Smart Sandwich Plate Research Articles

Active vibration suppression of tetrachiral auxetic core sandwich panel with CFRP skin: An RVE homogenization-assisted finite element approach

Free vibration as well as the controlled dynamic response of moderately-thick smart sandwich panel are numerically explored considering the size effect of chiral unit cells at the microscopic level, with the help of RVE-assisted-finite element (FE) approach. In this scientific article, the authors have made a debut attempt to analyse the smart damping behaviour of a tetrachiral-type auxetic core sandwich panel (with carbon/epoxy skin) deploying a real-time based constant velocity feedback controller in a closed loop configuration. Effective anisotropic elastic properties as well as the reduced stiffness matrix of the cellular core layer have been determined by using RVE-FE based full-scale homogenization technique in ANSYS® platform. Dynamic equation of motion governing the plate structure, has been derived using an energy-based variational principle, and further solved with the help of a quadratic interpolation based finite element method. The mid-plane kinematics of the plate structure are assumed to follow first order shear deformation theory (FSDT). A number of numerical examples have been solved and compared with previously published literature to ensure the consistency of the present homogenization-cum-numerical approach. From the observation it is found that, the natural frequency and the controlled dynamic response of tetrachiral-type sandwich structure are very much sensitive towards the geometry (cell wall thickness, ligament length etc.) and architecture of the unit cell of the auxetic core. Also, a comparison study has been performed between tetrachiral auxetic smart sandwich and regular hexagonal honeycomb smart sandwich plate, which confirms about the mechanical advantage of the former over the later configuration, due to the existence of out-of-plane negative Poisson's ratio (NPR) and axial-shear coupling stiffness. Afterwards, a few additional numerical examples have been solved by changing different influencing parameters of the auxetic core sandwich plate and important results are reported in the article.

The assessment of electric voltage influence on vibrational behavior of intelligent sandwich plates with GO-reinforced metal foam core and piezoelectric actuator face sheets

In this research, it is tried to study the effect of the external electric voltage on the vibrational behavior of a smart sandwich plate made of graphene oxide-strengthened metal foam nanocomposite core and two piezoelectric face sheets for the first time. The sandwich plate is modeled utilizing first-order shear deformation theory. The effective material properties of the core layer are estimated with the aim of the blend of Halpin-Tsai micromechanical model and rule of the mixture while considering different graded graphene oxide distribution patterns. Additionally, various porosity distributions are regarded in the metal matrix of the core layer. The partial differential equations of motion are derived using Hamilton’s principle and the derived governing equations are solved through Navier’s solution. To perform an accurate verification, the obtained results are compared with different literature investigations. Afterward, the influence of various important variants including external electric voltage, aspect ratio of plate, core to face sheet thickness ratio, different porosity distribution patterns, porosity coefficient, nanofillers weight fraction, and various distribution patterns of graphene oxides on the dimensionless frequency of smart sandwich plate in the framework of a group of tables and figures.

On Flexural Wave Dispersion of a Higher-Order Metamaterial Sandwich Composite Plate Based on a Visco-Pasternak Foundation

This paper elaborates on the wave propagation characteristics of a smart sandwich plate consisting of smart piezo composite layers on a plate’s upper and lower borders via an auxetic core. This study’s equation of motion was derived using a refined version of the Shear-deformation theory at a higher order, or HSDT. Additionally, detecting the properties of the auxetic core and piezoelectric composite layers employs a micromechanical model. The fundamental equations of the smart sandwich plates were formulated utilizing the Hamiltonian principle and Maxwell’s law. Then, the governing equations of a sandwich plate are solved using an exponential form and an analytical method. Furthermore, the phase velocity of the intelligent sandwich plate is provided based on the layer thicknesses of the auxetic core and thicknesses of intelligent piezoelectric composite layers. In addition, each figure calculates and presents the weight of the Winkler–Pasternak coefficient, the viscoelastic substances factor, the source of the outside electricity, and the volume percent of reinforcement in the matrix on the phase velocity.

