Magnetorheological Elastomer Core Research Articles

Topology optimization of adaptive sandwich plates with magnetorheological core layer for improved vibration attenuation.

In this study the optimum topology distribution of the magnetorheological elastomer (MRE) layer in an adaptive sandwich plate is investigated. The adaptive sandwich plate consists of an MR elastomer layer embedded between two thin elastic plates. A finite element model has been first formulated to derive the governing equations of motion. A design optimization methodology incorporating the developed finite element model has been subsequently developed to identify the optimum topology treatment of the MR layer to enhance the vibration control in wide-band frequency range. For this purpose, the dynamic compliance and density of each element are defined as the objective function and design variables in the optimization problem, respectively. The method of the solid isotropic material with penalization (SIMP), is extended for material properties interpolation leading to a new MRE-based penalization (MREP) model. Method of moving asymptotes (MMA) has been subsequently utilized to solve the optimization problem. The developed finite element model and design optimization method are first validated using benchmark problems. The proposed design optimization methodology is then effectively utilized to investigate the optimal topologies of the magnetorheological elastomer (MRE) core layer in MRE-based sandwich plates under various boundary and loading conditions. Results show the effectiveness of the proposed design optimization methodology for topology optimization of MRE-based sandwich panels to mitigate the vibration in wide range of frequencies.

Aeroelastic Stability and Design of Laminated Composite Sandwich MRE Plates Using Surrogate Metaheuristics Optimization

Sandwich composite materials with elastomeric cores and high-strength face layers have widespread applications in various engineering sectors as passive damping structural materials. This study examines the dynamic properties of sandwich plate with laminated composite face layers and smart magnetorheological elastomer (MRE) core under the action of the aerodynamic and hygrothermal loads. The dynamic model based on Kirchhoff’s plate theory is employed and the equations of motion are derived using Hamilton’s principle. The flow conditions are assumed supersonic and modeled by the first-order piston theory. The natural frequencies and aerodynamic pressure distributions are obtained from finite element model. Upon validating the model, the effects of various factors such as moisture, temperature and plate geometry on the critical aerodynamic pressure for different boundary conditions and magnetic fields are studied. Using these parametric data, a regression model is developed using Back-Propagation Neural Network to predict the critical aerodynamic pressure as a function of effective geometrical parameters. In order to enhance the aerodynamic stability, the critical aerodynamic pressure is maximized by the optimal selection of plate aspect ratio, face layer ply orientation sequence and core layer thickness ratio via the modified teaching–learning-based optimization (MTLBO) technique employing the trained neural network-based surrogate model. The approach is very convenient and it has been found that nondimensional aerodynamic pressure along with loss factor has improved almost twice. In the sensitivity analysis study, it is noticed that changes in aspect ratio around the optimal point have a relatively drastic effect on the critical aerodynamic pressure at all the face layer ply configurations.

Free vibration analysis of a sandwich conical shell with a magnetorheological elastomer core, enriched with carbone nanotubes and functionally graded porous face layers

In this paper, the free vibration behaviors of a sandwich conical shell with a magnetorheological elastomer (MRE) core enriched with carbon nanotubes (CNTs) and two functionally graded (FG) porous face layers are investigated. The mathematical modeling of the shell is performed via the first-order shear deformation theory (FSDT) incorporating the continuity conditions between the face layers and the core. The porosity parameters are adjusted to provide the same mass for all porosity dispersion patterns. The governing equations and boundary conditions are derived via Hamilton’s principle and are solved through a semi-analytical solution to attain the natural frequencies and the loss factors for various boundary conditions. First, appropriate triangular functions are utilized to provide an exact solution in the circumferential direction. Then, a numerical solution is presented in the meridional direction utilizing the differential quadrature method (DQM). The influences of various factors on the natural frequencies and loss factors are investigated including intensity of the applied magnetic field, mass fraction of the CNTs subjoined to the core, thickness of the CNT-reinforced MRE core, thickness of the FG porous face layers, porosity parameter and dispersion pattern of the pores in the FG porous face layers, and the boundary conditions. Numerical results show that although subjoining CNTs to the MRE core and applying magnetic field have weak effects on the natural frequencies of the shell, increases in the mass fraction of the CNTs and intensity of the applied magnetic field result in remarkable increases in the loss factors, and provide stronger vibration suppression.

