EQUIVALENT CONTINUUM MODELING OF GRAPHENE SHEETS

2005 ◽  
Vol 04 (04) ◽  
pp. 631-636 ◽  
Author(s):  
C. D. REDDY ◽  
S. RAJENDRAN ◽  
K. M. LIEW
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Graphene Sheet ◽  
Young's Modulus ◽  
Graphene Sheets ◽  
Continuum Modelling ◽  
Ring Cell ◽  
Equivalent Continuum

Carbon nanotubes have drawn tremendous interest due to their excellent mechanical and electronic properties. Carbon nanotubes have a similar molecular structure as that of graphene sheets. Hence, characterization of mechanical properties of graphene sheet based on equivalent continuum modelling is of considerable importance. Our initial studies are carried out on a single carbon ring/cell. The ring is then modelled as a truss (finite) element assemblage and equivalent Young's modulus is computed for a few fundamental modes. Next, these studies have been extended to model graphene sheet as a planar continuum to determine the mechanical properties (Young's modulus, shear modulus and Poisson's ratio) for typical modes of deformation. Further research is in progress to investigate how this set of different values can be integrated together towards a meaningful continuum characterization of the inherent discrete structure.

scholarly journals Effects of CNT Addition on Mechanical Properties, Electric Conductivity and Oxidation Resistance of Al2O3-TiC Composite

2013 ◽  
Vol 761 ◽  
pp. 83-86
Author(s):  
Hideaki Sano ◽  
Junichi Morisaki ◽  
Guo Bin Zheng ◽  
Yasuo Uchiyama
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Electric Conductivity ◽  
Young’S Modulus ◽  
Oxidation Resistance ◽  
Young's Modulus ◽  
Tic Particle

Effects of carbon nanotubes (CNT) addition on mechanical properties, electric conductivity and oxidation resistance of CNT/Al2O3-TiC composite were investigated. It was found that flexural strength, Young’s modulus and fracture toughness of the composites were improved by addition of more than 2 vol%-CNT. In the composites with more than 3 vol%-CNT, the oxidation resistance of the composite was degraded. In comparison with Al2O3-26vol%TiC sample as TiC particle-percolated sample, the Al2O3-12vol%TiC-3vol%CNT sample, which is not TiC particle-percolated sample, shows almost the same mechanical properties and electric conductivity, and also shows thinner oxidized region after oxidation at 1200°C due to less TiC in the composite.

scholarly journals Effective reinforcements for thermoplastics based on carbon nanotubes of oil fly ash

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Numan Salah ◽  
Abdulrahman Muhammad Alfawzan ◽  
Abdu Saeed ◽  
Ahmed Alshahrie ◽  
Waleed Allafi
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Fly Ash ◽  
Young’S Modulus ◽  
Raw Materials ◽  
Young's Modulus ◽  
Weight Fraction ◽  
Low Weight ◽  
Oil Fly Ash

AbstractCarbon nanotubes (CNTs) are widely investigated for preparing polymer nanocomposites, owing to their unique mechanical properties. However, dispersing CNTs uniformly in a polymer matrix and controlling their entanglement/agglomeration are still big technical challenges to be overcome. The costs of their raw materials and production are also still high. In this work, we propose the use of CNTs grown on oil fly ash to solve these issues. The CNTs of oil fly ash were evaluated as reinforcing materials for some common thermoplastics. High-density polyethylene (HDPE) was mainly reinforced with various weight fractions of CNTs. Xylene was used as a solvent to dissolve HDPE and to uniformly disperse the CNTs. Significantly enhanced mechanical properties of HDPE reinforced at a low weight fraction of these CNTs (1–2 wt.%), mainly the tensile strength, Young’s modulus, stiffness, and hardness, were observed. The tensile strength and Young’s modulus were enhanced by ~20 and 38%, respectively. Moreover, the nanoindentation results were found to be in support to these findings. Polycarbonate, polypropylene, and polystyrene were also preliminarily evaluated after reinforcement with 1 wt.% CNTs. The tensile strength and Young’s Modulus were increased after reinforcement with CNTs. These results demonstrate that the CNTs of the solid waste, oil fly ash, might serve as an appropriate reinforcing material for different thermoplastics polymers.

