Cylindrical Nanoshell Research Articles

Flexoelectronics of a centrosymmetric semiconductor cylindrical nanoshell

Cylindrical shell-type semiconductors are essential for sensing and energy harvesting when integrated into surfaces of certain equipment, such as spacecraft, marine devices, and portable electronics, where mechanical forces play a significant impact on charge transport. Traditionally, such functionalities are only manifested in piezoelectric or pyroelectric crystals that possess non-centrosymmetry. Here, we theoretically investigate electronic behaviors driven by strain gradient-induced flexoelectric polarization in a centrosymmetric semiconductor cylindrical nanoshell, expanding the flexoelectronics in shell structures. The governing equations and accompanying boundary conditions are formulated simultaneously using the principle of virtual work and the fundamental lemma of the calculus of variation. Electromechanical interactions through static bending and forced vibration analyses of the newly developed model are systematically investigated. Under localized force excitation, the distribution of mobile charges is manipulated by tuning loading magnitudes and areas. The effects of doping levels on electric potentials and mobile charges are explored to show the interaction mechanism between flexoelectric and semiconducting properties. Moreover, the natural frequencies and modes of all mechanical displacements, electric potentials, and carrier concentration perturbations within the shell are identified. This paper provides a new approach for designing shell-shaped sensors and energy harvesters specifically for centrosymmetric semiconductors.

A size-dependent electro-mechanical buckling analysis of flexoelectric cylindrical nanoshells

In this paper, a buckling analysis for flexoelectric cylindrical nanoshells under axial compression is performed by considering the higher-order shear deformation theory and non-uniform pre-buckling deformation. Size-dependent critical buckling stresses and buckling mode shapes are obtained by the Galerkin's method with newly proposed displacement functions. Numerical results are compared with existing solutions and excellent agreements are observed. Furthermore, a comprehensive parametric study of boundary conditions, geometrical parameters and applied electric voltage is carried out to reveal the influence of flexoelectric effect on the size-dependent buckling characteristics of flexoelectric cylindrical nanoshells.

Efficient and high-quality absorption enhancement using epsilon-near-zero cylindrical nano-shells constructed by graphene

This paper presents a detailed scattering analysis of a hollow-core plasmonic-shell cylindrical wire to design an efficient, compact, narrowband, and reconfigurable optical absorber. The shell is formed by a thin graphene material, investigated in its epsilon-near-zero (ENZ) plasmonic region. Compared to the graphene plasmonic resonances in the terahertz(THz)/far-infrared (FIR) frequencies, the ENZ plasmonic resonances offer a blue shift in the operating frequency of the second-order plasmonic resonances by increasing the geometrical dimensions. This feature is successfully used to design efficient optical wave absorbers with absorption cross-sections much larger than geometrical and scattering cross-sections. The observed blue shift in the resonance spectrum, which is the key point of the design, is further verified by defining each particle with its polarizability and fulfilling the resonant scattering condition in the framework of Mie’s theory. Furthermore, graphene relaxation time and chemical potential can be used to manipulate the absorption rate. Observed resonances have narrow widths, achieved with simple geometry. To consider more practical scenarios, the one-dimensional arrangement of the cylindrical elements as a dense and sparse array is also considered and the design key point regarding graphene quality is revealed. The quality factor of the sparse array resonance is 2272.8 and it demands high-quality graphene material in design. It is also observed that due to the use of small particles in the design, the near-field and cooperative effects are not visible in the absorption cross-section of the array and a clear single peak is attained. This polarization-insensitive absorber can tolerate a wide range of incident angles with an absorption rate above 90%.

