The Southwest Research Institute Split-Hopkinson Pressure Bar apparatus is a mechanical test instrument used to characterize the dynamic response of materials at high strain rates (typical of impacts and explosions).
The apparatus, based on devices invented by Bertram Hopkinson and Herbert Kolsky, was developed at SwRI in 1962 by Dr. Ulric Lindholm. Initially created to evaluate the behavior of metals under various conditions, the SwRI Split-Hopkinson Pressure Bar has since been applied to a wide range of materials.