Residual Strength Modeling and Reliability Analysis of Wind Turbine Gear under Different Random Loadings

Abstract

A novel method is proposed to investigate the pattern of variation in the residual strength and reliability of wind turbine gear. First, the interaction between loads and the effect of the loading sequence is considered based on the fatigue damage accumulation theory, and a residual strength degradation model with few parameters is established. Experimental data from two materials are used to verify the predictive performance of the proposed model. Secondly, the modeling and simulation of the wind turbine gear is conducted to analyze the types of fatigue failures and obtain their fatigue life curves. Due to the randomness of the load on the gear, the rain flow counting method and the Goodman method are employed. Thirdly, considering the seasonal variation of load, the decreasing trend of gear fatigue strength under multistage random load is calculated. Finally, the dynamic failure rate and reliability of gear fatigue failure under multistage random loads are analyzed. The results demonstrate that the randomness of residual strength increases with increasing service time. The seasonality of load causes fluctuations in the reliability of gear, providing a new idea for evaluating the reliability of the wind turbine gear.

Dynamic Behavior of a 10 MW Floating Wind Turbine Concrete Platform under Harsh Conditions

“…Based on the aforementioned structural analysis results, for the environmental loads with θ = 0 • , ψ = 0 • state, the stress state of the floating platform reaches its extreme value, compared with other working conditions. Considering the fact that fatigue failure mainly occurs in areas with high localized stress in the structure [41,42], the loading condition with θ = 0 • , ψ = 0 • is taken into consideration during the fatigue life analysis of the floating platform in this study. With the static structural analysis results, the time series loading spectrum obtained in Section 5.2 (shown in Figure 19) is applied to the floating platform.…”