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Papers by sharif zarei

Research paper thumbnail of RETRACTED: Dynamic response control of aluminum beams integrated with nanocomposite piezoelectric layers subjected to blast load using hyperbolic visco-piezo-elasticity theory

Journal of Sandwich Structures & Materials, 2018

Research paper thumbnail of Energy absorption and vibration of smart auxetic FG porous curved conical panels resting on the frictional viscoelastic torsional substrate

Mechanical Systems and Signal Processing

Research paper thumbnail of Heat transfer in a square cavity filled by nanofluid with sinusoidal wavy walls at different wavelengths and amplitudes

Case Studies in Thermal Engineering

Research paper thumbnail of Dynamic Buckling of Embedded Laminated Nanocomposite Plates Based on Sinusoidal Shear Deformation Theory

Applied and Computational Mechanics, 2016

In this study, the dynamic buckling of the embedded laminated nanocomposite plates is investigate... more In this study, the dynamic buckling of the embedded laminated nanocomposite plates is investigated. The plates are reinforced with the single-walled carbon nanotubes (SWCNTs), and the Mori-Tanaka model is applied to obtain the equivalent material properties of them. Based on the sinusoidal shear deformation theory (SSDT), the motion equations are derived using the energy method and Hamilton's principle. The Navier’s method is used in conjunction with the Bolotin's method for obtaining the dynamic instability region (DIR) of the structure. The effects of different parameters such as the volume percentage of SWCNTs, the number and orientation angle of the layers, the elastic medium, and the geometrical parameters of the plates are shown on DIR of the structure. Results indicate that by increasing the volume percentage of SWCNTs the resonance frequency increases, and DIR shifts to right. Moreover, it is found that the present results are in good agreement with the previous rese...

Research paper thumbnail of A layerwise theory for buckling analysis of truncated conical shells reinforced by CNTs and carbon fibers integrated with piezoelectric layers in hygrothermal environment

A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelect... more A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelectric truncated conical shell. The core is a multiphase nanocomposite reinforced by carbon nanotubes (CNTs) and carbon fibers. The top and bottom face sheets are piezoelectric subjected to 3D electric field and external voltage. The Halpin-Tsai model is used for obtaining the effective moisture and temperature dependent material properties of the core. The proposed layerwise theory is based on Mindlin's first-order shear deformation theory in each layer and results for a laminated truncated conical shell with three layers considering the continuity boundary condition. Applying energy method, the coupled motion equations are derived and analyzed using differential quadrature method (DQM) for different boundary conditions. The influences of some parameters such as boundary conditions, CNTs weight percent, cone semi vertex angle, geometrical parameters, moisture and temperature changes an...

Research paper thumbnail of Influence of temperature change and humidity condition on free vibration analysis of a nano composite sandwich plate resting on orthotropic Pasternak foundation by considering agglomeration effect

Journal of Sandwich Structures & Materials, 2017

This research presents an investigation into the free vibration of a sandwich plate with a transv... more This research presents an investigation into the free vibration of a sandwich plate with a transversely flexible polymeric core and two carbon nanotubes reinforced nanocomposite face sheets based on high-order sandwich plate theory. The material properties are considered to be temperature-and moisture-dependent. The mathematical model of the face sheets is developed based on the classical plate theory and modified strain gradient theory. Also, Eshelby-Mori-Tanaka approach is used to estimate the material properties of the face sheets and consider the agglomeration effect of carbon nanotubes. The governing equations of motion which included the size effect as well as hygrothermal effect are derived based on Hamilton's principle and solved by means of Navier's solution method. The influence of various parameters such as agglomeration effect and the volume fraction of carbon nanotubes, material length scale parameters, aspect and side ratios, temperature changes, and humidity condition is presented. In addition, orthotropic Pasternak foundation is taken into account to study

Research paper thumbnail of A new numerical approach and visco-refined zigzag theory for blast analysis of auxetic honeycomb plates integrated by multiphase nanocomposite facesheets in hygrothermal environment

