Large deformation and electromechanical instability of a dielectric elastomer tube actuator

2010 ◽  
Vol 108 (7) ◽  
pp. 074113 ◽  
Author(s):  
Jian Zhu ◽  
Hristiyan Stoyanov ◽  
Guggi Kofod ◽  
Zhigang Suo
Keyword(s):  
Large Deformation ◽  
Dielectric Elastomer ◽  
Electromechanical Instability ◽  
Dielectric Elastomer Tube

scholarly journals Delayed electromechanical instability of a viscoelastic dielectric elastomer balloon

2019 ◽  
Vol 475 (2229) ◽  
pp. 20190316 ◽  
Author(s):  
Xiongfei Lv ◽  
Liwu Liu ◽  
Jinsong Leng ◽  
Yanju Liu ◽  
Shengqiang Cai
Keyword(s):  
Hoop Stress ◽  
Mechanical Load ◽  
Viscoelastic Model ◽  
Dielectric Elastomer ◽  
Time Dependent ◽  
Convex Shape ◽  
Nonlinear Viscoelastic ◽  
Electromechanical Instability ◽  
Electromechanical Loading ◽  
Nonlinear Viscoelastic Model

When a dielectric elastomer (DE) balloon is subjected to electromechanical loading, instability may happen. In recent experiments, it has been shown that the instability configuration of a DE balloon under electromechanical loading can be very different from that only subjected to mechanical load. It has also been observed in the experiments that the electromechanical instability phenomena of a DE balloon can be highly time-dependent. In this article, we adopt a nonlinear viscoelastic model for the DE membrane to investigate the time-dependent electromechanical instability of a DE balloon. Using the model, we show that under a constant electromechanical loading, a DE balloon may gradually evolve from a convex shape to a non-convex shape with bulging out in the centre, and compressive hoop stress can also gradually develop the balloon, resulting in wrinkles as observed in the experiments. We have further shown that the snap-through instability phenomenon of the DE balloon also greatly depends on the ramping rate of the applied voltage.

Temperature Influence on the Viscoelastic Electromechanical Deformation of Dielectric Elastomer

2014 ◽  
Vol 1052 ◽  
pp. 137-142
Author(s):  
Jun Jie Sheng ◽  
Yu Qing Zhang ◽  
Shu Yong Li ◽  
Hua Ling Chen
Keyword(s):  
Dielectric Elastomer ◽  
Electric Load ◽  
Temperature Influence ◽  
Temperature Dependent ◽  
Influence Of Temperature ◽  
Dielectric Elastomer Actuators ◽  
Influence Of Temperature On ◽  
Electromechanical Instability ◽  
Increasing Temperature ◽  
Electromechanical Deformation

Temperature can significantly affect the performance of a viscoelastic dielectric elastomer (DE). In the current study, we use a thermodynamic model to characterize the influence of temperature on the viscoelastic electromechanical response undergoing a constant electric load by taking into account the temperature dependent elastic modus and dielectric constant. Due to the significant viscoelasticity in the dielectric elastomer, DE membrane creeps in time and the inelastic stretch of DE is smaller than that of the total stretch. The results show that the total stretch of the viscoelastic electromechanical deformation increases with the increasing temperature until suffering electromechanical instability at a high temperature; the actuation performance is dominated by the moduli of the elastomer. This may be used to guide the design of dielectric elastomer actuators undergoing temperature variation.

NONEQUILIBRIUM THERMODYNAMICS OF DIELECTRIC ELASTOMERS

2011 ◽  
Vol 03 (02) ◽  
pp. 203-217 ◽  
Author(s):  
XUANHE ZHAO ◽  
SOO JIN ADRIAN KOH ◽  
ZHIGANG SUO
Keyword(s):  
Nonequilibrium Thermodynamics ◽  
Dielectric Elastomer ◽  
Specific Model ◽  
Critical Voltage ◽  
Dielectric Elastomers ◽  
Internal Variables ◽  
Strain Rates ◽  
Dissipative Processes ◽  
Electromechanical Instability ◽  
External Loads

This paper describes an approach to construct models of dielectric elastomers undergoing dissipative processes, such as viscoelastic, dielectric and conductive relaxation. This approach is guided by nonequilibrium thermodynamics, characterizing the state of a dielectric elastomer with kinematic variables through which external loads do work, as well as internal variables that describe the dissipative processes. Within this approach, a method is developed to calculate the critical condition for electromechanical instability. This approach is illustrated with a specific model of a viscoelastic dielectric elastomer, which is fitted to stress-strain curves of a dielectric elastomer (VHB tape), measured at various strain rates. The model shows that a higher critical voltage can be achieved by applying a constant voltage for a shorter time, or by applying ramping voltage with a higher rate. A viscoelastic dielectric elastomer can attain a larger strain of actuation than an elastic dielectric elastomer.

