A linear parameter-varying modelling approach for dielectric elastomer loudspeakers

Moretti, Giacomo; Rizzello, Gianluca

doi:10.1016/j.ifacol.2022.09.150

Cited by 3 publications

(4 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This observation was confirmed by measurements in a follow-up work. 19 There, we observed that the acoustic cut-in frequency of the speaker (i.e., the frequency above which the speaker can produce hearable sound) lies in proximity to the natural frequency of the first structural mode (denoted (0, 1) in Fig. 1b).…”

Section: Problem Descriptionmentioning

confidence: 82%

“…18 High frequency excitation of the DE membrane leads to sound generation as a result of the excitation of the membrane structural modes. 16,19 In our previous work, 16 we presented a numerical investigation of a loudspeaker based on the cone DEA layout (i.e., a conically pre-loaded membrane with a floating rigid centre connected to a spring). In particular, we observed that, if the mass of the central rigid disc is much larger than the membrane mass, sound generation is entirely due to the membrane structural modes, whereas the longitudinal pumping motion of the rigid centre plays a minor role on the acoustic response.…”

Section: Problem Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Finite element modelling of the vibro-acoustic response in dielectric elastomer membranes

Moretti

Rizzello

Fontana

et al. 2022

Electroactive Polymer Actuators and Devices (EAPAD) XXIV

Self Cite

View full text Add to dashboard Cite

This paper focuses on the characterisation of the vibroacoustic response of dielectric elastomer (DE) membranes. We set our attention on a circular DE membrane, deformed three-dimensionally and mounted in between fixed frames, which is able to generate sound with no need for any elastic or pneumatic biasing element. We present a finite element model of the system entirely based on commercial software Comsol Multiphysics. The model combines: 1) a mechanical model of the DE membrane, which makes use of suitably defined energy functions that account for electro-elastic coupling; and 2) an acoustic model of the domain surrounding the DE. The model implements a bi-directional coupling between the DE and the acoustic domain. In particular, it accounts for the effect of the acoustic pressure loads applied on the DE membrane, which, given the small thickness and low density of the membrane, play a significant role in the system dynamics. We validate the model against experimental measurements of the DE surface velocity and the sound pressure level (SPL) in the surroundings of the membrane. Despite relying on strong simplifications in the geometry of the system and the viscous response of the material, the model is able to describe the main trends in the device frequency response, and how the SPL varies as a function of the mechanical pre-load and the voltage applied on the membrane.

show abstract

Section: Problem Descriptionmentioning

confidence: 82%

Section: Problem Descriptionmentioning

confidence: 99%

Finite element modelling of the vibro-acoustic response in dielectric elastomer membranes

Moretti

Rizzello

Fontana

et al. 2022

Electroactive Polymer Actuators and Devices (EAPAD) XXIV

Self Cite

View full text Add to dashboard Cite

show abstract

“…11,12 Several prototypes have been developed and tested by various research groups, and models have been proposed to estimate their performance. 13,14 Therefore, the main challenge in this field is to achieve significant actuation for a reduced applied electric field. 15 According to Perlin et al, 4 the electrostatic actuation strain of a DE membrane is caused by Maxwell stress 16 and is expressed by the following eq 1…”

Section: Introductionmentioning

confidence: 99%

“…Several prototypes have been developed and tested by various research groups, and models have been proposed to estimate their performance. , Therefore, the main challenge in this field is to achieve significant actuation for a reduced applied electric field …”

Section: Introductionmentioning

confidence: 99%

Improved Electromechanical Coupling in Silicone-Based Elastomer Thin Membranes Filled by Silica-Coated Multiwalled Carbon Nanotubes

Alfonso,

He,

Molinié

et al. 2024

ACS Appl. Eng. Mater.

View full text Add to dashboard Cite

Dielectric elastomers (DEs) are flexible, voltage-responsive materials that can undergo significant deformations upon being subjected to high actuation electric fields. Their efficient electromechanical conversion, along with their ability to operate across a wide frequency range, makes them highly promising for mechatronic applications. Herein, we propose DE nanocomposites based on silica-coated multiwalled carbon nanotubes (CNT@SiO 2 ) dispersed in liquid silicone rubber (LSR) elastomer thin membranes sandwiched between highly conductive and stretchable compliant electrodes made from carbon-black airbrushed ink. Dielectric spectroscopy showed an enhancement of dielectric constant from 2.6 of pure polymer up to 5.9 at 1 kHz, keeping a low dielectric loss of 0.0055 also under the effect of DC voltage bias of 100 V. High-voltage C−V hysteresis loops were employed to detect dielectric breakdowns occurring well beyond the actuation fields. Such DE nanocomposites showed outstanding elastic properties in a uniaxial tensile test at different elongation rates with a variation of Young's modulus from 0.024 to 0.084 MPa for a filling fraction of 2.0 wt. Moreover, precycling treatments showed Mullins effects softening with the decreases of elastic properties from 67 to 50% from low to high elongation rates for the LSR pure polymer and from 20 to 7% for CNT@SiO 2 -based DE nanocomposites. Further biaxial tensile tests were performed on the final device comprising membranes sandwiched by highly stretchable compliant electrodes showing comparable elastic properties (0.029−0.033 MPa), indicating the negligence on the mechanical properties by the presence of thin layers of conductive ink. Furthermore, the CNT@SiO 2 -based DE nanocomposites demonstrated an actuation strain exceeding 125% in comparison with the pure polymer for the same applied electric field, suggesting a scalable membrane fabrication process suitable for the efficient development of electroactive soft materials.

show abstract

An experimental parametric analysis of the acoustic response in dielectric elastomer loudspeakers

Addario,

Gratz-Kelly,

Naso

et al. 2024

Journal of Vibration and Control

View full text Add to dashboard Cite

This article presents an experimental parametric analysis of dielectric elastomer (DE) loudspeakers, which generate sound by means of soft lightweight electroactive polymer membranes, with no need for electromagnetic actuators. Attention is set on a simple topology, which consists of a DE actuator membrane deformed out-of-plane in a conical shape between fixed frames. Different scaled replicas of the system were built, featuring different diameters and elastomer membrane thickness, with the aim of highlighting the dependence of the acoustic response on the design parameters. An experimental analysis of the effect of different electrical and mechanical pre-loads was also carried out. Results suggest that the acoustic response is affected by both geometrical factors, possible effects of aero-elastic interactions, and the level of mechanical stress acting on the DE membrane. These findings provide valuable insights for the optimisation of DE loudspeaker design and operational parameters.

show abstract

A linear parameter-varying modelling approach for dielectric elastomer loudspeakers

Cited by 3 publications

References 9 publications

Finite element modelling of the vibro-acoustic response in dielectric elastomer membranes

Finite element modelling of the vibro-acoustic response in dielectric elastomer membranes

Improved Electromechanical Coupling in Silicone-Based Elastomer Thin Membranes Filled by Silica-Coated Multiwalled Carbon Nanotubes

An experimental parametric analysis of the acoustic response in dielectric elastomer loudspeakers

Contact Info

Product

Resources

About