Effect of Geometry on Energy Losses In Fused Silica Dual-Shell Gyroscopes

Abstract

This paper studies the energy loss mechanism through the substrate in 3D Fused Silica dual-shell gyroscopes (DSGs), focusing on design and geometry of anchor structures. In dual-shell gyroscopes, the sensing shell element (inner shell) is anchored to a substrate through an inner stem and an outer cap shell. This configuration creates a double-end clamped anchor to enhance the robustness of the device under mechanical shock and vibrations. However, the double-ended anchor, if not optimized by design, can become a major contributor to the energy loss and adversely affect the sensor’s performance. In our analysis, we studied the effect of different anchor geometries on the anchor loss in the n=2 wineglass mode, using FEA and the Perfectly Matched Layer model. We identified the inner-to-outer shell junction as one of the key geometric characteristics in defining anchor losses in DSGs. Based on our parametric study, we confirmed the significance of location of junctions connecting the two shells on energy losses, identified a trend for optimization of geometry, and confirmed our findings experimentally.