Nanocomposite microbeams for sensing applications

The nonlinear dynamic behavior of nanocomposite microbeams excited near the primary resonance of the lowest modes is investigated towards wide-band mass sensing applications. The aim of the study is to exploit and expand the frequency bandwidth of the microdevice taking into account both the nonlinear bending effect of the frequency response and the significant frequency shift of the frequencies due to the variation of carbon nanotubes (CNTs) volume fraction, a control parameter in the process design of the nanocomposite material. A nonlinear inextensible Euler-Bernoulli model is employed to describe the large bending motions, and the Ehelby-Mori-Tanaka theory is used to obtain an equivalent elastic law for the employed two-phase material. The nonlinear equation of motion is discretized via the Galerkin method, the eigenvalues analysis is carried out to detect the frequency shift and the nonlinear frequency response is unfolded and characterized using a pathfollowing technique.