scholarly journals Modeling the Mechanical Properties of Functionalized Carbon Nanotubes and Their Composites: Design at the Atomic Level

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qing-Sheng Yang ◽  
Bing-Qi Li ◽  
Xiao-Qiao He ◽  
Yiu-Wing Mai
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Atomic Level ◽  
Functionalized Carbon Nanotubes ◽  
Buckling Stress ◽  
Compressive Buckling

This investigation focuses on the design of functionalization configuration at the atomic level to determine the influence of atomic structure on the mechanical properties of functionalized carbon nanotubes (F-CNTs) and their composites. Tension and compressive buckling behaviors of different configurations of CNTs functionalized by H atoms are studied by a molecular dynamics (MD) method. It is shown that H-atom functionalization reduces Young’s modulus of CNTs, but Young’s modulus is not sensitive to the functionalization configuration. The configuration does, however, affect the tensile strength and critical buckling stress of CNTs. Further, the stress-strain relations of composites reinforced by nonfunctionalized and various functionalized CNTs are analyzed.

Influence of Injection Molding Parameters on Mechanical Properties of Low Density Polyethylene Filled With Multiwalled Carbon Nanotubes

2011 ◽  
Author(s):  
Catalin Fetecau ◽  
Felicia Stan ◽  
Daniel Dobrea ◽  
Dan Catalin Birsan
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Injection Molding ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Flow Direction ◽  
Mold Temperature ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Melt Temperature

In this paper, we investigated the effect of injection molding parameters such as melt temperature, mold temperature, injection speed and holding pressure on the mechanical properties of low density polyethylene reinforced with 2.5 wt% multi-walled carbon nanotubes. The Taguchi methodology with four factors and two levels was used for the design of the injection molding experiments. The mechanical properties were evaluated by tensile tests in the flow direction at room temperature (23 °C) at crosshead speeds of 1 and 5 mm/min. It was found that the mechanical properties can be modified by manipulating the injection molding parameters. The Young’s modulus of the LDPE-MWNTs composite decreased as the melt temperature increased, while mold temperature, injection molding speed and holding pressure have a moderate influence on the Young’s modulus.

Mechanical properties of zigzag-shaped carbon nanotubes: the roles of the geometric parameters

RSC Advances ◽  
2016 ◽  
Vol 6 (33) ◽  
pp. 27999-28004
Author(s):  
Lizhao Liu
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Geometric Parameters ◽  
Intrinsic Strength

Empirical formulae were fitted to describe relationships between the intrinsic strength/Young's modulus and curvature of the Z-CNTs.

Evaluation of Effective Elastic Mechanical Properties of Graphene Sheets

2012 ◽  
Author(s):  
Khalid I. Alzebdeh
Keyword(s):  
Boundary Conditions ◽  
Young’S Modulus ◽  
Graphene Sheet ◽  
Poisson’S Ratio ◽  
Elastic Moduli ◽  
Young's Modulus ◽  
Unit Cell ◽  
Poisson's Ratio ◽  
Graphene Sheets ◽  
Numerical Predictions

The mechanical behaviour of a single-layer nanostructured graphene sheet is investigated using an atomistic-based continuum model. This is achieved by equating the stored energy in a representative unit cell for a graphene sheet at atomistic scale to the strain energy of an equivalent continuum medium under prescribed boundary conditions. Proper displacement-controlled (essential) boundary conditions which generate a uniform strain field in the unit cell model are applied to calculate one elastic modulus at a time. Three atomistic finite element models are adopted with an assumption that force interactions among carbon atoms can be modeled by either spring-like or beam elements. Thus, elastic moduli for graphene structure are determined based on the proposed modeling approach. Then, effective Young’s modulus and Poisson’s ratio are extracted from the set of calculated elastic moduli. Results of Young’s modulus obtained by employing the different atomistic models show a good agreement with the published theoretical and numerical predictions. However, Poisson’s ratio exhibits sensitivity to the considered atomistic model. This observation is supported by a significant variation in estimates as can be found in the literature. Furthermore, isotropic behaviour of in-plane graphene sheets was validated based on current modeling.

