On the Characterisation of Cellular Materials Used in Sandwich Construction

The paper gives an overview of issues relating to the characterisation of the progressive collapse of core cellular materials used in sandwich construction. The specific structural application addressed is foreign object impact, and in this case the core cellular material is subject to multi axial stresses, progressive collapse and possible rupture. Crushable foams have been used for many years as core materials. Possible foam materials are based on polymers (e.g. Divinycell, Rohacell), metals (e.g. Alporas) and graphite. It has been shown that the mechanical properties of cellular materials, e.g. elastic behaviour, uniaxial crush and densification, are dependent on the cell geometry, on the cell size (foam density) and on the parent material.