Dielectric elastomer transducers with large deformation, high energy output, light weight and low cost have been drawing great interest from both the research and industry communities, and shown potential for versatile applications in biomimetics, dynamics, robotics and energy harvesting. Dynamic response of tubular dielectric elastomer transducers. Dielectric elastomers large deformations actuators energy harvesting devices finiteelement method abstract dielectric elastomers undergo large deformations in response to an electric field and consequently have attracted significant interest as electromechanical transducers. Modeling of dielectric elastomers design of actuators and. Highperformance electromechanical transduction using. Dielectric elastomers have gained substantial interest in the past few decades under research efforts aimed to improve electromechanical transducer technology. A short section of the balloon then forms a bulge, which coexists with the unbulged section of the balloon. One of the eap materials, 3m vhb acrylic tapes, have shown been outstanding electromechanical coupling performance.
Modeling and finite element simulation of dielectric. China 2state key laboratory for strength and vibration of mechanical structures. The high operating voltage of such devices is currently a large drawback, hindering their use in. Fundamentals, materials, devices, models and applications of an emerging electroactive polymer technology book jan 2008. Dielectric elastomers as electromechanical transducers 1st.
A dielectric elastomer transducer is a deformable capacitor, and is under development as a sensor, actuator, or generator. Dielectric elastomers can convert energy between mechanical and electrical forms, and hence significant effort has gone into using these materials as electromechanical transducers in a variety of. 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. Aksay1,b 1department of chemical and biological engineering, princeton university, princeton, new jersey 08544, usa 2vorbeck princeton research center, vorbeck materials corp. Response analysis of dielectric elastomer spherical. These features result in a very significant technology that permits the manufacture of actuators, and smart. Method to analyze electromechanical stability of dielectric.
They are soft and compliant by nature, and can be stretched, either via mechanical or electricallyinduced means, to very large strains. The positive feedback may cause the elastomer to thin down drastically, resulting in an electrical breakdown. Effect of temperature on the electromechanical properties. Electromechanical phase transition in dielectric elastomers. Plante and dubowsky, 2006, which limits the amount of energy conversion by dielectric elastomers in practical applications. Subject to an electric voltage, a layer of a dielectric elastomer reduces its thickness, so that the voltage induces a high electric field. Generalized electromechanical stability of dielectric elastomers fengxian xin1,2, and tian jian lu1,2, 1moe key laboratory for multifunctional materials and structures, xian jiaotong university, xian 710049, p. We investigated experimentally and theoretically the thermal and strainstiffening effects on the electromechanical breakdown strength. An investigation on electromechanical stability of. This technology can be used in a very broad range of applications, from robotics and automation to the biomedical field. Electromechanical hysteresis and coexistent states in dielectric elastomers xuanhe zhao, wei hong, and zhigang suo school of engineering and applied sciences, harvard university, cambridge, massachusetts 028, usa received 25 april 2007.
The scope of this study is to understand the electromechanical properties of vhb acrylic material. The dielectric elastomers are being developed as transducers for broad applications, including soft robots, adaptive optics, braille displays, and electric generators. Design of actuators and energy harvesting devices david l. This material is often termed a smart material due to its intrinsic transduction properties, allowing the elastomer to deform in response to electric stimulation. Download it once and read it on your kindle device, pc, phones or tablets. Dielectric elastomer actuators are stretchable capacitors that can offer musclelike strain and force response to an applied voltage. However, in addition to multiple failure modes such as electrical breakdown, electromechanical instability. Temperature influence on the viscoelastic electromechanical. Electromechanical instability has been recognized as a mode of failure for dielectric elastomers subject to increasing voltage stark and garton, 1955. Stacked dielectric elastomer transducers show thickness contraction originating from the electromechanical pressure of two compliant electrodes compressing an elastomeric dielectric when a voltage is applied. Large conversion of energy in dielectric elastomers by. Soft nanocomposites with enhanced electromechanical. Further, in addition to actuation, dielectric elastomers have also been shown to offer unique possibilities for improved generator and sensing devices. Threedimensional electromechanical impedance model for.
The timedependent dynamic deformation, the hysteresis, and the dynamic stability. Dielectric elastomers are an emerging transducer technology that fit an interesting niche. Dielectric elastomer actuators with elastomeric electrodes. Dielectric elastomers as nextgeneration polymeric actuators. Generalized electromechanical stability of dielectric elastomers. The high operating voltage of such devices is currently a. A common design of deas is to sandwich a soft insulating elastomer membrane between two compliant electrodes. Semicylindrical acoustic transducer from a dielectric elastomer film with compliant electrodes.
