Optimum design of flextensional piezoelectric actuators into two spatial dimensions
Résumé
In control of distributed parameter systems the piezoelectric actuators are of com-mon use. The topology optimization of a multiphysic model in piezoelectricity is considered. The topological derivative of a tracking-type shape functional is derived in its closed form for the pur-pose of shape optimization of piezoelectric actuators. The optimum design procedure is applied to a micromechanism which transforms the electrical energy supplemented via its piezoceramic part into elastic energy of an actuator. The domain decomposition technique and the Steklov-Poincaré pseudo-differential boundary operator are employed in the asymptotic analysis of the shape func-tional defined on a part of the boundary of the elastic body under consideration. The proposed method of sensitivity analysis is general and can be used for the purpose of the shape-topological optimization for a broad class of multiphysics models. The numerical results confirm the efficiency of proposed approach to optimum design in multiphysics. 1. Introduction . In this paper we are interested in the optimal design of piezo-electric actuators, which consist of multi-flexible structures actuated by piezoceramic devices that generate an output displacement in a specified direction on the boundary of the actuated part [5, 27]. The multi-flexible structure transforms the piezoceramic output displacement by amplifying and changing its direction. This kind of mecha-nism can be manufactured at a very small scale. Therefore, the spectrum of appli-cations of such microtools becomes broader in recent years including microsurgery, nanotechnology processing, cell manipulation, among others. Yet, the development of microtools requires the design of actuated multi-flexible structures which are able to produce complex movements originated from simple expansion/contraction of the piezoceramic actuator. The performance of microtools can be strongly enhanced by optimizing the actuated multi-flexible structures with respect to their shape and their topology [6, 7, 8]. The shape sensitivity analysis of such coupled models has been fully developed in [19] and [18] for quasi-electrostatic layered piezoelectric devices and for non-stationary elastic, piezoelectric and acoustic coupled system, respectively. For the mathematical theory concerning coupled PDEs systems the reader may refer to e.g., [17, 20, 21]. However, a more general approach to deal with shape and topology optimization design is based on the topological derivative. In fact, this relatively new concept
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