Dynamic Analysis Of Micro-machined Accelerometer Under High Overload

Under the launch condition of ultra-high speed, the accelerometer of bullet is supposed to bear high vertical-horizontal overload, high pressure, high-frequency vibration and acquire acceleration datum accurately. Compared to general accelerometers, the micro-machined accelerometer is preferred in measuring the acceleration of bullet, for longer life, higher reliability, lower cost and smaller volume.The measurement of bullet acceleration and research on theory of accelerometer are the new developing direction of testing system of interior ballistic. This research is a newest topic of interior ballistic test. Based on the technology of MEMS, this thesis focuses on the micro-machined accelerometer of the 76mm gun, whose greatest impact is 133,000g.In this thesis, we build a classical model of interior ballistics. By adopting this model, we calculate the trends of gas pressure in the bore, velocity and acceleration of bullet, in order to provide initial datum for designing the micro-machined accelerometer. Considering working environments and design requirement of accelerator, we adopt variable-gap capacitive accelerometer as our object of study. First, we build its mechanical model and analyze the stress, the static and dynamic performances, and the damp of the capacitive accelerometer. The structure parameters of the accelerometer are optimally designed. Secondly, we complete the simulation of statistics, the transient kinetics and the mode by utilizing ANSYS. The comparing between the analysis result and the theoretical value is presented. Finally, the analysis results show that the high g MEMS accelerometer designed in this thesis meets the demand of stress and impact resistance.