Restoring Mechanical Properties of Impact-Damaged Woven Glass Fiber-Reinforced Composites by Polymer Cold Spray Repair

Abstract This work investigates the applicability of polymer cold spray as a fast and efficient process for repairing impact damage in glass fiber-reinforced composites. Controlled projectile impacts applied by a gas gun instrument are first used to generate varying damage morphologies and depths in woven glass fiber-reinforced composites. The damaged areas are then repaired using two different thermosetting powders applied via cold spray, followed by short post-curing cycles. The thermosetting powders include a polyester-based and an epoxy-based powder reinforced with chopped glass fibers. Differences between the various repair methods are discussed in terms of their effectiveness in restoring lost properties and the apparent adhesion of the repair material to the composite substrate. Moreover, the efficacy of cold spray repair in restoring flexural strength due to impact is quantified for both feedstocks and compared to the conventional resin repair method. Results show that the thermosetting cold spray feedstock can restore up to 80% of the lost properties in cases of shallow impact damage and up to 40% for more severe, deeper damage. Regardless of damage severity and the type of feedstock, cold spray repair processes outperformed conventional resin repair in both efficacy and speed.