scholarly journals Nonlocal vibration and buckling of two-dimensional layered quasicrystal nanoplates embedded in an elastic medium

2021 ◽  
Author(s):  
Tuoya Sun ◽  
Junhong Guo ◽  
E. Pan
Keyword(s):  
Elastic Medium ◽  
Vibration Frequency ◽  
Surrounding Medium ◽  
Nonlocal Parameter ◽  
Buckling Load ◽  
Width Ratio ◽  
Two Dimensional ◽  
Coating Materials ◽  
Decagonal Quasicrystal ◽  
Critical Buckling Load

AbstractA mathematical model for nonlocal vibration and buckling of embedded two-dimensional (2D) decagonal quasicrystal (QC) layered nanoplates is proposed. The Pasternak-type foundation is used to simulate the interaction between the nanoplates and the elastic medium. The exact solutions of the nonlocal vibration frequency and buckling critical load of the 2D decagonal QC layered nanoplates are obtained by solving the eigensystem and using the propagator matrix method. The present three-dimensional (3D) exact solution can predict correctly the nature frequencies and critical loads of the nanoplates as compared with previous thin-plate and medium-thick-plate theories. Numerical examples are provided to display the effects of the quasiperiodic direction, length-to-width ratio, thickness of the nanoplates, nonlocal parameter, stacking sequence, and medium elasticity on the vibration frequency and critical buckling load of the 2D decagonal QC nanoplates. The results show that the effects of the quasiperiodic direction on the vibration frequency and critical buckling load depend on the length-to-width ratio of the nanoplates. The thickness of the nanoplate and the elasticity of the surrounding medium can be adjusted for optimal frequency and critical buckling load of the nanoplate. This feature is useful since the frequency and critical buckling load of the 2D decagonal QCs as coating materials of plate structures can now be tuned as one desire.

Critical Buckling Load of Chiral Double-Walled Carbon Nanotubes Embedded in an Elastic Medium

2018 ◽  
Vol 53 (6) ◽  
pp. 827-836 ◽  
Author(s):  
A. Chemi ◽  
M. Zidour ◽  
H. Heireche ◽  
K. Rakrak ◽  
A. A. Bousahla
Keyword(s):  
Carbon Nanotubes ◽  
Elastic Medium ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Nonlinear vibration and instability of embedded double-walled carbon nanocones based on nonlocal Timoshenko beam theory

2013 ◽  
Vol 228 (4) ◽  
pp. 690-702 ◽  
Author(s):  
Ali Ghorbanpour Arani ◽  
Reza Kolahchi
Keyword(s):  
Nonlinear Vibration ◽  
Elastic Medium ◽  
Timoshenko Beam ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Buckling Load ◽  
Nonlinear Frequency ◽  
Critical Buckling Load ◽  
Motion Equations ◽  
Carbon Nanocones

Nonlinear vibration and instability of embedded double-walled carbon nanocones subjected to axial load are investigated in this article based on Eringen's nonlocal theory and Timoshenko beam model. The elastic medium is simulated as Pasternak foundation and the van der Waals forces between the inner and the outer layers of double-walled carbon nanocones are taken into account. Using von Kármán geometric nonlinearity, energy method and Hamilton’s principle, the nonlocal nonlinear motion equations are obtained. The differential quadrature method is applied to discretize the motion equations, which are then solved to obtain the nonlinear frequency and critical fluid velocity of viscous-fluid-conveying double-walled carbon nanocones. A detailed parametric study is conducted, focusing on the combined effects of the nonlocal parameter, thickness-to-length ratio, temperature change, apex angles, elastic medium and van der Waals forces on the dimensionless frequency and critical buckling load of double-walled carbon nanocones. The results show that the small-size effect on the nonlinear frequency is significant and cannot be neglected; also, the nonlinear frequency and critical buckling load decrease with increasing the cone apex-angle.

