Dynamic Flexoelectric Actuation and Vibration Control of Beams

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Mu Fan ◽  
Bolei Deng ◽  
Hornsen Tzou
Keyword(s):  
Experimental Data ◽  
Dynamic Control ◽  
Longitudinal Direction ◽  
Bottom Surface ◽  
Internal Stresses ◽  
Control Effect ◽  
Flexoelectric Effect ◽  
Control Moment ◽  
Fixed End ◽  
And Control

A flexoelectric cantilever beam actuated by the converse flexoelectric effect is evaluated and its analytical and experimental data are compared in this study. A line-electrode on the top beam surface and a bottom surface electrode are used to generate an electric field gradient in the beam, so that internal stresses can be induced and applied to distributed actuations. The dynamic control effectiveness of the beam is investigated with a mathematical model and is validated by laboratory experiments. Analyses show that the actuation stress induced by the converse flexoelectric effect is in the longitudinal direction and results in a bending control moment to the flexoelectric beam since the stress in the thickness is inhomogeneous. It is found that thinner line-electrode radius and thinner flexoelectric beam lead to larger control effects on the beam. The position of the line-electrode on the top surface of the beam also influences the control effect. When the line-electrode is close to the fixed end, it induces a larger tip displacement than that is close to the free end. Analytical results agree well with laboratory experimental data. This study of flexoelectric actuation and control provides a fundamental understanding of flexoelectric actuation mechanisms.

Analytical and Experimental Studies of Flexoelectric Beam Control

2016 ◽  
Author(s):  
Xufang Zhang ◽  
Huiyu Li ◽  
Hornsen Tzou
Keyword(s):  
Electric Field ◽  
Design Parameters ◽  
Analytical Prediction ◽  
Probe Radius ◽  
Flexoelectric Effect ◽  
Control Moment ◽  
Probe Location ◽  
Afm Probe ◽  
Fixed End ◽  
Tip Displacement

Flexoelectricity includes two effects: the direct flexoelectric effect and the converse flexoelectric effect, which can be respectively applied to flexoelectric sensors and actuators to monitor structural dynamic behaviors or to control structural vibrations. This study focuses on the converse flexoelectric effect and its application to dynamic control of cantilever beams analytically and experimentally. In the mathematical model, a conductive atomic force microscope (AFM) probe with an external voltage is used to generate an inhomogeneous electric field driving the flexoelectric beam. The electric field gradient leads to an actuation stress in the longitudinal direction due to the converse flexoelectric effect. The actuation stress results in a bending control moment to the flexoelectric beam since the stress in the thickness is inhomogeneous. In order to evaluate the actuation effect of the flexoelectric actuator, the flexoelectric induced tip displacement is evaluated when the mechanical force is assumed zero. With the induced control moment, vibration control of the cantilever beam is discussed and the control effect is evaluated. Flexoelectric control effects with different design parameters, such as AFM probe location, AFM probe radius and flexoelectric beam thickness, are evaluated. Analytical results show that the optimal AFM probe location for all beam modes is close to the fixed end. Besides, thinner AFM probe radius and thinner flexoelectric beam enhance the control effects. Laboratory experiments are also conducted with different probe locations to validate the analytical predictions. Experimental results show that the induced tip displacement decreases when the input location moves away from the fixed end, which is consistent with the analytical prediction. The studies provide design guidelines of flexoelectric actuations in engineering applications.

