Search

Controlling vibration in thin symmetric laminated plates has been implemented with a closed-form solution with output feedback using distributed piezoelectric sensors and actuators. The plate structure is made up of a special orthotropic laminated plate combined with piezoelectric layers on the top and bottom layers. The top layer functions as an actuator while the bottom layer works as a sensor. The optimal gain is obtained by using the method for constructing the linear quadratic regulator with output feedback.

A finite element formulation for active vibration control of a laminated plate with piezoelectric polymer layers acting as distributed sensors shows a significant reduction in vibrational amplitude due to increased damping through feedback. The increase in damping ratio of thick plate is more than that of thin plate when both experience the same intensity of mechanical load. The substrate is a symmetric graphite-epoxy laminate and the sensor and actuator layers are made of polyvinylidene fluoride.

The precise solutions for static analysis of a simply supported rectangular plate-type intelligent structure were devised. The structure was composed of a laminated substrate of graphite/epoxy-composite combined with distributed sensor and actuator layers of biaxially polarized piezoelectric polymer (PVDF). The actuator layer is responsible for the layers of the substrate to bend. It also causes transverse compression, in-plane shear and transverse shear deformations. The actuator layer becomes more effective when there is a decrease in the length of the thickness ratio of the substrate. The results can be applied to verify solutions of later studies on the intelligent structure.

This paper is concerned with the static analysis of simply supported cross-ply substrate plates integrated with a layer of piezoelectric fiber reinforced composite material undergoing nonlinear deformations. The von Kármán type nonlinear strain displacement relations and first order shear deformation theory are used to formulate the variational model of this electromechanical coupled problem. Subsequently, Galerkin procedure is employed to derive the nonlinear algebraic governing equations which are solved by usingNewton-Raphson method. The results suggest the potential use of PFRC material for distributed control of nonlinear deformations of smart composite structures. The effect of variation of piezoelectric fiber orientation on the actuating capability of the PFRC actuator for counteracting the nonlinear deformations of the smart composite plates has also been investigated. [ABSTRACT FROM AUTHOR]

This paper deals with the analysis of vertically reinforced 1-3 piezoelectric composite materials as the material for the distributed actuator of smart laminated composite plates. A simple micromechanics model has been derived to predict the effective elastic and piezoelectric coefficients of these piezoelectric composites which are useful for the three dimensional analysis of smart structures. The main concern of this study is to investigate the performance of a layer of this vertically reinforced 1-3 piezoelectric composite material as the constraining layer of the active constrained layer damping (ACLD) treatment. A finite element model has been developed for analyzing the active constrained layer damping of laminated symmetric and antisymmetric cross-ply and angle-ply composite plates integrated with the patches of such ACLD treatment. Both in-plane and out-of-plane actuation of the constraining layer of the ACLD treatment have been utilized for deriving the finite element model. The analysis revealed that the vertical actuation dominates over the in-plane actuation. Particular emphasis has been placed on investigating the performance of the patches when the orientation angle of the piezoelectric fibers of the constraining layer is varied in the two mutually orthogonal vertical planes. Also, the effect of different boundary conditions on the performance of the patches has been studied. The analysis revealed that the vertically reinforced 1-3 piezoelectric composites which are in general being used for the distributed sensors can be potentially used for the distributed actuators of high performance light-weight smart structures. [ABSTRACT FROM AUTHOR]

The effective coefficients of piezoelectric fiber-reinforced composites (PFRC) have been determined through micromechanical analyzes. The method of cells (MOC) and the strength of materials (SM) approach have been employed to predict the coefficients. A constant electric field is considered in the direction transverse to the fiber direction and is assumed to be the same both in the fiber and the matrix. MOC and SM predictions for the effective piezoelectric coefficient of the PFRC assessing the actuating capability in the fiber direction are in excellent agreement. It has been found for the piezoelectric fibers considered that, when the fiber volume fraction exceeds a critical fiber volume fraction, this effective piezoelectric coefficient becomes significantly larger than the corresponding coefficient of the piezoelectric material of the fiber. The methods also show the excellent matching of the predictions of the effective elastic constants and the dielectric constant of the PFRC in the useful range of fiber volume fraction. [ABSTRACT FROM AUTHOR]