Nonlinear Static/Dynamic Analysis Of Piezoelectric Viscoelastic Microbeam In Thermal-electric Couple Field

Beam-type microstructures are the main MEMS structure s. They are used wide lyin microsensors, microactuators and other micro-compone nts for the ir simp le formsand excelle nt contro llability. The pie zoelectric microbeams cons ist of beam-typemicrostructures and piezoe lectric layers and their p iezoe lectric layers can effective lyimprove t he sensitivity o f microsensors and effic ie ncy o f the microactuators. In thisdissertation, cons idering viscoe lastic ity o f materia l in beam-type microstructures,piezoe lectric effect o f materia l in p iezoe lectric layers and the geo metry nonlinearityof who le microstructure, the nonlinear static and dyna mic beha vior of p iezoe lectricviscoelastic microbeam under therma l-electric couple fie ld is investigated. The ma inresearch works are as follows:Firstly，based on viscoelastic theory, Euler-Bernoulli beam assumptions andpiezoe lectric theory, the static and dyna mic differentia l go verning equations areestablis hed with the standard solid model. The static pull-in behavior of microbeam isresearched with Garlerk in method and Runge-Kutta method. The critica l cond it ion ofpull-in instability is investigated and the influence of materia l parameters and syste mparameters on critical condition is analyzed.Furthermore, cons idering geometry nonlinearity and coup le effect ofthermal-electric fie ld, the amp litude-frequenc y response characteristics ofpiezoe lectric viscoelastic microbeam in free vibration and forced vibration areinvestigated with the harmo nic ba lance method. The effect of re laxatio n modulus onresponse characteristics is firstly discussed. The result shows that the change ofrelaxation modulus leads to fluctuatio n of amplitude-frequency response within ashort duration a nd the term decaying with time can be ignored in steady vibration.Based on ana lytic result about re laxation modulus, the influences of the damp ingcoeffic ient, vo ltage a mplitude and other parameters on amp litude-freque ncycharacteristic c urve o f microbeam in free vibration a nd forced vibration areinvestigated.Fina lly, as a cla mped-guided microbeam under axia l period load ma y encounterdyna mic instability, the study on nonlinear dyna mic stability of the cla mped-guidedpiezoe lectric viscoe lastic microbea m under axia l period load and therma l-electriccoup le fie ld is necessary and performed in this dissertation. With the incre menta l harmo nic balance method (IHBM), the sens itivity o f ma inly nonlinear dyna micinstability region to the material parameters and system parameters is analyzed.