Application of the miniature small punch test for the mechanical characterization of polymer materials

All the polymer materials were characterized by means of small punch and tensile tests. The tensile stress-strain curves were compared with the load-displacement SPT curves and the representative SPT parameters were defined accordingly. A good correspondence was found between the tensile elastic modulus and the initial slope of the SPT plot (Slopeini/t), with t being the specimen thickness, and a good correlation was also observed between the tensile yield strength and the SPT Pym/t2 parameter. On the contrary, no corresponding relationship was found to predict the ultimate tensile strength or the failure elongation, since these properties depend greatly on the stress state of the test (uniaxial or biaxial).