Mapping hail meteorological observations for prediction of erosion in wind turbines

Wind turbines can be subject to a wide range of environmental conditions during a life span that could conceivably extend beyond 20 years. Hailstone impact is thought to be a key factor in the leading edge erosion and damage of the composite materials of wind turbine blades. Using UK meteorological data, this paper demonstrates that the rotational speed is a crucial factor in determining the magnitude of the kinetic energy associated with singular impact and is likely to be significant for incidents of hail. An improved representation of hail characteristics, occurrence probabilities and realistic impact component velocities is also proposed, from which the prospect of individual impact by large hailstones is found to be very scarce. Instead, the damage posed by multiple impacts throughout wind turbine operation is assessed. The annual average cumulative impact energy for a high frequency of hail case study is determined and evaluated against example composite failure threshold energies in the literature.