Molecular Mechanics Based Finite Element for Carbon Nanotube Modeling

2006 ◽  
Author(s):  
Theodosios C. Theodosiou ◽  
Dimitris A. Saravanos
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Nanotube ◽  
Molecular Mechanics ◽  
Potential Model ◽  
Element Analysis ◽  
Molecular Potential ◽  
Theoretical Predictions ◽  
Semi Empirical

In this paper a new method is introduced for carbon nanotubes modeling. It combines features of Molecular Mechanics and Finite Element Analysis. This method is based on the development of a new finite element, whose internal energy is determined by the semi-empirical Brenner molecular potential model; all quantities are calculated analytically in order to gain more accuracy. The method is validated through comparisons to results provided by other researchers and are obtained either by experimental procedures or theoretical predictions. The bending and shearing of CNTs is also simulated.

scholarly journals Vibrational Characteristics of Zigzag, Armchair and Chiral Cantilever Single-Walled Carbon Nanotubes

2013 ◽  
Vol 22 (6) ◽  
pp. 096369351302200
Author(s):  
S.K. Jalan ◽  
B. Nageswara Rao ◽  
S. Gopalakrishnan
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Single Walled Carbon Nanotubes ◽  
Finite Element Models ◽  
Element Analysis ◽  
Single Walled Carbon ◽  
Empirical Relations ◽  
Vibrational Characteristics ◽  
Walled Carbon Nanotubes

Finite element analysis has been performed to study vibrational characteristics of cantilever single walled carbon nanotubes. Finite element models are generated by specifying the C-C bond rigidities, which are estimated by equating energies from molecular mechanics and continuum mechanics. Bending, torsion, and axial modes are identified based on effective mass for armchair, zigzag and chiral cantilever single walled carbon nanotubes, whose Young's modulus is evaluated from the bending frequency. Empirical relations are provided for frequencies of bending, torsion, and axial modes.

scholarly journals Vibration and Modal Analysis of Low Earth Orbit Satellite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Asif Israr
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Integrity ◽  
Center Of Mass ◽  
Low Earth Orbit ◽  
Element Analysis ◽  
Satellite Structure ◽  
Modeling And Analysis ◽  
Material Optimization ◽  
Theoretical Predictions

This paper presents design, modeling, and analysis of satellite model used for remote sensing. A detailed study is carried out for the design and modeling of the satellite structure focusing on the factors such as the selection of material, optimization of shape and geometry, and accommodation of different subsystems and payload. The center of mass is required to be kept within the range of (1-2) cm from its geometric center. Once the model is finalized it is required to be analyzed by the use ofAnsys, a tool for finite element analysis (FEA) under given loading and boundary conditions. Static, modal, and harmonic analyses inAnsysare performed at the time of ground testing and launching phase. The finite element analysis results are also validated and compared with the theoretical predictions. These analyses are quite helpful and suggest that the satellite structure does not fail and retains its structural integrity during launch environment.

scholarly journals Dynamic instability of a compound nanocomposite shell

2021 ◽  
Vol 27 (5) ◽  
pp. 60-70
Author(s):  
N.H. Sakhno ◽  
◽  
K.V. Avramov ◽  
B.V. Uspensky ◽  
◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Supersonic Flow ◽  
Uniform Distribution ◽  
Critical Pressure ◽  
Natural Frequencies ◽  
Dynamic Instability ◽  
Element Analysis

Free oscillations and dynamic instability due to supersonic airflow pressure are investigated in a functional-gradient compound composite conical-cylindrical shell made of a carbon nanotubes-reinforced material. Nanocomposite materials with a linear distribution of the volumetric fraction of nanotubes over the thickness are considered. Extended mixture rule is used to estimate nanocomposite’s mechanical characteristics. A high-order shear deformation theory is used to represent the shell deformation. The assumed-mode technique, along with a Rayleigh-Ritz method, is applied to obtain the equations of the structure motion. To analyze the compound structure dynamics, a new system of piecewise basic functions is suggested. The pressure of a supersonic flow on the shell is obtained by using the piston theory. An example of the dynamic analysis of a nanocomposite conical-cylindrical shell in the supersonic gas flow is considered. The results of its modal analysis using the Rayleigh-Ritz technique are close to the natural frequencies of the shell obtained by finite element analysis. In this case, finite element analysis can only be used for shells made of material with a uniform distribution of nanotubes over the thickness. The dependence of the natural frequencies of a compound shell on the ratio of the lengths of the conical and cylindrical parts is studied. The dependence of the critical pressure of a supersonic flow on the Mach numbers and the type of carbon nanotubes reinforcement is investigated. Shells with a concentration of nanotubes predominantly near the outer and inner surfaces are characterized by higher values of natural frequencies and critical pressure than the shells with a uniform distribution of nanotubes or with a predominant concentration of nanotubes inside the shell.