As more air is pumped in, the bulged section elongates at the expense of the unbulged section, until the entire balloon is bulged. Modelling of high output force dielectric elastomer actuator. This book provides a comprehensive and updated insight into dielectric elastomers. Effect of mechanical force field on the electromechanical. Electromechanical characterization of the static and dynamic. Aug, 2015 the electromechanical breakdown strength determines the limit of a dielectric elastomer for its use in actuators and energy harvesters. Spontakab received 16th april 2007, accepted 6th june 2007 first published as an advance article on the web 18th july 2007 doi. The purpose of this research is to study the dynamic response of tubular dielectric elastomer transducers using both an experimental and numerical modeling approach. Electromechanical modelling of tapered ionic polymer metal. They can exploit their inherent elasticity to enable new types of transducers that convert between electrical energy and mechanical energy. Constant nanophase polymers with high electromechanical response c. From literatures, we have noticed dielectric elastomers, a group of electroactive polymers eaps, have especially been considered for artificial muscle application due to their high strain, comparably short response time, low cost, and high electromechanical coupling efficiency 12 21 23 26. Standards for dielectric elastomer transducers iopscience. Dielectric elastomers and compliant metal electrode.
Fox j w and goulbourne n c 2008 on the dynamic electromechanical loading of dielectric elastomer membranes j. The authors show that the electromechanical instability occurs when the hessian of the freeenergy function ceases to be positive definite. Huang materials research institute and electrical engineering department, the pennsylvania state university, university park, pa 16802, usa. Dets can be used as actuators capable of producing very large strains up to 1,700% surface strain has been demonstrated 2, soft strain sensors 3, or as soft. Dielectric elastomers des represent a class of electroactive polymers eaps that exhibit a significant electromechanical effect, which has made them very attractive over the last several decades for use as soft actuators, sensors and generators. Apr 15, 2016 stacked dielectric elastomer transducers show thickness contraction originating from the electromechanical pressure of two compliant electrodes compressing an elastomeric dielectric when a voltage is applied. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. Dielectric elastomers deform in the presence of stimulus which further delivers a function. Semicylindrical acoustic transducer from a dielectric.
Switchable adhesion for waferhandling based on dielectric. Dielectric elastomers in this paper, we investigated the temperaturedependent viscoelastic behavior of dielectric elastomers des and the effects of viscoelasticity on the electroactuation behavior. Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. The direct piezoelectric effect enables a transducer to function as a passive sound receiver or pickup by the conversion of acoustic energy into an. The relation among critical nominal electric field, critical true electric field, nominal stress and mechanical force field is derived. Electromechanical hysteresis and coexistent states in. Dielectric elastomer actuators with elastomeric electrodes michael bozlar,1,a christian punckt,1,2,a sibel korkut,1,2 jian zhu,3 choon chiang foo,3,4 zhigang suo,3 and ilhan a. The dynamic performance of dielectric elastomer transducers and their capability of electromechanical energy conversion are affected by dissipative processes, such as viscoelasticity, dielectric. Effect of temperature on the electromechanical properties of. The stainstiffening induced by large stretch highly enhance the maximum energy density and breakdown strength. Where r dc is the dc resistance z p is the element which stores electric charge r dc t effective d dc wl t t 0. Dielectric elastomer electromechanical coupling system. China 2state key laboratory for strength and vibration of mechanical structures, xian jiaotong university, xian 710049, p.
Dielectric elastomer actuators soft robotics toolkit. Dielectric elastomers des are a relatively new electroactive polymer eap transducer technology. Dielectric elastomer market material type and application. Kornbluh r, pei q and joseph j 2000 highspeed electrically actuated elastomers with strain greater than 100%. An electromechanical transducer is a device that converts electrical energy into mechanical vibration and vice versa by utilizing piezoelectricity or electrostriction jaffe et al. Highspeed electrically actuated elastomers with strain greater then 100% science. They are capable of large strains, high energy densities, and low costs, while possessing the additional. In the emi models, the pzt transducers are generally surface bonded to the host structure and are then subjected to onedimensional 1d voltage to interrogate. Dielectric elastomers can be employed as actuators, large strain sensors and for energy harvesting kornbluh, 2004, carpi et al.
