MS10.2: Micro- and Nano-Electro-Mechanical Systems

The nonlinear dynamics of nanomechanical resonators has drawn great interest for applications in sensing, material characterisation and for uncovering fundamental interactions at the nanoscale. Here, we explore multi-tone excitation as a route towards extracting the full nonlinear reduced order model of a multi-mode nanomechanical resonator. By driving at two frequencies, the nonlinear terms in the equation of motion will cause the generation of sum and difference frequencies. When these combination frequencies align with a natural resonance frequency of the resonator, they can be detected. We present an experimental methodology to perform these experiments and show how we can extract the relevant nonlinear reduced order model parameters by analyzing the amplitude of the response. The resulting experimentally extracted reduced order model can be used for validating nonlinear models, for characterizing nonlinearities in resonant systems, for estimating the magnitude of physics induced nonlinearities and for designing nonlinear mechanical systems with accurately tuned nonlinear properties. In this work we present the methodology and initial experimental results.

We identify the existence of nonlinear viscoelastic damping in conductive metallic nanowires that are subject to magnetic excitation and investigate its effects on the spatiotemporal dynamical system response. We derive a consistent continuum-based modal dynamical system for a geometrically nonlinear viscoelastic nanowire that is subject to magnetic excitation and employ a combined asymptotic and numerical methodology to estimate the magnitude of viscoelastic damping from controlled benchmark nanowire experiments. The criteria for bistable planar response estimated from experiments enables estimation of the cubic viscoelastic damping parameter for small magnetomotive excitation culminating with the transition to three-dimensional periodic and nonstationary whirling nanowire dynamics with increasing magnitude of excitation.

We study the nonlinear dynamics of 2D material nanoresonators during a second-order phase transition. We probe the dynamics of these resonators at the vicinity of the phase transition temperature. We observe dramatic changes in the nonlinear parameters of the system while sweeping the temperature at this vicinity. We explain the observed changes in these parameters with an analytical magnetostriction model.

Liquid density measurement using buried channel microresonators reduces the sample amount compared to those using macro-scale ones. In this study, we consider a buried channel microcantilever made of stainless-steel for density measurement use. We propose the utilization of electrostatic force to excite the stainless-steel microcantilever directly to eliminate the dynamic coupling between a microcantilever and its holder. The validity of electrostatic excitation is confirmed through the experiments on exciting stainless-steel microcantilever.

Amongst the many unique properties of chaos, the discovery of chaos synchronization has become a cornerstone in the understanding of nonlinear dynamical systems. While identical synchronization of mechanical structures has been demonstrated numerically in different configurations, very few investigations tackled experimental realizations due to the extreme sensitivity to parameter mismatch between the two synchronized systems. We present here an experimental demonstration of identical synchronization between two distinct chaotic micromechanical resonators exploiting dynamical bistability. Uncoupled, the two strange attractors are highly correlated while the time evolution of their dynamics are uncorrelated. When the two microresonators are synchronized in a master-slave configuration, their dynamics evolves within a standard deviation below 2%. Such a high quality of chaos synchronization between two distant structures paves the way towards micromechanical-based chaos applications, such as chaotic cryptography.