Effect of mechanical force field on the electromechanical stability of dielectric elastomers

Zhang, Zhen; Liu, Liwu; Liu, Yanju; Leng, Jinsong; Du, Shanyi

doi:10.1007/s11433-011-4537-0

Cited by 6 publications

(3 citation statements)

References 38 publications

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“…The equilibrium of the thermodynamic system requires H to be positive definite (Zhang et al, 2012;Zhao and Wang, 2014), and the DE transducer becomes unstable whenever the determinant of H vanishes. It should be noticed that det(H)≠0 does not distinguish stable and metastable cases, because the Hessian matrix is positive-definite in either of them.…”

Section: Electromechanical Instability Of Desmentioning

confidence: 99%

Mechanics of dielectric elastomers: materials, structures, and devices

Qian

2016

JZUS-A

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Dielectric elastomers (DEs) respond to applied electric voltage with a surprisingly large deformation, showing a promising capability to generate actuation in mimicking natural muscles. A theoretical foundation of the mechanics of DEs is of crucial importance in designing DE-based structures and devices. In this review, we survey some recent theoretical and numerical efforts in exploring several aspects of electroactive materials, with emphases on the governing equations of electromechanical coupling, constitutive laws, viscoelastic behaviors, electromechanical instability as well as actuation applications. An overview of analytical models is provided based on the representative approach of non-equilibrium thermodynamics, with computational analyses being required in more generalized situations such as irregular shape, complex configuration, and time-dependent deformation. Theoretical efforts have been devoted to enhancing the working limits of DE actuators by avoiding electromechanical instability as well as electric breakdown, and pre-strains are shown to effectively avoid the two failure modes. These studies lay a solid foundation to facilitate the use of DE materials, structures, and devices in a wide range of applications such as biomedical devices, adaptive systems, robotics, energy harvesting, etc.

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Section: Electromechanical Instability Of Desmentioning

confidence: 99%

Mechanics of dielectric elastomers: materials, structures, and devices

Qian

2016

JZUS-A

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“…The instability parameters (critical electric field and conforming stretch) are dependent on a number of factors, such as permittivity of the material, temperature, and the extent of prestress [23][24][25]. Several researchers have described previously the methods to extract the static instability parameters of DEAs subjected to equal and unequal prestress [16,[26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Dynamic instability of dielectric elastomer actuators subjected to unequal biaxial prestress

Sharma

Bajpayee

Joglekar

et al. 2017

Smart Mater. Struct.

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The paper presents a Hamiltonian approach for extracting the dynamic instability parameters of homogeneously deforming dielectric elastomer actuators subjected to an unequal biaxial prestress, and driven by a suddenly applied electric load. The approach relies on setting up the balance between the kinetic, strain, and electrostatic energy at the point of maximum overshoot in an oscillation cycle. The equation of the stagnation curve, obtained by invoking aforestated statement of energy-balance, is operated upon by the condition of instability to determine the instability parameters. The underlying principles of the approach are elucidated by considering the Ogden family of hyperelastic material models. The approach is however portrayed generically, and hence, can be extended to the other hyperelastic material models of interest. The estimates of the dynamic instability parameters are corroborated by examining the saddle-node bifurcation points in the time-history response obtained by integrating the equation of motion. A parametric study is conducted to bring out the effect of unequal biaxial prestress, and the trends of variation of the critical electric field and the thickness-stretch on the onset of dynamic instability are presented. A quantitative comparison with the static instability parameters reveals that the dynamic instability gets triggered for electric fields that are lower than those corresponding to the static instability. In contrast, the maximum stretch experienced by the actuator at the dynamic instability is significantly higher than that at the static instability. The crucial inferences can find their potential use in the design of DEAs subjected to a transient motion.

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“…coupling system is more and more deep and specific [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55].…”

mentioning

confidence: 99%

Dielectric elastomer energy harvesting undergoing polarization saturation

et al. 2012

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Mechanical energy can be converted into electrical energy by using a dielectric elastomer generator. The elastomer is susceptible to various models of failure, including electrical breakdown, electromechanical instability, loss of tension, and rupture by stretching. The models of failure define a cycle of maximal energy that can be converted. On the other hand, when subjected to voltage, the charge will be induced on a dielectric elastomer. When the voltage is small, the charge increases with the voltage. Along with the continuously increase of voltage, when the charge approaches a certain value, it would become saturated. This paper develops a thermodynamic model of dielectric elastomers undergoing polarization saturation. We studied the typical failure model with three variables of Gent Model silicone energy harvester and obtained an analytical solution of the constitutive equation of dielectric elastomer undergoing polarization saturation. These results can be used to facilitate the design and manufacture of dielectric elastomer energy harvesters.

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Effect of mechanical force field on the electromechanical stability of dielectric elastomers

Cited by 6 publications

References 38 publications

Mechanics of dielectric elastomers: materials, structures, and devices

Mechanics of dielectric elastomers: materials, structures, and devices

Dynamic instability of dielectric elastomer actuators subjected to unequal biaxial prestress

Dielectric elastomer energy harvesting undergoing polarization saturation

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