Experimental investigation into glass fiber/epoxy composite laminates subjected to single and repeated high-velocity impacts of ice

Many engineering components in aerospace structures which are made from polymer composite materials are often damaged during service life due to hail ice and bird impact. This study examines the damage which may be incurred by a single and repeated high-velocity impact of 11.7 g cylindrical-shaped ice on glass fiber/epoxy laminated composite panels carried out on a 20-mm diameter smooth barrel gas gun. The laminates were made from E-glass fiber/epoxy resin with 0/90, +/-45, chopped strand mat (CSM) and unidirectional fiber orientation and in different stacking sequence. The impact velocity was in the range of 130-140 m/s and the resulting damage extension zones from ice projectile impacts were measured. Damage extension was successfully identified in all specimens subjected to high-velocity ice projectile impact. Results showed specimens with +/-45 orientation and CSM fiber exhibited the lowest damage extension. The results also revealed that specimens with plain weave 0/90 lay-up of glass woven roving show the highest damage extension. Extended damages were observed in composite panels under repeated ice projectile impacts. Study of the stacking sequence effect indicated significant role played by presence of +/-45 reinforcement in reducing the damage extension in the laminated plates. Delamination constituted the major damage mechanism for most specimens tested followed by matrix and fiber fracture.