Measurement and modeling of supersonic hailstone impacts

Hailstone impacts can be detrimental to the lightweight structures of aerofoils - from ground-based wind turbine blades to supersonic aircraft wings. Hailstone impacts have been studied and modeled in recent years but the work has not yet reached a higher-velocity regime that is relevant to many current applications. We have pushed higher into this regime with new approaches in both modeling and experimental measurement of hailstone impacts. The impulses of hailstone impacts on a flat plate were measured up through supersonic velocities and over a range of impact angles using the Sum of Weighted Accelerations Technique (SWAT) developed at Sandia National Laboratories. These results are compared with the impulses predicted by finite element simulations that improve upon existing material models from literature. The result of this work is a hailstone impact model, calibrated by experiments, that is capable of capturing the impulses imparted on structures by hailstones traveling up to supersonic velocities and impacting over a range of angles.