Strain-rate – temperature superposition behavior of Polymethylene Diisocyanate (PMDI) based rigid Polyurethane foams with different densities

Abstract
In our previous study, compressive stress-strain responses of polymethylene diisocyanate (PMDI) based rigid polyurethane foams with three different densities have been experimentally determined at various strain rates and room temperature, as well as at various temperatures and a fixed high strain rate. On basis of the resulting data, the strain-rate – temperature superposition behavior of the PMDI-based foams was investigated in this study. A general strain-rate – temperature superposition principle was developed. Data of yield strength experimentally obtained at a fixed strain rate and various temperatures were numerically shifted to the strain-rate region at room temperature, based on the strain-rate – temperature superposition principle. The shifted data were found to be consistent with the experimental data obtained at various strain rates and room temperature.