DTA

Digital Theses Archive

 

Tesi etd-09042018-130620

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