Dynamic Response of Small Cantilever Beams in Viscous Media

We have considered two configurations of cantilever beam for characterization of rheological properties (density and viscosity) of viscous material. Both the beams are made of thin steel foils, having different free end condition. The beams were vibrated in various viscous fluids such as water and lubrication oils under sweeping modes, and the frequency response of the beam was measured using Polytec laser vibrometer. For both beam configurations, the resonance frequency decreased while the width of the resonance peak (related to Q-factor) increased with increasing viscosity and density. Thus, the viscosity and the density of a liquid can be determined simultaneously using the experimentally measured resonance frequency and peak width.