Hopkinson Bar Shock Accelerometer Calibration Services
Endevco now offers accelerometer calibration services
based upon the Hopkinson Bar. Endevco's Model 2973A
Shock Motion Accelerometer Calibrator (SMAC(tm)
will be used to perform controlled shock excitation for
sensitivity calibration of accelerometers from
10,000 g's to +100,000 g's.
The Model 2973A provides precise, repeatable control of drive
momentum by controlling pressure with a voltage-to-pressure
regulator and releasing it with an electrically-operated poppet
valve. It also eliminates the need for paper diaphragms and
features a simpler, more reliable bar suspension system.
Driven with pressurized air, a projectile with a shaped tip impacts
a deformable aluminum mitigator on one end of the bar, generating
a compression wave in the bar that imparts an acceleration to a test
transducer mounted on the opposite end. Strain gages on the bar
measure the compression wave. The relation between the strain
rate and the acceleration is the basis of the calibration.
Depending on the version of the Hopkinson bar ordered, the test
accelerometer can be mounted directly to the bar or onto a
breakaway fixture which flies free from the bar after the shock
pulse. The use of the breakaway eliminates repeated
exposures of the test transducer to reflections of the compression
wave, and allows zero shift measurements. The system can be
used either manually, as a standalone device, or in an automated
mode.
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October 2002
