Development of Shock Acceleration Calibration Machine in NMIJ

Hideaki Nozato, Takashi Usuda, Akihiro Oota, Tamio Ishigami and Katsuhisa Kudo
Abstract:
Calibrations of shock acceleration are industrially required from a view of human safety and product development. In NMIJ vibration group, a shock acceleration calibration machine (hereafter ‘calibration machine’) has been developed in response to much demand from Japanese industries, and can calibrate shock transducers in acceleration range from 200 m/s² to 5000 m/s². For primary calibration, accelerometer is calibrated by a combination of shock exciter and laser interferometer. In the shock exciter, shock acceleration is generated by rigid body collision between a hammer and an anvil. To avoid any disturbance motion, radial air bearing system is adapted to keep high stiffness in perpendicular directions to the collision. The hammer, supported by the air bearing, is accelerated by an air gun and collides with the anvil through a rubber pad. Thus, acceleration waveform of the anvil strongly depends on viscoelasticity of the rubber pad. Different hardness of the rubber pad is examined to realize various peak accelerations. As another significant issue, optimization of low-pass digital filter is necessary to obtain reliable acceleration waveforms. This manuscript reports not only a procedure of low-pass digital filtering but also cut-off frequency dependence of low-pass digital filter on peak acceleration.
Keywords:
acceleration standard, shock acceleration, air bearing, accelerometer, calibration, low-pass digital filter
Download:
IMEKO-TC22-2007-109u.pdf
DOI:
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Event details
IMEKO TC:
TC22
Event name:
Cultivating metrological knowledge
Title:
1st Conference on Vibration Measurement (together with 20th TC3 Conference on Measurement of Force, Mass and Torque & 3rd TC16 Conference on Pressure Measurement)
Place:
Merida, MEXICO
Time:
27 November 2007 - 01 December 2007