A Polymeric Split Hopkinson Pressure Bar Method and Its Applications to Low Impedance Materials

A new polymeric split Hopkinson pressure bar (SHPB) method is presented to study the dynamic behavior of low-strength and low-impedance materials, such as polymers and elastomers. To consider the low-impedance characteristics of test specimens, polymethyl methacrylate (PMMA) bars are used as the input and output bars. In the proposed polymeric SHPB method, the wave analysis of the strain pulses along the bars is performed in the frequency domain. Strain histories at the respective given points on the input and output bars obtained from polymeric SHPB tests are resolved into frequency components by Fourier transformation, and waveforms at the respective measurement points are corrected to those at the two interfaces between the specimen and the bars. The proposed method is applied to identify mechanical models for several low-impedance materials such as golf ball materials. The complex compliance for each material is determined as one of the dynamic viscoelastic properties in the frequency domain. Furthermore, from the FEM simulations on impact tests of a golf ball, it is verified that the proposed method provides an effective tool for modeling the dynamic behavior of low-impedance materials.