The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Madan Dubey - One of the best experts on this subject based on the ideXlab platform.
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surface micromachined microelectromechancial ohmic series switch using thin film Piezoelectric Actuators
IEEE Transactions on Microwave Theory and Techniques, 2007Co-Authors: Ronald G Polcawich, Jeffrey S Pulskamp, Daniel Judy, P Ranade, Susan Troliermckinstry, Madan DubeyAbstract:This paper presents results on a surface micromachined RF microelectromechanical switch that uses Piezoelectric Actuators. The switch uses solution chemistry-derived lead zirconate titanate thin films spun deposited onto a high-resistivity silicon substrate with coplanar waveguide transmission lines. Actuation voltages, applied via circuits independent of the RF circuitry, average less than 10 V, with switch operation demonstrated as low as 2 V. The series switch exhibits better than 20-dB isolation from dc up to 65 GHz and as large as 70 dB below 1 GHz. In the closed state, the switch has an insertion loss less than 1 dB up to 40 GHz, limited in this demonstration by substrate losses from the elastic layer used to stress control the Piezoelectric Actuators. Switching speeds for the different designs are in the range of 40-60 ms. Thermal sensitivity measurements show no change in isolation observed for temperatures up to 125degC. However, an increase in actuation voltage is required at elevated temperatures.
Zora Vrcelj - One of the best experts on this subject based on the ideXlab platform.
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new explicit solution for static shape control of smart laminated cantilever piezo composite hybrid plates beams under thermo electro mechanical loads using Piezoelectric Actuators
Composite Structures, 2016Co-Authors: Soheil Gohari, S Sharifi, Zora VrceljAbstract:Abstract In this paper, a new explicit exact analytical solution is proposed for obtaining static deformation and optimal shape control of smart laminated cantilever piezo composite hybrid plates and beams under thermo-electro-mechanical loads using Piezoelectric Actuators. The linear Piezoelectricity and plates theories were adapted for the analysis. A novel double integral multivariable Fourier transformation method combined with discretised higher order partial differential unit step function equations were employed. The effect of various parameters including arbitrary loads such as non-uniform thermal stresses, electrical and mechanical loads, layup thickness, Piezoelectric Actuators size and placement, stacking sequence, and geometrical dimension were considered. The results were then compared with some published benchmark results and good agreement was observed. Unlike the earlier studies, the proposed method does not require the characteristic and trial deflection function to be predetermined. Both, the embedded and bounded Actuators are considered. Until now, the shape control task of reducing mid-plane deformation at free end in smart laminated cantilever plates and beams was unsolvable and approximations were typically employed in numerical analysis Yu et al. (2009). This problem becomes more complicated for wider and longer plates but the method proposed herein successfully resolves this issue.
Liyong Tong - One of the best experts on this subject based on the ideXlab platform.
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design of Piezoelectric Actuators using a multiphase level set method of piecewise constants
Journal of Computational Physics, 2009Co-Authors: Liyong Tong, Michael Yu WangAbstract:This paper presents a multiphase level set method of piecewise constants for shape and topology optimization of multi-material Piezoelectric Actuators with in-plane motion. First, an indicator function which takes level sets of piecewise constants is used to implicitly represent structural boundaries of the multiple phases in the design domain. Compared with standard level set methods using n scalar functions to represent 2^n phases, each constant value in the present method denotes one material phase and 2^n phases can be represented by 2^n pre-defined constants. Thus, only one indicator function including different constant values is required to identify all structural boundaries between different material phases by making use of its discontinuities. In the context of designing smart Actuators with in-plane motions, the optimization problem is defined mathematically as the minimization of a smooth energy functional under some specified constraints. Thus, the design optimization of the smart actuator is transferred into a numerical process by which the constant values of the indicator function are updated via a semi-implicit scheme with additive operator splitting (AOS) algorithm. In such a way, the different material phases are distributed simultaneously in the design domain until both the passive compliant host structure and embedded Piezoelectric Actuators are optimized. The compliant structure serves as a mechanical amplifier to enlarge the small strain stroke generated by Piezoelectric Actuators. The major advantage of the present method is to remove numerical difficulties associated with the solution of the Hamilton-Jacobi equations in most conventional level set methods, such as the CFL condition, the regularization procedure to retain a signed distance level set function and the non-differentiability related to the Heaviside and the Delta functions. Two widely studied examples are chosen to demonstrate the effectiveness of the present method.
