Ground Motion Acceleration Sensor

The importance of seismic accelerometer on petroleum exploring, quake forecasting, municipal administration and military affairs is discussed firstly in the thesis. After overviewed the research situation of capacitive accelerometer in and abroad, a new structured silicon force-balanced capacitive accelerometer is put forward.By the known models of the accelerometer, we analysis many facets of how to design a capacitive accelerometer in this paper, especially the structure, work principium, dynamics and electrics. The supporting beams are classified by beam structure, the elastic modulus of z direction are calculated by dynamics and mechanics of materials. Finally, optimization design and arts design are performed.In order to calculate the deflection parameters of cantilever beam, a full static, mode and harmonic finite element analysis (FEA) using the ANSYS Finite-Element program is performed. The results derived from FEA are well analyzed for the discipline of structure and its displacement, resonant frequency and mode. The simulating results are verified by academic calculating. Instantaneous dynamics and coupled-field analysis are also conducted.In this article, the mechanics and the flow-mechanics are used, the air-damping of the microstructure and dynamic characters are researched, the squeezing air film model between the mass bulk and cover plate are established, and the damping optimal design about the microstructure is given.Potting is a key step for the packaging of low-g micro electro mechanical system (MEMS) accelerometer. The pouring can improve the reliability of packaging. Finite element simulations are applied in frequency-domain analysis and time-domain analysis.After the structure is confirmed, professional software is used to design the marks and constitute the fabrication process which adapts to the seismic accelerometer. Signal checking system for capacitive accelerometer is discussed, and the interface circuits are analyzed.