Hybrid Fuzzy PID Sound Radiation Control of a Functionally Graded Porous GPL-Reinforced Plate with Piezoelectric Sensor and Actuator Layers

This paper is the first attempt to investigate the sound radiation control of a functionally graded porous graphene platelet-reinforced composite (FGP-GPLRC) plate integrated with piezoelectric face sheets. A spatial state-space formulation based on the linear 3D piezoelasticity theory is utilized to derive a semi-analytic solution for the coupled vibroacoustic response of the simply-supported arbitrarily thick composite plate. A comprehensive parametric study examines the effect of GPLs’ distribution, weight fraction, and porosity parameters of the core layer on the radiated sound power. Then, the best material configuration is selected to be actively controlled. A hybrid Fuzzy Proportional-Integral-Derivative (FPID) controller, which utilizes an FPID controller integrated with a classical PID controller, is employed to mitigate sound radiation from the smart sandwich plate via the volume velocity approach. The gain parameters of the proposed controller are tuned using the Bat optimization algorithm. Finally, the performance of the active control strategy in attenuating radiated sound power is investigated through several numerical simulations. Results show the proposed control scheme's robustness and rapid disturbance rejection performance.

Modified couple stress theory (MCST) and refined zigzag theory (RZT) for wave propagation of embedded smart sandwich plates with magnetorheological fluid core and viscoelastic FG-CNTRC magnetostrictive face sheets

This paper discusses the wave propagation of a magnetorheological fluid (MRF) micro sandwich plate with magnetostrictive face sheets embedded in the Kerr foundation. The face sheets are reinforced with functionally graded carbon nanotubes (FG-CNT). It was hypothesized that the distribution of carbon nanotubes would be functionally graded along the thickness of face sheets in various patterns such as uniform distribution (UD), and three type of functionally graded (FG), that is, FG-O, FG-X, and FG-AV. The properties of the magnetostrictive layer are considered viscoelastic based on the Kelvin-Voigt model. The refined zigzag theory (RZT) is utilized to simulate displacements of the plate due to the sandwich nature of the system. The modified couple stress theory (MCST) is utilized to predict the influence of small-scale parameter. The equations of motion for the micro sandwich plate are derived by Hamilton's principle, and analytical solutions are utilized to acquire the phase speed, escape, and cut-off frequencies. After model verification, extensive analytical results are presented in detail. They demonstrated that the wave characteristics of the system are influenced by the micro sandwich plate parameters. Consequently, the dimensionless phase speed rises 66% via increasing the magnetic field magnitude from 12.5 to 17.5 G.

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.

Machine learning assisted nonlinear deflection analysis of agglomerated carbon nanotube core smart sandwich plate with three-phase magneto-electro-elastic skin

This research focuses on evaluating the combined effects of the interphase of the three-phase magneto-electro-elastic (TPMEE) composites and carbon nanotubes (CNTs) agglomeration on the nonlinear deflection of the multifunctional sandwich plate, using an artificial neural network (ANN) assisted finite-element (FE) approach. The data points collected from the in-house developed FE computational tool are used to train the ANN model. To this end, a backpropagation-based Levenberg–Marquardt algorithm is used. The core of the plate is made of agglomerated CNTs, and the facesheets are made of TPMEE composites. Two different agglomeration states, partial and complete, are considered for evaluation. Also, three variations of CNTs arrangement are assumed. On the other hand, the interphase effects are incorporated through its volume fractions and compositions. The plate kinematics is based on the higher-order shear deformation theory, and the nonlinearity is assumed to follow von Karman's strain-displacement relation. The equations of motion are derived using the total potential energy principle. Finally, the direct iterative method is used to arrive at the solutions. The numerical examples are also provided to understand the influence of coupling fields associated with the parameters, such as agglomeration, interphase volume fraction, interphase compositions and CNTs arrangement.

FEM-ANN approach to predict nonlinear pyro-coupled deflection of sandwich plates with agglomerated porous nanocomposite core and piezo-magneto-elastic facings in thermal environment

The present work deals with evaluating the nonlinear deflections of the smart sandwich plate with agglomerated Carbon Nanotubes (CNTs) porous core and piezo-magneto-electric (PME) facings, using a novel finite element method (FEM) – artificial neural network (ANN) approach. For the first time, an ANN-based computational tool that integrates the effects of agglomeration of CNTs, porosity and pyro-coupling of the PME materials is presented. Firstly, an in-house finite element (FE) computational tool is proposed and developed using the principle of virtual work in association with higher-order shear deformation theory (HSDT) and von-Karman’s nonlinearity. The data points owing to the nonlinear deflections are collected using the proposed FE formulation, which trains the ANN model using Levenberg–Marquardt algorithm. The externally applied thermal loads are assumed to vary uniformly and linearly across the thickness of the plate. The primary focus of this work is to assess the variation in the degree of pyro-coupling associated with agglomeration and porosity. Two states of agglomeration, such as partial and complete; three forms of porosity, such as uniformly distributed, and two variants of functionally graded porosity, are considered for investigation. Numerical examples are solved to understand the interrelated effects of these material properties. A significant variation in the deflection of the plate, which refers to its actuation capability, is witnessed when the parameters of agglomeration and porosity change.

