Sandwich structure

The thin, stiff facing laminate on each side of a sandwich structure, carrying the in-plane and bending loads while the core carries shear. The term is also used more generally for the outer aerodynamic or weathering surface of a composite structure.

A core material formed from thin walls arranged into an array of hexagonal or similar cells, used on edge between face sheets so the cell walls carry compression and shear. It offers very high stiffness and strength for its weight, with common types made from aluminium foil, resin-coated aramid paper and thermoplastics.

A separation at a bonded interface, such as within an adhesive joint or between the skin and core of a sandwich panel. Disbonds may originate in manufacture or grow in service, and are detected by tap testing or ultrasonic inspection.

The upright laminate member joining the spar caps inside a wind turbine blade or similar beam-like structure, transferring shear between them so the assembly behaves as an I-beam. Shear webs are commonly sandwich panels bonded in place with structural adhesive.