Buckling of Multilayer Graphene Sheets Subjected to Axial Compression Based on a Continuum Mechanics Model

2018 ◽  
Vol 85 (6) ◽  
Author(s):  
Moonhong Kim ◽  
Seyoung Im
Keyword(s):  
Axial Length ◽  
Md Simulations ◽  
Buckling Load ◽  
Single Layer Graphene ◽  
Graphene Sheets ◽  
Multilayer Graphene ◽  
Beam Model ◽  
Shear Rigidity ◽  
Buckling Loads ◽  
Number Of Layers

Buckling of multilayer graphene sheets (MLGSs) subjected to an axial compressive load in plane-strain condition is studied. Closed-form solutions for buckling load of MLGSs are obtained based on a continuum model for MLGSs. Two different kinematic assumptions, which lead to MLGS beam, which was recently proposed by the authors, and the Euler beam, are used to obtain the buckling loads. The obtained solutions yield significantly different buckling loads when the axial length is small. To validate obtained results, molecular dynamics (MD) simulations are conducted, and they show that the MLGS beam model well captures the buckling load of MLGSs. The buckling solution of MLGS beam model provides two interesting facts. First, the buckling load of MLGSs coincides with the Euler buckling load when the length is large. Second, when the number of layers is large, the buckling strain converges to a finite value, and could be expressed as a linear combination of the buckling strain of single-layer graphene and the ratio between the shear rigidity of interlayer and the tensile rigidity of graphene layer. We validate the asymptotic behavior of buckling strain through MD simulations and show that buckling occurs even when the overall thickness is larger than the axial length. Finally, we present a diagram that contains buckling strain of MLGSs according to the boundary conditions, the number of layers, and the axial length.

Critical Buckling Load of Triple-Walled Carbon Nanotube Based on Nonlocal Elasticity Theory

2020 ◽  
Vol 62 ◽  
pp. 108-119
Author(s):  
Tayeb Bensattalah ◽  
Ahmed Hamidi ◽  
Khaled Bouakkaz ◽  
Mohamed Zidour ◽  
Tahar Hassaine Daouadji
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Axial Compression ◽  
Buckling Load ◽  
Small Scale ◽  
Beam Model ◽  
Buckling Loads ◽  
Critical Buckling Load ◽  
Nonlocal Continuum Theory ◽  
Walled Carbon Nanotubes

The present paper investigates the nonlocal buckling of Zigzag Triple-walled carbon nanotubes (TWCNTs) under axial compression with both chirality and small scale effects. Based on the nonlocal continuum theory and the Timoshenko beam model, the governing equations are derived and the critical buckling loads under axial compression are obtained. The TWCNTs are considered as three nanotube shells coupled through the van der Waals interaction between them. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, a significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed, and these are then compared with: A single-walled carbon nanotubes (SWCNTs); and Double-walled carbon nanotubes (DWCNTs). These findings are important in mechanical design considerations and reinforcement of devices that use carbon nanotubes.

Graphene Production With Stirred Media Mills

2010 ◽  
Vol 1259 ◽  
Author(s):  
Catharina Knieke ◽  
Angela Berger ◽  
Wolfgang Peukert
Keyword(s):  
Large Scale ◽  
Chemical Properties ◽  
Single Layer ◽  
Single Layer Graphene ◽  
High Yield ◽  
Graphene Sheets ◽  
Multilayer Graphene ◽  
Scale Production ◽  
Graphite Particles ◽  
Media Milling

AbstractSince the discovery of stable graphene sheets by Novoselov und Geim in 2004 the one atom thick carbon material has been attracted great interest because of its outstanding physical, mechanical and chemical properties. Although there had been intensive research to find new ways in the preparation of single-layer graphene sheets in the last few years, especially the large-scale production of graphene still remains challenging. In this paper we present a new approach, which allows the high-yield production of graphene sheets in a simple stirred media milling process. Under mild milling conditions single- and multilayer graphene sheets have been successfully produced from commercial graphite powder in a liquid medium. During the delamination procedure, the graphite particles were stressed between the milling beads. Shear and compressive normal forces can lead under mild milling conditions, i.e. low stress energies, to a continuous mechanical peeling of graphene sheets from the graphite surface. By means of Atomic Force Microscopy a high yield of single- and multilayer graphene sheets was detected. A concentration of exfoliated sheets of 2 wt% starting from a 5 wt% suspension of coarse graphite particles could be determined after a milling time of only 3 h. This concentration is much higher than those, which were reached by most of the known chemical methods. Since stirred media milling can be realized as large-scale process, a high-yield and low-cost production of graphene flakes becomes possible at ambient temperature.

scholarly journals An ordinary state-based peridynamic model for the fracture of zigzag graphene sheets

2018 ◽  
Vol 474 (2217) ◽  
pp. 20180019 ◽  
Author(s):  
Xuefeng Liu ◽  
Xiaoqiao He ◽  
Jinbao Wang ◽  
Ligang Sun ◽  
Erkan Oterkus
Keyword(s):  
Crack Propagation ◽  
Single Layer ◽  
Coarse Graining ◽  
Md Simulations ◽  
Single Layer Graphene ◽  
Graphene Sheets ◽  
Nanoscale Systems ◽  
Fracture Failure ◽  
Peridynamic Model ◽  
Average Crack

This study develops an ordinary state-based peridynamic coarse-graining (OSPD-CG) model for the investigation of fracture in single-layer graphene sheets (SLGS), in which the peridynamic (PD) parameters are derived through combining the PD model and molecular dynamics (MD) simulations from the fully atomistic system via energy conservation. The fracture failure of pre-cracked SLGS under uniaxial tension is studied using the proposed PD model. And the PD simulation results agree well with those from MD simulations, including the stress–strain relations, the crack propagation patterns and the average crack propagation velocities. The interaction effect between cracks located at the centre and the edge on the crack propagation of the pre-cracked SLGS is discussed in detail. This work shows that the proposed PD model is much more efficient than the MD simulations and, thus, indicates that the PD-based method is applicable to study larger nanoscale systems.