A New Multi-DOF Photostrictive Actuator for Dynamic Control of Shells: Modeling and Analysis

2008 ◽  
Author(s):  
Hong-Hao Yue ◽  
Gui-Lan Sun ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Lead Zirconate Titanate ◽  
Photovoltaic Effect ◽  
Mechanical Strain ◽  
Dynamic Control ◽  
Lead Zirconate ◽  
Shell Structures ◽  
Control Effect ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Distributed Actuator

Based on the photovoltaic effect and the converse piezoelectric effect, the lanthanum-modified lead zirconate titanate (PLZT) actuator can transform the photonic energy to mechanical strain/stress — the photodeformation effect. This photodeformation process can be further used for non-contact precision actuation and control in various structural, biomedical and electromechanical systems. Although there are a number of design configurations of distributed actuators, e.g., segmentation and shaping, been investigated over the years, this study is to explore a new actuator configuration spatially bonded on the surface of shell structures to broaden the spatial modal controllability. A mathematical model of a new multi-degree-of-freedom (DOF) photostrictive actuator configuration is presented first, followed by the photostrictive/shell coupling equations of a cylindrical shell structure laminated with the newly proposed multi-DOF distributed actuator. Distributed microscopic photostrictive actuation and its contributing components are analyzed in the modal domain. Effects of shell’s curvature and actuator’s size are evaluated. Parametric analyses suggest that the new multi-DOF distributed actuator, indeed, provides better performance and control effect to shell actuation and control. This multi-DOF configuration can be further applied to actuation and control of various shell and non-shell structures.

Nonlinear Piezothermoelasticity and Multi-Field Actuations, Part 2: Control of Nonlinear Deflection, Buckling and Dynamics

1997 ◽  
Vol 119 (3) ◽  
pp. 382-389 ◽  
Author(s):  
H. S. Tzou ◽  
Y. H. Zhou
Keyword(s):  
Circular Plate ◽  
Geometrical Nonlinearity ◽  
Nonlinear Effects ◽  
Thermal Buckling ◽  
Control Effect ◽  
Control Moment ◽  
Piezoelectric Layers ◽  
Equivalent Control ◽  
High Control ◽  
And Control

Linear dynamics and distributed control of piezoelectric laminated continua have been intensively investigated in recent years. In this study, dynamics, electromechanical couplings, and control of thermal buckling of a nonlinear piezoelectric laminated circular plate with an initial large deformation are investigated. It is assumed that the transverse nonlinear component is much more prominent than the other two in-plane components—the von Karman type geometrical nonlinearity. In addition, the piezoelectric layers are uniformly distributed on the top and bottom surfaces of the circular plate. Accordingly, the control effect is introduced via an equivalent control moment on the circumference. Dynamic equations and boundary conditions including the elastic and piezoelectric couplings are formulated, and solutions are derived. Active control of plate’s nonlinear deflections, thermal buckling, and natural frequencies using high control voltages are studied, and their nonlinear effects are evaluated.

Piezoelectric Actuation of von Karman Circular Plates With Thermal Deformation and Nonlinear Oscillation

1995 ◽  
Author(s):  
H. S. Tzou ◽  
Y.-H. Zhou
Keyword(s):  
Circular Plate ◽  
Nonlinear Effects ◽  
Thermal Buckling ◽  
Control Effect ◽  
Control Moment ◽  
Von Karman ◽  
Equivalent Control ◽  
High Control ◽  
Von Kármán ◽  
And Control

Abstract Linear dynamics and distributed control of piezoelectric laminated continua have been intensively studied in recent years. In this study, dynamics, electromechanical couplings, and control of thermal buckling of a piezoelectric laminated circular plate with an initial nonlinear large deformation are investigated. It is assumed that the von Karman type geometrically nonlinear deformation is considered. In addition, the piezoelectric layers are uniformly distributed on the top and bottom surfaces of the circular plate. Accordingly, control effect is introduced via an equivalent control moment on the circumference. Dynamic equations and boundary conditions including elastic and piezoelectric couplings are formulated, and solutions are derived. Active control of plate’s nonlinear deflections, thermal buckling, and natural frequencies using high control voltages are studied, and their nonlinear effects are evaluated.

