Effect of Intra-Ply Hybrid Patches and Hydrothermal Aging on Local Bending Response of Repaired GFRP Composite Laminates

This study investigates the influence of intra-ply hybrid patches and hydrothermal aging on the indentation properties of patch repaired GFRP composites. Fabrics with various proportions of glass and Kevlar fibers were employed as the patches to achieve enhanced mechanical properties by hybridizing Kevlar and glass fibers together. Hydrothermal aging behavior of repaired composite laminates modified with water-resistant glass fibers in the outer layers was further investigated. Specimens were immersed in an environmental chamber containing seawater at temperatures of 30 (ambient), 50, and 70 °C until up to saturation. Damage mechanisms of repaired laminates were monitored using real-time acoustic emission (AE) technique. The experimental results showed that specimens repaired with 50G:50K patches offered superior performance than the virgin specimens. The hydrothermal aging effect on indentation behavior of the modified repaired specimens showed a considerable reduction in indentation properties, with higher strength retention exhibited by the repaired specimens modified with chopped glass fibers compared to the particulate fibers.