Leading edge erosion of wind turbine blades: Multiaxial critical plane fatigue model of coating degradation under random liquid impacts

A computational model of rain erosion of wind turbine blades is presented. The model is based on the transient fluid-solid coupled finite element (FE) analysis of rain droplet/coating interaction and fatigue degradation analysis. The fatigue analysis of the surface degradation is based on multiaxial fatigue model and critical plane theory. The random rain fields are constructed computationally, and the estimated droplet sizes are included in FE model to acquire a library of load histories. Subsequently, the resulted nonproportional multiaxial high cycle fatigue problem is solved to assess the damage and lifetimes of the coatings. The approach can be used to design new coating systems withstanding longer service times.