Dynamics Analysis For Cantilever Of Micro-accelerometer

Micro Electro-Mechanical System (MEMS) is an emerging interdisciplinary field, withpossessing a very broad application prospects, the MEMS has become a hotspot ofinternational Research&Development project. In recent years, with the rapid development ofmicro electro mechanical system, micro accelerometer is one of the most important part, inorder to ensure that the micro accelerometer is accurate and stable in working. the dynamicanalysis research of the micro accelerometer has important theoretical significance andpractical application value.This paper establishes its equivalent model system for a typical MEMS devices(cantilever of micro-accelerometer), which mainly studies the two parts of the vibrationcharacteristics and aerodynamic performance of the cantilever. To analyze the vibrationcharacteristics of the micro-cantilever beam, using finite element analysis software ANSYSWorkbench establishes the finite element model of the cantilever beam, and finishes its themodal analysis and harmonic response analysis, and gets the six order vibration frequency andvibration of the cantilever beam, and that the frequency of cantilever beam will increase withcantilever beam size decreasing, which provides relative theory basis for the relation ofcantilever beam size design and its effect for corresponding frequency; Under the harmonicresponse analysis, it obtains the curve of beam stress frequency response and displacementfrequency response of different frequency of the cantilever, and the biggest stress strength7.67MPa of cantilever beam in resonance meets limit of the allowed fatigue ultimate strength,the cantilever beam will be safe, at the same time, it determines the frequency response rangeof micro-accelerometer based on this cantilever beam. For the aerodynamic performance ofthe cantilever beam, it mainly studies the aerodynamic performance by using the different gapof cantilever and container wall in the range of1~9um, using the fluid flow calculationsoftware FLUENT studies the aerodynamic characteristics of the cross flow and cantileverflow around the cantilever beam, and gets the graphs of pressure distribution and velocitydistribution in the surrounding space under different circumstances around section flow fieldof cantilever beam. As a result, it shows that the gap between cantilever beam and containerwall is3um, the vibration resistance for cantilever beam is the largest, this situation should beavoided in the size design; the growing of gap can increase eddy current region, leading to thevibration amplitude of cantilever beam decreasing, So when it comes to a gap of5μm, the gas has the least effect for the damping of cantilever beam,and the micro-accelerometer has themost range. As a result, it range of this micro-cantilever beam accelerometer.