Intermediate Strain Rate Hopkinson Tension Bar Based on Cyclic Stress Wave Loading

Highly elastic polymers, such as rubber, exhibit significant research interest due to their large deformation mechanics at intermediate strain rates. Addressing this issue, the present study introduces a design for a Hopkinson Tensile Bar apparatus to capture the mechanical response of highly elastic soft materials. A striker tube-incident bar configuration of equal length and wave impedance was developed, generating superimposed cyclic stress waves on the bar, capable of producing an ultra-long incident pulse over 40 ms in duration. Based on this loading principle, an improved Hopkinson bar apparatus was designed. Simulation results indicate that the load strain, strain rate, and stress can be calculated from the strain signals on the bar, demonstrating good testing accuracy.