Characterize Dynamic Response of Cantilevers Submerged in Viscous Fluids

Miniaturized devices are essential to precisely determine the rheological properties of viscous fluid when the available sample volume is inadequate. In this paper, we have attempted to apply the finite element analysis (FEA) method to characterize the dynamic response of a mini cantilever beam to measure the rheological properties of viscous fluid. First, the dynamic response of a mini cantilever beam, partially submerged in viscous fluid, is experimentally measured, and then compared with corresponding FEA solutions. Once the FEA model is validated, further numerical analysis is conducted to investigate how the modal response would change with changing density and viscosity associated with different viscous fluids. The numerical simulations are also repeated with changing the dip-length to investigate the sensitivity analysis. It seems from numerical results that the resonant frequency, Q-factor, time constant and depth of penetration of acoustic wave are dominantly influenced by viscosity of submerged liquid. Results obtained from this study can be used to design the optimized MEMS based test set up for measuring the rheological properties of viscous fluid.