Active Constrained Layer Research Articles

Active Vibration Control and Parameter Optimization of Genetic Algorithm for Partially Damped Composites Beams.

The paper partially covered Active Constrained Layer Damping (ACLD) cantilever beams' dynamic modeling, active vibration control, and parameter optimization techniques as the main topic of this research. The dynamic model of the viscoelastic sandwich beam is created by merging the finite element approach with the Golla Hughes McTavish (GHM) model. The governing equation is constructed based on Hamilton's principle. After the joint reduction of physical space and state space, the model is modified to comply with the demands of active control. The control parameters are optimized based on the Kalman filter and genetic algorithm. The effect of various ACLD coverage architectures and excitation signals on the system's vibration is investigated. According to the research, the genetic algorithm's optimization iteration can quickly find the best solution while achieving accurate model tracking, increasing the effectiveness and precision of active control. The Kalman filter can effectively suppress the impact of vibration and noise exposure to random excitation on the system.

Active Constrained Layer Damping of Beams with Natural Fiber Reinforced Viscoelastic Composites

Abstract Viscoelastic composite reinforced with natural fibers is proposed here for the damping treatment of structures for vibration attenuation. The constrained layer damping (CLD) method is found a prominent structural vibration damping method and as a result of the inclusion of natural fiber, substantial damping could be achieved due to the development of shear as well as extensional strains in the viscoelastic material. Finite element analysis of a substrate beam combined with CLD treatment is used to investigate the corresponding improvement in damping. The influence of various geometry of presently considered natural viscoelastic composite layers on the CLD treatment's damping performance has been evaluated and discussed. Damping performances of natural as well as synthetic fibers have been assessed and compared for using natural fibers in viscoelastic composite for various structural applications. The addition of natural fiber has resulted from enhanced damping capacity due to substantial friction at the natural fiber-matrix interface compared to the case of interface with synthetic fiber. Natural fiber attributes less stiffness and a higher loss factor as compared to synthetic fiber and the insertion of stiff fibers affects the polymer chain's movements, decreasing the matrix phase's damping behavior. The dynamic mechanical analysis test is performed to evaluate the damping characteristics in the form of loss factor, storage, and loss modulus over the temperature range from frozen state to melting state.

Enhancing sound insulation performance with active constrained layer damping plates at low frequencies

In this paper, the normal incident sound transmission loss characteristics of active constrained layer damping (ACLD) plates are investigated numerically and experimentally. The sound insulation performance of the ACLD plate configuration with a centrally positioned 30 mm × 30 mm patch is initially examined in both passive and active control states. The analog feedback control strategy is employed to physically demonstrate that the ACLD treatment can effectively improve airborne sound insulation performance at low frequencies. To enhance control efficiency and mitigate control spillover effects, an edge-enhanced ACLD (EACLD) plate configuration is proposed, which enables a direct electrical connection between the PZT layer and base plate. Control mechanism is further analyzed from the perspectives of mean quadratic normal velocity and deformed modal shapes. Results show that, in the passive state, the formation of sound insulation peaks of the ACLD and EACLD plate configurations are attributed to structural anti-resonance effects. By applying active control, the shear deformation degree of the viscoelastic layer can be further increased, and the advantages of active and passive hybrid damping are formed. Therefore, the sound insulation performance of the EACLD plate configuration in the first-order resonance region around 190 Hz can be enhanced by approximately 20 dB. The proposed EACLD plate configuration demonstrates a broad low-frequency sound insulation bandwidth and holds strong potential for engineering applications.

