Smart Materials and Nonlinear Dynamics for Innovative Transducers

The exploitation of smart material properties and nonlinear dynamics behavior is the focus of this work, with emphasis on the realization of innovative transducers. Both ferromagnetic and ferroelectric properties are taken into account to develop sensors and actuators for various application fields. In particular, ferromagnetic materials have been used to realize sensors adopted in several innovative measurement solutions such as volcanic ash detection or magnetic bead-based estimation; they have also yielded innovative sensing strategies to estimate fluid viscosity with a very low invasive approach. The use of smart magnetic fluids has been considered, for their shock resistance and their intrinsic feature to be shapeless, for the development of suitable sensors and actuators. Ferrofluidic pumps, gyroscopes and inclinometers have been developed and characterized. Finally, a nonlinear dynamical system based on ferroelectric capacitors coupled into a unidirectional ring circuit is considered with particular interest for developing novel electric field sensors. The focused approach is based on the exploitation of circuits made up by the ring connection of an odd number of elements containing a ferroelectric capacitor, which under particular conditions exhibits an oscillating regime of behavior. For such a device a weak, external, target electric field interacts with the system thus inducing perturbation of the polarization of the ferroelectric material; this, the target signal can be indirectly detected and quantified via its effect on the system response.