PRIMARY CALIBRATION OF SHOCK TRANSDUCERS LASER POSITION INFLUENCES MEASUREMENT RESULTS

摘要

For the primary calibration of shock transducers according to ISO 16063-13 on a calibration system with Hopkinson-bar shock exciter a laser vibrometer is used as a reference sensor. Earlier publications have shown that the waves in the Hopkinson-Bar seem not to propagate exactly as plain waves and that it thus matters where the laser spot is positioned on the surface of the bar. However, in these investigations the shock duration could not be changed in a controlled way. This paper presents results from measurements by means of a special Hopkinson-bar that allows to vary the shock duration precisely and thus allows to measure the frequency dependency of such effects.