Progettazione e validazione di materiali compositi attivi rinforzati con fibra SMA per strutture adattative, nell’ambito del progetto Prin 2015 n. 2015RT8Y45-PE8 dal titolo Smart Composite Laminates

Smart materials such as piezoelectrics and shape memory alloys (SMA) are receiving increasing attention due to their possible application in actuators technology, shape morphing structures, energy harvesters, and vibration control. However, their practical diffusion is limited due to restrictions associated with scarce mechanical properties, low electro-mechanical conversion rates, or difficulties in the modulation of their morphed shape while actuated. Overarching objective of this project is developing and characterizing innovative smart structures which can either serve as conductors, energy harvesters, or selectively modulate their shape (shape morphing) by combining innovative piezoelectric materials with SMAs to form a new class of smart structural composites. Final effort of this project is not only the development of innovative smart composite materials, but also the development of prototypal energy harvester and shape morphing structures to assess their effective smart capabilities. The proper development of such a technology involves a broad range of expertises. First, the development, optimization, and characterisation of such smart composite materials. Second, the formulation of tools capable of predicting the complex thermo-electro-mechanical behaviour of the envisioned structures to aid the optimization of their design. Third, the development of mechatronic techniques for the autonomous implementation of the morphing process, which passes through the creation of a robust control policy capable of selectively actuate the morphing structure as a function of its application. To tackle such a challenging process, we here envisage developing smart structures by utilizing both SMAs and innovative piezoelectric nanofibers. In particular, the piezoelectric polymeric nanofibers production technology has been recently developed by members of the proposed research team. These offer the twofold advantage of significantly increase the electromechanical conversion rate with respect to traditional piezoelectric materials, whereby their morphology allows their introduction into composite laminates at the production stage, resulting into a piezoelectric structural material. Similarly, SMA fibers will be utilized as reinforce for the composite. These allow for higher actuation loads and larger deformations, extending the application ranges. Analytical and numerical models of the thermo-electro-mechanical response will be developed and utilised for the optimisation of the active structures. Results from the proposed research will be finally applied to specific case studies, e.g. a micro-actuator, a energy harvester from a broadband excitation, and plates with shape morphing capabilities under selective control. The potential impact and importance of these goals on materials science, and for a wide spectrum of industrial applications, high-tech industry, and finally in actuating and sensing technology is indeed of extreme interest.