Flexoelectric effects on wave propagation responses of piezoelectric nanobeams via nonlocal strain gradient higher order beam model

2019 ◽  
Vol 6 (10) ◽  
pp. 1050d5 ◽  
Author(s):  
Arian Masoumi ◽  
Ahad Amiri ◽  
Roohollah Talebitooti
Keyword(s):  
Wave Propagation ◽  
Strain Gradient ◽  
Higher Order ◽  
Beam Model ◽  
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

The Nonlocal Strain Gradient Theory for Hygrothermo-Electromagnetic Effects on Buckling, Vibration and Wave Propagation in Piezoelectromagnetic Nanoplates

2019 ◽  
Vol 11 (07) ◽  
pp. 1950067 ◽  
Author(s):  
Mohammad Alakel Abazid
Keyword(s):  
Wave Propagation ◽  
Strain Gradient ◽  
Nonlocal Parameter ◽  
Thermal Buckling ◽  
Strain Gradient Theory ◽  
Gradient Theory ◽  
Elastic Substrate ◽  
Nonlocal Strain Gradient Theory ◽  
Electromagnetic Effects ◽  
Nonlocal Strain Gradient

A nonlocal strain gradient theory (NSGT) is utilized to investigate the thermal buckling, free vibration and wave propagation in smart piezoelectromagnetic nanoplates in hygrothermal environments embedded in an elastic substrate. The main advantage of the NSGT over other continuum theories is that it contains both nonlocal parameter and material length scale parameter. The elastic substrate is modeled as Pasternak foundation model. According to the NSGT and the sinusoidal two-variable shear deformation plate theory, the governing equations of motion are derived involving the material parameters and hygrothermo-electromagnetic effects. The present solutions are checked through comparisons with those presented in the literature. Numerical results show the impacts of the nonlocal and gradient parameters, side-to-thickness ratio, hygrothermo-electromagnetic loads and substrate stiffness on the thermal buckling, frequencies and wave propagation in the smart nanoplates.

scholarly journals Study on the small-scale effect on wave propagation characteristics of fluid-filled carbon nanotubes based on nonlocal fluid theory

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882332
Author(s):  
Yang Yang ◽  
Wuhuai Yan ◽  
Jinrui Wang
Keyword(s):  
Wave Propagation ◽  
Fluid Flow ◽  
Carbon Nanotube ◽  
Scale Effect ◽  
Strain Gradient ◽  
Small Scale ◽  
Beam Model ◽  
Governing Equations ◽  
Mode Wave ◽  
Fluid Theory

In this article, Timoshenko’s beam model is established to investigate the wave propagation behaviors for a fluid-conveying carbon nanotube when employing the nonlocal stress–strain gradient coupled theory and nonlocal fluid theory. The governing equations of motion for the carbon nanotube are derived. The small-scale influences induced by the nanotube are simulated by nonlocal and strain gradient effects, and the scale effect induced by fluid flow is first investigated applying nonlocal fluid theory. Numerical results obtained by solving the governing equations indicate that the nonlocal effect induced by the nanotube leads to wave damping and a decrease in stiffness, while the strain gradient effect contributes to wave promotion and an enhancement in stiffness. The scale effect caused by the inner fluid only leads to a decay for a high-mode wave since there is no influence from fluid flow on the low-mode wave. The numerical solution is validated by comparing with Monte Carlo simulation and interval analysis method.

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