Free vibration of FG-GPLRC conical panel on elastic foundation

Arameh Eyvazian,Farayi Musharavati,Faris Tarlochan,Abdolreza Pasharavesh,Dipen Kumar Rajak,Mohammed Bakr Husain,Tron Nhan Tran 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.75 No.1

Present research is aimed to investigate the free vibration behavior of functionally graded (FG) nanocomposite conical panel reinforced by graphene platelets (GPLs) on the elastic foundation. Winkler-Pasternak elastic foundation surrounds the mentioned shell. For each ply, graphaene platelets are randomly oriented and uniformly dispersed in an isotropic matrix. It is assumed that the Volume fraction of GPLs reainforcement could be different from layer to layer according to a functionally graded pattern. The effective elastic modulus of the conical panel is estimated according to the modified Halpin-Tsai rule in this manuscript. Cone is modeled based on the first order shear deformation theory (FSDT). Hamilton’s principle and generalized differential quadrature (GDQ) approach are also used to derive and discrete the equations of motion. Some evaluations are provided to compare the natural frequencies between current study and some experimental and theoretical investigations. After validation of the accuracy of the present formulation and method, natural frequencies and the corresponding mode shapes of FG-GPLRC conical panel are developed for different parameters such as boundary conditions, GPLs volume fraction, types of functionally graded and elastic foundation coefficients.

Vibration response of FG-CNT-reinforced plates covered by magnetic layer utilizing numerical solution

Yan Cao,Farayi Musharavati,Shahrizan Baharom,Pouyan Talebizadehsardari,Tamer A. Sebaey,Arameh Eyvazian,Azlan Mohd Zain 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.37 No.2

Vibration response in a sandwich plate with a nanocompiste core covered by magnetic layer is presented. The core is armed by functionalyy graded-carbon nanotubes (FG-CNTs) where the Mori-Tanaka law is utilized assuming agglomeration effects. The structure plate is located on elastic medium simulated by Pasternak model. The governing equations are derived based on Mindlin theory and Hamilton’s principle. Utilizing diffrential quadrature method (DQM), the frequency of the structure is calculated and the effects of magnetic layer, volume percent and agglomeration of CNTs, elastic medium and geometrical parameters of structure are shown on the frequency of system. Results indicate that with considering magnetic layer, the frequency of structure is increased.

Vibration characteristics of microplates with GNPs-reinforced epoxy core bonded to piezoelectric-reinforced CNTs patches

Forsat, Masoud,Musharavati, Farayi,Eltai, Elsadig,Zain, Azlan Mohd,Mobayen, Saleh,Mohamed, Abdeliazim Mustafa Techno-Press 2021 Advances in nano research Vol.11 No.2

In the current study, vibration characteristics of a three-layered rectangular microplate with Graphene nanoplatelets (GNPs)-reinforced Epoxy core which is fully bonded to piezoelectric-reinforced single-walled Carbon nanotubes (SWCNTs) patches are provided. The face sheets are subjected to the electric field and the microplate is assumed to be in a thermal environment and also, is located on the visco-Pasternak model of the elastic substrate. The GNPs and SWCNTs are dispersed through the core's and face's thickness according to the given functions. To account the shear deformation effect, tangential shear deformation theory (TGSDT) as a higher-order theory is employed and the modified strain gradient theory (MSGT) with tree independent length-scale parameters is selected to capture the size effect. Using the extended form of Hamilton's principle and variational formulation, the governing motion equations are derived and solved mathematically via Navier's scheme for simply supported edges microplate. By ensuring the validity of the results after comparing them in a simpler state with previously published ones, the effects of the most prominent parameters on the results are investigated. It is seen GNPs and CNTs dispersion patterns play an important role in the microplate vibrational behavior, as well as temperature variations. Since the under consideration microstructure can be accounted as smart structures, therefore, the outcomes of this study may help to design and create more efficient engineering structures, such as sensors and actuators and also micro/nano electromechanical systems.

Free vibration of FG-GPLRC spherical shell on two parameter elastic foundation

Arameh Eyvazian,Farayi Musharavati,Pouyan Talebizadehsardari,Tamer A. Sebaey 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.6

In the present research, the free vibration analysis of functionally graded (FG) nanocomposite deep spherical shells reinforced by graphene platelets (GPLs) on elastic foundation is performed. The elastic foundation is assumed to be Winkler-Past ernak-type. It is also assumed that graphaene platelets are randomly oriented and uniformly dispersed in each layer of the nanocomposite shell. Volume fraction of the graphene platelets as nanofillers may be different in the layers. The modified HalpinTsai model is used to approximate the effective mechanical properties of the multilayer nanocomposite. With the aid of the first order shear deformation shell theory and implementing Hamilton’s principle, motion equations are derived. Afterwards, the generalized differential quadrature method (GDQM) is utilized to study the free vibration characteristics of FG-GPLRC spherical shell. To assess the validity and accuracy of the presented method, the results are compared with the available researches. Finally, the natural frequencies and corresponding mode shapes are provided for different boundary conditions, GPLs volume fraction, types of functionally graded, elastic foundation coefficients, opening angles of shell, and thickness-to-radius ratio.

