The analysis of gyro parameters degradation and finite element modeling

Considering the environmental stress characteristics of storage conditions, Fault Mode Mechanism and Effect Analysis (FMMEA) method is introduced to Dynamic Turned Gyroscopes (DTG) to determine the affecting stress type and the weak component. The analysis result shows that the temperature stress is confirmed as the most important influencing environmental factor, related to the performance degradation of DTG, the degradation of drift rate related to `g' is the main fault mode, and the rotor block is considered to be the weakest link in DTG. It is also confirmed that the structures and size unstable of rotor block as well as the glue creep are the main mechanism for the rotor centroid shift which is the dominated source of the drift rate related to `g' as one of the errors for DTG. On the basis of the analysed results above, materials, structures and their variations with temperature are investigated firstly. Combined with the existing research conclusions about DTG and its components, a Finite Element Model (FEM) of the rotor block is established. Then the computational relationship between temperature stress and the rotor centroid shift can be obtained by finite element simulation and the degeneration of drift rate related to g is calculated accordingly. Finally, one given DTG is simulated by finite element analysis method with its actual parameters and drift rate related to g error as the outcome. Comparison is made between the simulated results and the storage experiment data which shows that their trend is basically consistent. All of the above proves the location of the main failure mechanism and the correctness of the method. Hence, the research of this paper lays a foundation for DTG storage life prediction modeling.