Models currently used to simulate the behaviour of cellular material under compression use data from mechanical tests. Phenomenologic law such as the one developed by Deshpande and Fleck [1] makes it possible to represent the behavior of cellular materials under a complex compressive stress state, but the identification of these models requires the development of original experimental methods.

Today, uniaxial compression is the most common mechanical test used, but the results from this test alone are insufficient to characterise the cellular material response to three-dimensional stress states. Complementary tests must be developed to complete the experimental data base. Hydrostatic compression apparatus have been already developed by several authors [2, 3, 4] to identify the behaviour of cellular material under pressure. However, these devices are limited and cannot be used to determine the response of cellular materials under confined compression, uniaxial compression combined with pressure or any other multiaxial compression stress field.

During this study, a hydrostatic chamber was designed to impose a combination of uniaxial compression and hydrostatic pressure on cellular sample. The new apparatus makes it possible to obtain a large range of compression stress states from uniaxial compression to hydrostatic pressure. It is also possible to explore the influence of a pressure constant variable on the lateral surface of the sample on the response of the cellular material under axial compression.

The development of this new apparatus and its calibration are highlighted in this paper. First results on PVC foam are also presented. The foam response under uniaxial compression and hydrostatic compression shows a classical non-linear elastic stage, followed by a plastic plateau and densification. Some parameters such as compressibility modulus (the slope of the initial stage), yield stress and a tangent modulus of the plateau stress can be identified for the different states of stress.