The Effect of Microstructural Morphologies on the Effective Electromechanical Properties of Piezoelectric Particle Composites

2012 ◽  
Author(s):  
Vahid Tajeddini ◽  
Chien-hong Lin ◽  
Anastasia Muliana ◽  
Martin Lévesque
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Three Dimensional ◽  
Particle Sizes ◽  
Reinforced Composites ◽  
Electromechanical Properties ◽  
Particle Volume ◽  
Self Consistent

This study introduces a micromechanical model that incorporates detailed microstructures for analyzing the effective electro-mechanical properties, such as piezoelectric and permittivity constants as well as elastic moduli, of piezoelectric particle reinforced composites. The studied composites consist of polarized spherical piezoelectric particles dispersed into a continuous and elastic polymeric matrix. A micromechanical model generated using three-dimensional (3D) continuum elements within a finite element (FE) framework. For each volume fraction (VF) of particles, realization with different particle sizes and arrangements were generated in order to represent microstructures of a particle composite. We examined the effects of microstructural morphologies, such as particle sizes and distributions, and particle volume fractions on the overall effective electro-mechanical properties of the active composites. The overall electro-mechanical properties determined from the present micromechanical model were compared to those generated using the Mori-Tanaka, self-consistent, and simplified unit-cell micromechanical models.

scholarly journals New patterns in high-speed granular flows

2015 ◽  
Vol 769 ◽  
pp. 218-228 ◽  
Author(s):  
Nicolas Brodu ◽  
Renaud Delannay ◽  
Alexandre Valance ◽  
Patrick Richard
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Scaling Law ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Particle Volume ◽  
Rheological Models ◽  
Granular Gas ◽  
Internal Structures

We report on new patterns in high-speed flows of granular materials obtained by means of extensive numerical simulations. These patterns emerge from the destabilization of unidirectional flows upon increase of mass holdup and inclination angle, and are characterized by complex internal structures, including secondary flows, heterogeneous particle volume fraction, symmetry breaking and dynamically maintained order. In particular, we evidenced steady and fully developed ‘supported’ flows, which consist of a dense core surrounded by a highly energetic granular gas. Interestingly, despite their overall diversity, these regimes are shown to obey a scaling law for the mass flow rate as a function of the mass holdup. This unique set of three-dimensional flow regimes raises new challenges for extending the scope of current granular rheological models.

Interphase influences on the mechanical behavior of carbon nanotube–shape memory polymer nanocomposites: A micromechanical approach

2018 ◽  
Vol 30 (3) ◽  
pp. 463-478 ◽  
Author(s):  
MK Hassanzadeh-Aghdam ◽  
MJ Mahmoodi ◽  
R Ansari ◽  
A Darvizeh
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Shape Memory ◽  
Polymer Nanocomposites ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Shape Memory Polymer ◽  
Micromechanical Model ◽  
Elastic Behavior ◽  
Interphase Region

The effects of interphase characteristics on the elastic behavior of randomly dispersed carbon nanotube–reinforced shape memory polymer nanocomposites are investigated using a three-dimensional unit cell–based micromechanical method. The interphase region is formed due to non-bonded van der Waals interaction between a carbon nanotube and a shape memory polymer. The influences of temperature, diameter, volume fraction, and arrangement type of carbon nanotubes within the matrix as well as two interphase factors, including adhesion exponent and thickness on the carbon nanotube/shape memory polymer nanocomposite’s longitudinal and transverse elastic moduli, are explored extensively. Moreover, the results are presented for the shape memory polymer nanocomposites containing randomly oriented carbon nanotubes. The obtained results clearly demonstrate that the interphase region plays a crucial role in the modeling of the carbon nanotube/shape memory polymer nanocomposite’s elastic moduli. It is observed that the nanocomposite’s elastic moduli remarkably increase with increasing interphase thickness or decreasing adhesion exponent. It is found that when the interphase is considered in the micromechanical simulation, the shape memory polymer nanocomposite’s elastic moduli non-linearly increase as the carbon nanotube diameter decreases. The predictions of the present micromechanical model are compared with those of other analytical methods and available experiments.

