Abstract. Recently the Belgian company Recticel S.A. has developed a new composite material in which two different types of polyurethane foam – a open cell flexible foam and a closed cell rigid foam- are used. Both of these foams are produced in-house and a new production process was designed to combine these foams into one material known by its brand name “Compolite®”. This material will serve as core material in sandwich structures with complex 3D shapes.
The current research investigates the linear elastic behavior of the complex foam. A full factorial design of experiments was used to determine the mechanical properties of the complex foam and its constituents by means of compressive experiments. The results clearly show that foam density has a major impact on the mechanical properties as opposed to the cell size of the open cell foam. A significant difference in stiffness between the complex foam and the rigid closed cell foam was observed.
Using the commercial,l UGS NX 7.5 Finite Element software attempts are made to explain this difference. At first a classical simplification of cellular material into 2D honeycombs has been made followed by a more elaborate 3D model based on the Kelvin cell geometry.