Split-Hopkinson Pressure and Tension Bar Testing

K&C’s Split-Hopkinson Pressure  and Tension Bar System

With increasing needs to characterize high-performance materials in high-strain rate loadings that occur due to material rupture, impacts, blast, shock, or penetration, K&C has developed the capabilities to characterize materials accurately under intense high-strain rate (up to 1E4) up to ultra-high strain-rate (up to and beyond 1E6) conditions.


Materials can display favorable, or sometimes unfavorable behaviors when they are subjected to high-strain rates or high-pressure shocks. This makes understanding their characteristics under these conditions, up to and beyond failure, essential for designing and analyzing components and systems that utilize new or high-performance materials.


K&C’s laboratory includes several Split-Hopkinson Pressure and Tension Bars (SHPB and SHTB) that allows us to characterize the stress-strain or force-displacement response of materials under rapid rates of deformation. Using one of our several SHPB/SHTB setups, K&C places material specimens between an incident and transmission bar and then loads the sample in compression, tension, shear, or with confinement. The loading pulse is generated with a striker bar system that produces a stress pulse of finite duration and magnitude that propagates from the impact-side of the incident bar toward the sample (the incident wave). When the sample deforms, a portion of the signal is transmitted into the transmission bar (the transmitted wave) and a portion of wave is reflected into incident bar (the reflected wave). The stress-strain relationship is calculated from the transmitted signal and the reflected incident signal, and other advanced instrumentation including laser-based extensometers and high-speed video imaging of the sample.


Very high strain rates can be achieved, depending on the physical properties of the SHPB/SHTB and samples, the launcher capabilities, and the sample designs. Traditional SHPB tests engender some challenges with dynamic equilibrium in the sample, non-uniform deformations, and oscillatory signals, and K&C uses momentum traps and pulse shapers are used to modify the pulse into a smooth triangle-like wave or other shape waves to mitigate these effects.

Quasi-static and dynamic (SHPB) test data for a high-strength steel and comparison with FEA results.