Vibration control of piezoelectric beams with active constrained layer damping treatment using LADRC algorithm

Active constrained layer damping (ACLD) treatment has become an important smart structure for vibration suppression due to its ability to achieve enhanced damping effects through real-time control. The control algorithm is a critical factor that determines the damping performance of the ACLD treatment. In this work, we utilize the linear active disturbance rejection control (LADRC) algorithm for the first time in the vibration suppression of beams with the ACLD treatment by compensating for the disturbance. To optimize vibration suppression, we also propose an efficient parameter tuning approach by analyzing the effects of controller bandwidth, control gain, and observer bandwidth on vibration suppression performance. Firstly, the dynamic model of elastic beams with the ACLD treatment is established and the LADRC algorithm is designed. Subsequently, the accuracy of the model is verified by comparing it with open literature and experiments. Then, the influences of the control parameters and different positions of the ACLD treatment on the vibration suppression performance are studied. Finally, the vibration suppression effects of LADRC and traditional PID algorithms are compared. The results indicate that the vibration suppression performance of the ACLD treatment is better than that of the passive constrained layer damping (PCLD) treatment. Setting the controller bandwidth to a small value and then adjusting other control parameters can effectively reduce the difficulty of parameter tuning while achieving superior vibration suppression performance. Appropriately increasing the observer bandwidth or reducing the control gain is beneficial for enhancing the suppression efficiency. The parameter tuning approach in this study provides vital guidance for the application of the LADRC algorithm in structural vibration suppression.

Dynamic modeling and vibration control optimization of a rotating hollow beam with ESACLD treatment

As an active and passive hybrid control technology, enhanced segmented active constrained layer damping (ESACLD) is an intelligent damping structure for suppressing adverse vibrations in flexible structures. In this study, the three-dimensional spatial dynamic model of a rotating hollow beam with improved ESACLD treatment is established based on the finite element method in a floating frame of reference. The damping effects of the ESACLD with both edge elements and incisions are considered in the dynamic model for the first time. Simulation results show the damping performance of the ESACLD is better than traditional active constrained layer damping with or without incisions (SACLD or ACLD). The Genetic Algorithm-Backpropagation (GA-BP) neural network is used to optimize the physical parameters of ESACLD, and the optimized model can effectively suppress the transverse and flapping bending vibration. It is also found that flapping and transverse bending vibrations exhibit differential dependence on nutation and precession angular velocities; higher nutation and lower precession velocities suppress flapping bending. The existing commercial finite element software has some problems, such as low efficiency and inaccuracy. The new finite element proposed in this paper uses a new form function to ensure accuracy in the simulation of rotation and vibration and has obvious advantages in dealing with rotational structures and complex boundary conditions. Research in this work can provide a design framework for vibration prediction and control of flexible beam-like structures.

Dynamic Modeling and Vibration Suppression of a Rotating Flexible Beam with Segmented Active Constrained Layer Damping Treatment

This paper uses high-order approximate coupling (HOAC) dynamics equations for the hub–beam system with segmented active constrained layer damping treatment (SACLD). To improve the damping characteristics of traditional active constrained layer damping (ACLD), the viscoelastic damping layer, and the piezoelectric constraining layer are cut at the same position. The damping characteristics of the structure are enhanced by increasing the shear strain of the viscoelastic damping layer. The finite element method is used to discretize the SACLD beam. The discontinuity of the SACLD beam element-to-element displacement achieves the notch. Based on the theory of rigid–flexible coupling dynamics, the dynamic responses of the SACLD rotating beam under different cases are studied. The results show that the segmentation method is not always effective. A SACLD beam provides better vibration suppression than an ACLD beam only when appropriate material and dimensional parameters are used. The influences of base-layer thickness, piezoelectric constraining layer thickness, viscoelastic damping-layer thickness, angular velocity, the viscoelastic damping-layer loss factor, and control gains on the vibration of the rotating flexible beam with SACLD treatment are also discussed.

