Active Vibration Control of a Doubly Curved Composite Shell Stiffened by Beams Bonded with Discrete Macro Fibre Composite Sensor/Actuator Pairs

Doubly curved stiffened shells are essential parts of many large-scale engineering structures, such as aerospace, automotive and marine structures. Optimization of active vibration reduction has not been properly investigated for this important group of structures. This study develops a placement methodology for such structures under motion base and external force excitations to optimize the locations of discrete piezoelectric sensor/actuator pairs and feedback gain using genetic algorithms for active vibration control. In this study, fitness and objective functions are proposed based on the maximization of sensor output voltage to optimize the locations of discrete sensors collected with actuators to attenuate several vibrations modes. The optimal control feedback gain is determined then based on the minimization of the linear quadratic index. A doubly curved composite shell stiffened by beams and bonded with discrete piezoelectric sensor/actuator pairs is modeled in this paper by first-order shear deformation theory using finite element method and Hamilton’s principle. The proposed methodology is implemented first to investigate a cantilever composite shell to optimize four sensor/actuator pairs to attenuate the first six modes of vibration. The placement methodology is applied next to study a complex stiffened composite shell to optimize four sensor/actuator pairs to test the methodology effectiveness. The results of optimal sensor/actuator distribution are validated by convergence study in genetic algorithm program, ANSYS package and vibration reduction using optimal linear quadratic control scheme

Optimization of sizing, location and orientation of piezoelectric actuator-sensor pairs on composite plate

Piezoelectric actuators and sensors have a wide range of application in the active vibration control of flexible structures. Control performances of the smart structures depend on the size and position of piezoelectric actuators and sensors on a smart structure. This paper deals with the optimization of sizing, location and orientation of piezoelectric actuators-sensors pairs on thin-walled composite plate. Optimization criteria are based on eigenvalues of the controllability Grammian matrix. The optimization problem is formulated by integration of finite element method based on the third-order shear deformation theory and the particle swarm optimization method. Numerical examples are provided for symmetric cross ply cantilever quadratic composite laminates. Linear quadratic regulator has been implemented for active vibration control of the composite plates with the optimized piezoelectric actuator-sensor pairs in order to show the efficiency of presented optimization method

Optimization of sizing, location and orientation of piezoelectric actuator-sensor pairs on composite plate

Piezoelectric actuators and sensors have a wide range of application in the active vibration control of flexible structures. Control performances of the smart structures depend on the size and position of piezoelectric actuators and sensors on a smart structure. This paper deals with the optimization of sizing, location and orientation of piezoelectric actuators-sensors pairs on thin-walled composite plate. Optimization criteria are based on eigenvalues of the controllability Grammian matrix. The optimization problem is formulated by integration of finite element method based on the third-order shear deformation theory and the particle swarm optimization method. Numerical examples are provided for symmetric cross ply cantilever quadratic composite laminates. Linear quadratic regulator has been implemented for active vibration control of the composite plates with the optimized piezoelectric actuator-sensor pairs in order to show the efficiency of presented optimization method

