In this note we give fundamental existence, uniqueness, and continuous dependence results (well-posedness) for a variational formulation of a class of damped second order partial diierential equations with unbounded input or control coee-cients. Included as special cases in this class are structures with piezoceramic actua-tors. We then consider approximation techniques leading to computational...

O.A. Sapozhnikov, A.V. Morozov and D. Cathignol ACOUSTIC HOLOGRAPHY AND LASER VIBROMETRY TO CHARACTERIZE VIBRATION OF PIEZOCERAMIC AND PIEZOCOMPOSITE TRANSDUCERS USED IN ULTRASOUND THERAPY Moscow State University, Faculty of Physics, Department of Acoustics Russia 119992, Moscow, Leninskie Gory E-mail: [email protected] French Institute of Health and Medical Research, INSERM U556, 151, Co...

Analytical relations, describing the electrical fields of cylindrical piezoceramic radiators with circular polarization as a member systems baffle in inner cavity, using related method multiply connected regions were obtained. Comparative analysis results numerical experiments performed on frequency characteristics electric field radiating for different modes radiation allow to establish number...

We discuss the concept of lightweight segmented bimorph mirrors for adaptive optics. The segment consists of a monocrystal silicon substrate actuated by an array of in-plane piezoceramic (PZT) actuators with honeycomb electrodes. We focus on technological aspects of the segment design that are critical for space applications and describe a single segment demonstrator. The morphing capability of...

Many vibration suppression systems are required to function across a variety of different temperatures, yet most literature ignores the effects of temperature changes on the structure and on the closed loop response. This paper presents an experimental implementation of a vibration suppression system based on a piezoceramic actuator that effectively controls vibration of a clamped panel as it u...

the potential error magnitudes associated with angle bias. The effect of turbulence is also shown in comparing Figs. 2a and 2b. As would be expected, the increased turbulence tends to increase the PPD when the mean flow angle is close to parallel to the fringe planes. However, the PPD is slightly reduced when the mean flow angle is close to perpendicular to the fringe planes. Of particular inte...

A Faraday fiber-optic current sensor was employed to measure the tokamak plasma current. In order to decrease the influence of mechanical perturbations on the sensor sensitivity, a two-pass optical scheme with a variable Faraday mirror at the fiber end is proposed. A decrease, by two orders of magnitude, in the influence of the linear birefringence produced by an external piezoceramic fiber mod...

A ferroelastic switching model for single crystal piezoceramic compounds is developed. The model is based on a phenomenological Landau-Devonshire type thermodynamic theory for the materials. The model incorporates externally applied electric fields and compressive stress inputs to the crystals and models the 90 and 180 ferroelastic and ferroelectric switching induced by the inputs. Properties o...