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Static analysis of doubly curved laminated composite shells with rectangular plan form has been carried out using a novel hybrid Trefftz finite element (HTFE) model. A typical higher order shear deformation theory (HSDT) has been used for describing the kinematics of deformations delineating both internal and auxiliary displacement fields. This HSDT allows to derive the system of governing partial differential equations of the single layer equivalent to the element domain. The characteristic functions forming the exact solutions of these homogenous governing equilibrium equations are used as the Trefftz functions. A key aspect of our HTFE strategy is its efficiency in bypassing the use of particular solution of the governing equations. Validation against the exact solutions reveals the precision of this novel HTFE model. The versatility of the Trefftz functions allows them to accommodate a spectrum of geometric configurations, ranging from standard to complex polygonal HTFE designs. The HTFE model for the doubly curved composite shells employing the HSDT marks a significant advancement in the analysis of doubly curved spherical, paraboloid and hyperboloid cross-ply and antisymmetric angle-ply shells. [ABSTRACT FROM AUTHOR]

Geometrically nonlinear vibration control of fiber reinforced magneto-electro-elastic or multiferroic fibrous composite plates using active constrained layer damping treatment has been investigated. The piezoelectric (BaTiO 3 ) fibers are embedded in the magnetostrictive (CoFe 2 O 4 ) matrix forming magneto-electro-elastic or multiferroic smart composite. A three-dimensional finite element model of such fiber reinforced magneto-electro-elastic plates integrated with the active constrained layer damping patches is developed. Influence of electro-elastic, magneto-elastic and electromagnetic coupled fields on the vibration has been studied. The Golla–Hughes–McTavish method in time domain is employed for modeling a constrained viscoelastic layer of the active constrained layer damping treatment. The von Kármán type nonlinear strain-displacement relations are incorporated for developing a three-dimensional finite element model. Effect of fiber volume fraction, fiber orientation and boundary conditions on the control of geometrically nonlinear vibration of the fiber reinforced magneto-electro-elastic plates is investigated. The performance of the active constrained layer damping treatment due to the variation of piezoelectric fiber orientation angle in the 1–3 Piezoelectric constraining layer of the active constrained layer damping treatment has also been emphasized. [ABSTRACT FROM AUTHOR]

This paper is concerned with the smart constrained layer damping (SCLD) treatment of laminated composite shells with variable thickness undergoing geometrically nonlinear vibrations. Three dimensional fractional derivative model (FDM) has been implemented for modelling the constrained viscoelastic layer of the SCLD treatment. The constraining layer of the SCLD treatment is made of vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs) and acts as the distributed actuator. The strain-displacement relations are based on the simplified Novozhilov nonlinear shell theory to introduce the geometric nonlinearity in the large amplitude vibrations of the variable thickness shells. A three dimensional smart nonlinear finite element (FE) model has been developed for carrying out this analysis. Several numerical results are presented to check the accuracy of the present three-dimensional FDM for analyzing the passive and active control authority of the SCLD patch. Also the efficacy of the activated SCLD patch in controlling geometrically nonlinear vibration is computed for variable thickness shells and compared with shells of constant thickness. [ABSTRACT FROM AUTHOR]

This paper deals with the finite element analysis of active constrained layer damping (ACLD) of laminated composite plates using fractional order derivative constitutive relations for viscoelastic material. The constraining layer of the ACLD treatment is composed of the vertically/obliquely reinforced 1–3 piezoelectric composites (PZCs). The novelty of the present analysis is that the three dimensional fractional derivative model (FDM) of the constrained viscoelastic layer has been derived in time domain. A three-dimensional finite element model has been developed based on the FDM of the viscoelastic layer. Thin laminated plates with various boundary conditions and stacking sequences are emphatically analyzed to investigate the effectiveness of the three-dimensional FDM for both the passive and active control authority of the ACLD patch. [ABSTRACT FROM AUTHOR]

