Sensitivity analysis of single-layer graphene resonators using atomic finite element method

2013 ◽  
Vol 114 (12) ◽  
pp. 123506 ◽  
Author(s):  
Haw-Long Lee ◽  
Jung-Chang Hsu ◽  
Shu-Yu Lin ◽  
Win-Jin Chang
2015 ◽  
Vol 33 ◽  
pp. 92-105 ◽  
Author(s):  
Jia Fu ◽  
Fabrice Bernard ◽  
Siham Kamali-Bernard

An Atomic Finite Element Analysis is developed in this paper. At atomic scale, the interatomic bonding forces of Van der Waals and the covalent chemical bond are taken into account. The methodology is applied to study the behavior of carbon nanotubes, whose development has experienced strong growth in recent years and that can be used for quality mechanical reinforcement. These carbon nanotubes are formed by repeating zigzag carbon-carbon bonds. Development of atomic finite element method (AFEM) methodology can be traced back to the homogenized elastic properties of various graphene structures (single-layer graphene sheet, Zig-zag single-walled carbon nanotubes, triple-layer graphene sheet).


2016 ◽  
Vol 61 (1) ◽  
pp. 149-152 ◽  
Author(s):  
L.W. Żukowska ◽  
A. Śliwa ◽  
J. Mikuła ◽  
M. Bonek ◽  
W. Kwaśny ◽  
...  

The general topic of this paper is the computer simulation with use of finite element method (FEM) for determining the internal stresses of selected gradient and single-layer PVD coatings deposited on the sintered tool materials, including cemented carbides, cermets and Al2O3+TiC type oxide tool ceramics by cathodic arc evaporation CAE-PVD method. Developing an appropriate model allows the prediction of properties of PVD coatings, which are also the criterion of their selection for specific items, based on the parameters of technological processes. In addition, developed model can to a large extent eliminate the need for expensive and time-consuming experimental studies for the computer simulation. Developed models of internal stresses were performed with use of finite element method in ANSYS environment. The experimental values of stresses were calculated using the X-ray sin2ψ technique. The computer simulation results were compared with the experimental results. Microhardness and adhesion as well as wear range were measured to investigate the influence of stress distribution on the mechanical and functional properties of coatings. It was stated that occurrence of compressive stresses on the surface of gradient coating has advantageous influence on their mechanical properties, especially on microhardness. Absolute value reduction of internal stresses in the connection zone in case of the gradient coatings takes profitably effects on improvement the adhesion of coatings. It can be one of the most important reasons of increase the wear resistance of gradient coatings in comparison to single-layer coatings.


2016 ◽  
Vol 64 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Onic Islam Shuvo ◽  
Md Naimul Islam

One of the major problems with Electrical Impedance Tomography (EIT) is the lack of spatial sensitivity within the measured volume. In this paper, sensitivity distribution of the tetrapolar impedance measurement system was visualized considering a cylindrical phantom consisting of homogeneous and inhomogeneous medium. Previously, sensitivity distribution was analysed analytically only for the homogeneous medium considering simple geometries and the distribution was found to be complex1,2. However, for the inhomogeneous volume conductors sensitivity analysis needs to be done using finite element method (FEM). In this paper, the results of sensitivity analysis based on finite element method using COMSOL Multiphysics simulation software are presented. A cylindrical non-uniform, inhomogeneous phantom, which mimics the human upper arm, was chosen to do the experiments by varying different parameters of interest. A successful method for controlling the region of interest was found where the sensitivity was maximum. Refining the finite element mesh size and introducing multifrequency input current (up to 1 MHz) this simulation method can be further improved.Dhaka Univ. J. Sci. 64(1): 7-13, 2016 (January)


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