Calibration of accelerometers:: determination of amplitude and phase response upon shock excitation

A novel approach is proposed for the analysis of shock calibration measurements of accelerometers. The input/output behaviour of an accelerometer is represented by a physical model in terms of a second-order differential equation. The unknown model parameters, i.e. the coefficients of the differential equation, are estimated by a frequency domain least-squares approach. The derived model is then used to determine the frequency response of the accelerometer. The method was applied to calibration measurements upon shock excitations of two back-to-back accelerometers (ENDEVCO type 2270 and Bruel & Kjaer type 8305). The determined frequency response was then compared to additional calibration measurements upon sinusoidal excitation. The sinusoidal excitation measurements were analysed by means of the established sine approximation method. Consistent results were obtained by the two methods which confirm the validity of the proposed modelling approach.