Structural Optimization And Dynamic Characteristics Analysis Of MEMS Bistable Inertial Switch

As a special inertial switch,MEMS bistable switch has the advantages of pure mechanical structure,anti-electromagnetic interference and stable self-locking.It has important application in the fields of weaponry,aerospace and automobile safety.In this thesis,a novel MEMS bistable switch were designed,which can realize the function of closing at ultra low g acceleration and breaking at high g acceleration.The main contributions of this thesis are as follows:Firstly,the structural characteristics and working principle of MEMS inertia switch are briefly introduced.The characteristics and shortcomings of several common MEMS inertia switches at home and abroad are analyzed.The advantages and broad application prospects of MEMS bistable inertial switch are analyzed.Comparing the mechanical properties of different bistable structures,the three-segments long oblique beam is determined as the bistable structure of the switch,and its simulation analysis and design are carried out.According to the design requirements of the switch,a new type of MEMS bistable inertial switch is proposed and the basic working principle is introduced.The folding beam spring and mass block are designed respectively,and the overall structure size of the MEMS bistable inertial switch is determined preliminarilySecondly,the significance of MEMS bistable switch parameter optimization is analyzed,and the relevant theoretical basis of parameter optimization is introduced.According to the uncertainty factors in the micromachining process,the parameters of the MEMS bistable switch are optimized and the optimal structure is obtained.Then the mechanical properties of the optimized structure are analyzed.The maximum buckling elastic force of the bistable structure is significantly reduced,and the variance of the minimum force under the uncertain factor is significantly reduced,that is,the contact contact pressure fluctuation range is significantly reduced when the switch is closed.So the reliability of the switch is further improved.Finally,the uncertainty analysis and sensitivity analysis of the optimized structure are carried out to further guide the manufacturing processing.Thirdly,the dynamic characteristics of the optimized MEMS bistable switch are analyzed.Through the force analysis of large and small masses,the dynamic simulation model is established.The dynamic simulation of the switch under threshold excitation and disturbance excitation is carried out by using MATLAB.The dynamic response curve of the switch under different excitations is obtained.The complete working state of the switch is analyzed,and the function realization and anti-disturbance capability of the switch are preliminarily verified.Finally,the related micromachining process of MEMS bistable switch is introduced.The function of the completed switching device is tested.The MEMS bistable switch can close under the forward threshold excitation and disconnected under reverse threshold excitation,which achieving the desired goals of the switch design.In this thesis,a new MEMS bistable switch is designed,and a set of structural design,characteristic simulation,parameter optimization and flow processing for the switch is proposed,which provides a complete reference solutions for design,optimization,simulation,and machining of MEMS bistable switch and other complex MEMS device.