Experimental Testing and Computational Analysis of Viscoelastic Wave Propagation in Polymeric Split Hopkinson Pressure Bar

The use of polymeric bars in the traditional Kolsky or Split Hopkinson Pressure Bar (SHPB) has been suggested by several authors as a means of improving coupling to low impedance materials and to increase incident wave rise time to assist in achieving dynamic equilibrium when testing soft materials. However, one aspect that must be addressed in this application is viscoelastic wave propagation leading to wave attenuation and dispersion. The amount of dispersion and attenuation depends on the bar material selection and incident wave signal. Viscoelastic wave propagation has been successfully addressed in Polymeric SHPB through experimental determination of the wave propagation coefficients, and has been investigated through analytical techniques; however, there is no widely accepted method for computationally modeling these events, which would benefit test apparatus design and optimization.