Development and proving of a split Hopkinson pressure bar used for high strain rate materials testing

Abstract

As a result of increasing demand to improve analysis of manufacturing techniques and safety in structures, it is necessary to determine material properties at high strain rates. Conventional screw-driven or servo-hydraulic methods of testing materials at high strain rates are not adequate as oscillations and stress waves are set-up within the testing apparatus. These oscillations and stress waves foul the transducer reading, thus making the data obtained unusable. To overcome these limitations the split Hopkinson pressure bar (SHPB) was developed. A SHPB facility was developed at UCT to measure material properties at high strain rates. The development, discussed in this thesis, included the design and manufacturing of a SHPB, strain gauge amplifiers and a data acquisition system. In addition to this a data processing package, including a dispersion correction routine was also developed.