Theoretical And Experimental Study On The Shock Calibration For High-g Accelerometers

This paper is mainly research the high-g accelerometer shock calibration methods in order to improve the calibration accuracy for the penetration testing to provide a reliable accelerometer parameters. Having been searched abroad the related documents, the paper adopts the methods such as theoretical analysis, computer simulation and experimental study to investigate the issues in question:(1) In the Doppler signal decoding, a kind of arithmetic about decoding the Doppler signals is compiled to test the precision of the zero-cross method and the phase method. The simulating result shows that the phase method is superior to the zero-cross method with the error of 0.20%, under the SNR of 30dB. A 988-type accelerometer is calibrated with the input acceleration ranging from 18371g to 86806g, which has justified the efficiency of the calibration apparatus and the method for signal processing.(2) In the aspect of removing interference signals, because of the power frequency interference, frequency of 50Hz periodic signals mixed in the output signal of the accelerometer. It is difficult to distinguish the acceleration signal. This paper presents a filtering algorithm by analyzing the frequency components of interference signal, which effectively eliminates the influence that power frequency interference on the accelerometer output signals.(3) In the calibration data processing, using time-domain modeling methods to establish accelerometer dynamic mathematical model to obtain accelerometer dynamic characteristic parameter, the 8309-type accelerometer calculation results show that the resonant frequency of accelerometer and assembly seat is 76.8kHz, and frequency band is 0-53.8kHz or 0-69.2kHz.(4) In the calibration error analysis, on the basis of the mechanical model that establishment of Hopkinson bar mechanical quantities (stress, velocity, acceleration) communication and transformation, measurement error of transverse laser velocimetry system to excitation signal are discussed under two kinds of ideal limit conditions. According to the results estimate measurement error of excitation signal in the actual situation of calibration.In this paper,988-type and 8309-type piezoelectric accelerometers and a kind of piezoresistive-type accelerometer SIMIT-AYZ-3 are used. And the result of the calibrations entitled this calibration device and the method with validity.