Evaluation of offshore wind turbine leading edge protection coating failure mode under rain erosion

Offshore wind turbine blades are exposed to a wide range of environmental and loading conditions during operation. Rain droplet impact is one of the load cases that causes erosion of leading edge protection systems, which can have a detrimental effect on the performance and power output. Therefore, rain erosion is one of the major design considerations for wind turbine blades to improve the durability of leading edge protection coatings for continuous power generation and lower operational and maintenance costs. Rain droplet impact can result in several complex failure modes such as delamination of the interface between the coating and the substrate, which can significantly affect the rain erosion damage rate and the failure mode of leading edge protection. The objective of this work is to perform rain erosion testing on leading edge protection coupons in a whirling arm rain erosion test rig, CT-scan the failed coupons, and perform test correlations to develop numerical models to capture the failure modes. To do so, a single rain droplet FE parametric study will be used in this study to consider various rainfall conditions. In this research, a robust finite element modelling is developed for rain erosion that can capture the leading edge protection failure modes of wind turbine blades. The theoretical and experimental results reported in the literature are found to correlate well with the axisymmetric and 3D finite element models developed in this study. Finally, this baseline work can aid in the modelling of failure modes and analysing different coating designs for the development of more durable leading-edge protection coatings for wind turbine applications.