Multi-Material Structures

The use of graphite fiber reinforced composite materials in Navy ship applications has a number of potential benefits that can be attributed to the material’s high specific strength and stiffness. However, graphite fiber can form a galvanic cell with the steel structure, especially at the joints between the composite and steel, promoting corrosion that degrades both the composite and the steel. Texas Research Institute Austin, Inc. (TRI/Austin) has a proven COTS technology for preventing galvanic corrosion between dissimilar metals in marine applications that is based on the use of a dielectric barrier in the joint. This TRI/Austin patented technology offers a means to produce a lightweight, corrosion resistant, structurally robust graphite composite-to-steel joint. The technology is readily adapted to the manufacture of adhesive or mechanical composite-to-steel joints. Mechanical fasteners can be corrosion proofed as well. In that galvanic corrosion is a major cause of failure in adhesively bonded metals, the proposed technology can lead to robust, durable adhesive composite-to-metal joints for ship applications. The use of the proposed technology will permit the extensive use of graphite reinforced composite material structures on Navy vessels without the concern for galvanic corrosion between the graphite fiber and the ship’s steel.