Active damping of multiscale composite shells using Sinus theory incorporated with Murakami’s zig-zag function

This article is divided into two main sections, the focus of the first is to develop a finite element model using the in-house MATLAB codes, implementing the sinusoidal shear deformation theory incorporating Murakami’s zig-zag function to encounter the inherent zig-zag effects of the laminated structures. The focus of the second is to investigate the active damping behavior of laminated multiscale hybrid fiber-reinforced composite (HFRC) smart shells via active constrained layer damping (ACLD) treatment using the proposed theory. The ACLD treatment layers comprise a constrained layer of viscoelastic material and an advance constraining layer of 1–3 piezoelectric composite material with vertically/obliquely oriented piezo-fibers, responsible for the active control. The computed numerical results of the laminated HFRC shell are analyzed and compared with the laminated base composite shell for symmetric/anti-symmetric cross-ply and anti-symmetric angle-ply. Moreover, we investigated the effect of carbon nanotube waviness and piezo-fibers orientation on the damping performance of the laminated HFRC/ACLD smart shell system. The analysis shows that the damping behavior of laminated HFRC shells improved due to the waviness of carbon nanotubes and that the orientation of piezo-fibers greatly influenced the effectiveness of the ACLD treatment patches. The proposed laminated multiscale HFRC/ACLD shell system with straight and wavy carbon nanotubes can be extensively used in structural health monitoring applications to actively control the mechanical vibrations induced in structures.

Nonlinear active control of thermally induced pyro-coupled vibrations in porous-agglomerated CNT core sandwich plate with magneto-piezo-elastic facings

In this article, the damped nonlinear transient response of a smart sandwich plate (SSP) comprising of agglomerated CNT-reinforced porous nanocomposite core with multifunctional magneto-piezo-elastic (MPE) facesheets, subjected to the thermal environment, is numerically investigated. The synergistic influence of agglomeration, porosity and pyro-coupling on vibration control is studied for the first time under the finite element framework. The attenuation of the vibrations is caused by active constrained layer damping (ACLD) treatment. The kinematics of the plate is based on the layer-wise shear deformation theory and von-Karman’s nonlinearity. The viscoelastic properties of the ACLD patch and CNT agglomeration of the core are mathematically modelled using Golla–Hughes–McTavish and Eshelby–Mori–Tanaka methods, respectively. A comprehensive examination of the inter-related effects of different agglomeration states, porosity distributions and thermal loading profiles has been performed. The new insights on controlling pyro-coupled induced vibrations of smart sandwich plates by supplying control voltage directly to the MPE facesheets without ACLD treatment have been discussed thoroughly. The numerical analysis confirms the significant effects of pyro-coupling associated with active vibration control response of SSP.

Finite Element Modeling and Vibration Control of Plates with Active Constrained Layer Damping Treatment

An enhanced lightness and thinness is the inevitable trend of modern industrial production, which will also lead to prominent low-frequency vibration problems in the associated structure. To solve the vibration problem of thin plate structures in various engineering fields, the active constrained layer damping (ACLD) thin plate structure is taken as the research object to study vibration control. Based on the FEM method, energy method, and Hamilton principle, the dynamic model of an ACLD thin plate structure is derived, in which the Golla-Hughes-McTavish (GHM) model is used to characterize the damping characteristics of the viscoelastic layer, and the equivalent Rayleigh damping is used to characterize the damping characteristics of the base layer. The order of the model is reduced based on the high-precision physical condensation method and balance reduction method, and the model has good controllability and observability. An LQR controller is designed to actively control the ACLD sheet, and the controller parameters and piezoelectric sheet parameters are optimized. The results show that the finite element model established in this paper is accurate under different boundary conditions, and the model can still accurately and reliably describe the dynamic characteristics of the original system in the time and frequency domain after using the joint reduction method. Under different excitation and boundary conditions, LQR control can effectively suppress structural vibration. Considering the performance and cost balance, the most suitable control parameter for the system is: Q-matrix coefficient is between 1 × 104 and 1 × 105, the R-matrix coefficient is between 1 and 10, and the thickness of the piezoelectric plate is 0.5 mm.