Dynamic Behavior Modeling of Natural-Rubber/Polybutadiene-Rubber-Based Hybrid Magnetorheological Elastomer Sandwich Composite Structures.

This study investigates the dynamic characteristics of natural rubber (NR)/polybutadiene rubber (PBR)-based hybrid magnetorheological elastomer (MRE) sandwich composite beams through numerical simulations and finite element analysis, employing Reddy's third-order shear deformation theory. Four distinct hybrid MRE sandwich configurations were examined. The validity of finite element simulations was confirmed by comparing them with results from magnetorheological (MR)-fluid-based composites. Further, parametric analysis explored the influence of magnetic field intensity, boundary conditions, ply orientation, and core thickness on beam vibration responses. The results reveal a notable 10.4% enhancement in natural frequencies in SC4-based beams under a 600 mT magnetic field with clamped-free boundary conditions, attributed to the increased PBR content in MR elastomer cores. However, higher magnetic field intensities result in slight frequency decrements due to filler particle agglomeration. Additionally, augmenting magnetic field intensity and magnetorheological content under clamped-free conditions improves the loss factor by from 66% to 136%, presenting promising prospects for advanced applications. This research contributes to a comprehensive understanding of dynamic behavior and performance enhancement in hybrid MRE sandwich composites, with significant implications for engineering applications. Furthermore, this investigation provides valuable insights into the intricate interplay between magnetic field effects, composite architecture, and vibration response.

Optimization Design of the Bending-Vibration Resistance of Magnetorheological Elastomer Carbon Fibre Reinforced Polymer Sandwich Sheets

An optimization design of the bending-vibration resistance of magnetorheological elastomer carbon fibre reinforced polymer sandwich sheets (MECFRPSSs) was studied in this paper. Initially, by adopting the classical laminate theory, the Reddy's high-order shear deformation theory, the Rayleigh-Ritz method, etc., an analytical model of the MECFRPSSs was established to predict both bending and vibration parameters, with the three-point bending forces and a pulse load being considered separately. After the validation of the model was completed, the optimization design work of the MECFRPSSs was conducted based on an optimization model developed, in which the thickness, modulus, and density ratios of magnetorheological elastomer core to carbon fibre reinforced polymer were taken as design variables, and static bending stiffness, the averaged damping, and dynamic stiffness parameters were chosen as objective functions. Subsequently, an artificial bee colony algorithm was adopted to execute single-objective, dual-objective, and multi-objective optimizations to obtain the optimal design parameters of such structures, with the convergence effectiveness being examined in a validation example. It was found that it was hard to improve the bending, damping, and dynamic stiffness behaviours of the structure simultaneously as the values of design variables increased. Some compromised results of design parameters need to be determined, which are based on Pareto-optimal solutions. In further engineering application of the MECFRPSSs, it is suggested to use the corresponding design parameters related to a turning point to better exert their bending-vibration resistance.

Energy harvesting of nanofluid-conveying axially moving cylindrical composite nanoshells of integrated CNT and piezoelectric layers with magnetorheological elastomer core under external fluid vortex-induced vibration

This paper deals with the renewable energy that can be harvested as electrical voltage due to the vibrations of an axially moving composite nanoshell conveying nanofluid. The significance of the study and its main innovation is the investigation of the possibility of yielding electrical energy caused by natural mechanical vibrations in a smart dynamic composite nanostructure, which can have potential applications in the nano industry. To this end, oscillations of nanocomposite interacting with the internal nanofluids are investigated under both non-periodic and the harmonic excitations of an external vortex fluid flow colliding with the outer layer, as a natural phenomenon. The considered composite nanoshell consists of three integrated layers of piezoelectric, magnetorheological elastomer, and carbon nanotube. As a theoretical methodology, using the Navier-Stokes equations and energy method, the governing coupled mechanical–electrical equations of dynamic composite nanoshells are derived based on the Euler-Bernoulli beam theory applying nonlocal-piezo-elasticity theory utilizing the van der Pol equation for the external vortex shedding flow. The vortex fluid flow leads to the appearance of the added mass and damping terms in the motion equations. The effects of velocities of moving nanocomposite, passing internal nanofluid, and external vortex fluid, the effects of nano-scale structure and aspect ratio, the effect of applied magnetic field intensity on the smart middle layer, the internal and external fluid densities effects (gas/liquid), and the effect of electrical resistive load on the frequency response and the output voltage amplitude of the dynamic nanosystem are also studied. As one of the significant obtained results, it is revealed that the output voltage due to the vortex-induced vibration (VIV) of the nanosystem will significantly increase as the densities of both internal fluid flow and external vortex fluid flow decrease. In addition, the extractable voltage can be increased or decreased by controlling the intensity of the magnetic field through its effect on the magnetorheological layer.

