contents are as follows:(1)According to the size parameters of the test to establish a T-shaped tube node model by the ANSYS software,divide different mesh sizes and calculate the structural stress and stress concentration factor at the fatigue hot spot according to the Verity method proposed by Dong,and compare it with the interpolation method,C203 formula method and the test value.compare the master S-N curve,the test fitting S-N curve and the T curve to find that which is the appropriate S-N curve.(2)Use the Bladed software to calculate the wind load at the top of the wind turbine tower,and use the Ice Floe software to calculate the ice load on the ice surface of the wind turbine support structure.(3)Establish a finite element model of the wind turbine structure for modal analysis and damping calculations,respectively perform transient dynamic analysis under three conditions of wind load,ice load and the combined action of wind and ice loads,and analyze the maximum principal stress of the node at the fatigue check position.(4)Calculate the structural stress of the wind turbine under the above three time domain loading methods according to the Verity method,and then calculate the fatigue damage according to the time domain method.Use the fatigue damage under the combined action of wind and ice as the benchmark,calculate the fatigue damage of the wind turbine structure according to different damage combination methods,Compare the fatigue damage obtained by different methods with the benchmark,and then evaluate the appropriate damage combination method. |
