Natural frequency, damping and forced responses of sandwich plates with viscoelastic core and graphene nanoplatelets reinforced face sheets

2020 ◽  
Vol 26 (15-16) ◽  
pp. 1165-1177 ◽  
Author(s):  
Ali Mohseni ◽  
Meisam Shakouri
Keyword(s):  
Sandwich Plate ◽  
Effective Properties ◽  
Plate Theory ◽  
Equations Of Motion ◽  
Shear Deformation Theory ◽  
Graphene Nanoplatelets ◽  
Complex Eigenvalue ◽  
Viscoelastic Core ◽  
Forced Vibration Analysis ◽  
Forced Responses

The free and forced vibration analysis of a sandwich plate with the viscoelastic core and face layers reinforced functionally with multilayered graphene nanoplatelets is presented. Different graphene nanoplatelet distributions are considered through the thickness, and the effective properties of the graphene reinforced nanocomposite are obtained by the rule of mixture. The equations of motion are extracted using Hamilton’s principle and assuming the classical thin plate theory for face layers and the first-order shear deformation theory for the thick viscoelastic core. Assuming the simply-supported boundary condition for all edges, the displacement components are proposed by Fourier series and the complex eigenvalue problem is solved to obtain the natural frequencies as well as the loss factors. The results are validated with available investigations, and effects of some important parameters on the free and forced responses of the sandwich plate are studied.

Effect of carbon nanotube-reinforced magneto-electro-elastic facings on the pyrocoupled nonlinear deflection of viscoelastic sandwich skew plates in thermal environment

2021 ◽  
pp. 146442072110440
Author(s):  
Vinyas Mahesh
Keyword(s):  
Carbon Nanotube ◽  
Complex Modulus ◽  
Thermal Environment ◽  
Equations Of Motion ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Energy Principle ◽  
Design Engineers ◽  
Total Potential ◽  
Viscoelastic Core

This work presents a finite-element-based numerical formulation to evaluate the nonlinear deflections of magneto-electro-elastic sandwich skew plates with a viscoelastic core and functionally graded carbon nanotube-reinforced magneto-electro-elastic face sheets. Meanwhile, the proposed formulation accommodates the geometrical skewness as well. The magneto-electro-elastic sandwich skew plate is operated in the thermal environment and subjected to various multiphysics loads, including electric and magnetic loads. The viscoelastic core is modelled via the complex modulus approach. Two different forms of viscoelastic cores, such as Dyad 606 and EC 2216, are considered in this study. Also, different thickness configurations of core and facing arrangements are taken into account. The plate kinematics is presumed through higher-order shear deformation theory, and von Karman's nonlinear strain displacement relations are incorporated. The global equations of motion are arrived at through the total potential energy principle and solved via the direct iterative method. Special attention is paid to assessing the influence of pyroeffects, coupling fields and electromagnetic boundary conditions on the nonlinear deflections of magneto-electro-elastic sandwich plates working in the thermal environment and subjected to electromagnetic loads, which is the first of its kind. Also, parametric studies dealing with the skew angles, carbon nanotube distributions and volume fractions, thickness ratio, and aspect ratio have been discussed. The results of this work are believed to be unique and serve as a guide for the design engineers towards developing sophisticated smart structures for various engineering applications.

Dynamic analysis of three-layer cylindrical shells with fractional viscoelastic core and functionally graded face layers

2020 ◽  
pp. 107754632096622
Author(s):  
Meisam Shakouri ◽  
Mohammad Reza Permoon ◽  
Abdolreza Askarian ◽  
Hassan Haddadpour
Keyword(s):  
Natural Frequency ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Ritz Method ◽  
Shear Deformation Theory ◽  
Core Layer ◽  
Functionally Graded ◽  
Viscoelastic Layer ◽  
Viscoelastic Core ◽  
Graded Layers

Natural frequency and damping behavior of three-layer cylindrical shells with a viscoelastic core layer and functionally graded face layers are studied in this article. Using functionally graded face layers can reduce the stress discontinuity in the face–core interface that causes a catastrophic failure in sandwich structures. The viscoelastic layer is expressed using a fractional-order model, and the functionally graded layers are defined by a power law function. Assuming the classical shell theory for functionally graded layers and the first-order shear deformation theory for the viscoelastic core, equations of motion are derived using Lagrange’s equation and then solved via Rayleigh–Ritz method. The obtained results are validated with those in the literature, and finally, the effects of some geometrical and material parameters such as length-to-radius ratio, functionally graded properties, radius and thickness of viscoelastic layer on the natural frequency, and loss factor of the system are considered, and some conclusions are drawn.

scholarly journals Thermal Buckling of Laminated Composite Plates Using a Simple Four Variable Plate Theory