A Semi-Empirical Method for Estimating the Effective Leak and Vent Areas of an Airbag

1999 ◽  
Author(s):  
Aloysius U. Anagonye ◽  
J. T. Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Air Permeability ◽  
Empirical Method ◽  
Test Apparatus ◽  
Element Analysis ◽  
Test Setup ◽  
Surface Areas ◽  
Semi Empirical ◽  
Fabric Specimen

Abstract A semi-empirical method that utilizes tests from a small fabric specimen to quantify the effective leak and vent areas of an entire airbag is developed in this paper. The test setup and procedure used in the airbag material coupon tests are similar to the standard method used in determining air permeability of fabrics. A test apparatus for measuring the deflection of the fabric coupon was devised. Finite element analysis is used to compute the expanded vent and airbag surface areas of the coupon under various deformations. The leak and vent models were developed based on the results of a regression analysis. The effective vent area of a fabric coupon is a function of the ratio of the pressures across the fabric and the expanded vent area. Similarly, the effective leak area of a fabric coupon is a function of the ratio of the pressures across the fabric and the expanded surface area. The tested airbag materials were characterized with these models for use with finite element airbag models.

scholarly journals Theoretical Modelling of Plate with Attached Vibration Absorber

2015 ◽  
Vol 773-774 ◽  
pp. 33-37 ◽  
Author(s):  
Izzuddin Zaman ◽  
Muhammad Mohamed Salleh ◽  
Bukhari Manshoor ◽  
Amir Khalid ◽  
Mohd Zamani Ngali ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Modelling ◽  
Vibration Absorber ◽  
Element Analysis ◽  
Constant Frequency ◽  
Structural Alterations ◽  
Theoretical Predictions ◽  
The Common

There are many ways to control the vibration of plate structure. Conventional approaches that include structural alterations are frequently time consuming and costly. One of the common schemes is using vibration absorber attached to a structure. In this paper, a mathematical model is developed to determine the frequency response of fixed-fixed ends plate with attached vibration absorber. A finite element analysis was performed and compared with the theoretical predictions and showed that there was good resemblance. The results demonstrated that the addition of vibration absorber onto plate can attenuate vibration considerably at a constant frequency.

scholarly journals Performance Analysis of Reinforced Epoxy Functionalized Carbon Nanotubes Composites for Vertical Axis Wind Turbine Blade

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 422
Author(s):  
Yasser Elhenawy ◽  
Yasser Fouad ◽  
Haykel Marouani ◽  
Mohamed Bassyouni
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Epoxy Resin ◽  
Turbine Blade ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Epoxy Nanocomposites ◽  
Element Analysis ◽  
Vertical Axis Wind Turbines

Synthetic materials using epoxy resin and woven Kevlar fiber nanocomposites were fabricated in the presence of functionalized multiwalled carbon nanotubes (F-MWCNTs). Kevlar-reinforced epoxy nanocomposites were designed to manufacture a small blade of vertical axis wind turbines (VAWT). It is important to estimate the deflection of the versatile composite turbine blades to forestall the blades from breakage. This paper investigates the effect of F-MWCNTs on mechanics and deflection of reinforced epoxy composites. The outcomes show that the mixing of F-MWCNTs with epoxy resin using a sonication process has a significant influence on the mechanical properties. Substantial improvement on the deflections was determined based on finite element analysis (FEA). The vortices from the vertical axis wind turbines (VAWTs) blades have a negative impact on power efficiency, since small blades are shown to be effective in reducing tip vortexes within the aerospace field. To support the theoretical movement of the VAWT blade, modeling calculations and analyzes were performed with the ANSYS code package to achieve insight into the sustainability of epoxy nanocomposites for turbine blade applications below aerodynamic, gravitational, and centrifugal loads. The results showed that the addition of F-MWCNTs to epoxy and Kevlar has a significant effect on the bias estimated by finite element analysis. ANSYS analysis results showed lower deflection on the blade using epoxy with an additional of 0.50 wt.% of MWCNTs-COOH at tip speed ratios of 2.1, 2.6, and 3.1.

A Finite Element Analysis of Single-Walled Carbon Nanotube Deformation

2011 ◽  
Vol 78 (3) ◽  
Author(s):  
Chao Fang ◽  
Ajeet Kumar ◽  
Subrata Mukherjee
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Carbon Nanotube ◽  
Dominant Mode ◽  
Element Analysis ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Bending Modulus ◽  
Cosserat Rod ◽  
Rod Model

Chandraseker et al. (2009, “An Atomistic-Continuum Cosserat Rod Model of Carbon Nanotubes,” J. Mech. Phys. Solids, 57, pp. 932–958), in a 2009 JMPS paper, proposed an atomistic-continuum model, based on Cosserat rod theory, for deformation of a single-walled carbon nanotube (SWNT). This model allows extension and twist, as well as shear and bending (in two directions) of a SWNT. This present paper proposes a finite element method (FEM) implementation of the above mentioned Cosserat rod model for a SWNT, subjected, in general, to axial and transverse loads, as well as bending moments and torques. The resulting FEM implementation includes both geometric and material nonlinearities. Numerical results for several examples are presented in this paper. Finally, a recent experimental paper on SWNTs (Xu, Y-.Q., et al., 2009, “Bending and Twisting of Suspended Single-Walled Carbon Nanotubes in Solution,” ASAP Nano Lett., 9, pp. 1609–1614) is revisited herein. It is pointed out in the present paper that Xu et al. attempted to determine the bending stiffness of a SWNT from an experiment in which the dominant mode of deformation is stretching, not bending. (Their model, Euler–Bernoulli beam bending, should perhaps have been extended to include stretching.) As a result, their measured deflection is nearly insensitive to the bending modulus.

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