Dynamic Compression Testing on Polymeric Foams

In order to experimentally obtain valid dynamic material properties of polymeric foams with split Hopkinson bars, necessary modifications on the technique are necessary. A sensitive transmitted signal measurement method must be employed to accurately determine the weak signals transmitted from the soft specimen. Proper pulse shapers are required to ensure that the foam specimen deforms at a constant strain rate under dynamic stress equilibrium. Dynamic equilibrium must be monitored directly in experiments. These modifications are briefly reviewed and discussed. Examples are given to show the necessity and validity of the modifications.