MEMS加速度计在振动环境下的可靠性分析

Reliability analysis of MEMS accelerometer in vibration environment

摘要:

以电容式MEMS加速度计为研究对象，通过理论分析振动环境下MEMS加速度计的疲劳和塑性形变等关键退化机理。基于Miner理论和S-N曲线建立了疲劳可靠性模型；在考虑强度退化前提下，基于应力强度干涉理论建立了塑性形变可靠性模型；运用蒙特卡洛仿真方法验证了两种可靠性模型的准确性，并分析了模型关键参数对可靠性的影响。结果显示，振动应力水平和材料的屈服强度对可靠度有显著的影响，减小应力幅值，增大屈服强度，可以提高MEMS加速度计的可靠性。

Abstract:

Taking capacitive MEMS accelerometer as the research object, the key degradation mechanisms such as fatigue and plastic deformation of MEMS accelerometer under vibration environment were analyzed theoretically. The fatigue reliability model was established based on Miner''s theory and S-N curve. The reliability model of plastic deformation was established based on the stress intensity interference theory considering the strength degradation. The Monte Carlo simulation method was used to verify the accuracy of these two degradation failure models, and the influence of key parameters on the reliability of the models was analyzed. The results showed that the vibration stress level and the yield strength of the material had significant influence on the reliability. Reducing the stress amplitude and increasing the yield strength can improve the reliability of MEMS accelerometer.