Analysis of the vulnerability of MEMS tuning fork gyroscope during the gun launch

Micro-electromechanical systems (MEMS) gyroscope is fragile under mechanical impact. Especially, MEMS tuning fork gyroscope with movable structures, such as oscillating frames and folding beams, is susceptible to failure during the gun launch. However, the gyroscope usually presents better shock resistance in the shock test than in the ballistic environment. In this paper, the multiple high-frequency axial shocks and lateral shocks were studied to explain this phenomenon. A single-axis MEMS tuning fork gyroscope was used to analyze its behavior in response to the shock. First, theoretical analysis was performed regarding to the multiple high-frequency axial shocks and lateral shocks. Then the finite element analysis (FEA) was carried out to study the failure mode of the gyroscope under the typical shocks during the gun launch. The analysis results showed that the shocks with continuous oscillating acceleration had a significant amplification effect on the stress of the gyroscope structure. In addition, axial shocks can work with lateral shocks to cause severe stress on the weak positions of the gyroscope. Shock tests were carried out to simulate the in-bore ballistic environment, where the gyroscope experienced continuous oscillating acceleration. The experimental results showed that the critical acceleration of failure will be decreased when the gyroscope is in a state of continuous oscillations.