Engineering with Computers, 2018

The current work suggests a mathematical model for the dynamic response of sandwich plates subjec... more The current work suggests a mathematical model for the dynamic response of sandwich plates subjected to a blast load using a numerical method. The sandwich structure is made from an auxetic honeycomb core layer integrated by multiphase nanocomposite facesheets. The facesheets are composed of polymer-carbon nanotube (CNT)-fiber where the equivalent material properties of the multiphase nanocomposite layers are obtained using fiber micromechanics and Halpin-Tsai equations in hierarchy. The top and bottom layers are subjected to magnetic field and the material properties of them are assumed temperature and moisture dependent. The Kelvin-Voigt model is employed to consider the viscoelastic properties of the structure. The sandwich structure is rested on a viscoelastic foundation which is modeled by orthotropic visco-Pasternak medium. Based on refined zigzag theory (RZT), energy method and Hamilton's principle, the motion equations are derived. A new numerical method, namely differential cubature method (DCM) in conjunction with Newmark method is utilized for obtaining the dynamic deflection of the structure for different boundary conditions. The effects of various parameters such as blast load, viscoelastic foundation, structural damping, magnetic field, volume fraction of CNTs, temperature and moisture changes, geometrical parameters of honeycomb layer and sandwich plate are considered on the dynamic deflection of the structure. The results show that the magnetic field to the facesheets can be considered as effective parameters to control the dynamic deflection. In addition, hygrothermal condition leads to increase of 24% in the dynamic displacement of system.

Research paper thumbnail of Visco-piezoelasticity-zigzag theories for blast response of porous beams covered by graphene platelet-reinforced piezoelectric layers

Journal of Sandwich Structures & Materials, 2019

Blast response of the embedded porous beams covered by nanocomposite piezoelectric layers is pres... more Blast response of the embedded porous beams covered by nanocomposite piezoelectric layers is presented in this article. The facesheets are reinforced by non-uniform graphene platelet where the effective material properties are determined using modified Halpin-Tsai micromechanics model. The piezoelectric layers play the role of sensor and actuator of the core, however, a proportional-differential controller is used for controlling the dynamic deflection of the structure. The sandwich structure is rested on Kerr viscoelastic foundation with two springs, two damper, and one shear elements. Considering structural damping using Kelvin-Voigt model, using piezoelasticity theory, and applying zigzag shear deformation beam theory, the motion equations are derived. Differential quadrature method along with Newmark method is used for calculating the dynamic displacement of the sandwich structure. The effects of different parameters such as graphene platelets volume percentage and distribution type, porosity of the core, geometrical parameters of structure, applied voltage, structural

Research paper thumbnail of Dynamic buckling of polymer–carbon nanotube–fiber multiphase nanocomposite viscoelastic laminated conical shells in hygrothermal environments

Journal of Sandwich Structures & Materials, 2017

This paper deals with the dynamic buckling of a sandwich truncated conical shell composed of poly... more This paper deals with the dynamic buckling of a sandwich truncated conical shell composed of polymer-carbon nanotubes-fiber multiphase nanocomposite layers. The structure is located in hygrothermal environments. The equivalent material properties of the multiphase nanocomposite layers are obtained using fiber micromechanics and Halpin-Tsai equations in hierarchy. According to Kelvin-Voigt theory, the realistic behavior of the structure is considered by considering the viscoelastic properties. The surrounding medium is simulated using visco-Pasternak model. The governing equations of the system are derived based on the classical theory by employing Hamilton's principle. To obtain the dynamic instability region of the system, the differential quadrature method, and Bolotin's method are utilized. The influences of various parameters such as structural damping, viscoelastic medium, number of layers, volume fraction of carbon nanotubes, temperature, and moisture changes on the analysis of the dynamic instability region of the structure are studied. The results Journal of Sandwich Structures and Materials 0(00) 1-26 ! The Author(s) 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

Research paper thumbnail of Dynamic buckling of sensor/functionally graded-carbon nanotube-reinforced laminated plates/actuator based on sinusoidal-visco-piezoelasticity theories

Journal of Sandwich Structures & Materials, 2017

In this article, the dynamic buckling behavior of a sandwich plate composed of laminated viscoela... more In this article, the dynamic buckling behavior of a sandwich plate composed of laminated viscoelastic nanocomposite layers integrated with viscoelastic piezoelectric layers is investigated. The core due to the existence of carbon nanotubes is subjected to the magnetic field while the piezoelectric layers at the top and the bottom of the core are subjected to the electric filed and plays the role of the actuator and the sensor, respectively. The core layers are reinforced by functionally graded carbon nanotubes and their equivalent material properties are obtained using the extended rule of mixture. According to Kelvin–Voigt theory, the realistic behavior of the structure is simulated by considering the viscoelastic properties. The structure is assumed resting on viscoelastic medium which is simulated using orthotropic visco-Pasternak model. The governing equations of the system are derived based on the sinusoidal shear deformation theory and by employing Hamilton's principle. To obtain the dynamic stabili...

