Experimental Determination of Hydrostatic Compression versus Volume Change Curves for Cellular Solids

A floatable solid immersed in a liquid can be made to sink if enough pressure is applied to the liquid to increase the density of the solid to the value of the density of the liquid. If a counterweight, W, is attached to the solid, the sinking pressure is reduced. A simple equation gives the volume of the solid as a function of the sinking pressure for each value of W. This is the basis of an experimental method developed to obtain the volume change, Δ V, of a fairly deformable solid, as a function of pressure, p. The method was applied to cork and two polymer foams; (−Δ V/V0) versus p curves were obtained. These curves are compared with stress-strain curves obtained in uniaxial compression.