A method based on scattering parameters for model identification of piezoactuators with applications in colloidal suspension monitoring

Liquid colloids are mixtures where one substance is dispersed evenly throughout another. Piezoactuators can be reliably used to sense physical properties of colloids. However, to better understand and forecast the behavior of the system, a suitable and reliable model should be used to fit experimental data. In this work we will show how the scattering parameters, introduced for the first time in this field, can greatly improve model identification accuracy and give deeper insight into the resonant response of the system, especially in the case of viscous systems, whenever resonance peaks tend to shift or to vanish. Any change on the density and/or viscosity of the interacting fluid causes a well-predictable modification on each possible frequency response computable from measured data: the best choice in terms of sensitivity and orthogonal correlation has been investigated by means of parametric simulations with variable loads. Experimental results demonstrate that the conceived sensor is able to reliably discriminate different bentonite clay suspensions.