Research paper thumbnail of Wave propagation of embedded viscoelastic FG-CNT-reinforced sandwich plates integrated with sensor and actuator based on refined zigzag theory

International Journal of Mechanical Sciences, 2017

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  Wave propagation in a viscoelastic piezoelectric sandwich plate is studied.  The core is comprised of FG-CNT-reinforced laminas.  The piezoelectric layers play the role of actuator and sensor.  The refined piezoelasticity zigzag theory is used.  A PD controller is employed to control the phase velocity in the structure.

Research paper thumbnail of Visco-nonlocal-refined Zigzag theories for dynamic buckling of laminated nanoplates using differential cubature-Bolotin methods

Thin-Walled Structures, 2017

Present analysis, deals with dynamic buckling of sandwich nano plate (SNP) subjected to harmonic ... more Present analysis, deals with dynamic buckling of sandwich nano plate (SNP) subjected to harmonic compressive load based on nonlocal elasticity theory. The material properties of each layer of SNP are supposed to be viscoelastic based on Kelvin-Voigt model. In order to mathematical modeling of SNP, a novel formulation, refined Zigzag theory (RZT) is developed. Furthermore, the surrounding elastic medium is simulated by viscoorthotropic Pasternak foundation model in which damping, normal and transverse shear loads are taken into account. Using energy method and D′Alembert's principle, the size dependent governing motion equations are derived. In this study, the governing motion equations are solved numerically using new procedure namely differential cubature (DC) method in conjunction with Bolotin method. The effects of some remarkable parameters such as viscoelastic foundation, damping coefficient of viscoelastic plates, aspect ratio, amount of small scale effect, various boundary conditions, different values of fiber orientation of the face sheets, number of grid points and thickness-length ratio on the dynamic instability region (DIR) are investigated. The results show that considering viscoelastic property of system is essential to obtain real mechanical behavior and instability of systems. In addition, the surrounding elastic medium is an effective parameter on the DIR of SNP.

Research paper thumbnail of Thermal effect on the torsional buckling of double walled carbon nanotube embedded in Pasternak foundation

Research paper thumbnail of The thermal effect on buckling analysis of a DWCNT embedded on the Pasternak foundation

Physica E: Low-dimensional Systems and Nanostructures, 2011

In this article, the thermal effect on the buckling analysis of a double-walled carbon nanotube (... more In this article, the thermal effect on the buckling analysis of a double-walled carbon nanotube (DWCNT) embedded in an elastic medium subjected to a uniform external pressure is investigated. Based on the nonlocal continuum cylindrical shell theory, the following effects are studied: small scale effect, van der Waals (vdW) forces between inner and outer tubes, surrounding elastic medium, and influence of temperature change in high-temperature environment. The interaction between matrix and the outer tube is modeled as a Pasternak foundation. The obtained results of numerical simulation indicate that for any specific circumferential wave number (n), the nonlocal critical buckling pressure (p crit) is related directly to the axial half wave number (m). Furthermore, the effect of temperature change on the critical buckling pressure is negligible, especially for stiff elastic medium; however, this is not the case if the elastic medium is soft. The strength of the DWCNT is directly related to the Winkler and shear moduli; hence, increase in the latter leads to enhanced p crit .

Research paper thumbnail of Seismic response of underwater fluid-conveying concrete pipes reinforced with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer

Soil Dynamics and Earthquake Engineering, 2017

This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinf... more This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinforced with SiO 2 nanoparticles and fiber reinforced polymer (FRP) layer. The earthquake acceleration is consistent with the earthquake occurred in Tabas. It is assumed that the structure is subjected to external forces which exerted by inner and outer fluids. The force due to the inner fluid is evaluated using Navier-Stokes equation. Also, Mori-Tanaka model is employed to take into account the agglomeration effect of SiO 2 nanoparticles. The mathematical model of the structure is developed based on the first order shear deformation theory (FSDT) and the governing equations are derived using energy method and Hamilton's principle. Finally, the problem is solved employing differential quadrature method (DQM) and Newmark method and the effect of different parameters like SiO2 nanoparticles agglomeration and volume percent, inner and outer fluids, various boundary conditions and geometric parameters on the dynamic deflection of the structure is studied. The results indicate that with increasing the thickness to radius ratio and volume fraction of SiO2 nanoparticles and also employing the NFRP layer, the dynamic deflection of the structure decreases while considering the effect of inner and outer fluids and agglomeration of SiO2 nanoparticles and increasing the length to thickness ratio increases the dynamic deflection of the structure.

