Vibration Analysis Of Resonant Pressure Sensor

A microstructure resonant pressure sensor is characterized by its very small size, highaccuracy, excellent stability and convenient interface with digital electronics, so it haswide applications. This paper presents vibration of the resonant pressure sensor.In this dissertation, dynamic model of fixed-supported and elastic supported resonantbeam is established，and the vibration equation of resonant beam is given. The frequencyequation and the vibration model of resonant beam under the action of axial force aresolved. The inherent frequency and models of resonant beam that influenced by systemparameters and axial force are analyzed. The results show that with increase of axial force,the inherent frequency increases.An electromechanical coupled dynamic model of resonant beam is presented. Thestatic displacement, the vibration modes and the natural frequency are discussed. Based onthe mode superposition method, the forced response equation of electromechanicalcoupled resonant beam with the presence of axial force is given, and the forced vibrationis analyzed. The resonance vibration of electromechanical coupled resonant beam isstudied under considering air damping. The resonance vibration that influenced by systemparameters and axial force are analyzed. The results show that the influence of axial forceto the inherent frequency and the amplitude of electromechanical coupled resonant beamcan not be ignored.Based on the analysis of the vibration of the resonant beam, analytical formula of thesensitivity of a resonant pressure sensor is deduced, and the influence on a resonantpressure sensor of system parameters is analyzed. The results show that structureparameter, axial force, size of pressure film and width of byland all influence systemsensitivity, and system sensitivity depends on many facts, of which the size of pressurefilm is the crucial facts. With increase of pressure，the system sensitivity decreases.Considering the nonlinear characteristic of electrostatic force and axial forces, theequation of weakly nonlinear dynamics of the electromechanical coupled resonant beam isestablished. The nonlinear forced vibration that near to resonance and the nonlinear free vibration of the system dynamic rules are studied.The results show that nonlinear factorsbecome very important for the vibration of resonant beam, With chang of excitingmagnitude and small parameter, the inherent frequency of resonant beam changes,whichinfluence analytical results of a microstructure resonant pressure sensor’s sensiticity.