Variational approach for wave dispersion in anisotropic doubly-curved nanoshells based on a new nonlocal strain gradient higher order shell theory

2018 ◽  
Vol 129 ◽  
pp. 251-264 ◽  
Author(s):  
Behrouz Karami ◽  
Maziar Janghorban ◽  
Abdelouahed Tounsi
Keyword(s):  
Strain Gradient ◽  
Variational Approach ◽  
Shell Theory ◽  
Wave Dispersion ◽  
Higher Order ◽  
Doubly Curved ◽  
Nonlocal Strain Gradient

A New Hyperbolic Two-Unknown Beam Model for Bending and Buckling Analysis of a Nonlocal Strain Gradient Nanobeams

2019 ◽  
Vol 57 ◽  
pp. 175-191 ◽  
Author(s):  
Wafa Adda Bedia ◽  
Mohammed Sid Ahmed Houari ◽  
Aicha Bessaim ◽  
Abdelmoumen Anis Bousahla ◽  
Abdelouahed Tounsi ◽  
...  
Keyword(s):  
Shear Deformation ◽  
Strain Gradient ◽  
Deformation Theory ◽  
Shear Deformation Theory ◽  
Beam Theory ◽  
Higher Order ◽  
Buckling Analysis ◽  
Strain Gradient Theory ◽  
Beam Model ◽  
Nonlocal Strain Gradient

In present paper, a novel two variable shear deformation beam theories are developed and applied to investigate the combined effects of nonlocal stress and strain gradient on the bending and buckling behaviors of nanobeams by using the nonlocal strain gradient theory. The advantage of this theory relies on its two-unknown displacement field as the Euler-Bernoulli beam theory, and it is capable of accurately capturing shear deformation effects, instead of three as in the well-known first shear deformation theory and higher-order shear deformation theory. A shear correction factor is, therefore, not needed. Equations of motion are obtained via Hamilton’s principle. Analytical solutions for the bending and buckling analysis are given for simply supported beams. Efficacy of the proposed model is shown through illustrative examples for bending buckling of nanobeams. The numerical results obtained are compared with those of other higher-order shear deformation beam theory. The results obtained are found to be accurate. Verification studies show that the proposed theory is not only accurate and simple in solving the bending and buckling behaviour of nanobeams, but also comparable with the other shear deformation theories which contain more number of unknowns

Size-dependent thermally affected wave propagation analysis in nonlocal strain gradient functionally graded nanoplates via a quasi-3D plate theory

2016 ◽  
Vol 232 (1) ◽  
pp. 162-173 ◽  
Author(s):  
Farzad Ebrahimi ◽  
Mohammad Reza Barati
Keyword(s):  
Strain Gradient ◽  
Plate Theory ◽  
Micromechanical Model ◽  
Gradient Elasticity ◽  
Wave Dispersion ◽  
Functionally Graded ◽  
Thermal Environments ◽  
Size Dependent ◽  
Dispersion Behavior ◽  
Nonlocal Strain Gradient

This article examines the application of nonlocal strain gradient elasticity theory to wave dispersion behavior of a size-dependent functionally graded nanoplate in thermal environments. The theory contains two scale parameters corresponding to nonlocal and strain gradient effects. A quasi-3D plate theory considering shear and normal deformations is employed to present the formulation. Mori–Tanaka micromechanical model is used to describe functionally graded material properties. Hamilton’s principle is employed to obtain the governing equations of nanoplate accounting for thickness stretching effect. These equations are solved analytically to find wave frequencies and phase velocities of functionally graded nanoplate. It is indicated that wave dispersion behavior of functionally graded nanoplates is significantly affected by temperature rise, nonlocality, length scale parameter, and material composition.

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