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Tesi etd-09042018-130620

Tipo di tesi
Dottorato
Autore
RIGHI, MICHELE
URN
etd-09042018-130620
Titolo
Electroactive polymers, design and validation of new concepts in energy harvesting
Settore scientifico disciplinare
ING-IND/13
Corso di studi
INGEGNERIA - Ph.D. Programme in Emerging Digital Technologies (EDT)
Commissione
relatore SOLAZZI, MASSIMILIANO
Membro Prof. VERTECHY, ROCCO
Presidente Prof. FRISOLI, ANTONIO
Membro Dott. FONTANA, MARCO
Parole chiave
  • Dielectric Elastomer
  • Dielectric Fluid Transducer
  • Fluid Structure Interaction
  • Wave Energy
Data inizio appello
20/06/2019;
Disponibilità
completa
Riassunto analitico
This article-based thesis comprises a collection of six articles, each of which constitutes
a chapter written and formatted in pre-print manuscript form.
The thesis deals with new concepts and technologies employed in the field of the
electro-mechanical transducers, devices that are able to convert mechanical energy
into direct current electricity and vice-versa. They can be employed as sensors (to
measure strains and vibrations), actuators (i.e. artificial muscles and volumetric
pumps) or generators (as power-take-off system in wave energy application).
The thesis focuses on two main technologies used to develop new transducers, the
almost classic field of the dielectric elastomers and the emerging class of liquid
electroactive polymer. In the current work, both of them are mainly employed in the
generation mode, i.e. to convert an oscillating mechanical energy source into direct
current electricity.
Compared to conventional electro-mechanical transducers the electroactive polymers
class allows to design solutions with a simplified architecture; they feature lower
mass density and a reduced number of heavy and bulky mechanical components,
which potentially leads to higher reliable and lower cost devices. Electroactive polymers
transducers are also undoubtedly more compliant with respect to a potentially
unstructured environment, which allows them to be employed in a wider range of
scenarios.
The research outline comprises: a state of the art of the available materials that
are suitable for the transducer construction; a material characterization from both
chemical and mechanical point of view through specifically designed tests; static
and dynamic models that provide the electro-mechanical response and highlight
the operating limits of the transducers; experimental tests to validate the proposed
concepts and related models.
Successful energy conversion has been proved, with promising performance in
terms of energy density (with respect to the volume of dielectric material employed)
and efficiency (ratio between input and output energy source). Despite the encouraging
figure of merits obtained, the results achieved can be considered as a starting
point for further development aimed at bringing the electroactive polymers transducers
at a higher technology readiness level.
Several aspects need to be improved, e.g. the dielectric material viscosity and
electrical losses should be reduced; the electro-mechanical material fatigue has not
been completely investigated, yet; the power electronics, especially at the larger
scales, must be designed; the control of the energy conversion cycle is open to
improvement; the manufacturing of transducers of big dimensions is an open problem
to date.
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