Crater formation in a glass fiber-reinforced epoxy composite subject to high velocity, small mass impact

The leading edges of helicopter rotor blades are susceptible to high-velocity impact from small particles of a wide variety of materials. In this study, a glass fiber-reinforced epoxy composite was subjected to single impacts from spherical particles at velocities up to Mach 1. Target samples were cut from a 15-layer composite with 3070-style woven E-glass reinforcement. Erosive simulant particles were 1.6 mm in diameter spheres of silicon nitride, 2017 aluminum, hardened 52,100 steel, 260 brass, and 102 copper. In situ images were captured of each impact event, and samples were examined post-mortem with a scanning electron microscope. The crater formation in the target material was observed to follow a two-stage process. The Young’s Modulus of the projectile has a distinct effect on the depth of damage during both stages of material removal, and the yield stress of the projectile places a limit on the extent of damage during the second stage.