Development of a Hailstone Subtitute for Representative Impact Tests 2019-01-1942
Hailstone impacts still cause millions of dollars in airplane damages. Aircraft manufacturers have to study the effects of hail impacts on aeronautical structures. These studies are mainly conducted through impact experiments. The simulated hail used is often manufactured following an ASTM standard. The manufacturing protocol consists in reinforcing the ice by adding cotton in the water before the freezing process. Several impact tests performed in Thiot-Ingénierie Shock Physics laboratory have shown that the behaviour of this specific ice turn out to be not sufficiently realistic to correctly predict the damages caused to the tested structures. In addition, the mechanical behaviour of hailstone is not well studied and documented especially due to their complex microstructures and the difficulty to collect natural samples. Most studies are in reality conducted on either single crystals or polycrystalline ices. There is a consistent need in understanding the microstructure of real hail in order to develop an artificial ice with adapted microstructure whose behaviour is similar to real hailstone. Consequently, the behaviour of real hailstone has to be characterized through high strain rate dynamic testing. The work presented in this paper was initiated following these observations. It proposes an original approach to understand the impact behaviour of hail. The goal of this work is to develop a new ice, the behaviour of which is close enough to real hail.
International Conference on Icing of Aircraft, Engines, and Structures