Performance and Efficiency of Polyurethane Foams under the Influence of Temperature and Strain Rate Variation

Polyurethane foams with lower and higher densities (35, 93, and 200 kg/m(3)) were tested in compression at three levels of temperatures as: - 60 degrees C (213 K), 23 degrees C (296 K), and 80 degrees C (353 K). The span of chosen temperatures covers the usual possible environmental conditions. In testing strain rate starts from 0.0014 up to 545 1/s. Based on a set of experimental engineering stress-strain curves a phenomenological model with two density and temperature-dependent material parameters is proposed. Thus, it is possible to reconstruct the stress-strain curves and establish the variation of energy efficiency and onset strain of densification together with the absorbed specific strain energy up to that moment. It is shown that contrary to what was expected, the temperature and speed of testing do not influence significantly the onset of densification. Low temperatures and high speeds of testing lead to the increase of absorbed specific strain energy for the higher PUR foam density.