Nonlocal Thermal and Mechanical Buckling of Nonlinear Orthotropic Viscoelastic Nanoplates Embedded in a Visco-Pasternak Medium

2018 ◽  
Vol 10 (08) ◽  
pp. 1850086 ◽  
Author(s):  
Mohammed Sobhy ◽  
Ashraf M. Zenkour
Keyword(s):  
Boundary Conditions ◽  
Elastic Medium ◽  
Constitutive Relations ◽  
Nonlocal Parameter ◽  
Viscoelastic Model ◽  
Buckling Load ◽  
Damping Coefficient ◽  
Structural Damping ◽  
Variable Theory ◽  
Mechanical Buckling

This paper discusses the thermal and mechanical buckling of simply supported and clamped orthotropic viscoelastic graphene sheets (nanoplates) embedded in a visco-Pasternak elastic medium. For this purpose, the nonlocal continuum mechanical model is employed with two-variable plate theory. The material of the present nanoplate is assumed to be orthotropic and viscoelastic. The modified nonlinear Kelvin–Voigt viscoelastic model is utilized to formulate the constitutive relations depending on the viscoelastic structural damping coefficient. Moreover, the visco-Pasternak elastic medium is composed of both viscoelastic and shear layers. The viscoelastic layer includes a set of dashpots and elastic springs connected in parallel. In accordance with the two-variable theory, two governing equations are derived via Hamilton’s principle. These equations are analytically solved for various boundary conditions to obtain the explicit solution for critical buckling temperature and buckling load. The present buckling load and buckling temperature both are compared well with the published ones in the literature. In addition, various numerical studies are thoroughly carried out, concentrating on the influences of the plate geometric, nonlocal parameter, structural damping coefficient, elastic foundation parameters, foundation damping parameter and boundary conditions on the critical buckling load and temperature of the nanoplates. The results show that the involvement of the viscidity of the nanoplate and viscoelastic foundation enhances the strength of the nanoplates and therefore increases the resistance of them to external loads.

scholarly journals A semi-analytical model on the critical buckling load of perforated plates with opposite free edges

2022 ◽  
pp. 095440622110568
Author(s):  
Weigang Fu ◽  
Bin Wang
Keyword(s):  
Analytical Model ◽  
Perforated Plate ◽  
Beam Theory ◽  
Buckling Load ◽  
Width Ratio ◽  
Geometrical Parameters ◽  
Engineering Structures ◽  
Perforated Plates ◽  
Critical Buckling Load ◽  
Free Edges

Perforated plates are widely used in thin-walled engineering structures, for example, for lightweight designs of structures and access for installation. For the purpose of analysis, such perforated plates with two opposite free edges might be considered as a series of successive Timoshenko beams. A new semi-analytical model was developed in this study using the Timoshenko shear beam theory for the critical buckling load of perforated plates, with the characteristic equations derived. Results of the proposed modelling were compared with those obtained by FEM and show good agreement. The influence of the dividing number of the successive beams on the accuracy of the critical buckling load was studied with respect to various boundary conditions. And the effect of geometrical parameters, such as the aspect ratio, the thickness-to-width ratio and the cutout-to-width ratio were also investigated. The study shows that the proposed semi-analytical model can be used for buckling analysis of a perforated plate with opposite free edges with the capacity to consider the shear effect in thick plates.

scholarly journals The definition of the critical buckling load beam model and two-dimensional model of the round cylindrical shell that interact with the soil

2019 ◽  
Vol 15 (4) ◽  
pp. 291-298
Author(s):  
Sergey B. Kosytsyn ◽  
Vladimir Yu. Akulich
Keyword(s):  
Cylindrical Shell ◽  
Buckling Load ◽  
Beam Model ◽  
Equilibrium Stability ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Buckling Mode ◽  
Critical Buckling Load ◽  
Two Dimensional Model ◽  
Actual Load

Aims of research. The research is aimed at determining the critical buckling load at which the shell interacting with the soil loses equilibrium stability, and finding the buckling mode of the shell in the linear and nonlinear formulations of the task. Methods. The task is solved by a numerical method using a finite element complex, which allows investigating the stress-strain state and assessing the equilibrium stability of beam models and two-dimensional models of the round cylindrical shell. Three design cases of the beam model and two design cases of the two-dimensional model interacting with the soil are compiled. There is a load summary acting on the shell. The calculations are carried out in linear and geometrically nonlinear formulations using a linear elastic model of the material. Contact elements of one-side and two-side action are used. Critical buckling load are determined relative to the actual load of its own weight. Results. Critical buckling load are determined and the buckling mode of the round cylindrical shell interacting with the soil are found. There is a comparative analysis of the results. An assessment of the stability margin of the shell relative to the actual load is given.

scholarly journals Investigating Surface Effects on Thermomechanical Behavior of Embedded Circular Curved Nanosize Beams

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Farzad Ebrahimi ◽  
Mohsen Daman
Keyword(s):  
Natural Frequency ◽  
Surface Properties ◽  
Nonlocal Parameter ◽  
Surface Elasticity ◽  
Surface Effects ◽  
Buckling Load ◽  
Opening Angle ◽  
Governing Equations ◽  
Critical Buckling Load ◽  
Elastic Foundations

