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

-

IMEKO TC

TC22 - Vibration Measurement

Back to the proceedings