scholarly journals The improvement of mechanical properties of conventional concretes using carbon nanoparticles using molecular dynamics simulation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liang Zhao ◽  
Mahyuddin K. M. Nasution ◽  
Maboud Hekmatifar ◽  
Roozbeh Sabetvand ◽  
Pavel Kamenskov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Mechanical Behavior ◽  
Young’S Modulus ◽  
Carbon Nanoparticles ◽  
Young's Modulus ◽  
Dynamics Simulation ◽  
Matrix Structure ◽  
Concrete Matrix

AbstractIn the present study, the improvement of mechanical properties of conventional concretes using carbon nanoparticles is investigated. More precisely, carbon nanotubes are added to a pristine concrete matrix, and the mechanical properties of the resulting structure are investigated using the molecular dynamics (MD) method. Some parameters such as the mechanical behavior of the concrete matrix structure, the validation of the computational method, and the mechanical behavior of the concrete matrix structure with carbon nanotube are also examined. Also, physical quantities such as a stress–strain diagram, Poisson's coefficient, Young's modulus, and final strength are calculated and reported for atomic samples under external tension. From a numerical point of view, the quantities of Young's modulus and final strength are converged to 35 GPa and 35.38 MPa after the completion of computer simulations. This indicates the appropriate effect of carbon nanotubes in improving the mechanical behavior of concrete and the efficiency of molecular dynamics method in expressing the mechanical behavior of atomic structures such as concrete, carbon nanotubes and composite structures derived from raw materials is expressed that can be considered in industrial and construction cases.

Mechanical Characterization of Heterogeneous Polycrystalline Rocks Using Nanoindentation Method in Combination with Generalized Means Method

2020 ◽  
Vol 36 (6) ◽  
pp. 813-823
Author(s):  
M.R. Ayatollahi ◽  
M. Zare Najafabadi ◽  
S. S. R. Koloor ◽  
Michal Petrů
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Mechanical Characterization ◽  
Young's Modulus ◽  
Numerical Approach ◽  
Empirical Constant ◽  
Nanoindentation Experiment ◽  
Granite Rocks ◽  
Granite Samples

ABSTRACTThe mechanical characterization of rocks is important in engineering design and analysis of rock-related structures. In the current researches, rocks are classified as heterogeneous materials with anisotropic behavior, and advanced methods such as combined experimental-numerical approach are developed to characterize the behavior of rocks. In this study, the nanoindentation experiment in conjunction with the generalized means method is used to determine the Young’s modulus and hardness of eight different polycrystalline granite rocks. In the first step, the Young’s modulus and hardness of granites’ constituents are determined through nanoindentation tests on pure granite minerals. Then, the properties of granites are determined using generalized means method by considering the mechanical properties of minerals, their volume fractions and an empirical constant called the microstructural coefficient. Accurate results with less than 3% error are obtained for 62.5% of the granite samples. The generalized means is introduced as a simple and effective method to characterize the mechanical properties of heterogeneous polycrystalline rocks.

scholarly journals The Impact of Shear and Elongational Forces on Structural Formation of Polyacrylonitrile/Carbon Nanotubes Composite Fibers during Wet Spinning Process

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2797 ◽  
Author(s):  
Hamideh Mirbaha ◽  
Parviz Nourpanah ◽  
Paolo Scardi ◽  
Mirco D’incau ◽  
Gabriele Greco ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Shear Force ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Wet Spinning ◽  
Composite Fibers ◽  
Pan Fibers ◽  
Spun Fibers

Wet spinning of polyacrylonitrile/carbon nanotubes (PAN/CNT) composite fibers was studied and the effect of spinning conditions on structure and properties of as-spun fibers influenced by the presence of CNTs investigated. Unlike PAN fibers, shear force had a larger effect on crystalline structure and physical and mechanical properties of PAN/CNT composite fibers compared to the elongational force inside a coagulation bath. Under shear force CNTs induced nucleation of new crystals, whereas under elongational force nucleation of new crystals were hindered but the already formed crystals grew bigger. To our knowledge, this key effect has not been reported elsewhere. At different shear rates, strength, Young’s modulus and strain at break of PAN/CNT as-spun fibers were improved up to 20% compared to PAN fibers. Application of jet stretch had less influence on physical and mechanical properties of PAN/CNT fibers compared to PAN fibers. However, the improvement of interphase between polymer chains and CNTs as a result of chain orientation may have contributed to enhancement of Young’s modulus of jet stretched composite fibers.

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