This paper deals with the active vibration control of thin rotating laminated composite truncated conical shells using vertically and obliquely reinforced 1-3 piezoelectric composite (PZC) materials as the constraining layer of an active constrained layer damping (ACLD) treatment. A finite element model has been derived to formulate the dynamics of the rotating thin laminated truncated conical shells integrated with the patches of ACLD treatment. Hamilton′s principle has been used to derive the equations of motion of rotating shell integrated with patches. The finite element model includes the effects of the Coriolis, Centrifugal acceleration, and the initial hoop tension caused due to rotation. The effectiveness of these patches for the vibration attenuation of thin rotating symmetric/antisymmetric cross-ply and antisymmetric angle-ply laminated truncated conical shell has been examined. Both in-plane and out-of-plane actuations of the constraining layer of the ACLD treatment has been utilized. The effects of variation of the semi-cone angle and the rotational speed of the shell on the performance of these patches have been investigated. Particular emphasis has been placed on ascertaining the performance of patches when the orientation angle of the piezoelectric fibers in the constraining layer is varied in two mutually orthogonal vertical planes. It is found that the maximum performance of patches is obtained for the piezoelectric fiber orientation angle of 0° and the vertically and obliquely reinforced 1-3 PZCs have great potential for controlling the vibration of rotating shells. [ABSTRACT FROM AUTHOR]

Abstract: The effective thermal conductivities of a novel fuzzy fiber reinforced composite (FFRC) have been determined by employing the effective medium approach in conjunction with the composite cylinder assemblage approach. The novel constructional feature of this FFRC is that the uniformly spaced carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of the unidirectional carbon fiber reinforcements. The present study reveals that the transverse thermal conductivities of the FFRC are improved up to ∼1040% and ∼400% over those of the composite without CNTs when the values of CNT volume factions present in the FFRC are 6.88% and 4.27%, respectively. It is also found that the CNT/polymer matrix interfacial thermal resistance does affect the effective thermal conductivities of the FFRC, and the effective values of thermal conductivities of the FFRC are improved with the increase in the values of carbon fiber volume fraction and temperature. [Copyright &y& Elsevier]

Abstract: This work deals with the transient hydroelastic analysis of a sandwich beam which represents a boat hull. The beam is subjected to slamming pressure while it enters into water with constant vertically downward velocity. A coupled hydroelastic finite element model is developed using higher order shear and normal deformation theories for the faces and the core of the beam and the velocity potential theory for the fluid. Transient responses of the beam for transverse deflection and stresses are studied. Dynamic failure analysis has been carried out to investigate the initiation and cause of the failure of the beam due to slamming load. [Copyright &y& Elsevier]

Abstract: In this paper, the performance of the active constrained layer damping (ACLD) treatment for active control of thin laminated cylindrical shells conveying fluid has been investigated. The constraining layer of the ACLD treatment has been considered to be made of vertically or obliquely reinforced 1–3 piezoelectric composite (PZC) materials. A three-dimensional finite element model has been developed for the laminated shells integrated with the patches of ACLD treatment to describe the coupled hydroelastic behavior of the shells. Velocity feedback control law has been implemented to activate the patches. Symmetric and antisymmetric cross-ply and antisymmetric angle-ply shells have been considered for evaluating the numerical results. Emphasis has also been placed on investigating the effect of the variation of the piezoelectric fiber orientation angle in the PZC constraining layer on the performance of the patches. [Copyright &y& Elsevier]

Abstract: The effective properties of a continuous fuzzy fiber-reinforced composite have been determined by employing the method of cells approach and the finite element (FE) method. The novel constructional feature of this fuzzy fiber-reinforced composite is that the uniformly aligned carbon nanotubes (CNTs) are radially grown on the surface of the horizontal carbon fibers. The effective properties of this fuzzy fiber-reinforced composite are estimated with and without the consideration of an interphase formed due to non-boned interaction between a CNT and the polymer matrix. Effective elastic properties of the fuzzy fiber-reinforced composite estimated by the method of cells approach have been compared with those predicted by the FE method. It has been found that the transverse effective properties of this composite are significantly improved due to the radial growing of CNTs on the surface of the carbon fiber. It is also found that the consideration of the CNT/matrix interphase has a negligible effect on the effective elastic properties of the fuzzy fiber-reinforced composite. [Copyright &y& Elsevier]

