Th e Ef f e c t o f Ma s s Lo a d in g o n t h e Se n s it iv it y o f Sh o c k Ac c e l e r o m e t e r s

1. i n t r o d u c t i o n Mass loading affects the sensitivity of accelerometers. The mass loading effect can be corrected using mass loading correction curves published by manufacturers [1]. These curves, however, are only applicable to the sinusoidal acceleration below 500 m/s2. The mass loading effect on the sensitivity of accelerometer Endevco 2270 in shock calibration, from 500 m/s2 and up, is investigated using a vibrometer. The output waveforms of the accelerometer and vibrometer are compared in this study. Since the output waveform of the vibrometer is an integration of the acceleration waveform, small changes in the peak value of the acceleration waveform are masked by the acceleration waveform shape changes between measurements. Thus, the mass loading effect cannot be determined from the direct output of the vibrometer. Traditional differentiators that can convert the velocity output to acceleration suffer from noise. To overcome the noise problem, digital signal processing techniques are used. Existing filtering algorithms [2], [3] are not suitable for this application because of the rapid change of acceleration in shock calibration and the requirement for precision measurement.