Department of Applied Mechanics (1991 - Present)
mechanical engineering
, Amirkabir University of Technology,
mechanical engineering
, Amirkabir University of Technology,
mechanical engineering
, Amirkabir University of Technology,
PhD in Mechanical Engineering(Applied design)- AmirKabir University of Technology MSc in Mechanical Engineering(Applied design)- AmirKabir University of Technology BSc in Mechanical Engineering(Applied design)- AmirKabir University of Technology Professor in Mechanical Engineering faculty TarbiatModares University
This paper is carried out the free vibrational behavior of functionally graded polymer composite annular and circular plates reinforced with graphene nanoplatelets (GPLs) using three-dimensional elasticity theory. The weight fraction differs gradually across the thickness direction. Effective elasticity modulus of the nanocomposite has been estimated by the modified Halpin-Tsai model. Five different GPLs distribution patterns within the polymer matrix are considered. State space first order differential equation by employing the equation of motion and constitutive relation within the framework of three-dimensional elasticity theory across the thickness direction is derived. Present approach is validated by comparing the numerical results wi
This article explores the high-accuracy analysis of bending and frequency response of the sandwich cylindrical shell with functionally graded (FG) carbon nanotubes reinforced composite (FGCNTRC) face-sheets and polymeric core under the effect of initial axial stress and various mechanical loading based upon the three-dimensional theory of elasticity for various sets of boundary conditions. The sandwich structure is composed of multilayers with uniformly dispersed carbon nanotubes (CNT) in each fictitious layer of face-sheets, but its weight fraction changes layerby-layer along the thickness direction. With the aid of compatibility conditions, the sandwich structure with three layers is modeled. Analytical bending and frequency solutions are
For the first time, the structural dynamics and vibrational stability of a viscoelastic axially functionally graded (AFG) beam with both spinning and axial motions subjected to an axial load are analyzed, with the aim to enhance the performance of bi-gyroscopic systems. A detailed parametric study is also performed to emphasize the influence of various key factors such as material distribution type, viscosity coefficient, and coupled rotation and axial translation on the dynamical characteristics of the system. The material properties of the system are assumed to vary linearly or exponentially in the longitudinal direction with viscoelastic effects. Adopting the Laplace transform and a Galerkin discretization scheme, the critical axial and
Modeling of viscoelastic behavior can be useful to accurate study of micro-shell vibration. In this study, influence of viscoelastic coefficient and material length scale parameter on frequency of a cylindrical micro-shell with/without conveying fluid are investigated. Considering trapezoidal shape factor via Kirchhoff-Love’s hypotheses and modified couple stress theory (MCST), governing equations of motion are derived using Hamilton’s principle. Viscoelastic properties are modeled according to Kelvin-Voigt viscoelasticity. The novelty of the current study is the consideration of viscoelastic effect, trapezoidal shape factor and size effect based on shell theory as well as influence of conveying viscous fluid on the frequency of micro-s
A full understanding of the mechanical behaviors of a three-dimensional (3D) functionally graded carbon nanotube reinforced composite (FG-CNTRC) cylindrical panel is important for structural design of engineering composite components. In this paper, the buckling and free vibration studies of FG-CNTRC cylindrical panel with different patterns of CNT distribution are investigated using the three-dimensional theory of elasticity. The cylindrical panels are subjected to axial and circumferential initial stresses, which frequently occur in real engineer structures. The state space technique along the radial direction and the Fourier series expansion along the in-plane coordinate (are) employed to formulate the problem and solve it analytically.
In this paper, in order to improve the efficiency of the moving systems, vibrations and stability of axially functionally graded Rayleigh moving micro-beams are studied. Also, to clarify the influences of various parameters such as axially functionally graded, the length of the material characteristics, and the whirling inertia on the stability boundaries of Rayleigh and Euler-Bernoulli beams, a detailed parametric study is done. It is assumed that the material characteristics of the system change linearly or exponentially in longitudinal direction continuously. To calculate the natural frequencies, dynamics configuration, and divergence and flutter instability thresholds of the system, the strain gradient theory, Galerkin discretization me
In this research based on theory of elasticity, free vibration behavior of a viscoelastic cylindrical shell with different boundary conditions is studied. A constitutive equation for viscoelastic material is assumed to obey the Boltzmann model and Poisson's ratio is held to be constant. Moreover, the Prony series is used to model time dependent modulus of elasticity. Governing equations of motions for simply-supported edges conditions are solved analytically using the state-space technique along the radial coordinate and the Fourier series method along the axial and circumferential directions. In the case of other edges condition a semi-analytical solution is employed by using the differential quadrature method instead of Fourier series sol
Based on theory of piezoelectricity and using generalized coupled thermoelasticity, transient response of a simply supported functionally graded material rectangular plate embedded in sensor and actuator piezoelectric layers under applied electric field and thermal shock is studied. Thermoelastic properties of the plate vary continuously along the thickness direction according to exponential functions and Poisson ratio is assumed to be constant. Applying Fourier series state space technique to the basic coupled thermoelastic differential equations results in the ordinary differential equations which are solved analytically by using Laplace transform. Validation of the present approach is assessed by comparing the numerical results with the
Free vibrational and bending behavior of functionally graded graphene platelet reinforced composite (FG-GPLRC) circular and annular plate with various boundary conditions is studied using differential quadrature method (DQM). The weight fraction differs gradually across the thickness direction. Effective elasticity modulus of the nanocomposite has been estimated by the modified Halpin-Tsai model. Using equations of motion in the framework of elasticity theory and constitutive relation, state space first order differential equation along the thickness direction is derived. A semianalytical solution is carried out based on applying DQM along the radial direction and state-space technique across the thickness of the plate. Present approach is
Mechanical behavior of a viscoelastic cylindrical panel with various edge boundary conditions, made up of functionally graded material (FGM) and subjected to thermal or mechanical load is investigated. For cases of simply supported boundary conditions, analytical solution is presented through Fourier series expansion along the axial and circumferential coordinates as well as state space method along the radial coordinate. For nonsimply supported conditions, semi-analytical solution is performed using differential quadrature method instead of Fourier series solution. Governing differential equations are transformed to Laplace transform domain and using inverse Laplace transform, obtained solutions are converted to time domain. In the present
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