Instability Regions of a laminated Sandwich Plate with MRE Core Under Parametric Excitation Using Finite Element Method

This paper is concerned with the instability regions of a laminated sandwich plate with magneto-rheological elastomer (MRE) core under periodic axial loads. Structures operating under this unstable region cause large response even if the excitation force is small in magnitude. The governing equations of motion of the system are obtained by using finite element method [FEM].The parametric stable and unstable regions of the MRE cored composite sandwich plate for different system parameters and end constraints are found using modified Hsu method for simple parametric resonance condition. This analysis will help to design passive attenuation by using sandwich plates of varied dimensions, material parameters of both skin and core. Further active vibration reduction is possible by applying suitable magnetic field and operating the system outside of the instability region.

The Supersonic Flutter Behavior of Sandwich Plates with an Magnetorheological Elastomer Core and Gnp-Reinforced Face Sheets

This paper is provided to study the supersonic flutter behavior of sandwich plates with a magnetorheological (MR) core and polymeric face sheets reinforced with graphene nanoplatelets (GNPs). The mathematical modelings of the plate and the aerodynamic pressure of the fluid flow are performed utilizing the first-order shear deformation theory (FSDT) and the linear piston theory, respectively. The effective mechanical properties of the face sheets are estimated utilizing the rule of mixture along with the Halpin–Tsai model. Hamilton’s principle is employed to derive the governing equations and associated boundary conditions and these equations are solved using a semi-analytical approach for a Levy-type plate. The influences of different parameters on the aeroelastic stability of the plate are investigated such as the thickness of the MR core, magnetic field intensity, distribution pattern and mass fraction of the GNPs, boundary conditions, and geometrical parameters of the plate. This paper is the first theoretical attempt to study the effects of MR materials on the aeroelastic stability of Levy-type moderately thick sandwich plates and presents useful results that will be useful in the future of air vehicles.

Size-dependent dynamics and instability of sandwich magnetorheological elastomer (MRE)-cored shells in presence of moving flow, based on modified first strain gradient theory

This paper is devoted to developing a comprehensive size-dependent modeling for dynamic and stability analysis of a sandwich micro-shell with magnetorheological elastomer (MRE) core, subjected to a moving fluid flow. The mathematical formulation of this model is conducted on the basis of Donnell’s shell theory and modified first strain gradient theory (MFSGT). Additionally, perturbation pressure of the fluid flow is considered to model and add the effect of the existing fluid to the governing fluid–solid interaction (FSI) equations. After mathematical modeling, the obtained governing motion equations are solved analytically to attain the dynamic characteristics of the system namely imaginary and real parts of eigenvalues, frequencies and loss factors of the system. Verification study is implemented and thereafter the exact influences of the involved parameters such as length scale parameter, circumferential wave number, moving flow velocity, applied magnetic intensity to the smart core and MRE core thickness on the dynamic and stability response of the system are examined and discussed in detail for first three modes. The results show an excellent and considerable role of the MRE core properties on dynamic and stability control of the system. This effect could be detected in forms of diminishing some possible instabilities of various modes or expanding the stable region of the system. It is hopeful that, the analysis and acquired results may provide a data bank; helpful for increasing the knowledge about MRE-based sandwich structures and designing more adaptable and efficient systems benefiting from advanced and smart materials.

Analyzing the influence of the core pre-structure on the dynamic response of a magnetorheological elastomer sandwich structure

Recently, vibration control has been useful in various engineering fields such as aerospace, adaptive dynamic vibration absorbers, and infrastructure. Magnetorheological elastomer (MRE) is an interesting material for controlling and suppressing undesirable vibrations through the application of a magnetic field. The present study aims at analyzing the pre-structure of the magnetorheological viscoelastic core in the dynamic response of an MRE-sandwich structure. The forced vibration tests were performed under a non-homogenous magnetic field to evaluate the dynamic properties of the MRE-sandwich structure in a frequency bandwidth range of 0–250 Hz. Experimental results show that the proposed MRE-sandwich structures are capable of eliminating unwanted resonances due to induced magnetic field intensity in the activated region, especially at the fundamental mode. Moreover, results highlight that an oriented pre-structure in an MRE-sandwich has an attenuation effect on vibrations in the low frequency range. Additionally, the external magnetic field increased the structural vibrations damping capability by approximately 200%. In addition, the oriented pre-structures of the MRE core were also used to dissipate vibration. Consequently, they could potentially be used in vibration attenuation applications such as stop operations in dynamic structures.

