Hydrostatic compression on polypropylene foam

Models currently used to simulate the impact behaviour of polymeric foam at high strain rates use data from mechanical tests. Uniaxial compression is the most common mechanical test used, but the results from this test alone are insufficient to characterise the foam response to three-dimensional stress states. A new experimental apparatus for the study of the foam behaviour under a state of hydrostatic stress is presented. A flywheel was modified to carry out compression tests at high strain rates, and a hydrostatic chamber designed to obtain the variation of stress with volumetric strain, as a function of density and deformation rate. High speed images of the sample deformation under pressure were analysed by image