The Research of Air Precooling System Based on Generalize Predictive Control Strategy

2013 ◽  
Vol 433-435 ◽  
pp. 1091-1098
Author(s):  
Wei Bo Yu ◽  
Cui Yuan Feng ◽  
Ting Ting Yang ◽  
Hong Jun Li
Keyword(s):  
Predictive Control ◽  
Control Strategy ◽  
Control Algorithm ◽  
Exchange Process ◽  
Generalized Predictive Control ◽  
Matlab Simulation ◽  
Control Effect ◽  
Heat Exchange Process ◽  
Complex Control System ◽  
And Control

The air precooling system heat exchange process is a complex control system with features such as: nonlinear, lag and random interference. So choose Generalized Predictive Control Algorithm that has low model dependence, good robustness and control effect, as well as easy to implement. But due to the large amount of calculation of traditional generalized predictive control and can't juggle quickness and overshoot problem, an improved generalized predictive control algorithm is proposed, then carry out the MATLAB simulation, the experimental results show that the algorithm can not only greatly reduce the amount of computation, but also can restrain the overshoot and its rapidity.

Dynamic Temperature Testing and Modeling for an Automatic Transmission Clutch

2001 ◽  
Author(s):  
Thomas DeMurry ◽  
Yanying Wang
Keyword(s):  
Experimental Data ◽  
Real Time ◽  
Automatic Transmission ◽  
Thermal Characteristics ◽  
Torque Converter ◽  
Telemetry System ◽  
Temperature Model ◽  
And Control ◽  
Good Agreement ◽  
Dynamometer Test

Abstract The primary objectives of this study are (1) to validate the hardware design and control methodologies for preserving the thermo-mechanical integrity of a launch clutch emulating a torque converter and (2) to develop a simple, control oriented clutch-temperature model that may act as a virtual thermocouple in the processor of an automobile for real-time clutch-temperature predictions. In a dynamometer test cell, a Ford CD4E transaxle is instrumented with a thermocouple-based telemetry system to investigate clutch thermal characteristics during engagements, neutral idle, single and repeated launching, torsional isolation, and hill holding. A nonlinear, SIMULINK™-based model for estimating temperature is developed. The results from the simulations are in good agreement with the experimental data.

Modeling of Coupled Bending and Torsion in Elastic Structures

1993 ◽  
Author(s):  
H. T. Banks ◽  
C. A. Smith
Keyword(s):  
Experimental Data ◽  
Numerical Results ◽  
Computational Results ◽  
Elastic Structures ◽  
Approximation Techniques ◽  
Flexural Vibrations ◽  
And Control

Abstract In this presentation we will report on joint efforts with D.J. Inman and his colleagues at MSL, SUNY at Buffalo, to develop viable models for the analysis and control of elastic structures exhibiting coupled torsional and flexural vibrations. A model for coupled torsion and bending is developed which incorporates Kelvin Voigt damping and warping. Approximation techniques are introduced and preliminary numerical results are discussed. Experimental data is presented and used to test our computational results.

Nonlinear Axial and Transverse Oscillation and Control of a PZT Laminated Distributed Structronic System

2000 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding ◽  
W. K. Chai
Keyword(s):  
Distributed Control ◽  
Shape Control ◽  
Geometrical Nonlinearity ◽  
Axial Displacement ◽  
Beam Model ◽  
Control Effect ◽  
Laminated Beam ◽  
Practical Applications ◽  
Axial Oscillation ◽  
And Control

Abstract Piezoelectric laminated distributed systems have broad applications in many new smart structures and structronic systems. As the shape control becomes an essential issue in practical applications, the nonlinear large deformation has to be considered, and thus, the geometrical nonlinearity has to be incorporated. Two electromechanical partial differential equations, one in the axial direction and the other in the transverse direction, are derived for the nonlinear PZT laminated beam model. The conventional approach is to neglect the axial oscillation and distributed sensing and control of the distributed laminated beam is evaluated, excluding the effect of axial oscillation. In this paper, influence of the axial displacement to the dynamics and distributed control effect is evaluated. Analysis results reveal that the axial displacement, indeed, has significant influence to the dynamic and distributed control responses of the nonlinear distributed PZT laminated beam structronics systems.

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