Compressive deformation of Rohacell foams: Effects of strain rate and temperature

Uniaxial compression experiments have been performed on four different densities of Rohacell foam. The experiments explored the sensitivity of the response to the imposed strain rate (in the range 10−3 to 5 × 103 s−1) and temperature (203–473 K). The compressive collapse stress is generally found to increase with increasing strain rate and decreasing temperature; however this tendency is inverted at very low temperatures or very high strain rates. This behaviour is mainly due to embrittlement of the parent polymer but is also related to the details of the foamsʹ microstructures. Time–temperature superposition is employed to map the temperature sensitivity of the foams to their strain rate dependence. A simple design formula is provided to predict the foam stiffness as a function of temperature and relative density.