PIEZOELECTRIC ACTUATOR DESIGN OPTIMISATION FOR SHAPE CONTROL OF SMART COMPOSITE PLATE STRUCTURES

Shape control of a structure with distributed piezoelectric actuators can be achieved through optimally selecting the loci, shapes and sizes of the piezoelectric actuators and choosing the electric fields applied to the actuators. Shape control can be categorised as either static or dynamic shape control. Whether it is a transient or gradual change, static or dynamic shape control, both aim to determine the loci, sizes, and shapes of piezoelectric actuators, and the applied voltages such that a desired structural shape is achieved effectively. This thesis is primarily concerned with establishing a finite element formulation for the general smart laminated composite plate structure, which is capable to analyse static and dynamic deformation using non-rectangular elements. The mechanical deformation of the smart composite plate is modelled using a third order plate theory, while the electric field is simulated based on a layer-wise theory. The finite element formulation for static and dynamics analysis is verified by comparing with available numerical results. Selected experiments have also been conducted to measure structural deformation and the experimental results are used to correlate with those of the finite element formulation for static analysis. In addition, the Linear Least Square (LLS) method is employed to study the effect of different piezoelectric actuator patch pattern on the results of error function, which is the least square error between the calculated and desired structural shapes in static structural shape control. The second issue of this thesis deals with piezoelectric actuator design optimisation (PADO) for quasi-static shape control by finding the applied voltage and the configuration of piezoelectric actuator patch to minimise error function, whereas the piezoelectric actuator configuration is defined based on the optimisation technique of altering nodal coordinates (size/shape optimisation) or eliminating inefficient elements in a structural mesh (topology optimisation). Several shape control algorithms are developed to improve the structural shape control by reducing the error function. Further development of the GA-based voltage and piezoelectric actuator design optimisation method includes the constraint handling, where the error function can be optimised subjected to energy consumption or other way around. The numerical examples are presented in order to verify that the proposed algorithms are applicable to quasi-static shape control based on voltage and piezoelectric actuator design optimisation (PADO) in terms of minimising the error function. The third issue is to use the present finite element formulation for a modal shape control and for controlling resonant vibration of smart composite plate structures. The controlled resonant vibration formulation is developed. Modal analysis and LLS methods are also employed to optimise the applied voltage to piezoelectric actuators for achieving the modal shapes. The Newmark direct time integration method is used to study harmonic excitation of smart structures. Numerical results are presented to induce harmonic vibration of structure with controlled magnitude via adjusting the damping and to verify the controlled resonant vibration formulation

Design of laminated structures using piezoelectric materials

Composite structures incorporating piezoelectric sensors and actuators are increasingly becoming important due to the offer of potential benefits in a wide range of engineering applications such as vibration and noise supression, shape control and precisition positioning. This paper presents a finit element formulation based on classical laminated plate theory for laminated structures with integrated piezoelectric layers or patches, acting as actuators. The finite element model is a single layer triangular nonconforming plate/shell element with 18 degrees of freedom for the generalized displacements, and one electrical potential degree of freedom for each piezsoelectric elementlayer or patch, witch are surface bonded on the laminate. An optimization of the patches position is performed to maximize the piezoelectric actuators efficiency as well as, the electric potential distribuition is search to reach the specified structure transverse displacement distribuition (shape control). A gradient based algorithm is used for this purpose. The model is applied in the optimization of illustrative laminated plate cases, and the results are presented and discussed

Piezo-electromechanical smart materials with distributed arrays of piezoelectric transducers: Current and upcoming applications

This review paper intends to gather and organize a series of works which discuss the possibility of exploiting the mechanical properties of distributed arrays of piezoelectric transducers. The concept can be described as follows: on every structural member one can uniformly distribute an array of piezoelectric transducers whose electric terminals are to be connected to a suitably optimized electric waveguide. If the aim of such a modification is identified to be the suppression of mechanical vibrations then the optimal electric waveguide is identified to be the 'electric analog' of the considered structural member. The obtained electromechanical systems were called PEM (PiezoElectroMechanical) structures. The authors especially focus on the role played by Lagrange methods in the design of these analog circuits and in the study of PEM structures and we suggest some possible research developments in the conception of new devices, in their study and in their technological application. Other potential uses of PEMs, such as Structural Health Monitoring and Energy Harvesting, are described as well. PEM structures can be regarded as a particular kind of smart materials, i.e. materials especially designed and engineered to show a specific andwell-defined response to external excitations: for this reason, the authors try to find connection between PEM beams and plates and some micromorphic materials whose properties as carriers of waves have been studied recently. Finally, this paper aims to establish some links among some concepts which are used in different cultural groups, as smart structure, metamaterial and functional structural modifications, showing how appropriate would be to avoid the use of different names for similar concepts. © 2015 - IOS Press and the authors

Vibration Based Damage Identification in a Composite T-Beam Utilising Low Cost Integrated Actuators and Sensors

The development of integrated measurement systems for composite structures is\ud urged by the fact that a Structural Health Monitoring environment requires these systems to become an integral part of the structure. The feasibility of using low cost piezoelectric diaphragms for dynamic characterisation and vibration based damage identification in a composite T-beam structure is demonstrated. The dynamic behaviour is analysed by applying these basic electronic sound components for actuation and sensing. Impact induced damage at the skin-stiffener connection is detected and localized by applying the MSE-DI algorithm on the measured bending strain mode shapes