Postcritical Imperfection Sensitivity of Functionally Graded Piezoelectric Cylindrical Nanoshells Using Boundary Layer Solution

The nonlocal (NL) and the strain gradient (SG) based equivalent continuum theories were proposed for nanomechanics by accommodating the long-range molecular interactions and to bypass the computationally expensive atomistic simulations. Nanostructures are often made of smart materials (e.g., piezoelectric, piezoceramic, and flexoelectric) for multifunctional properties. Applications of nanostructures in critical systems deserve accurate analysis. The buckling and postcritical behavior of an axially loaded, piezoelectric, nonlocal strain gradient (NLSG) thin cylindrical shells with functionally graded elastic properties were presented in earlier studies following Donnell’s approach, leading to a set of stiff, nonlinear, partial differential equations, accommodating the prebuckling nonlinearity and large postcritical deflection. This study extends the previous work by accommodating geometric imperfections in the formulation. Furthermore, a consistent thickness-wise distribution for the electric potential is also adopted following the Maxwell equation. The boundary layer (BL) concept is employed to solve the resulting nonlinear equations via asymptotic expansions of the regular and the BL fields. The solution is numerically illustrated on moderately short shells, illustrating the influence of the geometric imperfections. The critical load remains imperfection sensitive, yet the imperfections change an unstable postcritical path into a stable one. The influence of the functional gradation and the external electric fields on the imperfection sensitivity behavior are illustrated.

Magnetic field and thermal environment effects on sound transmission loss of double-walled cracked piezoelectric cylindrical nanoshells

Based on a non-local strain gradient theory (NSGT), this article analytically studies the sound transmission loss (STL) performance of a special type of double-walled partially cracked piezoelectric nanoshell structures of cylindrical shape undergoing initial electric potential and longitudinal magnetic field. The structure, which includes a specific number of axial and circumferential surface cracks, is struck by a plane wave in a thermal setting. Such cracks have minimal size compared to the nano-shell structure as a whole, minimizing the effects of curvature for this problem. The first-order shear deformation theory (FSDT) is utilized to explain the displacement components, and Hamilton’s concept is applied to obtain the coupled vibroacoustic equations that are used to generate the governing equations of the system for the two crack types, giving us an idea of the resulting structural stiffness in the presence of cracks using coefficients of crack compliance that are derived from the line spring model (LSM). The mechanical and acoustic properties are then checked to see their effect on the system response followed by a series of validation case studies. This evaluation also allows one to optimize a similar structure by selecting appropriate external parameters such as electric voltage, magnetic field intensity, different crack types, nonlocal and strain gradient parameters, variations of temperature, and incident angle of sound waves.

Numerical modeling of a body vessel for dynamic study of a nano cylindrical shell carrying fluid and a moving nanoparticle

This study examines the dynamic and vibrational behavior of cylindrical nanotubes conveying fluid and moving particle. The first-order shear deformation theory and the nonlocal strain gradient theory have been taken into account for the simply supported boundary condition in the mathematical modeling. The governing equation of a cylindrical nanoshell is extracted using Hamilton's principle, and the Newmark technique is used to solve it. The simulation results are then contrasted with the suggested analytical model. Moreover, the behavior of the system was examined in relation to fluid flow, moving nanoparticles, and a viscoelastic basis. It should be mentioned that the current study is divided into two sections, the first of which presents the analytical methodology and elaborates on the findings. A simulation of the body vessel may be found in the second part. The findings of the current research reveal that a cylindrical nanotube with a fluid flow has a lower natural frequency than a cylindrical nanotube without a fluid flow due to the effect of the added mass of the fluid flow. The findings of this study offer pertinent data for modeling different drug delivery systems.

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.

Nonlinear Buckling Analysis of Cylindrical Nanoshells Conveying Nano-Fluid in Hygrothermal Environment

The present work addresses the critical buckling of circular cylindrical nano-shells containing static/dynamic nanofluids under the influence of different thermal fields that can also lead to appear the effect of thermal moisture so-called hygrothermal forces fields. To this end, the classical Sanders theory of cylindrical plates and shells is generalized by utilizing the non-classical nonlocal elasticity theory to derive the modified dynamic equations governing the nanofluid-nanostructure interaction (nano-FSI) problem. Then, the dimensionless obtained equations are analytically solved using the energy method. Herein, the applied nonlinear heat and humidity fields are considered as three types of longitudinal, circumferential, and simultaneously longitudinal-circumferential forces fields. The mentioned cases are examined separately for both high- and room-temperatures modes. The results show a significant effect of nanofluid passing through the nanostructure and its velocity on the critical buckling strain of the nano-systems, especially at high temperatures.

