Numerical Study of the Zinc Oxide Nanowire Geometry Effect on Nanogenerator Output

2013 ◽  
Vol 829 ◽  
pp. 222-226
Author(s):  
Samira Fathi ◽  
Tahereh Fanaei Sheikholeslami ◽  
Mitra Salami

Piezoelectric nanogenerator (NG) made of nanowires (NWs) is a suitable device for harvesting ambient mechanical energy, applicable for self-powered electronic systems and nanodevices that operate at low power. The coupled piezoelectric and semiconducting characteristics of the zinc oxide (ZnO) NW cause an output voltage generation that made it interesting to use as an energy harvesting device in nanoscale. In this paper, the piezoelectric potential distribution in a bent ZnO NW is investigated, numerically. To do this, a three-dimensional finite element simulation of the device is performed and the results are analyzed and discussed. It is found that the output piezoelectric potential, for a constant nanowire length, is decreased as the diameter of ZnO NW increases. Study on the effect of NW diameters shows the potential will remain constant for nanowire with aspect ratio below 15. Further, the NWs are considered with an inclination of 20 degree relative to the substrate to study by applying force in different directions. The latter indicates an improvement on the output piezoelectric potential. The obtained results show that the ZnO NW can be used as a good energy harvester device by considering a suitable diameter, length and with a justified inclination angle.

2012 ◽  
Vol 170-173 ◽  
pp. 1491-1496 ◽  
Author(s):  
Xin Wang ◽  
De Shen Zhao ◽  
Meng Lin Xu

Based on Dalian subway line 2 from Chun-guang street station to Xiang-gong street station,the three dimensional finite element model was established using FLAC3D software , the shield excavated surface against the pressure, the stress release, the shield tail escape and grouting. The numerical result indicated that the pipeline displacement increases gradually with the advance of the tunnel excavation. When one-sided tunnel excavation is carried out, the largest displacement is located at the tunnel axis, the settling curve basically conforms to the normal distribution curve with the unimodal characteristic. The excavation of right-side tunnel is disadvantageous to the left-side tunnel. The analysis indicated that the pipeline is in a secure state. The work in this paper provided theoretical basis and the practical guidance to this project.


Author(s):  
Enyang Wang ◽  
Wenxing Zhou ◽  
Guowu Shen ◽  
Daming Duan

Several well-known equations for estimating the crack length in the SE(B) specimens from the normalized CMOD compliance are evaluated based on two- and three-dimensional finite element analyses. Two-dimensional analyses are carried out first to verify the reported accuracy and applicable ranges for each equation based on the plane strain models with six different crack lengths. Three-dimensional analyses are then carried out to estimate the errors of prediction of the equations that evaluate the crack length from the plane stress- and plane strain-based CMOD compliances. Both plain-sided and side-grooved models are included in the three-dimensional analyses and have seven different thickness-to-width ratios. The error of prediction of a given equation is largely impacted by the thickness-to-width ratio, crack length, presence of side grooves, and use of the plane stress- and plane strain-normalized CMOD compliance. Based on the errors of prediction, the relevance of the plane strain and plane stress conditions to the actual state of stress in the ligament of the SE(B) specimens is inferred. Knowledge of the relevance of the plane stress and plane strain conditions can be used to select either plane stress- or plane strain-based CMOD compliance in the crack length-CMOD equations and improve the accuracy of the prediction.


Author(s):  
Abdulla Sherif Mahmoud Fathalla ◽  
◽  
Ali Akhavan Farid ◽  
Reza Moezzi ◽  
Seyed Saeid Rahimian Koloor ◽  
...  

Load distribution has been studied extensively for ISO thread, but the load distribution on power screw threads, specifically ACME and Square threads, has not been studied yet. In this article, axisymmetric two-dimensional and three-dimensional Finite Element Analysis have been conducted on bolts with different sizes and thread geometries to examine the effect of the thread geometry on the load distribution. The thread geometries were studied with ISO, ACME, and Square threads attention. The sizes used are from the ISO coarse series. In order to investigate on the effect of bolt thread geometry, several simulations have been performed. The two-dimensional simulation results have shown reliable performance in determining the load distribution behaviour when the thread geometry is modified. Moreover, the results agreed with the three-dimensional simulation outcomes regarding the load distribution behaviour when the size is varied.


2016 ◽  
Vol 51 (16) ◽  
pp. 2347-2361 ◽  
Author(s):  
K Furkan Çiçek ◽  
Merve Erdal ◽  
Altan Kayran

Process-induced total spring-in of corner-shaped composite parts manufactured via autoclave-forming technique using unidirectional prepreg is studied both numerically and experimentally. In the numerical study, a three-dimensional finite element model which takes into account the cure shrinkage of the resin, anisotropic material properties of the composite part and the tool-part interaction is developed. The outcome of the numerical model is verified experimentally. For this purpose, U-shaped composite parts are manufactured via autoclave-forming technique. Process-induced total spring-in, due to the combined effect of material anisotropy and tool-part interaction, at different sections of the U-shaped parts are measured with use of the combination of the three-dimensional optical scanning technique and the generative shape design. Total spring-in determined by the numerical model is found to be in good agreement with the average total spring-in measured experimentally. The effect of tool-part interaction mechanism on the total spring-in is studied separately to ascertain its effect on the total spring-in behavior clearly. It is shown that with the proper modeling of the tool-part interaction, numerically determined total spring-in approaches the experimentally determined total spring-in.


2013 ◽  
Vol 302 ◽  
pp. 212-215
Author(s):  
Xiao Long Wang ◽  
Zhi Luo ◽  
Hong Jie Jing ◽  
Heng An Wu

In the present work, the finite element analysis was employed to study the distribution and level of thermal residual stress generated in matrix reinforced with SO2 nanoparticles. Using Cohesive Element as the bonding of the interface between fiber and matrix, three–dimensional finite element models of periodic cells were established. The results of the models with and without nanoparticles were compared. The residual thermal stressdue to the mismatch of the thermal expansion coefficients between matrix and fibers, especially theshear stress in the interface, decreased with nanoparticles, which could explain the reinforcing mechanism of nanoparticles. Our numerical study can be of great significance in designing new composites with high performance


2021 ◽  
Vol 322 ◽  
pp. 100-105
Author(s):  
Ronaldas Jakubovskis ◽  
Domas Valiukas ◽  
Gintaris Kaklauskas

The importance of interaction between concrete and reinforcement for reinforced concrete (RC) mechanics is a known issue, yet its complexity enforces one to perform in-depth investigations at the microscopic level. In this paper, short RC ties with lengths less than transfer length of bond stresses were chosen to investigate contact zones between concrete and reinforcement. A three-dimensional finite element approach (Model-3D) with simplified geometry of ribs (rib-scale model) is modelled. Its effectiveness is checked against the results yielded by a number of double pull-out tests on RC prisms, where the strain distribution of the bars was measured with strain gauges. As it turns out, the considered model shows a good correlation with experimental data at different loading levels, and the most important factor describing the effectiveness is the geometry of ribs.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.


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