Dynamical analysis and vibration estimation of a flexible plate with enhanced active constrained layer damping treatment by combinatorial neural networks of surrogates

The effective estimation of the vibration of spacecrafts are frontier issues in the aerospace industry. But the vibration of aerospace components such as space solar panels and flexible manipulators under large overall rotating motion is usually very complex due to strong nonlinearity and often requires a lot of repetitive and burdensome calculations. Artificial neural network (ANN) is composed of interconnected neurons, and a surrogate model can be established to effectively predict the mechanical characteristics. In addition, the computational efficiency will be greatly improved if the object is changed from the model that is established by commercial finite element method (FEM) software or numerical calculations to the surrogates. However, the stochasticity of the estimation by single neural network is inevitable, and some neural networks much rely on the initial weight and threshold. This paper will implement a new combinatorial strategy that relies on multiple neural network models, which have different activation functions and regression feedback processes based on reasonable selection of sample points. To solve the elongated training time led by comparing these neural networks, genetic algorithm (GA) is used to optimize the iteration speed of one neural network when finding the optimal output value. Thus, better estimation accuracy will be achieved by designing an algorithm to combine these combinatorial neural networks of surrogates (CNNS). Based on the proposed method, the vibration estimation of a rotating flexible plate with enhanced active constrained layer damping (EACLD) treatment, and the vibration suppression capacity of the composite structure under various operating conditions will be investigated.

A smoothed finite element formulation using zig-zag theory for hybrid damping vibration control of laminated functionally graded carbon nanotube reinforced composite plates

The paper presents an efficient numerical approach to deal with the hybrid damping vibration control of laminated functionally graded carbon-nanotube reinforced composite plates (FG-CNTRC) structures. In order to evaluate the damped response, a smoothed finite element model has been derived to simulate the laminated FG-CNTRC plate integrated with active constrained layer damping (ACLD) treatment patches consisting of 1-3 piezoelectric composite (1-3 PZC) layer and a viscoelastic layer. The constrained layer of the ACLD patch is modeled as viscoelastic materials by using the complex modulus. In order to enhance the efficiency of the numerical approach, the proposed framework integrates the zig-zag theory into the cell-based smoothed discrete shear gap method (CS-DSG3) to help increase the accuracy and reduce the computational cost. The accuracy and reliability of the present study are validated by comparing its numerical results to those of other available numerical methods. Moreover, the effect of CNT distribution, nanotube volume fraction, and CNT orientation on the damping behavior of FG-CNTRC plates are investigated. Additionally, the influence of symmetrical and asymmetrical damping treatment configuration for controlling the vibration is also examined in detail. • An efficient numerical approach for the hybrid damping of FG-CNTRC plates is proposed. • Proposed framework helps increase the accuracy and reduce computational cost. • Effects of CNT distribution, volume fraction, and orientation on the damping behavior are examined. • Influence of symmetrical and asymmetrical configuration is examined.

Augmented active constrained layer damping of beams using graphite reinforced viscoelastic composite material

This paper deals with the use of viscoelastic composite material (VECM) for the constrained layer of an active constrained layer damping (ACLD) treatment for enhanced damping characteristics due to contributions of extensional strains in addition to transverse shear strain. The proposed VECM layer is composed of graphite fibers reinforced in a conventional viscoelastic matrix. The bending analysis of the overall beam is carried out and contributions of extensional and shear strains for damping behavior are found out. The effects of changing various geometric parameters of the present VECM layer on the control performance of the ACLD treatment have also been evaluated and presented.

