Free vibration of porous FG nonlocal modified couple nanobeams via a modified porosity model

Ghandourah, Emad E.,Ahmed, Hitham M.,Eltaher, Mohamed A.,Attia, Mohamed A.,Abdraboh, Azza M. Techno-Press 2021 Advances in nano research Vol.11 No.4

This paper explores the size-dependent vibration response of porous functionally graded (FG) micro/nanobeams based on an integrated nonlocal-couple stress continuum model (NLCS). The mutual effect of the microstructure local rotation and nonlocality are modelled using the modified couple stress theory and Eringen nonlocal elasticity theory, respectively, into the classical Euler-Bernoulli beam model. All the material properties of the bulk continuum including the microstructure material length scale parameter (MLSP) are assumed to be graded along the thickness according to a power law. For the first time, the effect of the porosity and voids on the modulus of elasticity and MLSP is taken as a ratio of the mass density with porosity-to-that without porosity. Accounting for the physical neutral axis concept and generalized elasticity theory, Hamilton's principle is utilized to formulate the equations of motion and boundary conditions for the FG porous micro/nanobeams. The analytical solution using Navier method is applied to solve the governing equations and obtain the results. The impact of different parameters such as the gradation index, porosity pattern, porosity parameter, nonlocal parameter, and MLSP on the free vibration characteristics of simply supported FG nanobeams are presented discussed in detail. The current model is efficient in many applications used porous FGM, such as aerospace, nuclear, power plane sheller, and marine structures.

Vibration analysis of double-walled carbon nanotubes based on Timoshenko beam theory and wave propagation approach

Emad Ghandourah,Muzamal Hussain,Amien Khadimallah,Abdulsalam Alhawsawi,Essam Mohammed Banoqitah,Mohamed R. Ali Techno-Press 2023 Advances in nano research Vol.14 No.6

This paper concerned with the vibration of double walled carbon nanotubes (CNTs) as continuum model based on Timoshenko-beam theory. The vibration solution obtained from Timoshenko-beam theory provides a better presentation of vibration structure of carbon nanotubes. The natural frequencies of double-walled CNTs against half axial wave mode are investigated. The frequency decreases on decreasing the half axial wave mode. The shape of frequency arcs is different for various lengths. It is observed that model has produced lowest results for C-F and highest for C-C. A large parametric study is performed to see the effect of half axial wave mode on frequencies of CNTs. This numerically vibration solution delivers a benchmark results for other techniques. The comparison of present model is exhibited with previous studies and good agreement is found.

Direct strength measurement of Timoshenko-beam model: Vibration analysis of double walled carbon nanotubes

Emad Ghandourah,Muzamal Hussain,Faisal Al Thobiani,Mohammed Hefni,Sami Alghamdi 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.84 No.1

In the last ten years, many researchers have studied the vibrations of carbon nanotubes using different beam theories. The nano- and micro-scale systems have wavy shape and there is a demand for a powerful tool to mathematically model waviness of those systems. In accordance with the above mentioned lack for the modeling of the waviness of the curved tiny structure, a novel approach is employed by implementing the Timoshenko-beam model. Owing to the small size of the micro beam, these structures are very appropriate for designing small instruments. The vibrations of double walled carbon nanotubes (DWCNTs) are developed using the Timoshenko-beam model in conjunction with the wave propagation approach under support conditions to calculate the fundamental frequencies of DWCNTs. The frequency influence is observed with different parameters. Vibrations of the double walled carbon nanotubes are investigated in order to find their vibrational modes with frequencies. The aspect ratios and half axial wave mode with small length are investigated. It is calculated that these frequencies and ratios are dependent upon the length scale and aspect ratio.

