Evaluation of Adhesively Bonded Repair and Scarf-Type Infused Repair of Impact Damaged Fiber Reinforced Composites

Abstract

The high specific stiffness and strength offered by composite materials has allowed significant adoption of these materials in aeronautic, automotive, naval, defense industries and construction sectors to substitute conventional materials such as steel, aluminum and other alloy materials. In transport sectors, specifically in aeronautical, automotive and marine, in which low velocity impacts are frequent, composite repair technologies have attracted much attention. Recently, various repair techniques have been developed to rehabilitate the damaged composite structures. Experimental and numerical studies to investigate the influence of different parameters on the strain-stress distribution, failure mode, ultimate strength, and stress concentration factor of repaired composite structures have been recently reported. In this paper two types of repairing methods were considered; adhesively bonded and infused scarf-type patches. The performance of both repair techniques applied to GFRP laminates was assessed under three-point bending test. The specimens were eight balanced plain weave S-glass layers/epoxy resin manufactured using infusion technique. In infused patches, two types of resins, namely, pristine and nano-modified resins were used to investigate their effects on the flexural strength and failure modes of the repaired composite specimens. Results indicate that depending on the type of repair and nano-filler used the flexural properties of repaired composite specimen exhibited significant improvements. The choice of the type of repair would vary on the desired application along with accessibility to the damaged area. Overall, repair of composites allow considerable economic benefits over the replacement of an entire structural component.