A nonlocal strain gradient shell model with the surface effect for buckling analysis of a magneto-electro-thermo-elastic cylindrical nanoshell subjected to axial load.

This paper develops a novel size-dependent magneto-electro-thermo-elastic (METE) cylindrical nanoshell which is made of BaTiO3-CoFe2O4 materials. To illustrate the newly developed model, the buckling problem of the METE cylindrical nanoshell subjected to temperature changes, initial magnetic and electric potentials, and axial load is analytically solved on the basis of Kirchhoff-Love theory. To model the size dependency effects, nonlocal strain gradient theory (NSGT) and surface elasticity theory are considered simultaneously. In the process, governing differential equations of the shell are derived using Hamilton's principle. Bifurcation conditions for buckling of the METE cylindrical nanoshell are obtained using Navier's method. The influences of the scale parameter, structure parameter, surface effect, temperature change, initial magnetic potential and initial electric potential on buckling behavior are examined in detail. The present model can be used as a basic model in the study of the effects of temperature changes, initial magnetic and electric potentials, and the axial load on the buckling behavior of METE cylindrical nanoshells. The results provide insights for future experimental research and show that METE cylindrical nanoshells are potential candidates for nanocomponents.

Study on dynamic stability of magneto-electro-thermo-elastic cylindrical nanoshells resting on Winkler–Pasternak elastic foundations using nonlocal strain gradient theory

Study on dynamic stability of magneto-electro-thermo-elastic cylindrical nanoshells resting on Winkler–Pasternak elastic foundations using nonlocal strain gradient theory

On the wave propagation in a high-speed rotating nanosystems via an optimization strategy and computer simulation

The current article attempted to investigate the vibration of laminated high-speed rotating cylindrical nanoshells using nonlocal stress/strain gradient theory (NSGT). Hybrid optimization, with low computational cost as well as high accuracy, is presented to find a solution for optimization problems. In this regard, genetic algorithm (GA), generalized differential quadrature element method, as well as particle swarm optimization are incorporated to enhance the frequency of the laminated high-speed rotating cylindrical nanoshells via obtaining fiber angle of layers and optimum frequency. The boundary conditions and the equation of motions associated with laminated high-speed rotating cylindrical nanoshells, are extracted by employing Hamilton’s principle in addition to first-order shear deformation theory. The particle swarm optimization method, as an operator of the GA, was utilized to enhance genetic algorithms. Also, the applicability, accuracy, and convergence of the presented method are exhibited. Also, it is demonstrated that the converged restates can be attained provided that more than sixteen iterations are employed.

Nonlinear hygro-thermo analysis of fluid-conveying cylindrical nanoshells reinforced with carbon nanotubes based on NSGT

This paper studies the vibration analysis of the cylindrical nanoshell reinforced with carbon nanotubes (CNTs) conveying viscous fluid in the hygro-thermal environment for the first time. Nonlocal strain gradient theory (NSGT) is applied to consider the small-scale effect, including both softening and stiffness impacts. First-order shear deformation theory (FSDT) is utilized to study the shear impacts. A general nonlinear relation is applied to study the hygro-thermal effects. To consider the fluid–solid interchange in several environments, Navier–Stokes equations are employed. Hamilton’s principle is utilized to achieve the governing equations of motion. Then, Navier analytical method is applied to derive the natural frequency of the nanoshell with simply-supported boundary conditions. The impacts of several variables are investigated on the vibration characteristics of the CNT cylindrical nanoshell.

