Mechanical Property Evaluation of Polyurethane Foam under Quasi-static and Dynamic Strain Rates- An Experimental Study

Polyurethane foams are widely used as thermal insulators and also as energy absorbers in radioactive material shipping casks. In view of this, an experimental study to observe the change in impact response of rigid polyurethane foam at different strain rates was conducted. For this purpose, uni-axial compression experiments were performed at quasi-static and dynamic rates of loading. The results reveal a significant change in mechanical properties of foam under compression at different strain rates. The response of foam gets stiffer with increase in strain rate, and densification (lockup) occurs well below the strains at which lockup occurs for foam deformed at quasi-static strain rates. Consequently, the energy absorption characteristics of foam are altered with change in strain rate. It is envisioned that nuclear industries could use this information for application of polyurethane foam as an impact limiter in nuclear shipping casks, without causing un-acceptable stresses in the cask structure.