Research paper thumbnail of Earthquake induced dynamic deflection of submerged viscoelastic cylindrical shell reinforced by agglomerated CNTs considering thermal and moisture effects

Composite Structures

Abstract This study gives a numerical work on dynamic response of cylindrical shells submerged in... more Abstract This study gives a numerical work on dynamic response of cylindrical shells submerged in an incompressible fluid subjected to earthquake, thermal and moisture loads. The cylindrical shell is reinforced by carbon nanotubes (CNTs) where the Mori-Tanaka model is used for calculating the effective material properties of the structure considering agglomeration effects. The effect of the fluid is assumed using the acoustic wave equation. The structural damping effect is considered using Kelvin-Voigt model. Sinusoidal shear deformation shell theory (SSDT) is utilized in the shell dynamical equations based on energy method and Hamilton’s principle. The problem is framed combining shell motion equations with the acoustic wave equation where the fluid-loaded terms are considered with Hankel function of second kind. Differential quadrature method (DQM) and Newmark approach are employed to solve the shell problem. The influences of fluid, boundary condition, thermal load, moisture changes, boundary condition, structural damping parameter, length to thickness ratio of shell, CNTs volume percent and agglomeration are shown on the dynamic deflection of the structure. The results show that increasing the CNTs volume percent, the dynamic deflection decreases while considering the CNTs agglomeration leads to increase in the dynamic deflection of the structure.

Research paper thumbnail of Dynamic response of auxetic honeycomb plates integrated with agglomerated CNT-reinforced face sheets subjected to blast load based on visco-sinusoidal theory

International Journal of Mechanical Sciences

Research paper thumbnail of Bending and buckling analysis of functionally graded annular microplate integrated with piezoelectric layers based on layerwise theory using DQM

Aerospace Science and Technology

Research paper thumbnail of RETRACTED: Dynamic response control of aluminum beams integrated with nanocomposite piezoelectric layers subjected to blast load using hyperbolic visco-piezo-elasticity theory

Journal of Sandwich Structures & Materials, 2018

Research paper thumbnail of Energy absorption and vibration of smart auxetic FG porous curved conical panels resting on the frictional viscoelastic torsional substrate

Mechanical Systems and Signal Processing

Research paper thumbnail of Heat transfer in a square cavity filled by nanofluid with sinusoidal wavy walls at different wavelengths and amplitudes

Case Studies in Thermal Engineering

Research paper thumbnail of Dynamic Buckling of Embedded Laminated Nanocomposite Plates Based on Sinusoidal Shear Deformation Theory

Applied and Computational Mechanics, 2016

In this study, the dynamic buckling of the embedded laminated nanocomposite plates is investigate... more In this study, the dynamic buckling of the embedded laminated nanocomposite plates is investigated. The plates are reinforced with the single-walled carbon nanotubes (SWCNTs), and the Mori-Tanaka model is applied to obtain the equivalent material properties of them. Based on the sinusoidal shear deformation theory (SSDT), the motion equations are derived using the energy method and Hamilton's principle. The Navier’s method is used in conjunction with the Bolotin's method for obtaining the dynamic instability region (DIR) of the structure. The effects of different parameters such as the volume percentage of SWCNTs, the number and orientation angle of the layers, the elastic medium, and the geometrical parameters of the plates are shown on DIR of the structure. Results indicate that by increasing the volume percentage of SWCNTs the resonance frequency increases, and DIR shifts to right. Moreover, it is found that the present results are in good agreement with the previous rese...

Research paper thumbnail of A layerwise theory for buckling analysis of truncated conical shells reinforced by CNTs and carbon fibers integrated with piezoelectric layers in hygrothermal environment

A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelect... more A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelectric truncated conical shell. The core is a multiphase nanocomposite reinforced by carbon nanotubes (CNTs) and carbon fibers. The top and bottom face sheets are piezoelectric subjected to 3D electric field and external voltage. The Halpin-Tsai model is used for obtaining the effective moisture and temperature dependent material properties of the core. The proposed layerwise theory is based on Mindlin's first-order shear deformation theory in each layer and results for a laminated truncated conical shell with three layers considering the continuity boundary condition. Applying energy method, the coupled motion equations are derived and analyzed using differential quadrature method (DQM) for different boundary conditions. The influences of some parameters such as boundary conditions, CNTs weight percent, cone semi vertex angle, geometrical parameters, moisture and temperature changes an...