To study the electromechanical stability of dielectric elastomer subjected to a mechanical force field, we use free energy functions of variable forms to analyze the mechanical performance of dielectric elastomer. Aug 10, 2007 the authors show that the electromechanical instability occurs when the hessian of the freeenergy function ceases to be positive definite. The timedependent dynamic deformation, the hysteresis, and the dynamic stability undergoing. Electromechanical characterization of the static and dynamic response of dielectric elastomer membranes jason william fox abstract dielectric elastomers des are a relatively new electroactive polymer eap transducer technology. Dielectric elastomers as nextgeneration polymeric actuators ravi shankar,ac tushar k. Yet due to the elasticity of the material which requires mechanical support and low output force generation, des havent been suggested for. Each thick blue line represents the limit by one particular value of the normalized breakdown.
Dielectric elastomers and compliant metal electrode technology r. Dielectric elastomers for actuation and energy harvesting. Figure 15 plots the electrical breakdown limits in the voltagecharge and force stretch diagrams, along with the electromechanical phasetransition lines. Dielectric elastomers as electromechanical transducers provides a comprehensive and updated insight into dielectric elastomers. Dielectric elastomer transducers are rapidly emerging as highperformance pseudomuscular actuators, useful for different kinds of tasks. Electromechanical characterization of the static and. The phenomenon is analogous to the liquidtovapor phase transition. Fabrication and electromechanical examination of a spherical. Not surprisingly, increasing the thickness stiffness. They, however, show limited actuation force without prestraining.
Silicone elastomers can operate over a wide range of temperatures 11. The fast and soft elastic response of thin dielectric elastomers to electric stimulus has established these materials as a paradigm for the development of a technology of low cost, lightweight, high energy density storage, large deformation elastomer actuators deas and smart materials. Electroviscoelastic response of an acrylic elastomer analysed by digital image correlation s thylander et al 2017 smart materials and structures 26 085021. The electromechanical breakdown strength determines the limit of a dielectric elastomer for its use in actuators and energy harvesters. Electroactive polymers have been studied for artificial muscle applications in last decades. Pdf perspectives for new dielectric elastomers with.
Feb 01, 2016 the authors wish to thank the members of our soft transducers group past and present for their contribution to the refining of our fabrication process flow. Dielectric elastomers with dual piezoelectrostatic response optimized through chemical design for electromechanical transducers c. Silicone elastomers, on the other hand, have the highest compliance in the category, which allows the dea to operate at a higher frequency with lower electrostatic charge losses 9,10. Dielectric elastomers actuators dea are a class of electroactive polymers which work based on inducing of deformation with an electric field, which was demonstrated in 1880 by wilhelm conrad roentgen by spraying charges on a piece of natural rubber rontgen 1880. Only in the last decade, pzt transducers have been used in the electromechanical impedance emi models as both sensor and actuator for the structural health monitoring of acm systems. Abstractdielectric elastomers have demonstrated most potential as musclelike actuators because they can undergo large. Their calculation shows that the stability of the actuator is markedly enhanced by prestresses, agreeing with existing experimental observations. Electromechanical characterization of a new synthetic. Dielectric elastomer loudspeakers, dielectric elastomers. Electromechanical transducer an overview sciencedirect. Electromechanical characterization of a new synthetic rubber. Electromechanical coupling behavior of dielectric elastomer.
Characteristics of dielectric elastomers and fabrication. Response analysis of dielectric elastomer spherical membrane to harmonic voltage and random pressure. They are capable of over 100% strain when actuated, and can be used as sensors to measure large strains. An investigation on electromechanical stability of dielectric. Since dests and the adhesive surfaces previously described are made of elastomers, it is selfevident to combine both systems in one device. Electromechanical transducers based on elastomer capacitors are presently considered for many soft actuation applications, due to their large reversible deformation in response to electric eld induced electrostatic pressure. When air is pumped in, a tubular balloon initially inflates slightly and homogeneously. An investigation on electromechanical stability of dielectric elastomers undergoing large deformation yanju liu 1,3, liwu liu,kaiyu2, shouhua sun1 and jinsong leng2,3 1 department of astronautical science and mechanics, harbin institute of technology hit, no. Faulttolerant dielectric elastomer actuators using single. When prestretched and sandwiched between two compliant electrodes. Generalized electromechanical stability of dielectric. In addition, the research explores new practical designs of soft actuators. The electromechanical responses of the actuators with solid electrodes of total thicknesses h 2. The transition from the occurrence of electromechanical instability to stable behavior occurs at k pre 2.
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