The effects of ring and fraction laws: Vibration of rotating isotropic cylindrical shell

Khadimallah, Mohamed A.,Hussain, Muzamal,Elbahar, Mohamed,Ghandourah, E.,Elimame, Elaloui,Tounsi, Abdelouahed Techno-Press 2021 Advances in nano research Vol.11 No.1

This paper deals with the specific influence of three different fraction laws for vibrational analysis of rotating cylindrical shells. The rotating cylindrical shells are stabilized by ring-stiffeners to increase the stiffness and strength. Isotopic materials are the constituents of these rings. The frequencies are investigated versus circumferential wave number, length- and height-to- radius ratios using three volume fraction laws. Moreover, the effect of rotation speed is investigated. It is examined that the backward and forward frequencies increase and decrease on increasing the ratio of height- and length-to-radius ratio. When the position of ring supports increases, the backward and forward frequency first increases and obtains its maximum value at the shell mid length position and then decreases and get a bell shape with clamped-clamped and clamped-free conditions. The assessment of present model is judged with the comparison of non-rotating and rotating results with former exploration.

Stability investigation of symmetrically porous advanced composites plates via a novel hyperbolic RPT

S. R. Mahmoud,E.I. Ghandourah,A.H. Algarni,M.A. Balubaid,Abdelouahed Tounsi,Abdeldjebbar Tounsi,Fouad Bourada 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.4

This paper presents an analytical hyperbolic theory based on the refined shear deformation theory for mechanical stability analysis of the simply supported advanced composites plates (exponentially, sigmoidal and power-law graded) under triangular, trapezoidal and uniform uniaxial and biaxial loading. The developed model ensures the boundary condition of the zero transverse stresses at the top and bottom surfaces without using the correction factor as first order shear deformation theory. The mathematical formulation of displacement contains only four unknowns in which the transverse deflection is divided to shear and bending components. The current study includes the effect of the geometric imperfection of the material. The modeling of the micro-void presence in the structure is based on the both true and apparent density formulas in which the porosity will be dense in the mid-plane and zero in the upper and lower surfaces (free surface) according to a logarithmic function. The analytical solutions of the uniaxial and biaxial critical buckling load are determined by solving the differential equilibrium equations of the system with the help of the Navier’s method. The correctness and the effectiveness of the proposed HyRPT is confirmed by comparing the results with those found in the open literature which shows the high performance of this model to predict the stability characteristics of the FG structures employed in various fields. Several parametric analyses are performed to extract the most influenced parameters on the mechanical stability of this type of advanced composites plates.

Mechanics of anisotropic cardiac muscles embedded in viscoelastic medium

Taj, Muhammad,Khadimallah, Mohamed Amine,Hussain, Muzamal,Ghandourah, E.,Safeer, Muhammad,Elbahar, Mohamed,Khan, Manzoor,Elimame, Elaloui Techno-Press 2021 Advances in concrete construction Vol.12 No.1

In the present work the author incorporated the surrounding medium with Hodgkin Huxley model to account the effect of surroundings on the flow of current in cardiac muscles fibers. The Hodgkin Huxley Kelvin like model is developed here and then the governing equations are solved by appropriate mathematical methods and the obtained results are compared with the previous experimental findings. Through obtained solutions, we check the mechanical properties in actual environment of cardiac muscles fibres and compare our findings with experimental results. Previous Hodgkin Huxley model did not give any idea about the medium, in which the cardiac muscles are immersed. The new developed model accounts the effect of medium efficiently on the current flow along with fiber's stimulation in cardiac muscles.

Design and behavior of two profiles for structural performance of composite structure: A fluid interaction

Faisal Al Thobiani,Muzamal Hussain,Mohamed Amine Khadimallah,Emad Ghandourah,Abdulsalam Alhawsawi,Adil Alshoaibi 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.43 No.2

Two-dimensional stagnation point slip flow of a Casson fluid impinging normally on a flat linearly shrinking surface is considered. The modeled PDEs are changed into nonlinear ODEs through appropriate nonlinear transformations.The flow is assumed to be steady and incompressible, with external magnetic field acting on it. Similarity transformation is utilized to investigate the behavior of many parameters for heat and velocity distributions using truncation approach.The influence of buoyancy parameter, slip parameter, shrinking parameter, Casson fluid parameter on the heat profile. The effect of the magnetic parameter on the streamwise velocity profile is also investigated.