To investigate the surface effects on thermomechanical vibration and buckling of embedded circular curved nanosize beams, nonlocal elasticity model is used in combination with surface properties including surface elasticity, surface tension, and surface density for modeling the nanoscale effect. The governing equations are determined via the energy method. Analytically Navier method is utilized to solve the governing equations for simply supported nanobeam at both ends. Solving these equations enables us to estimate the natural frequency and critical buckling load for circular curved nanobeam including Winkler and Pasternak elastic foundations and under the effect of a uniform temperature change. The results determined are verified by comparing the results with available ones in literature. The effects of various parameters such as nonlocal parameter, surface properties, Winkler and Pasternak elastic foundations, temperature, and opening angle of circular curved nanobeam on the natural frequency and critical buckling load are successfully studied. The results reveal that the natural frequency and critical buckling load of circular curved nanobeam are significantly influenced by these effects.

Flexural-Torsional Buckling of Pultruded Fiber-Reinforced Polymer Angle Beams under Eccentric Loading

2020 ◽  
Vol 982 ◽  
pp. 201-206
Author(s):  
Jaksada Thumrongvut ◽  
Natthawat Pakwan ◽  
Samaporn Krathumklang
Keyword(s):  
Buckling Load ◽  
Fiber Reinforced Polymer ◽  
Width Ratio ◽  
Fiber Reinforced ◽  
Torsional Buckling ◽  
Eccentric Load ◽  
Buckling Loads ◽  
Reinforced Polymer ◽  
Cross Sectional Dimension ◽  
Flexural Torsional Buckling

In this paper, the experimental study on the pultruded fiber-reinforced polymer (pultruded FRP) angle beams subjected to transversely eccentric load are presented. A summary of critical buckling load and buckling behavior for full-scale flexure tests with various span-to-width ratios (L/b) and eccentricities are investigated, and typical failure mode are identified. Three-point flexure tests of 50 pultruded FRP angle beams are performed. The E-glass fibre/polyester resin angle specimens are tested to examine the effect of span-to-width ratio of the beams on the buckling responses and critical buckling loads. The angle specimens have the cross-sectional dimension of 76x6.4 mm with span-to-width ratios, ranging from 20 to 40. Also, four different eccentricities are investigated, ranging from 0 to ±2e. Eccentric loads are applied below the horizontal flange in increments until beam buckling occurred. Based upon the results of this study, it is found that the load and mid-span vertical deflection relationships of the angle beams are linear up to the failure. In contrast, the load and mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at critical buckling loads lower than their concentric counterparts. Also, the quantity of eccentricity increases as buckling load decreases. In addition, it is noticed that span-to-width ratio increases, the buckling load is decreased. The eccentric location proved to have considerable influence over the buckling load of the pultruded FRP angle beams.

Designing pinhole vacancies in graphene towards functionalization: Effects on critical buckling load

2017 ◽  
Vol 103 ◽  
pp. 343-357 ◽  
Author(s):  
S.K. Georgantzinos ◽  
S. Markolefas ◽  
G.I. Giannopoulos ◽  
D.E. Katsareas ◽  
N.K. Anifantis
Keyword(s):  
Buckling Load ◽  
Critical Buckling Load

Meshing Method of High Precision FEM in Large Complex Structural Simulations

2012 ◽  
Vol 195-196 ◽  
pp. 701-704
Author(s):  
Yan Hua Xue ◽  
Zhi Guang Wang ◽  
Xiao Hong Li ◽  
Xin Jiang
Keyword(s):  
Finite Element ◽  
Complex Structure ◽  
Width Ratio ◽  
Two Dimensional ◽  
Element Analysis ◽  
Large Complex ◽  
Mesh Density ◽  
Length Width ◽  
Complex Structural ◽  
Dimensional Element

Shing is playing an important role in the large complex structural FEM simulations; it has a direct effect on calculating precision of structural simulations. For increasing the calculation accuracy and analysis accuracy of complex structure, the finite element meshing problems is proposed on the finite element analysis of large complicated structures. The effects caused by element type, mesh density and intergradations on calculating precision are studied and discussed. A research argues that with length-width ratio of 1~2 and length-thickness ration of 1.5~4.5 of two-dimensional rectangular element, the quality of meshing method of two-dimensional element is above normal. As the height of one-dimensional element is equal to the sum of reinforcing rib height of outer panel and half the thickness of panel, more accurate results can be obtained.

Sign in / Sign up

Export Citation Format

Share Document