scholarly journals Tuning Elastic Waves in Soft Phononic Crystal Cylinders Via Large Deformation and Electromechanical Coupling

2018 ◽  
Vol 85 (3) ◽  
Author(s):  
Bin Wu ◽  
Weijian Zhou ◽  
Ronghao Bao ◽  
Weiqiu Chen
Keyword(s):  
Large Deformation ◽  
Axial Force ◽  
Electromechanical Coupling ◽  
Phononic Crystal ◽  
Electrical Stimulus ◽  
Critical Voltage ◽  
Electric Voltage ◽  
Propagation Behavior ◽  
Electromechanical Instability ◽  
Longitudinal Stretch

Soft electroactive materials can undergo large deformation subjected to either mechanical or electrical stimulus, and hence, they can be excellent candidates for designing extremely flexible and adaptive structures and devices. This paper proposes a simple one-dimensional soft phononic crystal (PC) cylinder made of dielectric elastomer (DE) to show how large deformation and electric field can be used jointly to tune the longitudinal waves propagating in the PC. A series of soft electrodes, which are mechanically negligible, are placed periodically along the DE cylinder, and hence, the material can be regarded as uniform in the undeformed state. This is also the case for the uniformly prestretched state induced by a static axial force only. The effective periodicity of the structure is then achieved through two loading paths, i.e., by maintaining the longitudinal stretch and applying an electric voltage over any two neighboring electrodes or by holding the axial force and applying the voltage. All physical field variables for both configurations can be determined exactly based on the nonlinear theory of electroelasticity. An infinitesimal wave motion is further superimposed on the predeformed configurations, and the corresponding dispersion equations are derived analytically by invoking the linearized theory for incremental motions. Numerical examples are finally considered to show the tunability of wave propagation behavior in the soft PC cylinder. The outstanding performance regarding the band gap (BG) property of the proposed soft dielectric PC is clearly demonstrated by comparing with the conventional design adopting the hard piezoelectric material. One particular point that should be emphasized is that soft dielectric PCs are susceptible to various kinds of failure (buckling, electromechanical instability (EMI), electric breakdown (EB), etc.), imposing corresponding limits on the external stimuli. This has been carefully examined for the present soft PC cylinder such that the applied electric voltage is always assumed to be less than the critical voltage except for one case, in which we illustrate that the snap-through instability of the axially free PC cylinder made of a generalized Gent material may be used to efficiently trigger a sharp transition in the BGs.

Maximum Energy that can be Harvested from a Dielectric Elastomer Generator

2009 ◽  
Vol 1218 ◽  
Author(s):  
Adrian Koh
Keyword(s):  
Electrical Breakdown ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Dielectric Elastomer ◽  
Maximum Energy ◽  
Maximum Amount ◽  
Biaxial Stretching ◽  
Modes Of Failure ◽  
Electromechanical Instability

AbstractMechanical energy can be converted to electrical energy using a dielectric elastomer generator (DEG). The maximum amount of energy that can be harvested from a DEG is constrained by various modes of failure and operational limits. Known limiting mechanisms include electrical breakdown, electromechanical instability, loss of tension and rupture by stretch. These limits define a cycle where maximum energy can be harvested. The cycle was represented on work-conjugate planes, which can be used as a guide for the design of practical cycles. The amount of energy harvested is larger when a DEG is subject to equal-biaxial stretching.

scholarly journals Dielectric elastomer actuators with increased dielectric permittivity and low leakage current capable of suppressing electromechanical instability

2018 ◽  
Vol 6 (8) ◽  
pp. 2043-2053 ◽  
Author(s):  
Philip Caspari ◽  
Simon J. Dünki ◽  
Frank A. Nüesch ◽  
Dorina M. Opris
Keyword(s):  
Dielectric Permittivity ◽  
Leakage Current ◽  
Dielectric Elastomer ◽  
Electromechanical Properties ◽  
Low Leakage ◽  
Dielectric Elastomer Actuators ◽  
Low Leakage Current ◽  
Electromechanical Instability

A dielectric elastomer with increased permittivity and excellent dielectric and electromechanical properties suitable to transducer applications was developed.

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