Continuum-Micromechanical Modeling of Microcapsules-Based Composites

2017 ◽  
Vol 909 ◽  
pp. 311-316
Author(s):  
Abdalla Ahmed ◽  
Kazuaki Sanada ◽  
Mohamed Fanni ◽  
Ahmed Abd El-Moneim
Keyword(s):  
Phase Change Materials ◽  
Three Dimensional ◽  
Micromechanical Modeling ◽  
Service Needs ◽  
Self Healing ◽  
Numerical Investigations ◽  
Wide Range ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Properties Of Composites

Microcapsules are used in a wide range of applications, especially in self-healing composite materials and phase change materials. There is a growing body of literature that recognizes the importance of reinforcement on the mechanical properties of composites, however the effect of microcapsules during service needs to be further investigated. In this study, numerical investigations were conducted to examine the effects of the various geometric parameters on the mechanical behavior of microcapsules-based composites. The effective Young’s modulus and Poisson’s ratio of core-shell microcapsules distributed in a continuous matrix were predicted. A detailed three-dimensional finite element modeling (FEM) was presented. The numerical results were compared with a hierarchical proposed analytical model for three-constituent composites. Good agreements were achieved.

Selecting Suitable Probes Distances for Sizing Deep Surface Cracks Using the DCPD Technique

2006 ◽  
Vol 129 (1) ◽  
pp. 205-210 ◽  
Author(s):  
Fumio Takeo ◽  
Masumi Saka ◽  
S. Reaz Ahmed ◽  
Seiichi Hamada ◽  
Manabu Hayakawa
Keyword(s):  
Three Dimensional ◽  
Potential Drop ◽  
Surface Cracks ◽  
Deep Surface ◽  
Input And Output ◽  
Wide Range ◽  
Current Input ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
The Way

In this study, the way to enhance the sensitivity of evaluating deep surface cracks by DCPD technique using four probes is considered. The potential drops across two-dimensional cracks having different depths are analyzed by the three-dimensional finite-element method. The effect of the distance between current input and output probes and the distance between measuring probes on the change in potential drops are analyzed for a wide range of crack depths. By extending the distance between current input and output probes, the change in potential drop with the change in the depth of deeper crack becomes large. But the voltage of potential drop becomes small to measure. Finally, the way to select the appropriate distances between the probes for the measuring sensor is shown from the viewpoints of sensitivity and the required current.

scholarly journals Analysis and Mitigation of Stray Capacitance Effects in Resistive High-Voltage Dividers

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2278
Author(s):  
Jordi-Roger Riba ◽  
Francesca Capelli ◽  
Manuel Moreno-Eguilaz
Keyword(s):  
High Voltage ◽  
Three Dimensional ◽  
Alternating Current ◽  
Stray Capacitance ◽  
Element Analysis ◽  
Wide Range ◽  
Resistive Divider ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Capacitance Effects

This work analyzes the effects of the parasitic or stray distributed capacitance to ground in high-voltage environments and assesses the effectiveness of different corrective actions to minimize such effects. To this end, the stray capacitance of a 130 kV RMS high-voltage resistive divider is studied because it can severely influence the behavior of such devices when operating under alternating current or transient conditions. The stray capacitance is calculated by means of three-dimensional finite element analysis (FEA) simulations. Different laboratory experiments under direct current (DC) and alternating current (AC) supply are conducted to corroborate the theoretical findings, and different possibilities to mitigate stray capacitance effects are analyzed and discussed. The effects of the capacitance are important in applications, such as large electrical machines including transformers, motors, and generators or in high-voltage applications involving voltage dividers, conductors or insulator strings, among others. The paper also proves the usefulness of FEA simulations in predicting the stray capacitance, since they can deal with a wide range of configurations and allow determining the effectiveness of different corrective configurations.

scholarly journals 3-D Finite Element Investigation of Flux Regulation Performance of a Novel Hybrid Excitation Brushless Claw-Pole Alternator

2012 ◽  
Vol 614-615 ◽  
pp. 1226-1229
Author(s):  
Dong Wei Qiao ◽  
Xiu He Wang ◽  
Chang Qing Zhu
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Analysis ◽  
Wide Range ◽  
Hybrid Excitation ◽  
Field Control ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Control Principle

In consideration of low power density of electric excitation claw-pole alternator (EECA) and some difficulties in magnetic field regulation of permanent magnet claw-pole alternator (PMCA), a novel hybrid excitation brushless claw-pole alternator (HEBCA) is proposed in this paper. Its structure and field control principle are described. Three dimensional finite element analysis is used to obtain the no-load magnetic field distributions and field control capability under different field currents. The result shows that the flux of the prototype machine can be adjusted over a wide range with a relatively low field current

Three-dimensional tensile stress concentration in countersunk rivet holes

2007 ◽  
Vol 111 (1126) ◽  
pp. 777-786 ◽  
Author(s):  
A. Bhargava ◽  
K. N. Shivakumar
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Tensile Stress ◽  
Three Dimensional ◽  
Design Equation ◽  
Finite Element Stress Analysis ◽  
Wide Range ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Tension Loading

Abstract A detailed and accurate three-dimensional finite element stress analysis was conducted on countersunk rivet holes in a plate subjected to tension loading. The analysis included a wide range of countersunk depths, plate thicknesses, countersunk angles and plate widths. The study confirmed some of the previous results, addressed their differences, provided many new results, and investigated countersunk angle and width effects. Using the detailed FE results and the limiting conditions, a design equation for stress concentration was developed and verified.

Simulation Study of Static and Dynamic Characteristics of Piezoelectric Thin Film Coated Polymer Tube

2005 ◽  
Author(s):  
Ahalapitiya H. Jayatissa ◽  
Himabindu Gadupudi
Keyword(s):  
Stroke Volume ◽  
Three Dimensional ◽  
Element Analysis ◽  
External Power Source ◽  
Wide Range ◽  
Dimensional Finite Element ◽  
Peak Points ◽  
Polymer Tube ◽  
Piezoelectric Thin Film ◽  
Three Dimensional Finite Element

A novel piezoelectrically actuated micropump was designed and its characteristics were simulated. The proposed structure of micropump consists of a polymer pipe coated with three curved piezoelectric strips, which actuate the polymer pipe walls using an external power source. A three dimensional finite element analysis (FEA) was used to study the deformation in the polymer pipe. The pump prototype comprises three semi-cylindrical discs made of PZT-5H and a polyimide pipe; PZT discs are placed on the opposite sides of a polyimide pipe. The structure was simulated for a wide range of voltages and frequencies. The stroke volume of the micropump was calculated using the deformation profiles obtained from the FEA. The results indicated that the change of stroke volume of pipe was functions of both voltage and frequency of power. Also there were few peak points of stroke volume associated with bending mode of piezoelectric strips. At the lower frequency (<1 KHz) and voltage regions (<100 V), a flow rate of few μl/min could be achieved for a pump designed with check values at the end of the pipe.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

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.

Tire Modeling by Finite Elements

1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rolling Contact ◽  
Test Problems ◽  
State Behavior ◽  
Normal Contact ◽  
New Developments ◽  
Applied Torque ◽  
Dimensional Finite Element ◽  
Tire Modeling ◽  
Three Dimensional Finite Element

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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