Testing Techniques at High Rates of Strain

摘要

Techniques for studying the mechanical behavior of materials at high rates of strain are reviewed and typical results obtained by the use of these techniques are presented. At intermediate rates of strain from 1 to 100/s, where the effects of wave propagation do not have to be taken into account, hydraulically operated loading machines for both uniaxial and combined stress tests are described. For testing at the higher rates associated with impact loading, i.e., in the range 500 to 5000/s, the standard split Hopkinson pressure bar (SHPB) apparatus which involves stress wave loading is commonly used. The compression version of this apparatus and subsequent modifications for tension and torsion testing are fully described. The application of the SHPS to testing under biaxial stress, to the study of fracture dynamics, and to tests in which the specimen is subjected to a varying strain rate is then discussed and some of the attempts which have been made to adapt the SHPB technique to allow testing at strain rates in excess of 10,000/s are described.