Abstract: During the operation of wind turbine generator blade, the time-domain load is constantly changing. It is the key to evaluate the fatigue life of the blade to convert the time-domain load into the equal life test load which can be loaded under the test conditions. Taking a certain type of wind turbine blade as the research object, the time-domain load of the blade in the life cycle was calculated by Bladed, and then it was converted into Markov matrix load with different amplitudes under different average values by rain flow counting method. Then the load of each section was converted into equivalent load without considering the average load. However, this method, which do not consider the influence of mean load on the fatigue life of composite materials, will lead to great error. In view of this, an equivalent conversion method considering the mean load was proposed to convert the load of each section into the equivalent load. Finally, the fatigue test scheme of the blade, which is more in line with the actual situation of the wind field and can better assess the fatigue performance of the blade structure, was designed.

Key words: wind turbine generator blade, equivalent conversion, fatigue load, composites