Active control of nonlinear coupled transient vibrations of multifunctional sandwich plates with agglomerated FG-CNTs core/magneto-electro-elastic facesheets

This article investigates the controlled nonlinear transient response of sandwich plates made of magneto-electro-elastic (MEE) facesheets and agglomerated carbon nanotube (ACNT) core. The control is achieved by active constrained layer damping (ACLD) treatment which consists of piezoelectric (PE) and viscoelastic (VE) layers. The agglomeration is mathematically modelled using the Eshelby–Mori–Tanaka approach. The governing equations are derived under the framework of finite element (FE) methods using Hamilton’s principle and condensation technique. The VE patch of the ACLD treatment is modelled through the Golla–Hughes–McTavish method. This evaluation has considered two states of agglomerations, such as complete and partial agglomeration. The proposed FE model facilitates the integration of the three-field (magnetic, electric and elastic) coupling with the agglomeration and electromagnetic circuit effects, which makes this work interesting. It acts as a ready tool for the realistic design of a smart structure and system. In addition, the computational efforts and efficiency of the proposed FE model prove to be better than the commercial numerical software. Extensive numerical examples are solved to assess the influence of CNT distributions, electromagnetic circuits, coupling, mechanical boundary conditions, thickness configuration and ACLD patch position. This work serves as a novel benchmark solution for further research on the active control of agglomerated CNT structures.

Effect of orientation of CNTs and piezoelectric fibers on the damping performance of multiscale composite plate

The present work deals with the study of active constrained layer damping treatment of multiscale carbon nanotube-based hybrid carbon fiber-reinforced composite plates. The distinctive feature of novel multiscale hybrid carbon fiber-reinforced composites is that the wavy/straight carbon nanotubes are distributed uniformly in the matrix phase of hybrid carbon fiber-reinforced composites, and the waviness of carbon nanotubes is considered to be coplanar with two mutually orthogonal planes. Firstly, the effective elastic properties of hybrid carbon fiber-reinforced composites are estimated using the Mori-Tanaka method. The outcomes of the Mori-Tanaka method suggest that the transverse effective elastic properties of hybrid carbon fiber-reinforced composites containing wavy carbon nanotubes are better than those of hybrid carbon fiber-reinforced composites with straight carbon nanotubes. Secondly, a finite element model using the layer-wise first-order shear deformation theory is developed to study the damping performance of hybrid carbon fiber-reinforced composite plates integrated with the active constrained layer damping treatment. The constraining layer of active constrained layer damping treatment is a 1–3 piezoelectric composite layer with vertically/obliquely-oriented piezo-fibers. The piezo-fibers make an angle [Formula: see text] with the vertical plane of a layer coplanar with the xz- or yz-plane. The effect of the orientation of piezo-fibers angle on the control authority of active constrained layer damping treatment patches is investigated. Our results reveal that the performance of multiscale hybrid carbon fiber-reinforced composite plates has improved due to the incorporation of wavy carbon nanotubes, and the orientation angle of piezo-fibers has a major impact on the control authority of active constrained layer damping patches. The proposed multiscale composite with the combination of wavy carbon nanotubes and active constrained layer damping patches can be actively used in the aerospace and transport industries to control the mechanical vibrations of structures.

Multi-objective optimization of the active constrained layer damping for smart damping treatment in magneto-electro-elastic plate structures

Multi-objective optimization of the active constrained layer damping for smart damping treatment in magneto-electro-elastic plate structures

Analysis and optimal control of smart damping for porous functionally graded magneto-electro-elastic plate using smoothed FEM and metaheuristic algorithm

This paper proposed an effective numerical approach for free vibration analysis and optimal control of the porous functionally graded magneto-electro-elastic (PFGMEE) plates integrated with the active constrained layer damping (ACLD). Specifically, in order to analyze the free vibration characteristic of the PFGMEE plates based on the layer-wise shear deformation theory, a cell-based smoothed discrete shear gap (CS-DSG3) method is applied. The accuracy and convergence of the CS-DSG3 method are demonstrated by comparing its results with those available in the literature. Additionally, due to the coupling characteristic between magnetic, electric, and elastic fields, the coupled response of the PFGMEE plate is also considered. Furthermore, in order to obtain the optimal performance of the PFGMEE plates with the ACLD treatment, a combination of the CS-DSG3 method with an adaptive elitist differential evolution (aeDE) algorithm is used to determine the optimal placement of ACLD patches and the piezoelectric fiber orientation angle of the PFGMEE plates. The effect of several boundary conditions and porous distribution types on the free vibration response and the optimal control solution of the PFGMEE plates is also examined.

