【摘要】 以一种新型高G值MEMS加速度传感器为例进行有限元模拟,将实际封装简化为一种最简单的封装结构,进行频域分析和时域分析,讨论粘结传感器芯片和封装基体的封接材料对其输出信号的影响。频域分析表明,封接材料的杨氏模量对封装后加速度传感器整体的振动模态的影响很大,封接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G值传感器的封接材料。时域分析静态模拟表明,封接材料的杨氏模量对最大等效应力、最大正应力以及沿加载垂直方向的正应力的最大值与最小值基本无影响。时域分析动态模拟表明,随着封接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经数字滤波后输出的信号变好,封接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】 Finite element simulations are applied in frequency -domain analysis a nd time -domain analysis for a packaged accelerometer used in high G environments.In ord er to understand the effect of adhesive material between the sen sor chip and the package bulk on output signal of accelerometer,a simplified packaged construction is adopted in the analysis.Frequency -domain analysis shows that the Young’ s moduli of adhesive materials have a n important influence on the mode shape of packaged accelerometer and the small Young’ s modulus will bring in a strong disto rtion of outputs of accelerometer.The results of time -domain static an alysis show that the maximal equivalent stress,the maximal normal stress,and the maximal and minimal normal stress in vertical direction o f loading are not affected by the Young’ s modulus of adhesive in these simula tions.In time domain transient analysis,the results show that the wave shapes of accelero meter output signals become better a fter digital filtering as the Young’ s modulus increase.The results simu lated also show that the frequency an d average value of outputs are not affected by the Young’ s modulus of adhesives,and the outputs are dependent linearly on the inputs very well as the inputs o f the acceleration amplitudes change.更多还原