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.

scholarly journals CFRP Origami Metamaterial with Tunable Buckling Loads: A Numerical Study

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 917
Author(s):  
Houyao Zhu ◽  
Shouyan Chen ◽  
Teng Shen ◽  
Ruikun Wang ◽  
Jie Liu
Keyword(s):  
Numerical Study ◽  
Buckling Load ◽  
Fe Modelling ◽  
Buckling Loads ◽  
Folding Angle ◽  
Mechanical Responses ◽  
Reinforced Plastic ◽  
Rate Of Increase ◽  
Practical Engineering ◽  
Identical Rate

Origami has played an increasingly central role in designing a broad range of novel structures due to its simple concept and its lightweight and extraordinary mechanical properties. Nonetheless, most of the research focuses on mechanical responses by using homogeneous materials and limited studies involving buckling loads. In this study, we have designed a carbon fiber reinforced plastic (CFRP) origami metamaterial based on the classical Miura sheet and composite material. The finite element (FE) modelling process’s accuracy is first proved by utilizing a CFRP plate that has an analytical solution of the buckling load. Based on the validated FE modelling process, we then thoroughly study the buckling resistance ability of the proposed CFRP origami metamaterial numerically by varying the folding angle, layer order, and material properties, finding that the buckling loads can be tuned to as large as approximately 2.5 times for mode 5 by altering the folding angle from 10° to 130°. With the identical rate of increase, the shear modulus has a more significant influence on the buckling load than Young’s modulus. Outcomes reported reveal that tunable buckling loads can be achieved in two ways, i.e., origami technique and the CFRP material with fruitful design freedoms. This study provides an easy way of merely adjusting and controlling the buckling load of lightweight structures for practical engineering.

Meso-origami: Folding multilayer graphene sheets

2009 ◽  
Vol 95 (12) ◽  
pp. 123121 ◽  
Author(s):  
Steven Cranford ◽  
Dipanjan Sen ◽  
Markus J. Buehler
Keyword(s):  
Graphene Sheets ◽  
Multilayer Graphene

Pemodelan Numerik Perilaku Lentur Dan Defleksi Elemen Balok Ferrogeopolymer

2021 ◽  
Vol 1 (1) ◽  
pp. 1-12
Author(s):  
Bill J. Ebenheazar ◽  
Remigildus Cornelis ◽  
Partogi H. Simatupang
Keyword(s):  
Material Properties ◽  
Cement Mortar ◽  
Small Diameter ◽  
Wire Mesh ◽  
Beam Model ◽  
Thin Wall ◽  
Numerical Result ◽  
Number Of Layers ◽  
Geopolymer Cement ◽  
Experimental Values

Ferro-gepolymer is a type of thin-wall reinforced element constructed of geopolymer cement mortar reinforced with closely spaced relatively small diameter mesh in layers. In this investigation, the flexural and the deflection behavior of the ferro-geopolymer beams were determined numerically and the results compared to the experimental values. All the experimental material properties adopted for numerical modeling. The numerical model of all the five beams was 600 mm effective span, 100 mm width, and 100 mm height. Each specimen of the beam model having different layers of wire mesh that are 3, 5, 7, 9, and 11. The results showed that the greater the number of layers, the variation between numerical and experimental results follows the same path without much difference. The numerical result showed that the greater the number of layers, the strength was increases but insignificant.

Molecular Dynamics Simulation of the Buckling Behavior of Boron Nitride Nanotubes under Uniaxial Compressive Loading

2010 ◽  
Vol 297-301 ◽  
pp. 984-989 ◽  
Author(s):  
S. Ebrahimi-Nejad ◽  
Ali Shokuhfar ◽  
A. Zare-Shahabadi
Keyword(s):  
Boron Nitride ◽  
Compressive Loading ◽  
Pair Potential ◽  
Md Simulations ◽  
Boron Nitride Nanotubes ◽  
Dynamics Simulation ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Bond Stretching ◽  
Different Diameters

Boron Nitride nanotubes (BNNTs) together with carbon nanotubes (CNTs) have attracted the wide attention of the scientific community and have been considered as promising materials due to their unique structural and physical properties. In this paper, the behavior of BNNTs of different diameters under compressive loading has been studied through molecular dynamic (MD) simulations. We have used a Lennard-Jones pair potential to characterize the interactions between non-bonded atoms and harmonic potentials for bond stretching and bond angle vibrations. Results of the MD simulations determine the critical buckling loads of the BNNTs of various diameters under uniaxial compression, and indicate that for the simulated BNNTs of length L = 6 nm, the critical buckling loads increase by increasing the nanotube diameters.

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