Instability analysis of axially moving sandwich plates with a magnetorheological elastomer core and GNP-reinforced face sheets

Instability analysis of axially moving sandwich plates with a magnetorheological elastomer core and GNP-reinforced face sheets

Free damped vibration analysis of a truncated sandwich conical shell with a magnetorheological elastomer core

In this paper, free vibration analysis of truncated sandwich conical shells with the magnetorheological (MR) core is investigated. The mathematical modeling of the shell is performed based on the first-order shear deformation theory (FSDT) and the set of the governing equations and associated boundary conditions are derived utilizing Hamilton’s principle. A semi-analytical solution is provided for various boundary conditions through an exact solution in the circumferential direction and a numerical solution in the meridional direction via the differential quadrature method (DQM). After validation of the presented model, the influences of various variables on the natural frequencies and loss factors of the shell are investigated including circumferential wave number, magnetic field density, and geometrical parameters of the shell such as semi-vertex angle, length, total thickness and thickness of the MR core.

Static and dynamic performances of sandwich plates with magnetorheological elastomer core: Theoretical and experimental studies

This paper investigates the static and dynamic performances of sandwich plates with magnetorheological elastomer (MRE) core, in which the MRE core includes two copper wire layers, two inner metal layers, and one MRE layer. First, based on the complex modulus method, the Jolly theory and the pre-defined magnetic coefficients, the dynamic moduli, and loss factors of MRE are assumed as a function of magnetic induction intensity. Furthermore, a theoretical model of the MRE sandwich plates (MRESPs) is proposed, which considers the internal magnetic field excitation and four types of panel materials, namely fiber-reinforced polymer (FRP), fiber-reinforced polymer with carbon nanotubes (CNT-FRP), metal and fiber-metal hybrid (FMH) panels. After the deformation and energy equations are derived to solve the static bearing stiffness, dynamic stiffness, and damping parameters, some literature results are employed to provide the initial validation of the model developed. Subsequently, four MRESP specimens with the FRP, CNT-FRP, metal, and FMH panels are fabricated and measured to further verify the model as well as to evaluate the mechanical performance. The influence of critical geometric and material parameters related to MRE on static and dynamic properties is also discussed to summarize some practical conclusions for engineering applications.

Effect of carbon nanotubes reinforcement on eigenmodes of multi‐smart core sandwich composite cylindrical shell panels

AbstractThis study investigates the dynamic responses of carbon nanotubes (CNT) reinforced composite sandwich shells with multi magnetorheological elastomer (MRE) core. The CNT reinforced composite skin layers are made by using hand layup technique. An experimental modal test has been carried for with and without CNT reinforced composite cylindrical shells under clamped free condition. The 3D finite element model is verified by comparing the obtained natural frequencies with experimental results. The numerical results indicate that the CNT reinforced composite multi‐MRE cylindrical sandwich shell greatly influences the natural frequencies compared with single‐MRE cylindrical sandwich shell. The effect of many parameters on the natural frequencies of the CNT reinforced composite multi‐MRE cylindrical sandwich shells is also discussed, including the weight percent of CNT, magnetic fields, and support conditions.

Vibration and stability analysis of fluid-conveying sandwich micro-pipe with magnetorheological elastomer core, considering modified couple stress theory and geometrical nonlinearity

Vibration and stability analysis of fluid-conveying sandwich micro-pipe with magnetorheological elastomer core, considering modified couple stress theory and geometrical nonlinearity

Investigation of dynamic properties of a three-dimensional printed thermoplastic composite beam containing controllable core under non-uniform magnetic fields

This paper presents the dynamic responses of sandwich beams with 3D printed thermoplastic composite face sheets and multi-walled carbon nanotubes reinforced magnetorheological elastomer (MWCNT-MR elastomer) cores under non-uniform magnetic fields. A higher-order beam theory (HoBT) is employed to express the beam‘s displacement field. The governing equations of the 3D printed thermoplastic sandwich beam are derived using Lagrange‘s principle and discretized by the finite element method. The validity of the present method is confirmed through comparison with the results available in the literature. The stiffness and damping characteristics of the 3D printed thermoplastic sandwich beam are investigated in relation to support conditions, non-homogeneous magnetic flux, and core-face sheet thickness ratio.

