Two coatings or skins, made of reinforced resin or sometimes of metal, are solidly glued on a core of foam. The following figure 1 presents the schematic principle of the sandwich composite and the equivalent I-beam.
The sandwich composites are used in general purpose and high-tech applications such aeronautics, sports and leisure (ski, bicycle, hockey), railway and road transport, elements of body for isothermal or cooled vehicles, nautical structural components, blades of wind turbines, thermal and phonic insulation in construction...
The core and the final parts can have any shape: parallelepipedic for a lot of sandwich panels, parts in shape for the hulls of boats or bumpers and so on.
On the other hand, if we reason in terms of efforts by disregarding section:
* The tensile properties of the sandwich composite will be of the same order as those of the skins, the foam bringing only a weak contribution.
* The properties in compression will be weaker especially as foam is lighter and less resistant in compression.