Implementations and pilot comparison of primary low intensity shock calibration

Abstract

This paper first presents two main technical concerns for a possible low intensity shock comparison: variety of primary shock calibration systems and feasibility of comparison artifact. For the primary calibration system, the mechanical excitation includes hammer-anvil collision, pneumatic driven projectile impact and Hopkinson bar. The shock pulses generated are smooth monopole shape by the first two types with air bearings, but dipole shape by the third type. For the comparison artifact, a standard accelerometer of single-ended type with a charge amplifier consists of an accelerometer measuring chain whose nonlinearity of amplitude and phase frequency responses is investigated. Based on the nonlinear fact of comparison artifact at frequency domain and the spectrum range difference of mechanical excitations of the calibration system, strict comparison conditions had to be laid down for measurement of shock sensitivity at specific acceleration levels and pulse durations.

The pilot comparison, coded as APMP.AUV.V-P1, is successfully organized by Asia Pacific Metrology Programme. Some comparison results of both monopole excitation and dipole excitation are shown with the expanded uncertainty. The completion of this pilot comparison can serve as part of the basis for a planned key comparison targeted at a low intensity shock range at Consultative Committee level.