Unimorph based sensor modelling and rheological assessment of fluidic media using frequency response of improved sensor design

This work presents a hassle-free rheological assessment of fluidic media using the frequency response of a self-sensing and self-actuating piezoelectric cantilever sensor. Firstly, an analytical modelling approach for a unimorph-based cantilever sensor is derived and validated. Afterwards, the sensing performance of a rectangular cantilever sensor is improved by modifying its profile to a stepped shape. Frequency response parameters of the cantilever sensors are tracked in vacuum as well as in water, glycerin and varying concentration glycerin solution. These parameters are used to develop the calibration curves for the density and viscosity assessment of the water-glycerin solutions. The calculated density and viscosity utilizing the cantilever sensors are in good agreement with the respective values given by the standard instruments. This implies that the presented sensors can be successfully used for density and viscosity measurement of range 1000–1270 kg/m3 and 12.82–41.35 cP, respectively. The presented method is capable to simultaneously estimate the density and viscosity of the fluidic media without fully immersing the sensor in that media, which can tackle many operational troubles.