To accurately simulate the foam core in composite parts on a macroscopic scale the morphology, the characterisation, and the nonlinear behaviour of the foam must be understood properly. Accounting for the heterogeneity and the mechanical properties of the foam core affects the dimensioning of the final part. In the present study the microstructure of the foam samples were characterized using scanning electron microscopy. To determine the bulk material behavior and the strength limitations of the nonlinear foam, shear and compressions tests are performed. All numerical calculations were carried out on the macroscopic level. A basic challenge in the finite element modelling of hyperelastic materials by means of test data is the identification of material model coefficients which are appropriate to describe the behaviour of the considered foam.