Abstract: A novel short fuzzy fiber-reinforced composite reinforced with aligned short carbon fibers and carbon nanotubes (CNTs) has been analyzed in this study. The constructional feature of this composite is that the uniformly aligned CNTs are radially grown on the circumferential surfaces of short carbon fibers. Micromechanical model based on the Mori–Tanaka method is derived to estimate the effective elastic properties of the short fuzzy fiber-reinforced composite. Effective elastic properties of the short fuzzy fiber-reinforced composite estimated by the Mori–Tanaka method have been compared with those predicted by the finite element (FE) method. The effective properties of the short fuzzy fiber-reinforced composite are estimated in the presence and the absence of an interphase between a CNT and the polymer matrix formed due to non-bonded van der Waals interaction between them. It has been found that the transverse effective properties of this composite are significantly improved due to the radial growing of CNTs on the circumferential surface of the short carbon fibers and the CNT/ polymer matrix interphase has negligible effect on the effective properties of the short fuzzy fiber-reinforced composite. Effects of the different types of zig–zag CNTs and the variation of their volume fraction on the effective properties of the short fuzzy fiber-reinforced composite are also investigated. [Copyright &y& Elsevier]

Abstract: This paper addresses the analysis of active constrained layer damping (ACLD) of geometrically nonlinear transient vibrations of laminated thin composite plates using piezoelectric fiber-reinforced composite (PFRC) materials. The constraining layer of the ACLD treatment is considered to be made of the PFRC materials. The Golla–Hughes–McTavish (GHM) method has been used to model the constrained viscoelastic layer of the ACLD treatment in the time domain. A finite element model has been developed for the cross-ply and antisymmetric angle-ply plates integrated with the patches of ACLD treatment undergoing geometrically nonlinear vibrations. The Von Ka`rma`n-type nonlinear strain displacement relations and the first-order shear deformation theory (FSDT) are used for deriving this coupled electromechanical nonlinear finite element model. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of the cross-ply and antisymmetric angle-ply plates for suppressing the geometrically nonlinear transient vibrations of the plates. Emphasis has also been placed on investigating the effect of variation of fiber orientation in the PFRC material on the control authority of the ACLD patches. [Copyright &y& Elsevier]

Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of laminated cylindrical composite shells using vertically and obliquely reinforced 1–3 piezoelectric composite materials as the material of the constraining layer of the ACLD treatment. A finite element model has been developed for analyzing the ACLD of laminated symmetric and antisymmetric cross-ply and angle-ply composite shells integrated with the patches of such ACLD treatment. Both in-plane and out-of-plane actuation of the constraining layer of the ACLD treatment has 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. 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 cylindrical shells. [Copyright &y& Elsevier]

Abstract: In this paper, a nonlinear static finite element analysis of simply supported smart functionally graded (FG) plates in the presence/absence of the thermal environment has been presented. The substrate FG plate is integrated with the patches of piezoelectric fiber reinforced composite (PFRC) material which act as the distributed actuators of the plate. The material properties of the FG substrate plate are assumed to be temperature dependent and graded along the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The derivation of this nonlinear thermo-electro-mechanical coupled finite element model is based on the first order shear deformation theory and the Von Karman type geometric nonlinearity. The numerical solutions of the nonlinear equations of the finite element model are obtained by employing the direct iteration method. The numerical illustrations suggest the potential use of the distributed actuator made of the PFRC material for active control of nonlinear deformations of smart FG structures. The effects of volume fraction index of the FG material of the substrate plates and the locations of the PFRC patches on the control authority of the patches are investigated. Emphasis has also been placed on investigating the effect of variation of piezoelectric fiber orientation angle in the PFRC patches on their actuation capability for counteracting the large deflections of FG plates. [Copyright &y& Elsevier]

