A Hybrid Experimental/Numerical Investigation of the Response of Multilayered MEMS Devices to Dynamic Loading

In order to probe the mechanical response of microelectromechanical systems (MEMS) subjected to dynamic loading, a modified split Hopkinson pressure bar was used to load MEMS devices at accelerations ranging from 10³–10⁵  g. Multilayer beams consisting of a PZT film sandwiched between two metal electrodes atop an elastic layer of silicon dioxide were studied because of their relevance to active MEMS devices. Experiments were conducted using the modified split Hopkinson pressure bar to quantify the effects of dynamic loading amplitude, duration, and temporal profile on the failure of the multilayered cantilever beams. Companion finite element simulations of these beams, informed by experimental measurements, were conducted to shed light into the deformation of the multilayered beams. Results of the numerical simulations were then coupled with independent experimental measurements of failure stress in order to predict the material layer at which failure initiation occurred, and the associated time to failure. High-speed imaging was also used to capture the first real-time images of MEMS structures responding to dynamic loading and successfully compare the recorded failure event with those predicted numerically.