Research paper thumbnail of Influence of temperature change and humidity condition on free vibration analysis of a nano composite sandwich plate resting on orthotropic Pasternak foundation by considering agglomeration effect

Journal of Sandwich Structures & Materials, 2017

This research presents an investigation into the free vibration of a sandwich plate with a transv... more This research presents an investigation into the free vibration of a sandwich plate with a transversely flexible polymeric core and two carbon nanotubes reinforced nanocomposite face sheets based on high-order sandwich plate theory. The material properties are considered to be temperature-and moisture-dependent. The mathematical model of the face sheets is developed based on the classical plate theory and modified strain gradient theory. Also, Eshelby-Mori-Tanaka approach is used to estimate the material properties of the face sheets and consider the agglomeration effect of carbon nanotubes. The governing equations of motion which included the size effect as well as hygrothermal effect are derived based on Hamilton's principle and solved by means of Navier's solution method. The influence of various parameters such as agglomeration effect and the volume fraction of carbon nanotubes, material length scale parameters, aspect and side ratios, temperature changes, and humidity condition is presented. In addition, orthotropic Pasternak foundation is taken into account to study

Research paper thumbnail of A new numerical approach and visco-refined zigzag theory for blast analysis of auxetic honeycomb plates integrated by multiphase nanocomposite facesheets in hygrothermal environment

Engineering with Computers, 2018

The current work suggests a mathematical model for the dynamic response of sandwich plates subjec... more The current work suggests a mathematical model for the dynamic response of sandwich plates subjected to a blast load using a numerical method. The sandwich structure is made from an auxetic honeycomb core layer integrated by multiphase nanocomposite facesheets. The facesheets are composed of polymer-carbon nanotube (CNT)-fiber where the equivalent material properties of the multiphase nanocomposite layers are obtained using fiber micromechanics and Halpin-Tsai equations in hierarchy. The top and bottom layers are subjected to magnetic field and the material properties of them are assumed temperature and moisture dependent. The Kelvin-Voigt model is employed to consider the viscoelastic properties of the structure. The sandwich structure is rested on a viscoelastic foundation which is modeled by orthotropic visco-Pasternak medium. Based on refined zigzag theory (RZT), energy method and Hamilton's principle, the motion equations are derived. A new numerical method, namely differential cubature method (DCM) in conjunction with Newmark method is utilized for obtaining the dynamic deflection of the structure for different boundary conditions. The effects of various parameters such as blast load, viscoelastic foundation, structural damping, magnetic field, volume fraction of CNTs, temperature and moisture changes, geometrical parameters of honeycomb layer and sandwich plate are considered on the dynamic deflection of the structure. The results show that the magnetic field to the facesheets can be considered as effective parameters to control the dynamic deflection. In addition, hygrothermal condition leads to increase of 24% in the dynamic displacement of system.

Research paper thumbnail of Visco-piezoelasticity-zigzag theories for blast response of porous beams covered by graphene platelet-reinforced piezoelectric layers

Journal of Sandwich Structures & Materials, 2019

Blast response of the embedded porous beams covered by nanocomposite piezoelectric layers is pres... more Blast response of the embedded porous beams covered by nanocomposite piezoelectric layers is presented in this article. The facesheets are reinforced by non-uniform graphene platelet where the effective material properties are determined using modified Halpin-Tsai micromechanics model. The piezoelectric layers play the role of sensor and actuator of the core, however, a proportional-differential controller is used for controlling the dynamic deflection of the structure. The sandwich structure is rested on Kerr viscoelastic foundation with two springs, two damper, and one shear elements. Considering structural damping using Kelvin-Voigt model, using piezoelasticity theory, and applying zigzag shear deformation beam theory, the motion equations are derived. Differential quadrature method along with Newmark method is used for calculating the dynamic displacement of the sandwich structure. The effects of different parameters such as graphene platelets volume percentage and distribution type, porosity of the core, geometrical parameters of structure, applied voltage, structural

Research paper thumbnail of Dynamic buckling of polymer–carbon nanotube–fiber multiphase nanocomposite viscoelastic laminated conical shells in hygrothermal environments