Elastic wave phenomenon of nanobeams including thickness stretching effect

Eyvazian, Arameh,Zhang, Chunwei,Musharavati, Farayi,Khan, Afrasyab,Mohamed, Abdeliazim Mustafa Techno-Press 2021 Advances in nano research Vol.10 No.3

The present work deals with an investigation on longitudinal wave propagation in nanobeams made of graphene sheets, for the first time. The nanobeam is modelled via a higher-order shear deformation theory accounts for both higher-order and thickness stretching terms. The general nonlocal strain gradient theory including nonlocality and strain gradient characteristics of size-dependency in order is used to examine the small-scale effects. This model has three-small scale coefficients in which two of them are for nonlocality and one of them applied for gradient effects. Hamilton supposition is applied to obtain the governing motion equation which is solved using a harmonic solution procedure. It is indicated that the longitudinal wave characteristics of the nanobeams are significantly influenced by the nonlocal parameters and strain gradient parameter. It is shown that higher nonlocal parameter is more efficient than lower nonlocal parameter to change longitudinal phase velocities, while the strain gradient parameter is the determining factor for their efficiency on the results.

Investigation of expanding-folding absorbers with functionally graded thickness under axial loading and optimization of crushing parameters

Chunwei Zhang,Limeng Zhu,Farayi Musharavati,Afrasyab Khan,Tamer A. Sebaey 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.6

In this study, a new type of energy absorbers with a functionally graded thickness is investigated, these type of absorbers absorb energy through expanding-folding processes. The expanding-folding absorbers are composed of two sections: a thin-walled aluminum matrix and a thin-walled steel mandrel. Previous studies have shown higher efficiency of the mentioned absorbers compared to the conventional ones. In this study, the effect of thickness which has been functionally-graded on the aluminum matrix (in which expansion occurs) was investigated. To this end, initial functions were considered for the matrix thickness, which was ascending/descending along the axis. The study was done experimentally and numerically. Comparing the experimental data with the numerical results showed high consistency between the numerical and experimental results. In the final section of this study, the best energy absorber functionally graded thickness was introduced by optimization using a thirdorder genetic algorithm. The optimization results showed that by choosing a minimum thickness of 1.6 mm and the exponential coefficient of 3.25, the most optimal condition can be obtained for descending thickness absorbers.

Dispersion of waves characteristics of laminated composite nanoplate

Xinli Xu,Chunwei Zhang,Farayi Musharavati,Tamer A. Sebaey,Afrasyab Khan 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.3

The current work fills a gap of a small-scale study on wave propagation behavior of symmetric, antisymmetric, and quasi-isotropic cross/angle-plies laminated composite nanoplates. The governing equations are derived through the Hamiltonian principle for four-variable refined shear deformation plate theory in conjunction with the assumption of a non-classical theory, and then size-dependent formulations are solved via an analytical solution procedure. This work provides information to accurately analyze the influence of lay-up numbers and sequences, geometry, fiber orientations, and wave numbers on the size-dependent wave propagation response of laminated composite nanoplates.

Wave propagation analysis of porous functionally graded curved beams in the thermal environment

Xinli Xu,Chunwei Zhang,Farayi Musharavati,Tamer A. Sebaey,Afrasyab Khan 국제구조공학회 2021 Structural Engineering and Mechanics, An Int'l Jou Vol.79 No.6

In the present paper, wave propagation behavior of porous temperature-dependent functionally graded curved beams within the thermal environment is analyzed for the first time. A recently-developed method is utilized which considers the reciprocal effect of mass density and Young’s modulus in order to explore the influence of porosity. Three different types of temperature variation (uniform temperature change (UTC), linear temperature change (LTC), sinusoidal temperature change (STC)) are employed to study the effect of various thermal loads. Euler-Bernoulli beam theory, also known as classic beam theory is implemented in order to derive kinetic and kinematic relations, and then Hamilton’s principle is used to obtain governing equations of porous functionally graded curved beams. The obtained governing equations are analytically solved. Eventually, the influences of various parameters such as wave number, porosity coefficient, various types of temperature change and power index are covered and indicated in a set of illustrations.

Experimental and numerical investigations on axial crushing of square cross-sections tube with vertical wave

Arameh Eyvazian,Elsadig Eltai,Farayi Musharavati,Hossein Taghipoor,T.A. Sebaey,Pouyan Talebizadehsardari 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.2

In this paper, wavy square absorbers were experimentally and numerically investigated. Numerical simulations were performed with LS-Dyna software on 36 wavy absorbers and their crushing properties were extracted and compared with the simple one. The effect of different parameters, including wave height, wave depth, and wave type; either internal or external on the crushing characteristics were also investigated. To experimentally create corrugation to validate the numerical results, a set of steel mandrel and matrix along with press machines were used. Since the initial specimens were brittle, they were subjected to heat treatment and annealing to gain the required ductility for forming with mandrel and matrix. The annealing of aluminum shells resulted in a 76%increase in ultimate strain and a 60% and 56% decrease in yield and ultimate stresses, respectively. The results showed that with increasing half-wave height in wavy square absorbers, the maximum force was first reduced and then increased. It was also found that in the specimen with constant diameter and half-wave depth, an increment in the half-wave height led to an initial increase in efficiency, followed by a decline. According to the conducted investigations, the lowe maximum force can be observed in the specimen with zero half-wave depth as compared to those having a depth of 1 cm.