【摘要】 对一种新型双悬臂梁高gn 值MEMS加速度传感器进行有限元模拟。采用双悬臂梁传感芯片的一种实际封装结构 ,进行频域分析和时域分析 ,讨论封合传感器芯片和封装基体的封合材料对其输出信号的影响。频域分析表明 ,封合材料的杨氏模量对封装后加速度传感器整体的振动模态有一定影响 ,封合胶的杨氏模量很小时 ,会致使加速度传感器的信号失真 ,模拟表明可选用杨氏模量足够高的环氧树脂类作高gn 值传感器的封合材料。时域分析静态模拟表明 ,封合材料的杨氏模量 ,对最大等效应力和沿加载垂直方向的正应力最大最小值基本无影响。时域分析动态模拟表明 ,随着封合材料杨氏模量的提高 ,动态模拟输出的悬臂梁末端节点位移的波形和其经数字滤波后输出的信号变好 ,封合材料的杨氏模量不影响输出信号的频率和均值 ,在加速度脉冲幅值输入信号变化时 ,悬臂梁末端位移平均值输出信号与输入有良好的线性关系。更多还原

【Abstract】 The finite element simulations have been applied in frequency domain analysis and time domain analysis for a packaged accelerometer used in high g n environments.In order to understand the effect of seal material between the sensor chip and the package bulk on output signal of accelerometer,a practical packaging structure of sensor chip with double cantilevers has been simulated in this analysis.Frequency domain analysis shows that the Young’s moduli of seal adhesive materials have a significant influence on the mode shape of accelerometer packaged and the small Young’s modulus will bring in a strong distortion of outputs of accelerometer.The results of time domain static analysis showed that the maximal equivalent stress and the maximal and minimal normal stress in vertical direction of loading were not affected by the Young’s modulus of adhesive in these simulations.In time domain transient analysis,the results showed that the wave shapes of the displacements at the ends of cantilevers,and the output signals after digital filtering became better as the Young’s modulus increased.The results simulated also showed that the frequency and average value of outputs were not affected by the Young’s modulus of seal adhesives, and when the input signals of the acceleration pulse amplitudes changed the output signals of the average values of the displacements at the ends of cantilevers were dependent linearly on the inputs very well.更多还原