Piezoelectrically actuated microcantilevers: An experimental nonlinear vibration analysis

With daily growth of using microcantilevers in microelectromechanical systems, comprehensive analysis on their dynamical behavior is necessary since they are mostly utilized as the main sensing device. In this paper, out-of-plane vibrations of a piezoelectrically actuated microcantilever are experimentally investigated. The microcantilever's top layer is covered with a piezoelectric material (here, ZnO) through which it can be excited. The nonlinear frequency response of the microcantilever is studied and the resulting shift in natural frequency due to nonlinearity is examined. By observing the subharmonics of the fundamental frequencies at second and third order, it is experimentally shown that there exist cubic and quadratic nonlinearities in the microcantilever. Mathematical models based on these experimental tests are then proposed and verified. The out-of-plane measurements provide the experimental ability to observe both transversal and torsional modes. In addition, the modes in which the microcantilever acts like a plate are observed and discussed.