Investigation Of Micro-beam Device Dynamic

Micro-electro-mechanical System (MEMS) device has become ahallmark technology for the21st century. Reliability is an importantdevelopment bottleneck. Micro-cantilever is a typical structure and keycomponent， and the cracks will lead to the change of the dynamiccharacteristics of the structure. Introducing the aperture in the structure ispossible to improve the sensitivity of piezoresistive cantilever MEMSsensor. In this paper, the dynamics of cracked micro-cantileverelectromechanical coupled system and high sensitive piezoresistivecantilever MEMS sensors by introducing stress concentration region (SCR)were investigated. The main research work is as follows:(1) The single degree of freedom model of cracked micro-cantileverelectromechanical coupled system with breathing crack under squeeze filmdamping effect was established. The effects of cracks on the stiffness andnatural frequency, and Stiffness softening caused by static electricity, andnonlinear dynamic of cracked micro-cantilever were analyzed.(2) Based on Euler-Bernoulli theory, the continuous model of crackedmicro-cantilever electromechanical coupled system with masslessrotational spring model under squeeze film damping effect was established.The effects of crack position and severity on natural frequency withdifferent boundary conditions were analyzed. The effects of structureparameters on system performance parameters, such as static displacement,natural frequency, dynamical response of free vibration and forced vibration were discussed.(3) The different SCR designs for improving the sensitivity ofpiezoresistive cantilever MEMS sensor were discussed, and the method ofaverage stress was proposed which is more accurate to measure thesensitivity.In a word, the content and methods of this paper are of greatsignificance in both theoretical explorations and practical applications.