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Multi-field Coupled Dynamics Research Of Micro-Beam Resonant Pressure Sensor

Posted on:2016-05-24Degree:MasterType:Thesis
Country:ChinaCandidate:Z C WangFull Text:PDF
GTID:2308330479450825Subject:Mechanical design and theory
Abstract/Summary:PDF Full Text Request
Micro-beam resonant pressure sensor, which has broad application prospects with the advantage of high sensitivity, can measure pressure by testing the changes of the resonant frequency of the micro resonant beam. Here, the multi-field coupled dynamics characteristic of micro-beam resonant pressure sensor is studied.The vibration balance equation of micro resonant beam, under the effects of the electrostatic force, the molecular force and the squeezed film damping force, is established. The multi-field coupled static balance equation and dynamic equation of micro resonant beam under multi-field forces is deduced. The multi-field coupled free vibration of a micro resonant beam is analyzed. Results show that considering the molecular interaction, the pull-in voltage decreases; when the length and the width increases, the thickness decreases, and the initial clearance between the micro beam and base plate decreases, the molecular force has more significant effect on the sensitivity of the micro resonant beam; considering squeezed film damping, the effects of electrostatic force and molecular force on the resonant frequency of micro resonant beam increase.The nonlinear vibration balance equation of the micro resonant beam are established when the electrostatic force, the air damping force and the molecular force are considered. Based on the multiple scales method, the equation of the amplitude-frequency relationship of the micro beam are also deduced. The forced vibration of a micro resonant beam is analyzed. Results show that when the voltage between the micro beam and the base plate is large, the initial clearance between the micro beam and base plate is small, and the dynamic viscosity of the air is small, the effects of the electrostatic force and the molecular force on the vibrations of the micro resonant beam are obvious and can not be ignored.The relationship between the resonant frequency of the micro resonant beam and the pressure on the pressure film is found. The equation of the sensitivity of the sensor is obtained. The factors influencing the sensitivity of resonant pressure sensor are discussed. Results show that when the pressure on the pressure film drops, the effect of the molecular force on the sensitivity of the sensor grows.Based on ANSYS, the stress on the the pressure film is analyzed, as well as the resonant frequency and the harmonic response of the micro resonant beam. The micro-beam resonant pressure sensor is manufactured. The resonant frequency of the sensor is tested by the experimental platform of electrostatic excitation and capacitive detecting method. The validity of the theory analysis in this paper is proved.
Keywords/Search Tags:micro-beam, resonant pressure sensor, multi-field coupled, resonant frequency, amplitude-frequency relationship, nonlinear vibration, molecular force, sensitivity
PDF Full Text Request
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