Journal of Sandwich Structures & Materials, 2017

This paper deals with the dynamic buckling of a sandwich truncated conical shell composed of poly... more This paper deals with the dynamic buckling of a sandwich truncated conical shell composed of polymer-carbon nanotubes-fiber multiphase nanocomposite layers. The structure is located in hygrothermal environments. The equivalent material properties of the multiphase nanocomposite layers are obtained using fiber micromechanics and Halpin-Tsai equations in hierarchy. According to Kelvin-Voigt theory, the realistic behavior of the structure is considered by considering the viscoelastic properties. The surrounding medium is simulated using visco-Pasternak model. The governing equations of the system are derived based on the classical theory by employing Hamilton's principle. To obtain the dynamic instability region of the system, the differential quadrature method, and Bolotin's method are utilized. The influences of various parameters such as structural damping, viscoelastic medium, number of layers, volume fraction of carbon nanotubes, temperature, and moisture changes on the analysis of the dynamic instability region of the structure are studied. The results Journal of Sandwich Structures and Materials 0(00) 1-26 ! The Author(s) 2017 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav

Research paper thumbnail of Dynamic buckling of sensor/functionally graded-carbon nanotube-reinforced laminated plates/actuator based on sinusoidal-visco-piezoelasticity theories

Journal of Sandwich Structures & Materials, 2017

In this article, the dynamic buckling behavior of a sandwich plate composed of laminated viscoela... more In this article, the dynamic buckling behavior of a sandwich plate composed of laminated viscoelastic nanocomposite layers integrated with viscoelastic piezoelectric layers is investigated. The core due to the existence of carbon nanotubes is subjected to the magnetic field while the piezoelectric layers at the top and the bottom of the core are subjected to the electric filed and plays the role of the actuator and the sensor, respectively. The core layers are reinforced by functionally graded carbon nanotubes and their equivalent material properties are obtained using the extended rule of mixture. According to Kelvin–Voigt theory, the realistic behavior of the structure is simulated by considering the viscoelastic properties. The structure is assumed resting on viscoelastic medium which is simulated using orthotropic visco-Pasternak model. The governing equations of the system are derived based on the sinusoidal shear deformation theory and by employing Hamilton's principle. To obtain the dynamic stabili...

Research paper thumbnail of Wave propagation of embedded viscoelastic FG-CNT-reinforced sandwich plates integrated with sensor and actuator based on refined zigzag theory

International Journal of Mechanical Sciences, 2017

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service... more This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights  Wave propagation in a viscoelastic piezoelectric sandwich plate is studied.  The core is comprised of FG-CNT-reinforced laminas.  The piezoelectric layers play the role of actuator and sensor.  The refined piezoelasticity zigzag theory is used.  A PD controller is employed to control the phase velocity in the structure.

Research paper thumbnail of Visco-nonlocal-refined Zigzag theories for dynamic buckling of laminated nanoplates using differential cubature-Bolotin methods

Thin-Walled Structures, 2017

Present analysis, deals with dynamic buckling of sandwich nano plate (SNP) subjected to harmonic ... more Present analysis, deals with dynamic buckling of sandwich nano plate (SNP) subjected to harmonic compressive load based on nonlocal elasticity theory. The material properties of each layer of SNP are supposed to be viscoelastic based on Kelvin-Voigt model. In order to mathematical modeling of SNP, a novel formulation, refined Zigzag theory (RZT) is developed. Furthermore, the surrounding elastic medium is simulated by viscoorthotropic Pasternak foundation model in which damping, normal and transverse shear loads are taken into account. Using energy method and D′Alembert's principle, the size dependent governing motion equations are derived. In this study, the governing motion equations are solved numerically using new procedure namely differential cubature (DC) method in conjunction with Bolotin method. The effects of some remarkable parameters such as viscoelastic foundation, damping coefficient of viscoelastic plates, aspect ratio, amount of small scale effect, various boundary conditions, different values of fiber orientation of the face sheets, number of grid points and thickness-length ratio on the dynamic instability region (DIR) are investigated. The results show that considering viscoelastic property of system is essential to obtain real mechanical behavior and instability of systems. In addition, the surrounding elastic medium is an effective parameter on the DIR of SNP.

