Dynamic Electromechanical Response of a Viscoelastic Dielectric Elastomer under Cycle Electric Loads

Abstract

Dielectric elastomer (DE) is able to produce large electromechanical deformation which is time-dependent due to the viscoelasticity. In the current study, a thermodynamic model is set up to characterize the influence of viscoelasticity on the electromechanical and dynamic response of a viscoelastic DE. The time-dependent dynamic deformation, the hysteresis, and the dynamic stability undergoing viscoelastic dissipative processes are investigated. The results show that the electromechanical stability has strong frequency dependence; the viscoelastic DE can attain a larger stretch in the dynamic response than the quasistatic actuation. Furthermore, with the decreasing frequency of the applied electric load, the viscoelastic DE system will present dynamic stability evolution from an aperiodic motion to the quasiperiodic motion. The DE system may also experience a stability evolution from a single cycle motion to multicycle motion with the increasing relaxation times. The value and variation trend of the amplitude of the stretch are highly dependent on the excitation frequency and the relaxation time.

Viscoelasticity Modeling of Dielectric Elastomers by Kelvin Voigt-Generalized Maxwell Model

“…Based on the assumption that the DE membrane acted as a parallel capacitor with compliant electrodes, the relationship between the charges Q and applied voltage U could be expressed as follows [28][29][30]:…”

“…The membrane expanded in area and shrunk in thickness, and the system reached a new equilibrium state with dimensions , , and . Based on the assumption that the DE membrane acted as a parallel capacitor with compliant electrodes, the relationship between the charges Q and applied voltage U could be expressed as follows [ 28 , 29 , 30 ]: where is the dielectric permittivity of the DE membrane. When the DE membrane was subjected to force and voltage, the variables in Equation (3) are , , and , the variation in the charge is …”

Modeling and control of planar dielectric elastomer energy harvester

“…A Gent model of the DEG is used to account for strain stiffening. The DEG model is adopted from [14] with the governing equation of motion of the DEG as where ρ is the density of the dielectric membrane, μ = μ A + μ B the shear modulus of the DEG, μ A and μ B the shear moduli of the two dash-pot springs, λ the membrane stretch, χ = μ A /μ the ratio between the equilibrium and instantaneous moduli, J A and J B are the extension limits, and ò the elastomer permittivity. s = P/(LL 3 ) is the nominal stress where P is the mechanical force and c is the damping coefficient.…”

Faraday Instabilities Leading to Electrochemomechanical Generation of Sub<em>-</em><em>&mu;</em>A ACupon Application of DC Voltage Across Free Standing Oil-water Interfaces

“…It is evident from the schematic shown in figures4& 5, depicting the bending phenomenon, that stage V is mechanically analogous to stage I of the OW interface. The vibrations of the free standing OW interfacial membranes could be modelled using the methods described in reference [10][11][12][13][14]. Such periodic movements of OW membrane would therefore generate an alternating electrochemical current of the frequency same as that of oscillating membrane.The same has been shown in figure 3, left panel of which shows high noise levels at the start of the experiment whereas the right panel shows the periodic oscillatory current owing to the oscillations of the OW membrane (after ~250 s of the start of the experiment).…”