Measuring shock acceleration with peak accelerations ranging from 200 to 5000 m s−2 is a significant concern for mechanical or electrical applications in industries. To precisely calibrate accelerometers using shock acceleration, we developed a shock acceleration calibration system at the National Metrology Institute of Japan. In the calibration system, the shock acceleration exciter generates shock acceleration using rigid-body collisions between three metallic bars inside an air bearing. The pick-up to be calibrated is fixed on an edge surface of the third metallic bar so that the pick-up moves together with the metallic bar. The displacement of the pick-up is measured by a He–Ne laser interferometer with traceable voltage, length and time standards. The sensitivity of the pick-up is evaluated by analysing signals from the accelerometer and laser interferometer. We describe the calibration procedure, the specification of the shock acceleration calibration system and the uncertainty in the shock-acceleration calibration. The shock acceleration calibration result has the expanded uncertainty of roughly 1.0% with a coverage factor 2 and is comparable to the vibration acceleration calibration result with an En value below 0.3.

This study describes the uncertainty of measurement about accelerometer sensitivity in shock calibration based on ISO 16063-13. The typical shock approximates to a sine-squared waveform with peak acceleration in the range from 200 to 5000 m s−2 and a pulse width of several milliseconds. The shocks are generated by a transient collision motion on contact with a rubber surface between two rigid bodies. A laser interferometer with a He–Ne laser measures the displacement change that is input to the accelerometer to be calibrated. The accelerometer sensitivity is evaluated in the time domain and defined by the ratio of the accelerometer's output peak value to the input acceleration peak value. The individual uncertainty components are assessed to formulate an uncertainty budget that includes an expanded uncertainty with a coverage factor of k = 2 at approximately 6.5 × 10−3.

Zero shift caused by the low frequency response of charge amplifiers is one of the most significant factors in shock measurements with long duration, such as low shock calibration of accelerometers. In order to reproduce the same zero shift as the charge amplifier, infinite impulse response (IIR) filters were developed by applying a second order transfer function to the high pass characteristic in the low frequency part of the measured frequency response of charge amplifiers. For the experimental verification of the zero shift using the IIR filter, input/output signals of the charge amplifier were investigated by using rectangular waveforms with a peak voltage of 2 V and pulse width of 10 ms and 5 ms, respectively. As indicated by the results, the IIR filter succeeds in following the same zero shift as the charge amplifier.

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