Full-field mechanical characterization of polyurethane foams under large deformations by digital image correlation

In this work the response of soft open-cell polyurethane foams with three different densities, respectively of 85, 63 and 46 kg/m3, were obtained by quasi-static tensile, shear and cyclic compression tests. The presence of an intrinsic random pattern inside the material given by the small black dot of expanded graphite, that makes it fireproof, allowed to detect large displacement fields exploiting digital image correlation technique, without painting the surface to quantify the full-field displacement of the samples. The displacements’ maps, the strain fields and the stress-strain curves obtained by digital image correlation allowed the analysis and the evaluation of the mechanical properties.