Split Pressure Hopkinson Device

A Split Hopkinson Pressure Bar (SHPB) is used to test the high strain rate material properties of materials. The Hopkinson bar is used to impose a dynamic load on a material specimen akin to that which the material will experience in dynamic situations like vehicle crashes or other high-energy events.Split Hopkinson pressure bars, or Kolsky bars, can be miniaturized to achieve very high strain-rates, and rates in excess of 1,000,000/s have been achieved.

A Split Hopkinson Pressure Bar / Kolsky Bar system will contain a precision accelerator, an incident bar, a transmission bar, and a stopping mechanism that are aligned and mounted on a REL flat base.

The accelerator is charged with pressurized gas to accelerate a striker bar at a measured velocity to create an impact incident. Striker bars of various lengths are used to produce a range of loading durations i.e. short striker bars impart short time duration loads. The impact of the striker bar on the incident bar sends a stress pulse traveling down the incident bar (at the speed of sound) that is detected by a strain gage mounted on the bar.
In DBM, for material assessment in higher loading rates, a Split Hopkinson Pressure Bar (SHPB) which enjoys a 1 MHz data logger would examine specimens’ behavior with maximum of 900 Mpa.