A Note on Data Processing in the Split Hopkinson Pressure Bar Tests

netic energy in SHPB test, Davies and Hunter recommended an optimal length/ diameter ratio of specimen in order to provide minimal correction or error due to inertial effects as well as to minimize the problem due to interfacial friction^.^ Gong et al. used FFT technique to rehe Split Hopkinson Pressure Bar (SHPB), or Kolsky’s apparatus, has been widely used for the study of dynamic behaviors of materials. It was initially developed for use in compressive tests,’ and later, was modified for tensile2 and torsion3 as well as other impact loading configuration^.^ The concept of the SHPB test involves the determination of dynamic stress, strain and displacement occurring at the end of a bar through observation of the strain at a position some distance away. The experimental method is based on some assumptions, i.e., onedimensional wave in the bars, uniform stress and strain fields in the specimen, and neglecting the effect of specimen inertia. The deviation of real SHPB configuration from the assumptions will result in errors in the measured stressstrain relation. Hence, in spite of its widespread use, it has been the subject of extensive analytical and numerical studies to evaluate the assumptions in order to improve the accuracy of the measured stress-strain curves.