Patches Of Active Constrained Layer Damping Treatment Research Articles

Smart damping of a simply supported laminated CNT-based hybrid composite plate using FE approach

We present the finite element (FE) model using the first-order shear deformation theory (FSDT) to investigate the damping performance of laminated hybrid fiber-reinforced composite (HFRC) smart plates via the active constrained layer damping (ACLD) treatment. A unique feature of the HFRC is that the nanoscale carbon nanotubes (CNTs) are embedded in the matrix phase of carbon fiber composite to improve the overall properties, especially the damping characteristics of the resulting HFRC. Two- and three-phase micromechanical models are employed to determine the effective elastic properties of the base composite and HFRC respectively. The constraining layer of the ACLD treatment is considered to be made of vertically reinforced 1–3 piezoelectric composite (PZC) material. The system consists of a laminated HFRC plate integrated with the two patches of ACLD treatment and the numerical results are computed for three cases: symmetric and anti-symmetric cross-ply, and anti-symmetric angle-ply. The damping performance of the laminated HFRC square plate is significantly enhanced over the laminated base composite plate due to the incorporation of a small amount of CNTs. In particular, the anti-symmetric angle-ply case provides better damping than symmetric/anti-symmetric cross-ply cases. Analysis of the HFRC plate showed that its vibration amplitudes can be attenuated from ∼8 to ∼16% by adding a small amount CNTs. The effect of in-plane and transverse actuation of 1–3 PZC on the damping characteristics of the overall plate was also studied. We found that the transverse actuation significantly influences the damping performance of the overall plate. The outcomes of our study provide substantial evidence that the addition of a small amount of CNTs in the conventional composite structure can improve its damping performance significantly. This is practically possible in view of the recent research activities in the field of fabrication of large-scale CNT-based hybrid composite structures.

Effect of carbon nanotube waviness on active damping of laminated hybrid composite shells

In this article, we investigate the effect of carbon nanotube (CNT) waviness on the active constrained layer damping (ACLD) of the laminated hybrid composite shells. In particular, the effect of CNT waviness has been studied for the case of a novel nano-tailored composite—continuous fuzzy fiber-reinforced composite (FFRC). The distinctive feature of the construction of the FFRC is that the uniformly spaced straight or wavy CNTs are radially grown on the circumferential surfaces of carbon fibers. The constraining layer of the ACLD treatment is considered to be made of vertically or obliquely reinforced 1–3 piezoelectric composite material. A three-dimensional finite element model has been developed to study the damping characteristics of the laminated FFRC shells integrated with the patches of ACLD treatment. Our results reveal that (i) the planar orientation of CNT waviness has a significant influence on the damping characteristics of the laminated FFRC shells, (ii) damping characteristics of the symmetric cross-ply, and antisymmetric angle-ply laminated FFRC shells are improved if CNT waviness is coplanar with the longitudinal plane of the carbon fiber, and (iii) for the antisymmetric cross-ply laminated FFRC shells, the performance of the ACLD patches becomes maximum for attenuating the fundamental mode when CNT waviness is coplanar with the transverse plane of the carbon fiber.

Control of smart rotating laminated composite truncated conical shell using ACLD treatment

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.

Smart damping of fuzzy fiber reinforced composite plates using 1--3 piezoelectric composites

This article is concerned with the investigation of active constrained layer damping (ACLD) of smart laminated fuzzy fiber reinforced composite (FFRC) plates. The distinctive feature of the construction of this novel FFRC is that the uniformly spaced short carbon nanotubes (CNTs) are radially grown on the circumferential surfaces of carbon fibers. The effect of CNT waviness on the damping characteristics of the laminated FFRC plates is investigated when wavy CNTs are coplanar with either of the two mutually orthogonal planes. The constraining layer of the ACLD treatment is made of vertically/obliquely reinforced 1–3 piezoelectric composite material. A finite element model is developed for the laminated FFRC plates integrated with the patches of ACLD treatment. The effects of different boundary conditions of the FFRC plates and orientation angle of piezoelectric fibers on the damping characteristics of the laminated FFRC plates have also been investigated. Results reveal that if the plane of radially grown wavy CNTs on the circumferential surface of carbon fiber is coplanar with the plane of carbon fiber axis then the attenuation of amplitude of vibrations and the natural frequencies of the laminated FFRC plates are significantly improved over those of the FFRC containing straight CNTs or wavy CNTs being coplanar with the transverse plane of carbon fiber.

Performance of Smart Damping Treatment Using Piezoelectric Fiber-Reinforced Composites

This study deals with the active constrained layer damping (ACLD) of laminated composite plates to demonstrate the performance of piezoelectric fiber-reinforced composite (PFRC) layer as the constraining layer of ACLD treatment. A finite element model is developed for the smart composite plates integrated with the patches of ACLD treatment. The performance of the constraining PFRC layer has been investigated for active damping of thin symmetric and antisymmetric crossply and antisymmetric angle-ply laminated composite plates. The main concern of this study has been focused on investigating the significant effect of variation of piezoelectric fiber orientation in the PFRC layer on enhancing the damping characteristics of the laminated substrate plates, and the fiber angle in the PFRC layer for which the control authority of the patches becomes maximum has been determined.

Performance of piezoelectric fiber-reinforced composites for active structural-acoustic control of laminated composite plates

This paper deals with the active structural acoustic control of thin laminated composite plates using piezoelectric fiber-reinforced composite (PFRC) material for the constraining layer of active constrained layer damping (ACLD) treatment. A finite element model is developed for the laminated composite plates integrated with the patches of ACLD treatment to describe the coupled structural-acoustic behavior of the plates enclosing an acoustic cavity. The performance of the PFRC layers of the patches has been investigated for active control of sound radiated from thin symmetric and antisymmetric cross-ply and antisymmetric angle-ply laminated composite plates into the acoustic cavity. The significant effect of variation of piezoelectric fiber orientation in the PFRC layer on controlling the structure-borne sound radiated from thin laminated plates has been investigated to determine the fiber angle in the PFRC layer for which the structural-acoustic control authority of the patches becomes maximum.

Effect of Delamination on Active Constrained Layer Damping of Smart Laminated Composite Beams

An ove lw ork 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.

Optimal control of thin circular cylindrical laminated composite shells using activeconstrained layer damping treatment

Active control of the vibration of laminated circular cylindrical composite shells has beendemonstrated using optimally placed patches of active constrained layer damping (ACLD)treatment. A finite element model has been derived to formulate the dynamics of thecomposite shells integrated with the patches of ACLD treatment. Optimal placements ofthe patches are determined by employing a modal controllability criterion to control thefirst two modes of vibration. The optimal size of the patches located at the optimal placeshas been determined on the basis of a frequency constraint. The performance ofthese patches in enhancing the damping of the symmetric cross-ply and angle-plylaminated shells has been illustrated with frequency response functions of the shells.