Vibration of smart sandwich plate with an auxetic core and dual-FG nanocomposite layers integrated with piezoceramic actuators

In the current research, a thorough investigation of the free vibrational characteristics of a novel smart sandwich plate has been performed utilizing two different analytical and numerical solution techniques. The proposed structure is a sandwich plate with an auxetic core and super stiff dual-FG nanocomposite layers integrated with piezoceramic actuators. The nanocomposite layers of the structure are made of FG metal-ceramic matrix to which carbon nanotubes (CNTs) are added through various FG distribution patterns. Besides, two thin piezoceramic actuators are attached to the nanocomposite layers, which causes the structure to be controllable by applying an electrical voltage. Using such super stiff dual-FG nanocomposite layers together with piezoceramic actuators and ultra-light auxetic core with negative Poisson’s ratio results in the light and smart sandwich plate with high structural stiffness, which its natural frequency responses will be analyzed in this study. For this purpose, the governing equations are derived according to the first-order shear deformation theory (FSDT) and then solved using two different strategies, including numerical and analytical solution methods. The responses obtained by these solution methods by the name of generalized differential quadrature (GDQ) and Navier are compared and verified with each other and other reputed references in the literature. Accordingly, detailed parametric studies in the framework of tabulated and graphical results are performed to reveal the impacts of all involved parameters on the natural frequency responses of the proposed smart sandwich plate.

Artificial neural network (ANN) based investigation on the static behaviour of piezo-magneto-thermo-elastic nanocomposite sandwich plate with CNT agglomeration and porosity

In this article, a novel finite element method (FEM) – artificial neural network (ANN) approach is adopted to investigate the coupled static parameters (stresses and potentials) of a smart sandwich plate with agglomerated Carbon Nanotubes (CNTs) porous nanocomposite core and piezo-magneto-thermo-electric (PMTE) facings. The main focus of this work is to study the synergistic effects of agglomeration of CNTs, porosity and pyro-coupling of the PMTE materials. Nearly 5184 data points collected from the in-house developed house finite element (FE) computational tool are used to train the ANN model using Levenberg–Marquardt algorithm. The FE formulation is derived using the principle of virtual work in association with higher-order shear deformation theory (HSDT) and von-Karman’s nonlinearity. The externally applied thermal loads are assumed to vary uniformly and linearly across the thickness of the plate. Two states of agglomeration, such as partial and complete; three forms of porosity, such as uniformly distributed, and two variants of functionally graded porosity, have been considered for investigation. Numerical examples are solved to understand the interrelated effects of these material properties on the direct (potentials) and derived (stresses, electric displacement, and magnetic flux densities) static parameters.

Wave Propagation in Smart Sandwich Plates with Functionally Graded Nanocomposite Porous Core and Piezoelectric Layers in Multi-Physics Environment

This research provides a mathematical model and solution for investigating wave propagation in graphene platelets (GPLs)-reinforced functionally graded (FG) metal foam plates integrated with piezoelectric actuator and sensor layers resting on an orthotropic visco-Pasternak medium in magneto-electro-thermo environment. The FG porous nanocomposite core and the actuator piezoelectric layer are exposed to steady magnetic and electric fields, respectively. The electric potential between two piezoelectric layers is governed by a proportional-derivative controller. The Halpin–Tsai micromechanics model and the Kelvin–Voigt model are adopted to express the effective elastic modulus of the FG porous nanocomposite core and material viscoelasticity of the core and piezoelectric layers, respectively. The governing equations of smart FG porous nanocomposite plates under thermal environment are derived grounded on the refined third-order shear deformation theory. Upon the validated theoretical model, the wave velocities and frequencies in plates are obtained by solving governing equations analytically. Finally, the effects of material viscoelasticity, porosity distribution and coefficient, GPL distribution and weight fraction, the plate and GPL geometries and external environment on wave propagation characteristics are demonstrated comprehensively. This work provides guidance on tunable control of wave propagation in smart sandwich plates affected by complex external environments.

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.

