Reliability-based design of wind-turbine rotor blades against failure in ultimate loading

摘要

A probabilistic model of analysis of the safety of a wind-turbine rotor blade against failure in ultimate loading is presented. Only failure in flapwise bending during the noraml operating condtion of the wind turbine is considered. The model is based on an extreme-value analysis of the load response process in conjunction with a stochastic representation of the ogverning ensile strength of the rotor balde materal. The model is applied to an analysis of the reliability of a site-specific wind turbine of a prescribed make. A 20 yr design life is considered. The probability of failure in flapwise bending of the rotor balde is calculated by means of a first-order reliability method, and contributions to this probability from all local maxima of the load response process over the operational life are integrated. It is demonstrated how the reliabilty analysis results can be used to calibrate partial safety factors for load and resistnace for use in conventional deterministic desgin.