Validity of describing resonant viscosity and mass density sensors by linear 2nd order resonators
Sprache des Titels:
Resonant viscosity and mass density sensors are based on the determination of a mechanical oscillator?s frequency response at a characteristic resonant mode upon immersion in a liquid. In many cases the sensors? characteristics and sensitivities are demonstrated by showing the dependence of their quality factor Q and resonance frequency fr to viscosity ? and mass density ?. Commonly, the transfer function of a linear second order resonator is fit into the recorded frequency response to extract fr and Q, which are then related to the liquid?s ? and ?. This approach is widespread in the field of resonant (viscosity and mass density) sensors and thus became a common procedure. However, as from a theoretic point of view, resonators which are interacting with a liquid do not yield linear second order functions, the applicability of this standard approach and its limits are investigated in this work.