The Study On Calibration Of Dynamic Amplitude-frequency Characteristics Of High Natural Frequency High-g Accelerometer

With the rapid development of sensor technology, high natural frequency high-gaccelerometer is increasingly applied to the key areas of military and defense, and thedynamic characteristics of the accelerometer has played a decisive role on accuracy andperformance of the measurement system. High overload test often leads to changes in thedynamic characteristics, thus the dynamic calibration of amplitude-frequency characteristic isnecessary. Based on the brief analysis on the basic mode and calibration of dynamicamplitude-frequency characteristic of the sensor, several aspects are mainly studied asfollowings:(1) Excitation signal generation and measurement. Comparative experiments show thatmicro Hopkinson bar proposed here, can produce an excitation signal required for calibration,whose amplitude could reach10,0000gn, while pulse width could be less than10μs; and theaxial laser measurement method is better than both the strain gages method and horizontallaser measurement method.(2) The installation structure model analysis and the finite element simulation. Thesensor and its installing carrier thin-walled cylinder are equivalent for a biquad system, andthrough the ANSYS/LS-DYNA software, installation structure models which include themounting seat-sleeve conventional type, the gasket-smooth hole improved type, and the rodend-smooth hole direct type, are conducted the finite element model simulation. Results showthat in these installation structures, the axial laser measuring signals and the sensor excitationsignals which are measured at the bottom actually are different. The simulation results pointout the next improvement direction of installation way.(3) Amplitude-frequency characteristics calibration experiments. Three differentinstallation methods are adopted to conduct the dynamic amplitude-frequency characteristics calibration experiments. The results show that: the system designed this paper can provokehigher order resonance components; compared to mounting seat-sleeve conventional type andthe gasket-smooth hole improved type, amplitude-frequency characteristic curve is morestraight in working band obtained by the rod end-smooth hole direct type, the maximumfluctuations of the amplitude is-2dB.