Nonlinear damping of auxetic sandwich plates with functionally graded magneto-electro-elastic facings under multiphysics loads and electromagnetic circuits

This work addresses the damped transient response of smart sandwich plates subjected to coupled/multiphysics loads. The plate is made of an auxetic core with magneto-electro-elastic functionally graded (MEEFG) facesheets. The well known active constrained layer damping (ACLD) technique making use of the piezoelectric (PE) patch also known as1-3 PZC layer embedded on the viscoelastic (VE) layer is adopted to attenuate the vibrations. A finite element (FE) based approach has been adopted in order to derive the governing equations. Further, the solutions to the considered problem are obtained by adopting the direct iterative method. The primary focus of this work is to evaluate the effects of the auxetic core's rib-length ratio, inclination angle on the damped structural response, which has been carried out for the first time in the literature. Also, parametric studies on the geometric and material properties such as thickness configuration of core and facesheets, ACLD patch positions, PE fiber orientation angle, control gain, functional gradation pattern, and gradient index have been carried out. Emphasize has been made to understand the impact of applying open and closed circuits associated with the rest of the parameters, on the controlled nonlinear behaviour of smart sandwich plates. The numerical results of this work make some major revelation about the implementation of auxetic cores in the smart structures, which make this work interesting.

Influence analysis of control signal phase on the vibration reduction effect of active constrained layer damping

The phase of the control signal applied on the piezoelectric constrained layer will have a direct influence on the vibration reduction effect in the process of implementing active constrained layer damping (ACLD) to the structure. Taking the ACLD cantilever beam system as the object, this paper focused on the study of the effect of control signal phase on the vibration suppression using the ACLD by establishing the experimental system and creating the relevant dynamic model. By analyzing the shear deformation of viscoelastic layer and combining piezoelectric equation, dynamic viscoelastic theory and mechanical analysis, a dynamic model of ACLD cantilever beam was created, which can effectively simulate two damping mechanisms and include the influence of control signal phase. The rationality of the dynamic model was verified by comparing the natural frequency and the time-domain vibration response corresponding to different control signal phases obtained by simulation and experiment. Using the presented dynamic model and the experimental results, the influence of the control signal phase on the vibration reduction effect was determined. Specifically, the control signal phase and the vibration response amplitude of the cantilever beam show a harmonic relationship centered on the response amplitude without control. The phase value corresponding to the best vibration reduction effect is not 180° like pure piezoelectric active vibration reduction and it is about 140° because of the hysteresis effect of viscoelastic material (for ZN-1 viscoelastic material selected in this study, the loss angle is about 40°).

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.

Vibration control of a rotating hub-plate with enhanced active constrained layer damping treatment

A rigid-flexible coupled dynamic model for a rotating hub-plate with enhanced active constrained layer damping (EACLD) treatment is established. To improve the transmissibility of the active control of the piezoelectric (PZT) layer, the edge elements are attached to the rim of the traditional active constrained layer damping (ACLD) treatment in the present EACLD model. The coupling effect of transverse bending and in-plane stretching of the rotating EACLD plate is considered in the first-order approximate coupling (FOAC) dynamic equation. The sandwich layer in the EACLD structure is composed of edge elements and viscoelastic material (VEM), in which the edge elements are fabricated by epoxy glue and modeled as two slender body with mass and stiffness. After the modal validation under different cases, numerical simulation and vibration analysis including the influences of the rotation speed of the hub, the control gains, the equivalent shear modulus of the edge elements, the thickness ratio of the VEM layer and the base plate, the coverage area and the location of the EACLD patch are analyzed. Transient response results show that the vibration controllability of the rotating plate with EACLD treatment behaves preferably compared to the traditional ACLD configuration.