The effects of strain rate, density, and temperature on the mechanical properties of polymethylene diisocyanate (PMDI)-based rigid polyurethane foams during compression

Compressive experiments on three types of rigid polyurethane foams were conducted by employing modified split Hopkinson pressure bars (SHPBs). The foam materials, which were based on polymethylene diisocyanate (PMDI), varied only in density (0.31 × 10³, 0.41 × 10³, and 0.55 × 10³ kg/m³) and were compressed at strain rates as high as 3 × 10³ s⁻¹. Dynamic experiments were also performed on these three foam materials at temperatures ranging from 219 to 347 K, while maintaining a fixed high strain rate of ~3 × 10³ s⁻¹. In addition, an MTS materials testing frame was used to characterize the low-strain-rate compressive response of these three foam materials at room temperature (295 K). Our study determined the effects of density, strain rate, and temperature on the compressive response of the foam materials, resulting in a compressive stress–strain curve for each material.