An Investigate on Degradation Models of Resonant Frequency and Mechanical Sensitivity for Butterfly Resonator Gyroscope

Analysis of degradation model of butterfly resonator gyroscope (BRG) is essential to predict its reliability. In order to establish the degradation model of the BRG, three parts of investigation are conducted. Firstly, an analytical model is developed to describe the effect of residual stress on the resonant frequency of excitation mode for BRG. Modal analysis of the BRG under different residual stresses (29 groups) is also simulated by finite element method (FEM), and the FEM results are close to the proposed analytical model within the range of residual stress (-24 MPa to 70 MPa). Secondly, the degradation models of resonant frequency at excitation mode and mechanical sensitivity of BRG are developed based the analytical model. Finally, the long-time static test of four BRGs at same environment temperature is designed and carried out. The test results show that the resonant frequency and mechanical sensitivity of the BRG decreases gradually with time increasing, which is consistent with the results of numerical simulation. Based on the degradation model of mechanical sensitivity, the mechanical sensitivity would degrade by 20.27% in 10 years. This work contributes to reliability evaluation and life prediction of BRG. [2019-0202].