The behavior of helicopter brownout endangers flight safety, induces rotor blade erosion, and reduces its performance. An analyzed method of helicopter blade erosion in brownout condition is then proposed. In this method, variations of the sand cloud are simulated by a helicopter brownout model based on a viscous vortex particle method and a discrete element method, a collision and erosion models between blade and sand cloud are coupled, and the characteristics of blade erosion with high velocity is also considered. It compares with experimental data of plane erosion with different impact velocities, impact angles, and materials, including stainless steel (SS304), nickel, titanium (Ti-6Al-4V), glass fiber reinforced epoxy (CF/EP), bidirectional carbon fiber reinforced epoxy (GF/EP), and polyurethane (PU), to validate the method. The characteristics of blade erosion for the EH-60L helicopter in brownout condition is then analyzed, and the influence of flight speed on the blade erosion is also investigated. The results show that the predicted erosion rate by the present method agrees well with the experiment. As time increases, the collision between the blade and the sand cloud, the blade erosion, and the rotor erosion zone significantly increases in helicopter brownout condition. Furthermore, the erosion in blade tip is obvious worse than inner blade due to the longer time period, larger impact velocity and angle. Additionally, the blade erosion and the rotor erosion zone increase firstly and then reduce with increasing flight speed.
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