Experimental and numerical analysis of the Poisson’s ratio on soft polyurethane foams under tensile and cyclic compression load

In this paper results on the evolution of Poisson’s ratio under tensile and cyclic compression on low-density soft open-cell polyurethane foams (85, 63, 46 kg/m3) up to 80% of strain are presented as obtained by full-field deformation measurements. The Poisson’s ratio was investigated using a Poisson’s function and a tangent Poisson’s function formulation, more capable to capture the instantaneous behavior of the foam and a possible auxetic behavior. The displacements’ maps and the stress-strain curves obtained experimentally by digital image correlation are compared with the numerical results of the FEM analysis obtained for ν = 0 and ν ≠ 0.