Composite sandwich panel

Composite honeycomb sandwich construction is used on aircraft for wing spoilers, fairings, ailerons, flaps, nacelles, floor boards and rudders.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority

A sandwich panel consists of two relatively thin, parallel face sheets bonded to and separated by a relatively thick, lightweight core; the core supports the face sheets against buckling and carries out-of-plane shear, so it must have high shear strength and compression stiffness. In a composite sandwich panel the face sheets are fibre-reinforced polymer laminates — glass, aramid or carbon — on a core of honeycomb, foam or balsa.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority

Composite sandwich construction is usually fabricated by autoclave cure, press cure or vacuum-bag cure, with the skin laminates either precured and then bonded to the core, co-cured with the core in one operation, or a combination of the two; foaming adhesive is used to splice pieces of honeycomb core together.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority

Carbon fibre face sheets cannot be used with an aluminium honeycomb core, because the combination causes the aluminium to corrode.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority

Sandwich construction gives high bending stiffness at minimal weight compared with aluminium or a solid composite laminate: increasing the core thickness greatly increases stiffness while adding little weight, so external stiffeners such as stringers and frames are not needed; most honeycomb cores are anisotropic.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority

The face sheets of many sandwich components such as spoilers and flight controls are very thin, sometimes only three or four plies, and field reports indicate that they do not have good impact resistance.

Evidence support: Supported by the cited evidence · one source

Evidence: U.S. Department of Transportation, Federal Aviation Administration, Flight Standards Service 2023 · Primary authority