Modeling and analysis of the stress effects for trimmed cupped resonator under varying temperature

Trimming of resonators is an important process to improve the performance of the cupped gyroscopes. However, it may cause uneven thermal stress which destroys the stability of frequency split and mode shape. Though frequency splits can be reduced to the same degree by trimming at different positions of the resonator, the thermal stresses caused by varying temperatures are significantly different. In this paper, the stress effects of trimmed cupped resonators considering the influence of temperature are studied. The dynamical behavior of the cupped resonators at various temperatures is presented. The stress effects of trimmed resonators due to temperature variation are analyzed based on FE model. Simulation results show that under the same conditions, the bottom trimming gives rise to much more thermal stress than suspension trimming and ring trimming. In addition, a trimming method based on adding mass is studied. Finally, experiments were set up to validate the stress effect by using vibration measurement equipments and frequency analysis equipments. Experimental results show that with reference to the temperature variation the bottom trimming affects the frequency split and the mode deflection of the cupped resonator significantly.