Papers by Keyword: Piezoelectricity

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Authors: Johannes Scheller, Gurvan Jodin, Karl Joseph Rizzo, Eric Duhayon, Jean François Rouchon, Michael Triantafyllou, Marianna Braza
Abstract: This article will present a morphing wing actuated using both surface embedded Shape memory alloys (SMAs) and trailing edge Macro-fiber composites (MFCs). This combination enables the airfoil to simultaneously achieve large scale deformations at low frequencies as well as rapid actuation with a limited amount of displacement. Thereby not only can the shape of the airfoil be optimized in function of the current mission profile but also the shear layer can be influenced. Each actuator is modelled using both a finite element and/or an analytical model and the results will be verified experimentally.
Authors: Christian N. Della, Dong Wei Shu
Abstract: In this research, a comparative study of the hydrostatic performances of 1-3 piezoelectric composites with a porous matrix is presented. The piezoelectric fibers PZT-5H and PZT-7A are considered in the present study. The micromechanics based Mori-Tanaka model is used. Results of the study show that PZT-5H/Aradite D composite have better hydrostatic performance than PZT- 7A/Aradite D composite, and this advantage of PZT-5H/Aradite D composite over PZT-7A/Aradite D composite increases with the increase of porosity in the matrix.
Authors: Zheng Hua Qian, Feng Jin, Sohichi Hirose
Abstract: In this paper, we study the propagation of electro-elastic Love waves in a piezoelectric layered solid consisting of a transversely isotropic piezoelectric ceramic film deposited on an isotropic metal substrate. Dispersion relations are obtained in a very concise mathematical form for both electrically open and shorted circuits. Numerical example is given for a PZT-4/steel system. An interesting phenomenon on the fundamental mode of the Love waves in the case of electrically shorted circuit is realized and validated through the discussion on the limit values of phase velocity using the obtained dispersion relations. This validation appears new and is significant to understand the Love wave modes themselves and to the design of acoustic wave devices.
Authors: Paulo Inácio, José N. Marat-Mendes, C.J. Dias
Authors: Na Xin Dai, Ping Tan, Fu Lin Zhou
Abstract: A smart base-isolation system, composed of low damping bearings and piezoelectric friction damper is studied in this paper. The semi-active piezoelectric friction damper (PFD[1]) is proposed for control of peak dynamic response of seismic-excited structures. In the proposed PFD device, the friction force between two sliding plates is regulated by controlling the normal force using piezoelectricity across the damper, and its advantage is that its operation requires only minimal external power. A high efficient control algorithm is proposed for the semi-active control of the friction damper using a simple static output. The effectiveness of the PFD device and the control strategy in reducing the peak dynamic response of structures is investigated through an application to a 5-story base-isolated building. Numerical results demonstrate that the proposed PFD device and the control strategy are effective in reducing the peak drift of rubber-bearings of the base-isolated building subject to earthquakes.
Authors: K.P. Jayachandran, J.M. Guedes, H.C. Rodrigues
Abstract: A stochastic optimization procedure incorporating a continuum modelling is used to identify the optimal texture (orientation distribution) parameters of ferroelectrics (FEs) for piezoelectric applications. FE polycrystals differ significantly from single crystals because of the presence of variously oriented crystallites. The orientation of FE crystals plays a critical role in the anisotropy of their piezoelectric properties. The set of combination of variables, known as solution space, which dictates the texture of crystallites is unlimited. Crystallographic orientation in FEs is characterised through Euler angles . The macroscopic properties of a ceramic FE, differ significantly from those of single crystals mainly due to the imperfect alignment of the crystallographic axes of the constituent domains or crystallites. This suggests that piezoelectric properties can be tailored by a proper choice of the parameters which control the orientation distribution. Nevertheless, this choice is complicated and it is impossible to analyze all possible combinations of the distribution parameters or the angles themselves. Stochastic optimization combined with a generalized Monte Carlo scheme optimizes the objective functions, the effective piezoelectric coefficients . Objective functions are calculated using the homogenization method at each orientation configuration chosen by the optimization algorithm. A modified simulated annealing is employed to describe the stochastic optimization. Here we have simulated the texture of polycrystals using a simple model with a Gaussian distribution. Optimal design variables that enhance the macroscopic piezoelectricity are identified.
Authors: Juh Wan Yang, Chang Sung Park, Won Chul Sim, Young Jae Kim, Soon Young Kim, Chung Mo Yang, Sung Jun Park, Young Seuck Yoo, Jae Woo Joung
Abstract: In this study, specially used in fluidic jetting apparatus, the electrical properties of piezoelectric ceramics were investigated by the resonance method and from its vibratory motion point of view. The piezoelectric ceramics were a rectangular bar type bulk and estimated by their piezoelectric constants, for example, electromechanical coupling factor, piezoelectric strain constant and so on. The measured values were compared with the displacement by the Laser Doppler Vibrometer analysis and with the droplet properties.
Authors: Hong Yang, Wei Chen, Yang Xia, Gao Lin Xiang
Abstract: In this paper, based on the constitutive equations of piezoelectric effect and piezomagnetic effect, a 1-3 model of laminate magnetoelectricity composite materials is established. By combining material mechanical kinematic equations and circuit state equations, magnetical-mechanical-electrical equivalent circuit of laminate magnetoelectric composite materials is raised and magneto-electricity switch effect is analyzed. Upon these, a new kind of laminate magnetoelectricity composite material, Terfenol-D/PMNT/Terfenol-D, is put forward. Taking 1-3 model as an example, with the help of MATLAB, we simulate and calculate the magnetoelectric response of this new material. Through calculation, a conclusion is drawn that this new materials magnetoelectricity switch coefficient is higher than that of Terfenol-D/PZT/Terfenol-D. This theoretical basis will put this new material in a good position in magnetoelectric materials preparation.
Authors: Keith J. Bowman, R. Moon, E. Drewry, S. Wan, P. Tortorici, Mysore A. Dayananda
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