Linear dynamic analysis of axially moving cylindrical nanoshells considering surface energy effect with constant velocity

Linear dynamic analysis of axially moving cylindrical nanoshells considering surface energy effect with constant velocity

Effects of thermal environment and external mean flow on sound transmission loss of sandwich functionally graded magneto-electro-elastic cylindrical nanoshell

Similar to many new engineering ideas that are actually interdisciplinary subjects, magneto-electro-elastic (MEE) structures also need accurate ways of describing their structural behaviors. Based on nonlocal elasticity theory, the present article investigates the vibroacoustic behavior of a hollow multilayer cylindrical nanoshell where the core layer is made of isotropic functionally graded material (FGM) and other layers are made of MEE materials. The proposed system also is subjected to combined loads which contain a plane sound wave, the initial external electric and magnetic loads, and external mean airflow. The displacement field of structure is described using the third-order shear deformation assumption (TSDA). The derivation of vibroacoustic equations in the form of coupled relations is realized by implementing Hamilton's principle. The material properties of FGM core layer are supposed to vary along the in-plane and thickness directions based on the power-law model. The final objective is to analyze the sound transmission loss (STL) characteristics of the structure and inspect the accuracy of the developed method against existing data followed by comparing the results in terms of geometric and acoustic parameters. The obtained results and the described method can be used advantageously to better optimize such structures by choosing appropriate initial electric and magnetic potentials, flow Mach number, nonlocal parameter, material gradient index, incident angles.

Buckling analysis of FG cylindrical nano shell integrated with CNTRC patches

Buckling analysis of a functionally graded (FG) cylindrical nano shell is studied in this paper based on nonlocal elasticity theory and first-order shear deformation theory. The nano shell is made from a combination of ceramic and metal integrated with carbon-nanotube reinforced composite (CNTRC) sheets on outer radius. The reinforced composite nano shell is resting on Pasternak’s foundation. The governing equations of motion are derived using vitual work principle. The effective material properties of carbon-nanotube reinforced composite (CNTRC) sheets are evaluated using rule of mixture. A comparative study is performed before full presentation of numerical results for verification of the model and solution procedure. A large parametric analysis is performed to investigate effect of dimensions of the core as well as CNTRC sheets, CNT volume fraction, nonlocal parameter, number of CNTRC sheets, FG-index and foundation parameters on the buckling results.

Porous flexoelectric cylindrical nanoshell based on the non-classical continuum theory

Porous flexoelectric cylindrical nanoshell based on the non-classical continuum theory

Generalized thermoelasticity model for thermoelastic damping in asymmetric vibrations of nonlocal tubular shells

The present article intends to provide a size-dependent generalized thermoelasticity model and closed-form solution for thermoelastic damping (TED) in cylindrical nanoshells. With the aim of incorporating size effect within constitutive relations and heat conduction equation, nonlocal elasticity theory and Guyer–Krumhansl (GK) heat conduction model are exploited. Donnell–Mushtari–Vlasov (DMV) equations are also employed to model the cylindrical nanoshell. By adopting asymmetric simple harmonic form for oscillations of nanoshell and merging the motion, compatibility and heat conduction equations, the nonclassical frequency equation is extracted. By solving this eigenvalue problem and separating the real and imaginary parts of complex frequency analytically, an explicit expression is given to estimate the magnitude of TED in cylindrical nanoshells with arbitrary boundary conditions. Good agreement between the results of this study in special cases and those available in the literature affirms the validity of present formulation. In the following, for some vibration modes, a detailed parametric study is conducted to illuminate the determining role of structural and thermal nonlocal parameters in the amount of TED in simply-supported cylindrical nanoshells. The augmentation of difference between classical and nonclassical results by reduction in dimensions of nanoshell confirms the small-scale effect on TED value at nanoscales.

An analytical study of sound transmission loss of functionally graded sandwich cylindrical nanoshell integrated with piezoelectric layers

The multidisciplinary nature of piezoelectric (PZ) structures necessitates precise and efficient methods to express their behavior under different conditions. This article extends the general usage of PZ materials by introducing acoustic and fluid loading effects in a way that an unfilled multilayer cylindrical nanoshell with a functionally graded (FG) material core and PZ layers is subjected to preliminary external electric load, acoustic waves and external flow motion. As the properties of a functionally graded material changes along the shell thickness, a power law model is assumed to be governing such variations of desired characteristics. Evidently, this system includes different types of couplings and a comprehensive approach is required to describe the structural response. To this aim, the first-order shear deformation theory (FSDT) is used to define different displacement components. Next, the coupled size-dependent vibroacoustic equations are derived based on in conjunction with nonlocal strain gradient theory (NSGT) with the aid of Hamilton’s variational principle and fluid/structure compatibility conditions. NSGT is complemented with hardening and softening material effects which can greatly enhance the precision of results. It is expected to use the findings of this paper in the optimization of similar systems by selecting suitable FG index, incident angle of sound waves, flow Mach number, nonlocal and strain gradient parameters, starting electric potential and geometric features. One of the important findings of this study is that increasing the electric voltage can obtain better sound insulation at small frequencies, specially prior to the ring frequency.