Abstract: In this paper performance of a new piezoelectric fiber reinforced composite (PFRC) material has been investigated for active constrained layer damping (ACLD) of laminated thin simply supported composite cylindrical panels. The constraining layer of the ACLD treatment has been considered to be made of this PFRC material. A finite element model of smart composite panels integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches on enhancing the damping characteristics of thin cross-ply and angle-ply laminated composite cylindrical panels. Particular emphasis has been placed on studying the effect of variation of the piezoelectric fiber orientation in the constraining PFRC layer and the shallowness angle of the panels on the control authority of the patches. [Copyright &y& Elsevier]

Abstract: This paper deals with the derivation of a finite element model for the static analysis of functionally graded (FG) plates integrated with a layer of piezoelectric fiber reinforced composite (PFRC) material. The layer of PFRC material acts as the distributed actuator of the FG plates. The Young’s modulus of the FG plate is assumed to vary exponentially along the thickness of the plate while the Poisson’s ratio is assumed to be constant over the domain of the plate. The finite element model has been verified with the exact solutions for both thick and thin plates. Emphasis has been placed on investigating the effect of variation of piezoelectric fiber angle in the PFRC layer on its actuating capability of the FG plates. The finite element solutions also revealed that the activated PFRC layer is more effective in controlling the deformations of the FG plates when the layer is attached to the surface of the FG plate with minimum stiffness than when it is attached to the surface of the same with maximum stiffness. [Copyright &y& Elsevier]

Abstract: This paper deals with the analysis of active constrained layer damping (ACLD) of laminated thin composite shells using piezoelectric fiber reinforced composite (PFRC) materials. The constraining layer of the ACLD treatment is considered to be made of the PFRC materials. A finite element model of the smart composite shells integrated with the patches of such ACLD treatment has been developed to demonstrate the performance of these patches on enhancing the damping characteristics of thin symmetric and antisymmetric cross-ply and anti-symmetric angle ply laminated composite shells. The effect of variation of piezoelectric fiber orientation in the constraining PFRC layer on the control authority of the patches has also been investigated. [Copyright &y& Elsevier]

Static analysis of laminated smart composite plates integrated with a piezoelectric fiber, reinforced composite PFRC) layer acting as distributed actuators has been carried out by a generalized-energy-based finite element model. A simple first-order shear deformation theory is used for deriving the model. Eight noded isoparametric serendipity elements are used for discretizing the domain. The performance of the PFRC layer has been investigated for both symmetric and antisymmetric cross-ply and antisymmetric angle-ply laminated composite shell substrates. The effect of piezoelectric fiber orientation on the control authority of the PFRC layer has also been studied. [ABSTRACT FROM AUTHOR]

A novel work demonstrates the effect of delamination in smart laminated composite beams on the performance of active constrained layer damping (ACLD) treatment. A finite element model has been derived to formulate the dynamics of the composite beams integrated with a patch of ACLD treatment and a patch of piezoelectric film acting as a distributed sensor with and without the presence of delamination at different locations. Frequency response functions of the beams have been examined to observe the effect of delamination on the performance of ACLD treatment. It has been observed that the ACLD treatment improves the active damping characteristics of the beams, even in the presence of delamination, and that the responses of the beams are sensitive to the variation of the location of delamination. The responses due to active constrained layer damping presented may provide a useful guide to detect the presence of delamination in smart composite beams by the use of the existing numerical techniques. [ABSTRACT FROM AUTHOR]

Presents a generalized finite element formulation for active vibration control of a laminated plate integrated with piezoelectric polymer layers acting as distributed sensors and actuators. Derivation of an eight-noded two-dimensional quadratic quadrilateral isoparametric element; Reduction in vibration amplitude.