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

Abstract

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 -5x10 3 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 foams' microstructures. Timetemperature 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.

One-dimensional response of sandwich plates to underwater blast: Fluid-structure interaction experiments and simulations

“…Equation (4) Table 1 and the strain rate sensitivity of the foam was neglected, as reported by Arezoo et al [28].…”

“…Dynamic experiments on Rohacell and Alporas foams [28,32,33] revealed that the dependence of the yield stress upon the strain rate can be neglected for these foams. However, when a foam material is subject to intense shock loading, the compressive dynamic response entails propagation of a plastic shock wave leading to additional energy dissipation in the core.…”

Dynamic compression response of self-reinforced poly(ethylene terephthalate) composites and corrugated sandwich cores

“…In Type II structures, the buckling of the struts is stabilised by the inertia of the struts under high rates of loading (referred to as micro-inertial effects) while the bending-dominated response of the Type I structures is relatively inertia insensitive. The dynamic strength enhancements of the SrPET corrugated core are compared to a polymethacrylimide (PMI) Rohacell foam of similar density (75 kgm -3 and 200 kgm -3 ) [18,19] in Fig. 14. Here 8 9 2 is the ratio of the dynamic peak strength at a strain rate +, to the corresponding peak strength at the quasi-static strain rate +, % where +, % 10 0 s ) and 10 s ) for the corrugated cores and PMI foams, respectively.…”

“…Both types of cellular structures are made from relatively rate-insensitive polymers and have similar strut aspect ratios as indicated in Fig. 14 but rather different topologies. The strut aspect ratio of the foam material corresponds to the ratio between the length and thickness of the cell wall edges as measured using Scanning Electron Microscopy [18,19] The comparison clearly shows that for the same strut aspect ratio the corrugated core is significantly more rate sensitive compared to the PMI foam and this sensitivity increases with decreasing /ℓ for the reasons discussed above. The comparison clearly shows the role of topology in governing the rate sensitivity of polymeric cellular materials.…”

Numerical Simulations of Quasi-Static Indentation and Low Velocity Impact of Rohacell 51 Wf Foam

“…4a. The quasi-static curve was taken from [Flores-Johnson (2008)] and the high strain rate curves were taken from [Arezoo et al (2013)]. Figure 4b shows the numerical results of uniaxial compression of Rohacell 51 WF foam cube specimen at various strain rates.…”