Split Hopkinson Bar

Split Hopkinson Pressure Bar (SHPB) testing is one of the most versatile methods for determining dynamic mechanical properties at high strain rates in the range of 1×10² – 1×10⁵ s^-1. Suitable configuration of the SHPB test setup allows testing of specimens to generate the respective stress-strain curves.

In the compression test, a small cylindrical specimen is clamped between two long, identical and high-strength steel bars, called the loading and transmission bars. The free end of the loading bar is hit axially by a projectile fired from a gas pistol. The approximately flat-pointed longitudinal tension pulse generated by the impact travels along the loading rod to the specimen, where it is partly reflected and partly transmitted.

Strain gauges on each bar monitor strains due to the incident pulse, reflected pulse, and transmitted pulse as functions of time. A high-bandwidth bridge amplifier such as the Elsys SGA2 is required to measure the signal from the strain gauge. A TraNET FE with a sampling rate of 2 MS/s per channel or higher is suitable for acquiring the measurement signals.