Vortex Simulation for Behavior of Solid Particles Falling in Air

2011 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Air Flow ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Vortex Method ◽  
Solid Particles ◽  
Particle Volume ◽  
Two Phase ◽  
Spherical Region

The behavior of small solid particles falling in an unbounded air is simulated. The particles, initially arranged within a spherical region in a quiescent air, are made to fall, and their fall induces the air flow around them, resulting in the gas-particle two-phase flow. The particle diameter and density are 1 mm and 7.7 kg/m3 respectively. A three-dimensional vortex method proposed by one of the authors is applied. The simulation demonstrates that the particles are accelerated by the induced downward air flow just after the commencement of their fall. It also highlights that the particles are whirled up by a vortex ring produced around the downward air flow after the acceleration. The effect of the particle volume fraction at the commencement of the fall is also explored.

The 3-D Finite Element Analysis on Elastic-Plastic Micromechanical Response of the Particle Volume Fraction

2019 ◽  
Vol 962 ◽  
pp. 210-217
Author(s):  
Yong Ming Guo ◽  
Nozomi Fukae
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Particle Volume ◽  
Two Phase ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Microstructural Parameters ◽  
Commercial Software Package ◽  
Properties Of Materials

It is well known that the properties of materials are a function of their microstructural parameters. The FEM is a good selection for studies of three-dimensional microstructure-property relationships. In this research, the elastic-plastic micromechanical response of the particle volume fraction of two-phase materials have been calculated using a commercial software package of the FEM, some new knowledges on the microstructure-property relationships have obtained.

Numerical Investigation on the Effect of Abrasive Property for Abrasive Flow Machining

2014 ◽  
Vol 574 ◽  
pp. 406-410
Author(s):  
Li Feng Yang ◽  
Chun Yan Dong ◽  
Wei Na Liu
Keyword(s):  
Material Removal ◽  
Volume Fraction ◽  
Metal Removal ◽  
Particle Volume Fraction ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Particle Volume ◽  
Micro Holes ◽  
Micro Hole ◽  
Abrasive Property

Numerical investigations of the abrasive influence on material removal efficiency of the micro-hole for AFM process is conducted in this paper. A three-dimensional model is constructed for this process. The abrasive with various particles volume fraction and different micro-holes with various diameters are selected in this study. The simulation results show that the lower particle volume fraction may be in favour of the metal removal uniformity, but the processing time will be too long if too low fraction is selected.

Structural and Mechanical Properties of Mandibular Condylar Bone

2006 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
T.M.G.J. van Eijden ◽  
P.N. van der Helm ◽  
L.J. van Ruijven ◽  
L. Mulder
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Sagittal Plane ◽  
Mandibular Condyle ◽  
Mechanical Anisotropy ◽  
Bone Volume Fraction ◽  
Shear Moduli ◽  
Trabecular Density ◽  
Ct System

The trabecular bone of the mandibular condyle is structurally anisotropic and heterogeneous. We hypothesized that its apparent elastic moduli are also anisotropic and heterogeneous, and depend on trabecular density and orientation. Eleven condyles were scanned with a micro-CT system. Volumes of interest were selected for the construction of finite element models. We simulated compressive and shear tests to determine the principal mechanical directions and the apparent elastic moduli. Compressive moduli were relatively large in directions acting in the sagittal plane, and small in the mediolateral direction. The degree of mechanical anisotropy ranged from 4.7 to 10.8. Shear moduli were largest in the sagittal plane and smallest in the transverse plane. The magnitudes of the moduli varied with the condylar region and were proportional to the bone volume fraction. Furthermore, principal mechanical direction correlated significantly with principal structural direction. It was concluded that variation in trabecular structure coincides with variation in apparent mechanical properties.

