Which material is listed as a possible facing or core material for bonded honeycomb structures?

• A. Glass
• B. Aluminum foil
• C. Wood blocks
• D. Foam rubber

Answer: (A)

In bonded honeycomb panels, a lightweight core is sandwiched between two face sheets, and both the core and faces must bond well to the adhesive and carry loads without failing. Glass fits into this idea because glass can be used in glass-fiber reinforced laminates or as part of glass-based honeycomb constructions, providing the rigidity and bonding compatibility needed for a stiff, lightweight panel. When combined with suitable resins, glass or glass-containing composites can serve as either a facing sheet or a core material in these structures.

Aluminum foil is far too thin to serve as a core or effective facing for structural bonding. Wood blocks aren’t suitable for bonding in high-performance aerospace panels due to moisture sensitivity, dimensional stability, and bonding issues. Foam rubber lacks the stiffness and structural durability required for load-bearing skins and cores. Thus, glass is the best fit among the options for a material that can function as a facing or core in bonded honeycomb structures.