Forced vibration of porous functionally graded nanoplates under uniform dynamic load using general nonlocal stress–strain gradient theory

2017 ◽  
Vol 24 (20) ◽  
pp. 4700-4715 ◽  
Author(s):  
Mohammad Reza Barati ◽  
Hossein Shahverdi

Forced vibration analysis of porous functionally graded nanoplates under uniform dynamic loads is performed based on generalized nonlocal strain gradient theory. In this model, both stiffness-softening and stiffness-hardening effects are considered for more reliable forced vibration analysis of nanoplates. The present model is based on a vibrating higher order nanoscale plate subjected to transverse uniform dynamic load. Nanopores or nanovoids are incorporated to the model based on a modified rule of mixture. According to t Hamilton’s principle, the formulation of dynamically loaded nanoplate is derived. Applying Galerkin’s method, the resonance frequencies and dynamic deflections are obtained. It is indicated that the forced vibration characteristics of the nanoplate are significantly influenced by the porosities, excitation frequency, nonlocal parameter, strain gradient parameter, material gradation, elastic foundation and dynamic load location.

2020 ◽  
Vol 31 (12) ◽  
pp. 1511-1523
Author(s):  
Mohammad Mahinzare ◽  
Hossein Akhavan ◽  
Majid Ghadiri

In this article, a first-order shear deformable model is expanded based on the nonlocal strain gradient theory to vibration analysis of smart nanostructures under different boundary conditions. The governing equations of motion of rotating magneto-viscoelastic functionally graded cylindrical nanoshell in the magnetic field and corresponding boundary conditions are obtained using Hamilton’s principle. To discretize the equations of motion, the generalized differential quadrature method is applied. The aim of this work is to investigate the effects of the temperature changes, nonlocal parameter, material length scale, viscoelastic coefficient, various boundary conditions, and the rotational speed of this smart structure on natural frequencies of rotating cylindrical nanoshell made of magneto-viscoelastic functionally graded material.


2019 ◽  
Vol 40 (12) ◽  
pp. 1723-1740 ◽  
Author(s):  
Z. Sharifi ◽  
R. Khordad ◽  
A. Gharaati ◽  
G. Forozani

AbstractIn this paper, we analytically study vibration of functionally graded piezoelectric (FGP) nanoplates based on the nonlocal strain gradient theory. The top and bottom surfaces of the nanoplate are made of PZT-5H and PZT-4, respectively. We employ Hamilton’s principle and derive the governing differential equations. Then, we use Navier’s solution to obtain the natural frequencies of the FGP nanoplate. In the first step, we compare our results with the obtained results for the piezoelectric nanoplates in the previous studies. In the second step, we neglect the piezoelectric effect and compare our results with those obtained for the functionally graded (FG) nanoplates. Finally, the effects of the FG power index, the nonlocal parameter, the aspect ratio, and the side-tothickness ratio, and the nanoplate shape on natural frequencies are investigated.


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