Dielectric elastomers are active materials capable of large deformations. They are made of a thin elastomer membrane (typically silicone), sandwiched between two flexible electrodes (for example conductive carbon grease). When a voltage is applied between the electrodes, the membrane thins down, and because of the elastomer incompressibility this results in an area increase. This phenomenon can be exploited to create a displacement normal to the membrane when it is inflated over a cavity.
Loudspeakers using this electro-activation principle have been studied and tested by several research groups. Sound radiation over the whole audible frequency range has been demonstrated, and good efficiency has been reached. Models of the electro-activation principle have also been developed and used to study the dynamics of dielectric-elastomer membranes. However, no complete model taking in account the different physics that matter for a use as a loudspeaker has been presented.
In the present research, we aim at optimizing a dielectric elastomer loudspeaker using optimization algorithms. For this purpose, we need a validated model of the dynamics and sound radiation of this loudspeaker. This is the first part of my work, where I set up a finite element model in FreeFem++ that couples electro-statics, acoustics, hyper-elasticity, and structural vibrations.
More info is available in:
Garnell, E., Doaré, O., & Rouby, C. (2020). Coupled vibro-acoustic modeling of a dielectric elastomer loudspeaker. The Journal of the Acoustical Society of America, 147(3), 1812–1821. https://doi.org/10.1121/10.0000930
Garnell, E., Rouby, C., & Doaré, O. (2019). Dynamics and sound radiation of a dielectric elastomer membrane. Journal of Sound and Vibration, 459, 114836. https://doi.org/10.1016/j.jsv.2019.07.002