Expedient Repair for Composite Rotorcraft Structure

The US Army has defined, analyzed, and executed a repair demonstration on a curved, stiffened, damaged composite panel. It was shown through analysis that most of the compressive buckling resistance of the panel is provided by its thickness and curvature, and that the composite repair patch largely restores the strength lost to the damage. Unique to this repair approach is the use of repair plies with interstices between yarns of the plain-weave carbon fabric repair patch plies, intended to increase surface area for enhanced bond strength. The repair demonstration showed good results in terms of visual inspection and porosity, and could typically be completed in 6-8 hours on thin-skin aviation composite structures. Verification of the repair is expected from upcoming structural testing.