Mechanics of thin ultra-light stainless steel sandwich sheet material: Part I. Stiffness Original Research Article

Three variants of a novel steel sandwich sheet material have been studied. The geometrical arrangements of the steel fibres in the core have been characterised. Certain mechanical properties of the fibres have also been investigated. The beam stiffnesses of the sheets, and also their through-thickness Young’s moduli, have been measured. These results have been compared with model predictions. It is shown that the beam stiffnesses are in all cases significantly lower than expected from simple bending theory. This is attributed to the low through-thickness stiffness of the core and also to a low resistance to shear. Modelling of these properties has facilitated the identification of changes to the core structure, which should lead to improved beam stiffness, while retaining a low density. Increased fibre diameter, and possibly an alteration to the fibre sectional shape, are the most promising changes. Of course, implications for other properties, and for ease of manufacture, will also need to be borne in mind.