PMN-PT based smart sensing system for viscosity and density measurement

This paper presents a smart sensing system for viscosity and density measurement of viscous fluids. The proposed system is based on the vibrational properties of a cantilever probe bonded with newly developed piezoelectric materials-Lead Magnesium Niobate/Lead Titanate (PMN-PT) transducer, which has a piezoelectric charge constant (d33) more than 3 times larger than that of traditional piezoelectric material Lead zirconate titanate (PZT). The proposed system utilizes a PMN-PT single crystal for actuation and laser vibrometer for vibration detection. Using the PMN-PT transducer, the measured viscosity and density of fluids were extracted by analyzing the vibrational properties of the smart probe. Finite element analysis was conducted with COMSOL Multiphysics for theoretical calculation and lab tests were carried out to verify and evaluate the simulation results. This smart sensing system can be applied to in-field, in situ and real-time monitoring of viscous fluids, such as blood, engine oil and early-age concrete.