The Mechanical Analysis Of Micromachined Accelerometer With Piezoelectric Thin Films Read-out

Having simple structure and high sensitivity , micromachined accelerometer is a type of popular transducer used to measure the acceleration in a great variety of conditions . The micromachined accelerometer with piezoelectric thin film read-out is a typical micromachined accelerometer and has many different configurations . The thesis presents the mechanical properties of different structures of micromachined accelerometer with piezoelectric thin film read-out , and the results may be the guideline to choose the optimum one .The thesis has done the analysis of the three different structure , both with two type :one-layer PZT thin film and two-layer PZT thin film , in which the two-layer PZT thin film is presented first time in the thesis .First , for proving the fundamental mode of the structure can measure acceleration , the program ANSYS is used to analyze the mode of these three structure.Then , combining with piezoelectric effect , elastic mechanics , composite mechanics , vibration theory , stress theory , the statistic analysis has been done with particular emphasis on the elastic characteristics of the thin film . The analytical formula of transducer , sensitivity , maximum stress are obtained . Using MATLAB software , also discuss the geometrical parameters in sensitivity . At last, a numerical calculation of certain practical micromachined accelerometer size is given .Next , the dynamic analysis has been done . The noise , quality factor , bandwidth , minimum detectable signal are obtained . Using ANSYS software to do the harmonic analysis , the dynamic response curves can be get . Finally , a calculation of certain practical micromachined accelerometer size is done .