Investigation On The Viscoelastic Behaviors Of Dielectric Elastomer Membrane Actuators

Compared to metals and other conventional hard materials,Soft materials have multi-field response,large deformation and other characteristics.Subjected to external stimuli,they can produce deformation or a certain response.So researchers pay more and more attention to the soft materials.While the dielectric elastomer as a typical soft materials,it is better than other soft materials.It has a light weight,good flexibility,short reaction time,high power conversion rate and other characteristics.So the material can be used to manufacture and design into a variety of transducers,such as actuators,energy harvesters,sensors and so on.Dielectric elastomer transducers are usually composed of flat,thin dielectric elastomer membranes,under the large external load the film prone to happen failure to destroy.At present,many researches mainly involve the time-independent elastic behavior of dielectric elastomer materials.While most of the dielectric elastomers are rubber-like materials,Its nonlinear deformation and power conversion capacity will be affected by the time-dependent dissipation process that the impact of power dissipation.Therefore,the study of viscoelasticity of dielectric elastomer can improve the electromechanical behavior and electromechanical properties of the transducer.The main contents of this paper include(1)Based on dissipative dielectric elastomer nonlinear theory and non-equilibrium thermodynamics principle,the viscoelastic behavior of the circular dielectric elastomer membrane actuator under the force coupling is studied.The circular membrane center connects a light weight rigid disc,the membrane is then fixed around the rigid ring.When subjected to force and voltage,the circular membrane has a large deformation of the outer axis.Selecting the Neo-Hookean model and the viscoelastic model,through the theory of non-equilibrium thermodynamics and the use of energy variational principle we derive the control equation describing large deformation.And the viscoelastic behavior of the membrane is described by two parallel cells containing a spring stick pot model.The numerical solution of the control equation is obtained by using the target method.And the deformation of the relevant variables and the deformation law of the membrane are plotted.The results show that when the membrane is only affected by external forces,at the same time with the increase in external force,radial stretching,verticaldisplacement and other physical values also increase;When the force is constant,their values gradually increase over time and eventually stabilize.While the membrane in the force coupling,when the force is certain,at the same time as the voltage increases,radial stretching,vertical displacement and other physical values also increase;When the voltage is constant,their values gradually increase over time and eventually stabilize.This study is helpful to improve the electromechanical properties of dielectric thin membrane actuators.(2)On the basis of the above conclusions,the influence of the design parameters on the viscoelastic behavior of the circular dielectric membrane actuator is studied.The results show that the membrane is pre-stretched,the values of radial stretching,vertical displacement,electric field strength and other physical values tends to stable over time.And in addition to the vertical displacement of the disc decreases as the pre-stretching increases,the values of other physical quantities increase as the pre-stretching increases.The membrane is under the action of force coupling,changing the ratio of its internal and external diameter,the value of radial stretching,vertical displacement,electric field strength and other physical values tends to stable over time.And the vertical displacement of the disc increases as the ratio of inner to outer diameter increases,the value of other physical quantities decreases with the ratio of inner to outer diameter.It is helpful to select the dielectric actuator material and optimize the design of the device.