A simplified directly determination of natural frequencies of CNT: Via aspect ratio

Banoqitah, Essam Mohammed,Hussain, Muzamal,Khadimallah, Mohamed A.,Ghandourah, Emad,Yahya, Ahmad,Basha, Muhammad,Alshoaibi, Adil Techno-Press 2022 Advances in nano research Vol.13 No.3

In this paper, a novel model is developed for frequency behavior of single walled carbon nanotubes. The governing equation of motion is constructed method based on the Sander theory using Rayleigh-Ritz's method The frequencies enhances on increasing the power law index using simply supported, clamped and clamped free end conditions. The frequency curve for C-F is less than other conditions. It is due to the physical constraints which are applied on the edge of the CNT. It is observed that the C-F boundary condition have less frequencies from the other two conditions. The frequency phenomena for zigzag are insignificant throughout the aspect ratio. Moreover when index of power law is increased then frequencies increases for all boundary conditions. The natural frequency mechanism for the armchair (10, 10) for various values of power law index with different boundary conditions is investigated. Here frequencies decrease on increases the aspect ratio for all boundary conditions. The frequency curves of SS-SS edge condition is composed between the C-C and C-F conditions. The curves of frequency are less significant from small aspect ratio (L/d = 4.86 ~ 8.47) and decreases fast for greater ratios. It is found that the frequencies via aspect ratios, armchair (10, 10) have higher values from zigzag (10, 0). It is due to the material structure which is made by the carbon nanotubes. The power law index have momentous effect on the vibration of single walled carbon nanotubes. The present frequency result is also compared numerically experimentally with Raman Spectroscopy.

A nonlocal system for the identification of active vibration response of chiral double walled CNTs

Sami Alghamdi,Muzamal Hussain,Mohamed A. Khadimallah,Sehar Asghar,Emad Ghandourah,Ahmed Obaid M. Alzahrani,M.A. Alzahrani 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

In this study, an estimation regarding nonlocal shell model based on wave propagation approach has been considered for vibrational behavior of the double walled carbon nanotubes with distinct nonlocal parameters. Vibrations of double walled carbon nanotubes for chiral indices (8, 3) have been analyzed. The significance of small scale is being perceived by developing nonlocal Love shell model. The influence of changing mechanical parameter Poisson’s ratio has been investigated in detail. The dominance of boundary conditions via nonlocal parameter is shown graphically. It is found that on increasing the Poisson’s ratio, the frequencies increases. It is noted that the frequencies of clamped-clamped frequencies are higher than that of simply-supported and clamped-free edge conditions. The outcomes of frequencies are tested with earlier computations.

Effect of suction on flow of dusty fluid along exponentially stretching cylinder

Iqbal, Waheed,Jalil, Mudassar,Qazaq, Amjad,Khadimallah, Mohamed A.,Naeem, Muhammad N.,Hussain, Muzamal,Mahmoud, S.R.,Ghandourah, E.,Tounsi, Abdelouahed Techno-Press 2021 Advances in nano research Vol.10 No.3

The present manuscript focuses the effects of suction on the flow of the dusty fluid along permeable exponentially stretching cylinder. Derived PDEs for this work are changed into ODEs by adopting right transformations. Numerical procedure is carried out for the obtained resultant equations by Shooting Technique in accordance with Runge-Kutta (RK-6) technique. Obtained results for the parameters namely, particle interaction parameter, suction parameter and Reynold number parameters are probed thoroughly. Some salient points are: (a) Fluid velocity decreases and the dust phase velocity rises for the higher values of particle interaction parameter; (b) more suction produces retarding velocities for both the phases; (c) high Reynold number slows down the fluid velocity while the speed of dust phase and (d) skin friction coefficient goes high for all these parameters.