Dynamic characteristics of laminated composite CNT reinforced MRE cylindrical sandwich shells using HSDT

The vibration and damping characteristics of the laminated composite cylindrical sandwich shell with carbon nanotube reinforced magnetorheological elastomer (CNT-MRE) core is presented in this article. Higher order shear deformation theory (HSDT) based on finite element (FE) formulation is employed to derive the governing equations of motion of the laminated composite cylindrical CNT-MRE sandwich shell. The present HSDT model of the cylindrical CNT-MRE sandwich shell is validated with the ABAQUS model in terms of natural frequencies on cantilever boundary condition. The influence of CNT reinforcement in the MRE layer of the cylindrical sandwich shell is also studied through the structural rigidity. The detailed parametric investigations are performed to study the influence of magnetic field intensities, thickness ratio, radius of curvature and ply orientation on the stiffness and damping behavior of composite cylindrical CNT-MRE sandwich shell.

Modeling and simulation of the static and vibratory behavior of hybrid composite plate off-axis anisotropic

This study presents the static and vibratory behavior of a hybrid sandwich plate with a magnetorheological elastomer core. In order to improve the static and vibrational behavior of the plate, the pseudo-fibers formed by the effect of the magnetic field on the elastomer charged by the ferromagnetic particles are oriented at 45° with respect to the direction of the magnetic field at 0°. Ritz's approach is taken to solve the physical problem. In order to verify and compare the results obtained by the Ritz approach, an analysis using the finite element method was carried out. The effect of the magnetic field on bending displacements, normal stresses, shear stresses, and static strain modes of the off-axis anisotropic hybrid sandwich plate are discussed. The rheological property of the MRE material at 0° and at 45° are determined experimentally, and are exploited in the two numerical approaches. The natural frequencies and the modal damping of the sandwich plate are calculated and discussed for various magnetic field intensities. The results obtained by the two methods are compared. These off-axis anisotropic MRE structures could open up new opportunities in various fields of aeronautics, aerospace, mechanical engineering and civil engineering.

Vibration characteristics and optimal design of composite sandwich beam with partially configured hybrid MR-Elastomers

The free and forced vibration characteristics of a sandwich beam with composite face layers and partially configured carbon nanotubes reinforced magnetorheological elastomer (hybrid MR elastomer) core is presented in this article. Higher order shear deformation theory (HSDT) based on finite element (FE) formulation is employed to derive the governing equations of motion of the partially configured hybrid MR elastomer sandwich beam. The efficacy of the present FE method is evaluated by comparing its numerical solutions with those reported in the literature. The effects of partial configurations, magnetic fields, and support conditions on the vibration characteristics of partially configured hybrid MR elastomer sandwich beams are discussed. Further, the structural optimization problem is formulated to identify the optimal positions for the hybrid MR elastomers and optimal face sheet ply orientations to maximize the vibration characteristics of the composite structures. The solution of the optimization problem, attained using the genetic algorithm (GA) coupled with FE formulations. The numerical results show that the location of the hybrid MR elastomer and optimal ply orientation have significant influences on the vibration and damping performances of the partially configured hybrid MR elastomer sandwich structures.

Dynamic stability analysis of a sandwich beam with magnetorheological elastomer core subjected to a follower force

In the present study, the effect of using magnetorheological elastomer materials and a magnetic field on the dynamic stability of a sandwich beam under a follower force has been investigated for various boundary conditions. The considered sandwich beam consists of a magnetorheological elastomer core constrained by elastic layers. The structural governing equations are derived using Hamilton’s principle and solved by the finite element method. The validity of the result is examined by comparison with those in the literature. The effects of variation in the parameters such as magnetic field intensity and the thickness of the layers on the stability of the sandwich beam are studied. Finally, some conclusions for the effects of the magnetic field intensity on the magnetorheological elastomer sandwich beam subjected to the follower force are discussed.