Research paper thumbnail of Thermal effect on the torsional buckling of double walled carbon nanotube embedded in Pasternak foundation

Research paper thumbnail of The thermal effect on buckling analysis of a DWCNT embedded on the Pasternak foundation

Physica E: Low-dimensional Systems and Nanostructures, 2011

In this article, the thermal effect on the buckling analysis of a double-walled carbon nanotube (... more In this article, the thermal effect on the buckling analysis of a double-walled carbon nanotube (DWCNT) embedded in an elastic medium subjected to a uniform external pressure is investigated. Based on the nonlocal continuum cylindrical shell theory, the following effects are studied: small scale effect, van der Waals (vdW) forces between inner and outer tubes, surrounding elastic medium, and influence of temperature change in high-temperature environment. The interaction between matrix and the outer tube is modeled as a Pasternak foundation. The obtained results of numerical simulation indicate that for any specific circumferential wave number (n), the nonlocal critical buckling pressure (p crit) is related directly to the axial half wave number (m). Furthermore, the effect of temperature change on the critical buckling pressure is negligible, especially for stiff elastic medium; however, this is not the case if the elastic medium is soft. The strength of the DWCNT is directly related to the Winkler and shear moduli; hence, increase in the latter leads to enhanced p crit .

Research paper thumbnail of Seismic response of underwater fluid-conveying concrete pipes reinforced with SiO2 nanoparticles and fiber reinforced polymer (FRP) layer

Soil Dynamics and Earthquake Engineering, 2017

This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinf... more This study aims at investigating the seismic response of the fluid-conveying concrete pipes reinforced with SiO 2 nanoparticles and fiber reinforced polymer (FRP) layer. The earthquake acceleration is consistent with the earthquake occurred in Tabas. It is assumed that the structure is subjected to external forces which exerted by inner and outer fluids. The force due to the inner fluid is evaluated using Navier-Stokes equation. Also, Mori-Tanaka model is employed to take into account the agglomeration effect of SiO 2 nanoparticles. The mathematical model of the structure is developed based on the first order shear deformation theory (FSDT) and the governing equations are derived using energy method and Hamilton's principle. Finally, the problem is solved employing differential quadrature method (DQM) and Newmark method and the effect of different parameters like SiO2 nanoparticles agglomeration and volume percent, inner and outer fluids, various boundary conditions and geometric parameters on the dynamic deflection of the structure is studied. The results indicate that with increasing the thickness to radius ratio and volume fraction of SiO2 nanoparticles and also employing the NFRP layer, the dynamic deflection of the structure decreases while considering the effect of inner and outer fluids and agglomeration of SiO2 nanoparticles and increasing the length to thickness ratio increases the dynamic deflection of the structure.

Research paper thumbnail of Earthquake induced dynamic deflection of submerged viscoelastic cylindrical shell reinforced by agglomerated CNTs considering thermal and moisture effects

Composite Structures

Abstract This study gives a numerical work on dynamic response of cylindrical shells submerged in... more Abstract This study gives a numerical work on dynamic response of cylindrical shells submerged in an incompressible fluid subjected to earthquake, thermal and moisture loads. The cylindrical shell is reinforced by carbon nanotubes (CNTs) where the Mori-Tanaka model is used for calculating the effective material properties of the structure considering agglomeration effects. The effect of the fluid is assumed using the acoustic wave equation. The structural damping effect is considered using Kelvin-Voigt model. Sinusoidal shear deformation shell theory (SSDT) is utilized in the shell dynamical equations based on energy method and Hamilton’s principle. The problem is framed combining shell motion equations with the acoustic wave equation where the fluid-loaded terms are considered with Hankel function of second kind. Differential quadrature method (DQM) and Newmark approach are employed to solve the shell problem. The influences of fluid, boundary condition, thermal load, moisture changes, boundary condition, structural damping parameter, length to thickness ratio of shell, CNTs volume percent and agglomeration are shown on the dynamic deflection of the structure. The results show that increasing the CNTs volume percent, the dynamic deflection decreases while considering the CNTs agglomeration leads to increase in the dynamic deflection of the structure.

Research paper thumbnail of Dynamic response of auxetic honeycomb plates integrated with agglomerated CNT-reinforced face sheets subjected to blast load based on visco-sinusoidal theory

International Journal of Mechanical Sciences

Research paper thumbnail of Bending and buckling analysis of functionally graded annular microplate integrated with piezoelectric layers based on layerwise theory using DQM

Aerospace Science and Technology