Effect of the Matrix and Reinforcement Sizes on the Microstructure, the Physical and Mechanical Properties of Al-SiC Composites

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
M. A. Salem ◽  
I. G. El-Batanony ◽  
M. Ghanem ◽  
Mohamed Ibrahim Abd ElAal
Keyword(s):  
Mechanical Properties ◽  
Powder Metallurgy ◽  
Volume Fraction ◽  
Physical And Mechanical Properties ◽  
Particle Sizes ◽  
Matrix Composites ◽  
Volume Fractions ◽  
The Matrix ◽  
Sic Composites ◽  
Sic Particle

Different Al-SiC metal matrix composites (MMCs) with a different matrix, reinforcement sizes, and volume fractions were fabricated using ball milling (BM) and powder metallurgy (PM) techniques. Al and Al-SiC composites with different volume fractions were milled for 120 h. Then, the Al and Al-SiC composites were pressed under 125 MPa and finally sintered at 450 °C. Moreover, microsize and combination between micro and nano sizes Al-SiC samples were prepared by the same way. The effect of the Al matrix, SiC reinforcement sizes and the SiC volume fraction on the microstructure evolution, physical and mechanical properties of the produced composites was investigated. The BM and powder metallurgy techniques followed by sintering produce fully dense Al-SiC composite samples with different matrix and reinforcement sizes. The SiC particle size was observed to have a higher effect on the thermal conductivity, electrical resistivity, and microhardness of the produced composites than that of the SiC volume fraction. The decreasing of the Al and SiC particle sizes and increasing of the SiC volume fraction deteriorate the physical properties. On the other hand, the microhardness was enhanced with the decreasing of the Al, SiC particle sizes and the increasing of the SiC volume fraction.

Mechanical properties and mechanical behavior of (SiO2)f/SiO2 composites with 3D six-directional braided quartz fiber preform

2012 ◽  
Vol 19 (2) ◽  
pp. 113-117 ◽  
Author(s):  
Yong Liu ◽  
Zhaofeng Chen ◽  
Jianxun Zhu ◽  
Yun Jiang ◽  
Binbin Li
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Thermal Structure ◽  
Three Dimensional ◽  
Shear Loading ◽  
Failure Behavior ◽  
Fiber Volume ◽  
Strain Behavior ◽  
Highly Nonlinear ◽  
Nonlinear Stress

Abstract(SiO2)f/SiO2 composites reinforced with three-dimensional (3D) six-directional preform were fabricated by the silicasol-infiltration-sintering method. The nominal fiber volume fraction was 47%. To characterize the mechanical properties of the composites, mechanical testing was carried out under various loading conditions, including tensile, flexural, and shear loading. The composite exhibited highly nonlinear stress-strain behavior under all the three types of loading. The results indicated that the 3D six-directional braided (SiO2)f/SiO2 composites exhibited superior flexural properties and good shear resistant as compared with other types of preform (2.5D and 3D four-directional)-reinforced (SiO2)f/SiO2 composites. 3D six-directional braided (SiO2)f/SiO2 composite exhibited graceful failure behavior under loading. The addition of 5th and 6th yarns resulted in controlled fracture and hence these 3D six-directional braided composites could possibly be suitable for thermal structure components.

An Interfacial Debonding Model for Particle-Reinforced Composites

2002 ◽  
Author(s):  
H. T. Liu ◽  
L. Z. Sun ◽  
J. W. Ju
Keyword(s):  
Volume Fraction ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Interfacial Debonding ◽  
Elastic Behavior ◽  
Reinforced Composites ◽  
Stiffness Tensor ◽  
Particle Reinforced Composites ◽  
Damage Process ◽  
Multi Phase

To simulate the evolution process of interfacial debonding between particle and matrix, and to further estimate its effect on the overall elastic behavior of particle-reinforced composites, a two-level microstructural-effective damaged model is developed. The microstructural damage mechanism is governed by the interfacial debonding of reinforcement and matrix. The progressive damage process is represented by the debonding angles that are dependent on the external loads. For those debonded particles, the elastic equivalency is constructed in terms of the stiffness tensor. Namely, the isotropic yet debonded particles are replaced by the orthotropic perfect particles. The volume fraction evolution of debonded particles is characterized by the Weibull’s statistical approach. Mori-Tanaka’s method is utilized to determine the effective stiffness tensor of the resultant multi-phase composites. The proposed constitutive framework is developed under the general three-dimensional loading condition. Examples are conducted to demonstrate the capability of the proposed model.

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