Aircraft Composite Materials and Repair Quiz

Aircraft Composite Materials and Repair Overview

• Composite components for aircraft lightning strike protection use layers of conductive materials, such as nickel-coated graphite cloth, metal meshes, aluminized fiberglass, and conductive paints.
• Technicians repairing these structures must ensure the electrical conductivity is restored, often requiring a conductivity test with an ohmmeter.
• Approved materials, like potting compounds, sealants, and adhesives, must be used from authorized vendors for repairing these structures.
• Thermosetting resins, such as polyester, vinyl ester, phenolic, and epoxy, are widely used in aircraft composite materials due to their diverse properties and curing methods.
• Polyamides are used in high-temperature environments for circuit boards and hot engine and airframe structures, requiring high cure temperatures.
• Poly benzimidazole and bismaleimide resins are used for high-temperature resistance in aircraft components like aero engines, with processing similar to epoxy resins.
• Thermoplastic resins offer advantages like processing speed, and their properties vary based on whether they are semicrystalline or amorphous.
• Polyether ether ketone (PEEK) is a high-temperature thermoplastic used in aircraft components and can be reinforced with glass and carbon.
• Thermosetting resins undergo three curing stages: A, B, and C, with prepreg materials being cured with elevated temperatures and stored in freezers.
• Dry fiber materials, such as carbon, glass, and Kevlar, are used in aircraft repair procedures through a wet layup process, offering the advantage of long-term storage.
• Thixotropic agents are used to create adhesive materials that are gel-like at rest but become fluid when agitated, with high static shear strength and low dynamic shear strength.
• Film adhesives for aerospace applications are generally supplied as thin film supported on a release paper and stored under refrigerated conditions.