CHARACTERISTICS METHOD FOR VISCOELASTIC ANALYSIS IN A HOPKINSON TENSILE BAR

A mini-Split Hopkinson Tensile bar (mSHTB) system is developed. The system employs small diameter polymeric bars, which can achieve a closer impedance match with the specimens, thus it provides a lower noise-to-signal ratio and a longer duration of tensile pulse, which results in a higher maximum strain. With the three element viscoelastic model, a characteristic method for reconstruction of the profiles of strain, particle velocity, and stress in an arbitrary cross section of a viscoelastic bar on the basis of the strain signal measured in one section is developed. Experiments using the mSHTB enable us to appropriately characterize the dynamic behavior of small-sized, low-impedance material under a particular range of high strain rate.