Dynamic Identification of MEMS by Eigensensitivity and Newmark Simulation

The study of dynamic behavior is essential for a large number of applications involving microelectromechanical systems (MEMS). Although solutions for static analysis are reaching maturity the simulation of dynamic behavior is still a demanding problem. As analytical solutions for coupled-field problems are hard to be obtained, numerical methods are preferred. In this work, three different numerical strategies for physical level dynamic analysis of MEMS are reported and evaluated. The first approach is based on the Newmark direct integration method, modified to consider the electromechanical coupled-field effects of MEMS. A second method describes the system dynamic behavior through the modal solution of an eigenvalue problem. The numerical algorithms for these two methods are inserted in the software MefLab++. MefLab++ is an object-oriented computer code (written in C++) for numerical simulation of physical problems. The third dynamic simulation is carried out with the ANSYS commercial software by using its transducer element TRANS126 to model the electrical field. The three methods are applied to simple beams and results are compared. The tested methods showed to be suitable for computing the natural frequencies of MEMS structures. Simulation with the ANSYS reduced order element TRANS126 was faster while MefLab++ displacements values were more precise.