Optimization of damping characteristics of tapered MWCNT/glass fiber reinforced composite rectangular sandwich plates: A higher-order finite element formulation

The research work presented in this paper is focused on the investigation of damping characteristics and structural optimization of the tapered composite hybrid smart rectangular sandwich plates. The composite rectangular hybrid sandwich plate contains the constraining and base layers made of multi-walled carbon nanotubes reinforced composite (CNTRC) face sheets and the core layer made of multi-walled carbon nanotubes reinforced magnetorheological elastomer. Higher-order shear deformation theory (HSDT) and finite element (FE) formulations are employed to derive the governing equations of the CNTRC rectangular hybrid smart sandwich plate. The performance of the derived HSDT model is validated by comparing the results in terms of natural frequencies evaluated using experimental tests on the composite hybrid smart sandwich structures under different support conditions. The influence of CNT reinforcement on the damping performance of the tapered rectangular hybrid smart sandwich plates are explored. Also, the optimal ply orientations of the tapered CNTRC rectangular sandwich plates with hybrid core is identified using the developed HSDT model coupled with Genetic Algorithm (GA) to enhance the natural frequencies and loss factors. Further, it can be observed that the reinforcement of CNTs in composites significantly influences the stiffness and damping characteristics of the tapered composite rectangular smart sandwich plates.

Damping and instability characteristics of uniform and non-uniform composite multifunctional semi-active sandwich structures under rotating environment

In the present study, vibration and instability characteristics of the rotating carbon nanotubes (CNT) reinforced magnetorheological (MR) elastomer embedded sandwich composite plate with uniform and non-uniform composite face sheets under in-plane loading have been investigated numerically using finite element (FE) method. The efficacy of the FE method by deriving the governing equations using higher order theory is verified by comparing the natural frequencies assessed using experimental studies on the MR elastomer and CNT reinforced MR elastomer sandwich composite structures under different rotational speeds. This research also predicts the effects of CNT and magnetic fields on material damping, as well as rotating effects on structural damping due to geometrical non-linearity, in terms of natural frequencies and their corresponding modal loss factors of uniform and non-uniform multifunctional smart sandwich composite plates. Further, the instability regions of the uniform and non-uniform multifunctional smart sandwich plates under in-plane periodic load are analysed with the influence of various rotating speeds and magnetic field intensities. Therefore, it could be concluded that the CNT reinforcement on the MR elastomer layer significantly improves the stiffness, damping and reduces the instability regions of spectra of the rotating uniform and non-uniform multifunctional smart sandwich composite plates.

Nonlinear thermal dynamic buckling and global optimization of smart sandwich plate with porous homogeneous core and carbon nanotube reinforced nanocomposite layers

The analytical investigation for the nonlinear thermal dynamic buckling of smart sandwich plate subjected to mechanical, thermal and electric loadings is presented. The sandwich plate is composed of a porous homogeneous core, two carbon nanotube reinforced composite (CNTRC) layers and two piezoelectric face sheets. Basic equations are derived based on the Reddy's higher order shear deformation plate theory and Hamilton's principle in which the initial imperfection and Pasternak-type elastic foundations are included. The external pressure is assumed to be uniformly distributed on the surface of the sandwich plate and depend on time according to the linear functions. The nonlinear dynamic response, the frequency – amplitude relation are obtained by using the Galerkin and Runge – Kutta methods and the critical dynamic buckling load is determined by using Budiansky – Roth criterion. Bees Algorithm is used to determine the maximum value of natural frequency of smart sandwich plate and the corresponding optimum values of geometrical and material parameters. The effects of geometrical parameters, CNT volume fraction, elastic foundations, temperature increment, initial imperfection and porosity coefficient on the nonlinear vibration and dynamic buckling of the smart sandwich plate are considered specifically. The numerical results are also compared with existing results using different theories.

Quasi-3D theory for the vibration and deflection of a magnetostrictive composite plate resting on a viscoelastic medium

In this study, the vibration and deflection of a multilayered composite plate are investigated based on simple and refined sinusoidal shear deformation plate theories. The plate’s core is made of a homogeneous material. Hamilton’s principle is used to derive the dynamic system of equations. The interaction between the smart composite sandwich plate and the surrounding medium is simulated by the visco-elastic foundations model. The analytical solution for the vibration problem of the simply supported plate is obtained by Navier’s approach. Influence of the magnitude of feedback control gain, magnetostrictive layer location, half-wave numbers, lamination schemes, thickness ratios, aspect ratios, core-thickness ratios, magnetostrictive-thickness ratio, and viscoelastic foundations on eigenfrequency values and deflections of the sandwich plate are discussed. Numerical results illustrate that the vibration behavior of the smart sandwich plate is dependent on the stiffness of the viscoelastic foundations, the feedback control gain value, and the magnetostrictive-thickness ratio. Also, the vibration suppression process can be improved by changing the location of the smart layers in the structure.

