U-shaped, wire-based oscillators for rheological applications bridging the gap between 100 Hz and 100 kHz

A viscosity sensor based on an oscillating, U-shaped wire, which is operated at its fundamental resonance frequency as well as the effect of scaling of its geometry on its resonance frequency is presented in this contribution. Actuation and read-out of the sensor are both based on Lorentz forces, which allow for high long term stability of the devices, good repeatability of the measurements, relatively easy sensor designs and thus low-cost production of the sensor. The measurement setup, the sensor design as well as the approach for a complete analytical model relating input to output signals are explained. First measurements are shown, which affirm the used models and which show the functionality of the sensor. Measurements obtained in a set of scaling experiments show that with this type of devices a range of operating (i.e., resonance) frequencies of 100 Hz to 100 kHz can be obtained for device lengths of 1 mm to 3 cm.