Actuator materials

Pelrine, R., Kombluh, R., and Kofod, G., High strain actuator materials based on dielectric elastomers, J. Adv. Mater., 12, 1223, 2000. 

Actuating Materials Conversion of Light and Heat Energy into Mechanical Energy... 

The use of shape-memory alloys as actuators depends on their use in the plastic martensitic phase that has been constrained within the structural device. Shape-memory alloys (SMAs) can be divided into three functional groups one-way SMAs, tw o-vvav SMAs, and magnetically controlled SMAs. The magnetically controlled SMAs show great potential as actuator materials for smart structures because they could provide rapid strokes with large amplitudes under precise control. The most extensively used conventional shape-memory alloys are the nickel-titanium- and copper-based alloys (see Shape-Memory Alloys). 

Functional fibres, filaments and yams are the basic building blocks of electrotextiles. The textile industry has demonstrated a remarkable capability to incorporate both natural and man-made filaments into yarns and fabrics to satisfy a wide range of physical parameters which survive the manufacturing process and are tailored to specific application environments. Electronic components can be fabricated within and/or on the surface of filaments and can subsequently be processed into functional yams and woven into fabrics. Passive components such as resistors, capacitors and inductors can be fabricated in several different manners. Diodes and transistors can be made on long, thin, flat strands of silicon or formed in a coaxial way. Progress has been made in the development of fibre batteries and fibre-based solar cells. In addition, a variety of actuated materials (piezoelectric, etc.) can be made into multiple long strands (filaments) and subsequently be woven into fabric. 

W. Yang (ed) IUTAM Symposium on Mechanics and Reliability of Actuating Materials. Proceedings of the IUTAM Symposium held in Beijing, China, 1-3 September 2004. 2005... 

Relaxor ferroelectrics47-49 (RFEs) have attracted considerable attention in recent years due to their unusual physical behaviour. Relaxors are technologically important as transducer/actuator materials. Relaxors are intermediate between dipolar glasses and classical FEs and exhibit both substitutional and charge disorder. They exhibit very large dielectric, piezoelectric, and electromechanical... 

Geoffrey Spinks, Ph.D., is currently discipline advisor for materials engineering at the University of Wollongong and a program leader in the ARC Centre of Excellence for Electromaterials Science. His research interests relate to the mechanical behavior of organic conductors and polymeric nanomaterials. A particular focus of his involves the development of actuator materials and systems, from the nano- to the macro-scale. 

Uchino, K., Electrostrictive actuators Materials and applications, Ceram. Bull., 65, 4 (1986). 

Peltine R, Komblith R, Kofod G et al. (2000) High-strain actuator material based on dielectric elastomers. Adv. Matez 12 1223-1225. 

Zhang QM, Li H, Poh M, Xia F, Cheng ZY, Xu H, Huang C (2002) An all-organic composite actuator material with a high dielectric constant. Nature 419 284... 

The dielectric elastomer films presented here appear promising as actuator materials because their overall performance can be good. The available literature indicates that the actuated strains of silicone are greater than for any known highspeed electrically actuated material (that is, a bandwidth above 100 Hz). Silicone elastomers also have other desirable material properties such as good actuation pressures and high theoretical efficiencies (80-90%) because of the elastomers low viscoelastic losses and low electrical leakage [12]. 

Beyond the ongoing research on the previously described smart materials, there are a few new innovative materials. Whether they are already investigated basically, recent material-related publications show an outstanding potential for them to serve as actuator materials in the future. 

Using the neat PANi fibre, the actuation stri / isotonic stress relationship gives a sharp negative slope the actuation strain decreased quickly with the increasing stress. While for the here with 2% w/w CNT, the actuation strain was much more stable with increased stress. The effect of applied stress on actuation strain is known to be related to the change in elastic modulus of the actuator material that occurs during the actuation process [48]. 

Zhao J, Cheng F, Yu Y. Light-responsive actuation materials based on the photodeformable liquid crystal polymers. In Esteve J, Ter-entjev EM, Campo EM, editors. Nano-opto-mechanical systems (NOMS). SPIE - International society for optical engineering 2011. p. 810705-8. 

The actuator materials currently used for MEMS have heen found to he suitable in all cases except one actuators for locomotion, gripping, and other interactions with the environment. Actuators made from inorganic materials face two key stumhhng blocks in this arena large footprints and brittleness. As pointed out in 1992 by Elwenspoek et al. [107], microrobots are still science fiction because there are no actuators usefiil for locomotion (and also no suitable miniature power supplies), and this situation has not changed in intervening years. 

Lee et al. [144] presented a microfabrication process for a membrane pump using polypyrrole as the actuating material. The diaphragm displacement in liquid electrolyte was hundreds of micrometers. Although further work to improve reliability is required, this is a promising development. 

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