LAUSR

In this paper we analyze the flexural dynamics of MEMS cantilever immersed in a fluid medium by taking into account the effect of tangential viscous drag due to beam curvature. The latter appears as an additive nonlinear damping term in the equation of motion. The cantilever motion is described within the framework of Euler-Bernoulli beam theory by using the normal mode representation. It is found that the tangential drag with beam curvature makes the cantilever oscillation frequency to depend on its amplitude. This effect is more pronounced for the large aspect ratio cantilevers in high viscosity media. Implications of this for the interpretation of AFM and biosensor data are discussed and a method for correction is suggested.