2021 ◽  
Vol 27 (9) ◽  
pp. 1-19
Author(s):  
Hussein Tawfeeq Yahea ◽  
Wedad Ibraheem Majeed
Keyword(s):  
Plate Theory ◽  
Equations Of Motion ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Thermal Buckling ◽  
Design Parameters ◽  
Laminated Composite Plates ◽  
Buckling Behavior ◽  
Uniform Temperature Field

In this study, the thermal buckling behavior of composite laminate plates cross-ply and angle-ply all edged simply supported subjected to a uniform temperature field is investigated, using a simple trigonometric shear deformation theory. Four unknown variables are involved in the theory, and satisfied the zero traction boundary condition on the surface without using shear correction factors, Hamilton's principle is used to derive equations of  motion depending on a Simple Four Variable Plate Theory for cross-ply and angle-ply, and then solved through Navier's double trigonometric sequence, to obtain critical buckling temperature for laminated composite plates. Effect of changing some design parameters such as, orthotropy ratio (E1/E2), aspect ratio (a/b),  thickness ratio (a/h), thermal expansion coefficient ratio (α2/α1), are investigated, which have the same behavior and good agreement when compared with previously published results with maximum discrepancy (0.5%).

A Numerical Study on Forced Vibration Analysis and Optimum Design of Rotating Composite Multiwalled Carbon Nanotubes-Reinforced Smart Sandwich Plate

2021 ◽  
Author(s):  
Sardar S. Shareef ◽  
S. Rajeshkumar ◽  
Hozan Latif Rauf
Keyword(s):  
Carbon Nanotubes ◽  
Numerical Model ◽  
Optimum Design ◽  
Sandwich Plate ◽  
Numerical Study ◽  
Research Work ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Multiwalled Carbon ◽  
Forced Vibration Analysis

The research work presented in this paper is focused on the investigation of dynamic characteristics and optimum design of rotating laminated composite multi-walled carbon nanotubes-reinforced magnetorheological elastomer (MWCNT-MRE) sandwich plate. Higher-order shear deformation theory (HSDT) and finite element (FE) formulations are employed to derive the governing equations of the composite MWCNT-MRE sandwich plate. The performance of the derived numerical model is validated by comparing it with the results available in the published literature. The free and forced vibrations of the composite MWCNT-MRE sandwich plate are examined at different magnetic fields and rotating speeds. Also, the optimal ply orientations of the MWCNT-MRE sandwich plate are identified using the developed numerical model coupled with a genetic algorithm (GA) to enhance the natural frequencies and loss factors.

Bending analysis of functionally graded sandwich plates using the refined finite strip method

2021 ◽  
pp. 109963622110204
Author(s):  
Mohammad Naghavi ◽  
Saeid Sarrami-Foroushani ◽  
Fatemeh Azhari
Keyword(s):  
Shear Deformation ◽  
Deformation Theory ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Sandwich Plates ◽  
Finite Strip ◽  
Strip Method ◽  
Finite Strip Method

In this study, static analysis of functionally graded (FG) sandwich plates is performed using the finite strip method based on the refined plate theory (RPT). Two types of common FG sandwich plates are considered. The first sandwich plate is composed of two FG material (FGM) face sheets and a homogeneous ceramic or metal core. The second one consists of two homogeneous fully metal and ceramic face sheets at the top and bottom, respectively, and a FGM core. Differential equations of FG sandwich plates are obtained using Hamilton's principle and stiffness and force matrices are formed using the finite strip method. The central deflection and the normal stress values are obtained for a sinusoidal loaded FG sandwich plate and the accuracy of the results are verified against those obtained from other theories such as the classical plate theory (CPT), the first-order shear deformation theory (FSDT), and the higher order shear deformation theory (HSDT). For the first time, this study presents a finite strip formulation in conjunction with the RPT to analyze FG Sandwich plates. While the proposed method is fast and simple, it is capable of modeling a variety of boundary conditions.

Effect of Boundary Conditions on Transient Response of Sandwich Plates with Electrorheological Fluid Core

2011 ◽  
Vol 462-463 ◽  
pp. 372-377
Author(s):  
Jafar Rahiminasab ◽  
Jalil Rezaeepazhand
Keyword(s):  
Finite Element ◽  
Electric Field ◽  
Boundary Conditions ◽  
Transient Response ◽  
Sandwich Plate ◽  
Natural Frequencies ◽  
Plate Theory ◽  
Equations Of Motion ◽  
Electrorheological Fluid ◽  
Fluid Core

Electrorheological (ER) fluids are a kind of smart material whose rheological properties can be controlled by an external electric field. In the present paper, the transient vibration of a rectangular three layer sandwich plate with electrorheological fluid core is analyzed based on the classical plate theory. The Bingham plastic model is used to consider the post-yield behavior of ER fluid. The structure is modeled using a finite element method. Hamilton’s principle is employed to derive the finite element equations of motion. The constant average acceleration scheme is used to integrate the equations of motion. The effects of change in electric field and core thickness on the structure settling time and its natural frequencies are studied for various boundary conditions. The results show that the thickness of the core layer and the electric field strength has significant effects on damping behavior of the sandwich plate. When the applied electric field increases a linear decay in transient response of the structure is observed. It is also found that the electric field changes have no influence on the system natural frequencies.

