AI has announced three types of Split Hopkinson bar apparatuses .
Advance Instrument
Inc. (AI) has announced three types of Split Hopkinson bar apparatuses in 2012.
They are mainly for researching and determining material properties at high rates of strains. For different types of strains,
AI has developed these three models for the practical application. They are Split
Hopkinson pressure bar (SHPB), Split Hopkinson tension bar and Split Hopkinson
torsion bar. Users are recommended to consult with AI to get the right information
for the appropriate application.
The split Hopkinson bar apparatus consists
of two long slender bars that closely sandwich a
short cylindrical specimen between them.
By striking the end of one bar, a
compressive stress wave shall be generated and will immediately traverse across
the stricken bar and reaching at one end of the specimen. The wave shall be partially reflected back and traverse back to the
impact end.
The remainder of the wave shall then go
through the specimen and into the second bar causing the irreversible plastic
deformation on the specimen.
It is observed that the
reflected and
transmitted waves are proportional to the specimen’s strain rate and stress
respectively. The specimen strain can hence be determined by integrating
the strain rate. And by monitoring the strains in the two
bars, the specimen stress-strain properties can then be calculated
out.
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