In this paper, the influence of nanoclay on the hail impact damage resistance of glass fibre/epoxy composites under single and repeated high-velocity hail impact has been investigated. The damage extension was investigated to gain insight into the damage behaviors of the composite materials in the presence of nanoclay. Nanocomposite specimens containing nanoclay in 0, 0.5, 1.5 and 3 (wt%) were prepared by liquid-state mixing method using a high shear homogenizer. X-ray diffraction and transmission electron microscopy analysis confirmed intercalation and exfoliation of the nanoclay in the epoxy resin matrix used. Woven roving fabric with AE45 stacking sequence showed highest resistance to damage for composite laminates under high-velocity hail impact. Glass fiber/epoxy containing nanoclay resulted in smaller damage area and higher strength. The existence of nanoclay in the epoxy matrix induced the transition of failure mechanisms of glass fiber/epoxy laminates during the high-velocity hail impact test. Addition of 1.5wt% clay proved to be an optimized value with the highest damage resistance.

The impact strength, energy absorption, and failure modes of hybrid sandwich panels with corrugated aluminum core and laminated composite face-sheets are investigated. Numerical simulation of hail impact of hybrid sandwich panels is presented using LS-DYNA software. The effects of hail projectile shape, face-sheet stacking sequences, and reinforcement type on the impact response of sandwich panels are investigated. The standard test specimens of the composite face-sheets are manufactured and experimentally evaluated to obtain required mechanical properties of the lamina for hail impact simulation. The results presented herein revealed that [Formula: see text] laminated composite face-sheets achieved the lowest damage. The hail projectile with sharper nose created higher damage on hybrid sandwich panels. The glass/epoxy face-sheets of corrugated core hybrid sandwich panel presented a significant improvement in impact response and failure modes compare to carbon/epoxy.

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