Thermal Vibrations of a Graphene Sheet Embedded in Viscoelastic Medium based on Nonlocal Shear Deformation Theory

2019 ◽  
Vol 24 (3) ◽  
pp. 485-493 ◽  
Author(s):  
Ashraf M. Zenkour ◽  
A. H. Al-Subhi
Keyword(s):  
Shear Deformation ◽  
Graphene Sheet ◽  
Deformation Theory ◽  
Plate Theory ◽  
Equations Of Motion ◽  
Nonlocal Parameter ◽  
Shear Deformation Theory ◽  
Thermal Parameter ◽  
Thermal Vibration ◽  
Thermal Vibrations

The nonlocal first-order shear deformation plate theory is used to present the thermal vibration of a single-layered graphene sheet (SLGS) resting on a viscoelastic foundation. The viscous damping term is added to the elastic foundation to get a three-parameter visco-Pasternak medium. The nonlocal shear deformation theory is applied to obtain the equations of motion of the simply-supported SLGSs. The effects of the nonlocal parameter as well as the length of the SLGS, mode numbers, three-parameters of the foundation, and the thermal parameter are discussed carefully for the vibration problem. The validation of the present frequencies is discussed with excellent comparison to the existing literature. For future comparisons, additional thermal vibration results of SLGSs are investigated to take into consideration the effects of thermal, nonlocal, and visco-Pasternak mediums.

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

2020 ◽  
pp. 146442072097669
Author(s):  
Hamid R Talebi Amanieh ◽  
S Alireza S Roknizadeh ◽  
Arash Reza
Keyword(s):  
Power Law ◽  
Sandwich Plate ◽  
Plate Theory ◽  
Sheet Thickness ◽  
Functionally Graded ◽  
Shear Stresses ◽  
Sandwich Plates ◽  
Porosity Distribution ◽  
Viscoelastic Core ◽  
Porosity Coefficient

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.

THE EFFECT OF TRANSVERSE SHEAR AND NORMAL DEFORMATIONS ON THE THERMOMECHANICAL BENDING OF FUNCTIONALLY GRADED SANDWICH PLATES

2009 ◽  
Vol 01 (04) ◽  
pp. 667-707 ◽  
Author(s):  
ASHRAF M. ZENKOUR
Keyword(s):  
Shear Deformation ◽  
Sandwich Plate ◽  
Volume Fraction ◽  
Mechanical Load ◽  
Plate Theory ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Sandwich Plates ◽  
Power Law Distribution ◽  
Equilibrium Equations

A thermomechanical bending analysis for a simply supported, rectangular, functionally graded material sandwich plate subjected to a transverse mechanical load and a through-the-thickness thermal load is presented using the refined sinusoidal shear deformation plate theory. The present shear deformation theory includes the effect of both shear and normal deformations and it is simplified by enforcing traction-free boundary conditions at the plate faces. Material properties and thermal expansion coefficient of the sandwich plate faces are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The equilibrium equations of different sandwich plates are given based on various plate theories. A number of examples are solved to illustrate the numerical results concern thermo-mechanical bending response of functionally graded rectangular sandwich plates. The influences played by transversal shear and normal deformations, plate aspect ratio, side-to-thickness ratio, volume fraction distributions, and thermal and mechanical loads are investigated.

Temperature effects on buckling and vibration characteristics of sandwich plate with viscoelastic core and functionally graded material constraining layer

2017 ◽  
Vol 21 (4) ◽  
pp. 1557-1577 ◽  
Author(s):  
Shince V Joseph ◽  
SC Mohanty
Keyword(s):  
Shear Deformation ◽  
Functionally Graded Material ◽  
Sandwich Plate ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Element Formulation ◽  
External Temperature ◽  
Viscoelastic Core ◽  
Graded Material

This article deals with the buckling and free vibration analysis of a sandwich plate with viscoelastic core and functionally graded material constraining lamina under high temperature environment. The first-order shear deformation theory is used for the finite element formulation of the plate. Along with the shear deformation, the longitudinal and transverse deformation of the core is also taken into account. The rise in the external temperature is found to reduce the critical buckling loads and fundamental frequencies, and to increase the corresponding modal loss factors. Various parametric studies such as effect of aspect ratio, core thickness ratio and volume fraction index on static and dynamic behaviour of the sandwich plate are also examined.

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