Determination of Mechanical and Electrical Damages of Piezoelectric Material with Periodically Distributed Microvoids

2007 ◽  
Vol 23 (3) ◽  
pp. 239-244 ◽  
Author(s):  
X. H. Yang ◽  
G. W. Zeng ◽  
C. Y. Chen
Keyword(s):  
Volume Fraction ◽  
Effective Properties ◽  
Three Dimensional ◽  
Electromechanical Properties ◽  
Dimensional Finite Element ◽  
Microstructure Parameters ◽  
Three Dimensional Finite Element ◽  
The Continuum ◽  
Mechanical And Electrical Damages

AbstractThis paper emphasizes on determining the mechanical and electrical damages of piezoelectric ceramics with periodically distributed ellipsoidal or spherical microvoids. Based on the unit cell method, detailed three-dimensional finite element analyses are carried out to acquire the effective electromechanical properties of voided PZT-7A materials, and then the mechanical and electrical damages are determined through the relations between the damage variables and the effective properties in the continuum piezoelectric damage constitutive theory. The quantitative connections between the damages and microstructure parameters, including the microvoid volume fraction and the microvoid aspect ratio, are analyzed in detail. Some interesting conclusions are obtained.

Evaluation of Intensity of Singularity at 3D Piezoelectric Bonded Joints Using a Conservative Integral

2015 ◽  
Author(s):  
Chonlada Luangarpa ◽  
Hideo Koguchi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electric Potential ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Bonded Joints ◽  
Conservative Integral ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In the present study, a conservative integral based on the Betti reciprocal principle is formulated in order to obtain the intensity of singularity at a vertex of the interface in three-dimensional piezoelectric bi-material bonded joints. To our knowledge, there are few studies on the determination of the intensity of singularity in the three-dimensional piezoelectric bonded joints. In addition, no study on the determination of the intensity of singularity in the 3D piezoelectric bonded joints using the conservative integral has been conducted. Eigenanalysis formulated using a three-dimensional finite element method (FEM) is used to calculate the order of stress singularity, angular variables of mechanical displacements, stresses, electric displacements and electric potential. In order to investigate the influence of an integral area on the accuracy of the results, models with various integral areas are used. The results are compared with those obtained from FEM.

scholarly journals Simulations Of Air Flow Over A Parabolic Antenna

2012 ◽  
Vol 56 (1) ◽  
pp. 81-87
Author(s):  
Liviu Bereteu ◽  
Dorin Simoiu
Keyword(s):  
Finite Element ◽  
Air Flow ◽  
Three Dimensional ◽  
Parabolic Antenna ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

AbstractIn this paper it is present the influence of the wind on a parabolic antenna, in order to study this influence it was made simulations of air flow over a parabolic antenna. The simulations are made with antenna positioned at 90°, 135°. A three – dimensional finite element is simulated for determination of the antenna displacement.

FEM Stress Analysis of Tee Intersections With LTA

2008 ◽  
Author(s):  
T. Ahmad ◽  
M. Qadir ◽  
D. Redekop
Keyword(s):  
Stress Analysis ◽  
Three Dimensional ◽  
Local Area ◽  
Collapse Load ◽  
Wall Thinning ◽  
Dimensional Finite Element ◽  
Cyclical Loading ◽  
Different Depths ◽  
Three Dimensional Finite Element

In this work a three-dimensional finite element study is carried out of pressurized piping tee (tee) intersections, with local area wall thinning (LTA). Two types of stress analysis are carried out, dealing respectively with the determination of the stress concentration factor (SCF), and of the plastic collapse load. Stress values determined for vessels with uniform thickness are compared with previously published work. An evaluation is then made of the effect on the SCF values of varying the size and shape of the LTA around the intersection. This is followed by a parametric study in which the SCF and the collapse load are computed for intersections with different depths of wall thinning. Finally, comments are made on the fatigue of tees with LTA having cyclical loading superimposed on the constant pressure loading.

scholarly journals Interaction of rack-and-pinion lock parts under external load

2019 ◽  
pp. 105-112
Author(s):  
Evgeniy Gusev ◽  
Viktor Krasavtsev
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
External Load ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Design Criteria ◽  
Finite Element Models ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

This paper describes numerical simulation and analysis of interaction between the parts of rack-and-pinion lock under operational external load, so as to develop design criteria and recommendations for its joints, as well as for more accurate determination of clearances between coamings and hatch covers, required to develop water-tight rubber sealings. These tasks are accomplished by means of detailed three-dimensional finite-element models representing two variants of rack-and-pinion lock, with their further verification. The study included numerical simulation of contact interaction between the parts of the lock, as well as analysis of design solutions for its main joints. As a result, coaming-cover clearances have been determined and manufacturing requirements to rubber sealings of the lock variants under investigation have been successfully formulated.

Effect of substrate deformation in the nanowire/nanotube bending test

2005 ◽  
Vol 880 ◽  
Author(s):  
Wingkin Chan ◽  
Yong Wang ◽  
Jianrong Li ◽  
Tong-Yi Zhang
Keyword(s):  
Three Dimensional ◽  
Great Influence ◽  
Young Modulus ◽  
Bending Test ◽  
Fe Model ◽  
Simply Supported ◽  
Dimensional Finite Element ◽  
Load Displacement ◽  
Three Dimensional Finite Element

AbstractThe present work analyses the effect of substrate deformation during the nanowire/nanotube bending test. An individual nanowire or nanotube is treated as a linear isotropic continuum. The substrate deformation is modeled by two coupled springs and the spring compliances arefunctions of the nanowire/nanotube diameter, and the Young moduli of the nanowire/nanotube and the substrates. An atomic potential is used to determine the adhesion between the nanowire/nanotube and its substrate. Consequently, a simple three dimensional Finite Element (FE) model is built to calculate the spring compliances. The load-displacement relation, which takes into account of substrate deformation, is derived in a closed form, which can be reduced to the load-displacement relations based on the simply-supported ends and the built-in ends. The numerical results indicate that the substrate deformation has a great influence on the determination of the Young modulus of a nanowire/nanotube from the bending test. The nanobridge test on carbon nanotubes is taken as an example to demonstrate the feasibility of the developed method.

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