Topic
Smart material
About: Smart material is a research topic. Over the lifetime, 3704 publications have been published within this topic receiving 74280 citations. The topic is also known as: intelligent material & responsive material.
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TL;DR: This paper addresses recursive identification and adaptive inverse control of hysteresis in smart material actuators, where hystereresis is modeled by a Preisach operator with a piecewise uniform density function.
Abstract: Hysteresis hinders the effective use of smart materials in sensors and actuators. This paper addresses recursive identification and adaptive inverse control of hysteresis in smart material actuators, where hysteresis is modeled by a Preisach operator with a piecewise uniform density function. Two classes of identification schemes are proposed and compared, one based on the hysteresis output, the other based on the time-difference of the output. Conditions for parameter convergence are presented in terms of the input to the Preisach operator. An adaptive inverse control scheme is developed by updating the Preisach operator (and thus its inverse) with the output-based identification method. The asymptotic tracking property of this scheme is established, and for periodic reference trajectories, the parameter convergence behavior is characterized. Practical issues in the implementation of the adaptive identification and inverse control methods are also investigated. Simulation and experimental results based on a magnetostrictive actuator are provided to illustrate the proposed approach.
282 citations
TL;DR: In this article, a smart material made from a metallized ionomer membrane called Nafion has been developed to sense mechanical vibrations and generate a voltage response with a unique vibrational damping property.
Abstract: Vibration control has been achieved using state-of-the-art 'smart' materials. A 'smart' material has been developed from a metallized ionomer membrane called Nafion. This electroded material can sense mechanical vibrations and generate a voltage response. Electroded Nafion has a unique vibrational damping property. Damping with this material is achieved by dissipating the electrical energy generated as heat. This can be done using an external resistance or optimally by creating an internal conductive path. A prototype accelerometer cell has been developed which shows excellent linear characteristics and high sensitivity. It is found that the most critical element in both of the applications is the sum of the internal and the contact resistances of the electroded Nafion hydrogen pressure cell. Accordingly, a study of the resistance of these Nafion-based cells has been made and the results are included and discussed.
281 citations
TL;DR: A broad overview of the growth techniques that have been used to produce thin films and nanoparticles of VO2, including chemical vapor deposition, solgel synthesis, sputter deposition and pulsed laser deposition, is presented in this article.
Abstract: Thin-film materials with 'smart' properties that react to temperature variations, electric or magnetic fields, and/or pressure variations have recently attracted a great deal of attention. Vanadium dioxide (VO2) belongs to this family of 'smart materials' because it exhibits a semiconductor-to-metal first-order phase transition near 340 K, accompanied by an abrupt change in its resistivity and near-infrared transmission. It is also of great interest in condensed-matter physics because it is a classic strongly correlated electron system. In order to integrate vanadium dioxide into microelectronic circuits, thin-film growth of VO2 has been studied extensively, and studies of VO2 nanoparticles have shown that the phase transition is size-dependent. This paper presents a broad overview of the growth techniques that have been used to produce thin films and nanoparticles of VO2, including chemical vapor deposition, sol–gel synthesis, sputter deposition and pulsed laser deposition. Representative deposition techniques are described, and typical thin-film characteristics are presented, with an emphasis on recent results obtained using pulsed laser deposition. The opportunities for growing epitaxial films of VO2, and for doping VO2 films to alter their transition temperature and switching characteristics, are also discussed.
271 citations
TL;DR: The ability to use light to initiate physicochemical changes in polymers represents one of the most powerful and rapidly evolving approaches as discussed by the authors, which has the unique capacity for enabling 4D manipulation of each of those processes.
264 citations
TL;DR: In this article, the theoretical principles associated with SiC cage-like clusters and experimental work resulting from them are discussed and a review is placed on the theoretical and experimental results of these structures.
Abstract: Because of its superior properties silicon carbide is one of the most promising materials for power electronics, hard- and biomaterials. In the solid phase, the electronic and optical properties are controlled by the stacking of double layers of Si and C atoms. In thin films, a change in the stacking order often requires stress, which can be achieved naturally in systems with nanometre length scale. For this reason, nanotubes, nanowires and clusters can be used as building blocks for the synthesis of novel materials. Furthermore, playing at the nanometre length scale enables the nature of the SiC bonding to be modified, which is of prime importance for atomic engineering of nanostructures. In this review, emphasis is placed on the theoretical principles associated with SiC cage-like clusters and experimental work resulting from them.
264 citations