A polymeric split Hopkinson pressure bar instrumented with velocity gages

Polymeric split Hopkinson pressure bars are often used to test low-impedance materials at elevated strain rates. However, they tend to be viscoelastic, and a viscoelastic wave propagation model is required to analyze the data. This considerably complicates the analysis over the more common linear elastic split Hopkinson bar. In this research, a polymeric split Hopkinson bar is instrumented with electromagnetic velocity gages. The gages are placed at the interfaces between the bars and the specimen. By using this arrangement, viscoelastic effects in the bars are negligible and the need for a viscoelastic correction is eliminated. The method is applied by testing low-density foams.