Yu Zhanqing, Chen Shiping, Mou Ya, Hu Fade
State Key Lab of Power Systems, Department of Electrical Engineering, Tsinghua University, Beijing 100084, China.
Department of Precision Instrument, Tsinghua University, Beijing 100084, China.
Sensors (Basel). 2022 Jan 29;22(3):1056. doi: 10.3390/s22031056.
The reliability and stability of MEMS electrostatic comb resonators have become bottlenecks in practical applications. However, there are few studies that comprehensively consider the nonlinear dynamic behavior characteristics of MEMS systems and devices in a coupled field so that the related simulation accuracy is low and cannot meet the needs of design applications. In this paper, to avoid the computational complexity and the uncertainty of the results of three-field direct coupling and take into the damping nonlinearity caused by coupled fields, a novel electrostatic-fluid-structure three-field indirect coupling method is proposed. Taking an actual microcomb resonant electric field sensor as an example, an electrostatic-fluid-structure multiphysics coupling 3D finite element simulation model is established. After considering the influence of nonlinear damping concerning the large displacement of the structure and the microscale effect, multifield coupling dynamics research is carried out using COMSOL software. The multiorder eigenmodes, resonant frequency, vibration amplitude, and the distribution of fluid load of the microresonator are calculated and analyzed. The simulated data of resonance frequency and displacement amplitude are compared with the measured data. The results show that the fluid load distribution of the microelectrostatic comb resonator along the thickness direction is high in the middle and low on both sides. The viscous damping of the sensor under atmospheric pressure is mainly composed of the incompressible flow damping of the comb teeth, which is an order of magnitude larger than those of other parts. Compared with the measured data, it can be concluded that the amplitude and resonance frequency of the microresonator considering the nonlinear damping force and residual thermal stress are close to the experimental values (amplitude error: 15.47%, resonance frequency error: 12.48%). This article provides a reference for studies on the dynamic characteristics of electrostatically driven MEMS devices.
MEMS静电梳状谐振器的可靠性和稳定性已成为其实际应用中的瓶颈。然而，很少有研究全面考虑MEMS系统和器件在耦合场中的非线性动态行为特性，导致相关仿真精度较低，无法满足设计应用的需求。本文为避免三场直接耦合的计算复杂性和结果的不确定性，并考虑耦合场引起的阻尼非线性，提出了一种新颖的静电-流体-结构三场间接耦合方法。以实际的微梳谐振电场传感器为例，建立了静电-流体-结构多物理场耦合三维有限元仿真模型。考虑结构大位移引起的非线性阻尼和微尺度效应的影响后，使用COMSOL软件进行多场耦合动力学研究。计算并分析了微谐振器的多阶本征模态、谐振频率、振动幅度以及流体载荷分布。将谐振频率和位移幅度的仿真数据与实测数据进行比较。结果表明，微静电梳状谐振器沿厚度方向的流体载荷分布中间高两侧低。传感器在大气压力下的粘性阻尼主要由梳齿的不可压缩流动阻尼组成，比其他部分大一个数量级。与实测数据相比，可以得出考虑非线性阻尼力和残余热应力的微谐振器的幅度和谐振频率接近实验值（幅度误差：15.47%，谐振频率误差：12.48%）。本文为静电驱动MEMS器件的动态特性研究提供了参考。
