Study of bolt fatigue strength for tower of Hawt based on Schmidt-Neuper algorithm

In order to realize fatigue-resisting design for flange bolts in the tower of large-scale horizontal axis wind turbines(HAWT), the fatigue strength check method was presented based on Schmidt-Neuper model. According to the stiffness distribution ratio of the single fan flange system, a nonlinear relationship between bolt load and external pull was established. The timing stresses of the bolts were obtained through the linear interpolation of load. The damage distribution of fatigue accumulation of bolts on the whole ring was calculated based on rain flow counting and accumulated damage calculation. Furthermore, the position of the maximum fatigue cumulative damage was found. The effect of some parameters such as bolt preload, number of bolts and flange thickness on the maximum cumulative damage was analyzed. The results showed that the method and procedure are feasible and effective in the fatigue strength analysis for tower bolts.