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Reference : UMR8579-JINBAI1-002
Workplace : GIF SUR YVETTE
Date of publication : Thursday, February 11, 2021
Type of Contract : FTC Scientist
Contract Period : 12 months
Expected date of employment : 1 June 2021
Proportion of work : Full time
Remuneration : post-doc salary in secteur public
Desired level of education : PhD
Experience required : 1 to 4 years
This post-doctoral subject is part of research on the modeling and design of electroacoustic actuators based on the principle of dielectric elastomers. Composed of an elastomer film between two flexible electrodes, the system considered behaves electrically like a capacitor whose capacity varies with the electric charge . When an electrical voltage is applied across its terminals, the attraction between the opposing charges of the two electrodes generates an electrostatic pressure on the incompressible dielectric membrane. This then contracts in its thickness and stretches in the other directions. The electromechanical coupling of such a system has already been the subject of numerous studies for applications in robotics , medical prosthetics  or energy recovery  for example. It is also mentioned in some scientific works the use of this type of coupling for the design of loudspeakers [5,6].
As part of this post-doctorate, we wish to carry out electrical charge measurements on the elastomeric membrane in operation using an electric field. These measurements should allow a better understanding of these couplings, and help the development of other applications such as for example sensors making use of this coupling to predict the dynamics of the membrane from purely electrical measurements. This work will be carried out at the GEEPS laboratory, of CentraleSupélec. On a second aspect of the project, we want to be able to reduce the operating voltage of the prototypes by producing multilayer dielectric elastomer membranes. This work will be carried out at the MSSMAT laboratory, of Centrale Supélec.
Holder of a thesis in materials science, mechanics or physics, interested in multiphysics problems, experimenter or having a strong attraction for the experimental. The subject does not relate to the modeling and the implementation of numerical methods, but skills in this area could be a plus for the use of tools already developed at IMSIA.
At IMSIA, we recently developed a multiphysics model coupling electromagnetism, the dynamics of an elastomeric membrane, and acoustics [7,8]. This model makes it possible to very satisfactorily reproduce the properties of acoustic radiation from a dielectric elastomer loudspeaker (acoustic efficiency, directivity, etc.). The first numerical results highlighted the coupling between the movement of electric charges on the membrane and the vibratory response of the latter, which can under certain conditions significantly influence the behavior of the system.
 Suo, Acta Mechanica Solida Sinica 23, 549 (2010)
 Kovacs et al., Sensors and Actuators A 155, 299–307 (2009)
 Bidiss & Chau, Medical Engineering & Physics 30, 403–418 (2008)
 McKay et al., Applied Physics Letters 98, 142903 (2011)
 Hosoya, Baba & Maeda, The Journal of the Acoustical Society of America, 138 (4) (2015)
 Heydt et al, Proc. SPIE 6168:61681M (2006)
 Garnell, Rouby & Doaré, Journal of Sound and Vibration, 459, 114836 (2019)
 Garnell, Doaré, Rouby, Journal of the Acoustical Society of America, 147 (3), 1812-1821 (2020)
 Garnell, Doaré, Rouby, Smart Materials and Structures, 30 (2), 025031 (2021)
Constraints and risks
no particular constraints
zones ZRR (the three lab involved)
from 2021 May or June
preparation of polymer and polymer composite films, device tests of acoustic behaviour, in situ measurement of electric charge distribution, comparaison with modelling
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