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evolutionary Piezoelectric Actuators design optimisation for static shape control of smart plates
Computer Methods in Applied Mechanics and Engineering, 2007Co-Authors: Quan Nguyen, Liyong TongAbstract:This paper presents a new evolutionary algorithm to solve various structural shape control problems of smart composite plate structures with active Piezoelectric Actuators. The linear least square (LLS) method and the features of evolutionary strategies are employed to find the applied voltages and shapes for the active Piezoelectric Actuators, respectively, in order to achieve the desired structural shapes by gradually removing the active Piezoelectric material part of the element based on the error function sensitivity number. In the finite element (FE) analysis, an error function sensitivity number, including electro-mechanical effect, is one derived to compute the change in error functions that are defined in terms of least square difference between calculated and desired structural shapes. The evolutionary Piezoelectric actuator design optimisation (EPADO) is proposed here to optimise the active Piezoelectric actuator shape at a given applied voltage. Finally, several numerical examples are presented to verify that the proposed algorithm improves structural shape control by reducing the error function.
Jiashi Yang - One of the best experts on this subject based on the ideXlab platform.
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thin film Piezoelectric Actuators of nonuniform thickness and nonhomogeneous material properties for modulating actuation stress
Mechanics of Advanced Materials and Structures, 2015Co-Authors: Nan Liu, Jiashi Yang, Weiqiu ChenAbstract:The effects of the thickness variation and the material property variation of thin-film Piezoelectric Actuators on the actuation shear stress when the Actuators are attached to an elastic plate are studied. A system of 2D equations for the flexure and shear of an elastic plate with symmetric Piezoelectric Actuators on the plate surfaces is derived. The equations are reduced to the case of elementary flexure without shear as a special case. The effects of the actuator thickness variation and material property variation on the actuation stress are examined using the equations obtained. It is shown that the distribution of the actuation stress depends on the thickness and material property variations of the Actuators, and that Actuators with varying thickness or varying material properties can be used to make modal Actuators for producing a particular deformation or exciting a particular vibration mode.
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the vibration of a simply supported rectangular elastic plate due to Piezoelectric Actuators
International Journal of Solids and Structures, 1996Co-Authors: R C Batra, X Q Liang, Jiashi YangAbstract:Abstract An analysis of a simply supported rectangular elastic plate forced into bending vibrations by the application of time harmonic voltages to Piezoelectric Actuators attached to its bottom and top surfaces is performed by using the equations of linear elasticity. The Actuators have been modeled as thin surface films and mixed edge conditions are employed to simulate simple supports.
Q S Wang - One of the best experts on this subject based on the ideXlab platform.
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active buckling control of beams using Piezoelectric Actuators and strain gauge sensors
Smart Materials and Structures, 2010Co-Authors: Q S WangAbstract:In this paper, a finite element model incorporating active control techniques has been developed to stabilize the first two buckling modes of both a simply supported and a cantilevered beam. The goal is to increase the corresponding beam buckling loads by using Piezoelectric Actuators along with optimal feedback control. The uniform beams are bonded with two pairs of segmented Piezoelectric Actuators at the top and bottom. Resistive strain gauges are attached to the centres of the Actuators as sensors. Measurements are taken using these, to estimate the system states. The beams are simply supported or cantilevered and subjected to a slowly increasing axial compressive load. Finite element formulations based on the classical Euler–Bernoulli beam theory and linear Piezoelectric constitutive equations for the Actuators are presented. The associated reduced-order modal equations and the state-space equations are derived for the design of a standard linear quadratic regulator (LQR). The finite element analysis and the active control simulation results are consistent with both theoretical analysis results and experimental data. The designed full state feedback LQR controller is shown to be successful in stabilizing the first two buckling modes of the beams. Also the control simulation shows that the present optimally located segmented actuator pairs along the beam are more effective for buckling control.
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active buckling control of beams using Piezoelectric Actuators and strain gauge sensors
Smart Materials and Structures, 2010Co-Authors: Q S WangAbstract:In this paper, a finite element model incorporating active control techniques has been developed to stabilize the first two buckling modes of both a simply supported and a cantilevered beam. The goal is to increase the corresponding beam buckling loads by using Piezoelectric Actuators along with optimal feedback control. The uniform beams are bonded with two pairs of segmented Piezoelectric Actuators at the top and bottom. Resistive strain gauges are attached to the centres of the Actuators as sensors. Measurements are taken using these, to estimate the system states. The beams are simply supported or cantilevered and subjected to a slowly increasing axial compressive load. Finite element formulations based on the classical Euler–Bernoulli beam theory and linear Piezoelectric constitutive equations for the Actuators are presented. The associated reduced-order modal equations and the state-space equations are derived for the design of a standard linear quadratic regulator (LQR). The finite element analysis and the active control simulation results are consistent with both theoretical analysis results and experimental data. The designed full state feedback LQR controller is shown to be successful in stabilizing the first two buckling modes of the beams. Also the control simulation shows that the present optimally located segmented actuator pairs along the beam are more effective for buckling control.