Thermal post buckling analysis of smart SMA hybrid sandwich composite plate

Thermal post-buckling analysis of smart sandwich plates has been presented with the incorporation of shape memory alloy (SMA) and shape memory polymer (SMP) in laminated composite structure under uniform temperature distribution. Buckling analysis is based on higher order shear deformation theory (HSDT) with von Karman nonlinearity by finite element method (FEM). Evaluation of critical buckling temperature has been performed under the action of inplane uniform temperature distribution for different boundary conditions, plate’s aspect and thickness ratio, modulus ratio, ply orientations of smart SMA hybrid sandwich composite plate. Shape memory alloys itself acting uniquely under temperature variation and with SMA reinforced SMP laminated composite plate this phenomenon extended further under dynamic temperature condition for thermal buckling behavior. Also SMA with different strain rate and variation in SMA volume fraction is also presented to understand the cumulative buckling behavior.

Free vibration response of smart sandwich plates with porous CNT-reinforced and piezoelectric layers

This work concerns with the free vibration behaviors of a multifunctional smart sandwich plate (MSSP) using an advanced and reliable method. The layers of the MSSP includes two thin active piezoceramic faces which integrate a passive multifunctional lightweight core. The passive layer is enhanced with carbon nanotubes (CNTs) and lightened by embedding voids. Moreover, using the concept of functionally graded (FG) materials, both CNTs and voids are assumed to be distributed in FG patterns. In addition, the common drawback in such nanocomposites i.e., the formation of CNT agglomeration is distinguished by utilizing Eshelby-Mori-Tanaka (EMT)'s procedure. To obtain the governing equation of free vibration analysis, Reddy's third order shear deformation theory (TSDT) is employed. This equation has been handled by developing a weak form mesh-free solution with the shape functions of moving least squares (MLSs). The effects of lightening with voids, enhancing with nanofillers and its agglomerations, geometrical dimensions, and electro-mechanical boundary conditions on the natural frequency of MSSPs have been characterized. The results indicate that because of forming CNT agglomerations, the increase of the natural frequencies of MSSPs by adding CNTs is restricted. In addition, embedding voids inside the core results in MSSPs with higher natural frequencies in most cases.

Magneto-electro-mechanical vibration of porous functionally graded smart sandwich plates with viscoelastic core

In this paper, the vibrations of a sandwich plate with functionally graded magneto-electro-elastic (FG-MEE) face sheets and porous and viscoelastic core were investigated. Power-law rule modified by two types of porosity distributions was used to model the FG-MEE plates. The plate with even porosity distribution was considered as the FG-MEE-I model, while the one with uneven porosity distribution was labeled as the FG-MEE-II model. The normal and shear stresses were considered in the core layer, and the interlayer was modeled by the standard linear solid scheme. First-order shear deformation plate theory was used to derive the governing equation of the sandwich panel including the FG-MEE plate and viscoelastic core interaction. The governing equations were solved by the Navier method. A detailed parametric analysis was conducted to assess the effects of electric and magnetic fields, core-to-face sheet thickness ratio, and power-law index on the linear vibration characteristics of sandwich plates with functionally graded MEE face sheets. It is observed that for the FG-MEE-I model, an increase in the porosity coefficient led to a reduction in the frequency of the FG-MEE sandwich plate. On the contrary, for the FG-MEE-II model, an increment in the porosity coefficient enhanced the natural frequency.

Hygrothermal effect on vibration of magnetostrictive viscoelastic sandwich plates supported by Pasternak's foundations

In hygrothermal environment, vibration study of a simply supported smart sandwich plate embedded in an elastic substrate medium is presented in the present article. The sandwich plate contains layers of fiber-reinforced and magnetostrictive materials and core of viscoelastic material. The kinematic equations system is derived via employing Hamilton's principle with considering the transverse shear strains with and without the normal strains effect. Various numerical examples are carried out to study the effects of temperature rise, degree of moisture concentration, elastic foundations parameters, thickness ratio, aspect ratio, thickness ratio of magnetostrictive layer to viscoelastic layer, modes, lamination schemes, magnitude of the feedback coefficient, position of the magnetostrictive layers and viscoelastic structural damping coefficient on controlled motion and vibration characteristics of plate. Some observation about influences of the temperature and humidity concentrations on vibration characteristics of studied plate are presented in detail. The outcomes indicate that the hygrothermal environments have negative effects on vibration suppression of advanced composite structures especially the uniform hygrothermal distribution. The frequencies increase with increasing the viscoelastic structural damping coefficient and the foundation constants.