Hydro–Hygro–Thermo–Magneto–Electro​ elastic wave propagation of axially moving nano-cylindrical shells conveying various magnetic-nano-fluids resting on the electromagnetic-visco-Pasternak medium

The present study addresses hydro-magneto-electro wave propagation of the axially moving circular cylindrical nanoshells conveying magnetic nanofluid and embedded on an electromagnetic-visco-Pasternak foundation under three types of the longitudinal, circumferential, and simultaneous longitudinal–peripheral thermal and hygrothermal forces fields. It is assumed that the visco-Pasternak elastic medium consists of springs in the form of airy coils, so the application of an electric field to the system will also create a magnetic field and thus, the nano-system will become a magnetic–electric–elastic (MEE) state. The magnetic field will affect both the nanostructure as a Lorentz force and the passing nanofluid. The effect of magnetic nano-fluid on phonon dispersion is considered using Knudsen and Hartmann numbers. The equations governing the nano-fluid–structure interaction (Nano-FSI) problem under thermal, moisture, electrical, magnetic, and shear forces are derived using the proposed generalized theory of high-order shear deformation in cylindrical coordinates considering sinusoidal parameters and non-local elasticity, which we call CSN-HSDT for short. The Hamilton principle and the generalized Navier–Stokes equations are used for this purpose. In addition, the densities variations of nanostructures and different nanofluids (liquid or gas) due to thermal and thermal humidity fields, as well as the effects of the velocity of the nanostructure and the passing nanofluid on the system’s natural frequency are investigated. The results demonstrate that the axial velocity of the nanoshell will have a greater effect on the wave scattering and increasing the natural frequency of the system than the velocity of the transient fluid and this effect is decreased by increasing the wavenumber. Moreover, increasing the nanosystem stability and shifting the magnitude values of wave frequencies to higher amounts occurs by applying the fields of thermal and resulting humidity at room-temperatures, and using the negative voltage electric field, Lorentz force, and shear modulus. While the different results are obtained by utilizing the heat and humidity forces at high-temperatures, a positive voltage electric field, passing the magnetic nanofluid, and Winkler modulus. Here, the simultaneous effect of the mentioned force fields on the manner and speed of energy dispersion on a dynamic nanosystem under the influence of electromagnetic substrate and passing magnetic nanofluid is discussed for the first time. The results of the simultaneous application of these force fields in this study can be profitably exploited in the design and manufacturing of new smart structures used in structural health monitoring, energy harvesting, and drug delivery vessels in nanoscale.

On size-dependent wave propagation of flexoelectric nanoshells interacted with internal moving fluid flow

In this study, dynamic properties of fluid-conveying flexoelectric cylindrical nanoshells subjected to an electric field are examined throughout the wave propagation approach. Employing nonlocal strain gradient theory (NSGT) and constitutive flexoelectric relations for shell-type structure, a new model has been represented regarding the Love shell theory. Governing motion equations are derived exploiting Hamilton’s principle and are then solved numerically to acquire the wave propagation properties. A discussion on numerical results is then implemented to highlight the exact wave propagation response of the structure against the flexoelectric effect, electric field, flow velocity and external force. The results reveal a remarkable effect of flexoelectricity on wave propagation response especially for some modes in specific wave number domains. As a prominent result, the flexoelectricity effect on wave dispersion response is found more pronounced for second and third modes, compared to the first mode. In addition, this effect is more tangible for lower wave numbers. The applied positive or negative electric and mechanical force exhibits a decreasing or increasing effect on the phase velocity of all the modes. The presented investigation and the reported results may be useful in designing the systems which are benefiting from wave propagation phenomenon properties of cylindrical nanoshells.