Progettazione e realizzazione di smart materials a controllo passivo per applicazioni acustiche = Design and manufacturing of passive materials for acoustic applications

The Dilatancy (Shear-thickening) is a time-independent behaviour exhibited by some non-Newtonian fluids, consisting in an abrupt increase in the apparent viscosity with the shear rate. These fluids can be used to design novel composite materials with increased sound insulating properties: in order to optimize their rheological properties, a refined model of their constitutive behaviour is necessary. The objective of the first part of the thesis is the optimization of the rheological behaviour of these fluids. A coupled steady/oscillatory shear rheological approach was employed in order to derive a novel master curve for the material: this allows to predict the best combinations of fillers and carriers capable of granting the final product with the highest sound insulation capabilities. Finally, during the second part of the thesis, numerical models for the sound insulation of the fully assembled smart material were developed and validated with experimental sound insertion loss tests.