A study of Experimental Method for Mechanical Properties of Rigid Polyurethane Foam under Hydrostatic Compressive Loading

Mechanical behavior of foam under multi-axial loads has attracted much attention in engineering practice.A new experimental method for volumetric strain measurement of polyurethane(PU) foam materials was put forward by utilizing soil tri-axial compressive device.Mechanical properties of a kind of closed-cell rigid PU foam under hydrostatic loading were investigated,and some useful parameters were obtained.Results show that the shape of hydrostatic pressure versus nominal volumetric strain curve of the PU foam is an initial elastic regime followed by a long plastic plateau region and then a rapid increase with the foam densifying.And the foam under hydrostatic compression has a slightly greater plateau stress and a smaller densification strain than that under uniaxial compression.At last,some reasons resulting in the PU foam nonuniform deformation and bending of foam sample were analyzed through contrastive tests for two types of PU foam samples with different heights,which influence the experimental results greatly.