Numerical Analysis of the GF/UHMWPEF Interply Hybrid NOL Ring Critical Volume Fraction

2012 ◽  
Vol 457-458 ◽  
pp. 449-452
Author(s):  
Ming Lin Xu ◽  
Xiao Qing Wu ◽  
Ming Kang An
Keyword(s):  
Finite Element ◽  
Volume Fraction ◽  
Critical Volume ◽  
Tooth Contact Analysis ◽  
Breaking Strain ◽  
Finite Element Software ◽  
Critical Volume Fraction ◽  
The Matrix ◽  
The Relationship ◽  
Strain Model

The tensile test of NOL ring composites with different interply hybrid ratio is simulated by finite element software. The relationship between the stress of Naval Ordnance Laboratory(NOL) ring and the volume fraction of UHMWPEF is linear when the matrix suffering from the equal loading, but tower suddenly appears at the point of 56.25% which is about the critical volume fraction. The critical volume fraction of hybrid NOL ring is figured out on the basis of the constant strain model. By contrast, the results of the Finite Element Method (FEM) and constant strain model have subtle differences. Tooth contact analysis can exactly predict the stress of the interply hybrid NOL ring and the critical volume fraction of GF in interply hybrid NOL ring which has lower breaking strain than UHMWPEF does.

Piezoelectric Properties of 1-3 Piezoelectric Tubular Composites

2012 ◽  
Vol 217-219 ◽  
pp. 24-30 ◽  
Author(s):  
Yu Ting Ma ◽  
Jun Zhong ◽  
Li Zhang ◽  
Yun Liang Wu
Keyword(s):  
Finite Element ◽  
Aspect Ratio ◽  
Electric Field Distribution ◽  
Piezoelectric Properties ◽  
Volume Fraction ◽  
Uniform Electric Field ◽  
Finite Element Software ◽  
The Relationship ◽  
Tube Density ◽  
Theoretical Results

The piezoelectric coefficients of 1-3 piezoelectric tubular composites are studied. Taking into account the non-uniform electric field distribution in piezoelectric tube, the piezoelectric coefficients as functions of volume fraction, aspect ratio, tube density and matrix materials were discussed. By means of finite element software, the relationship between piezoelectric coefficients and ceramic volume fraction was derived to validate theoretical results. This research provides theoretical guidance and basis for the design of 1-3 piezoelectric tubular composites.

scholarly journals The AC and DC Conductivity of Nanocomposites

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
David S. McLachlan ◽  
Godfrey Sauti
Keyword(s):  
Electrical Properties ◽  
Volume Fraction ◽  
Matrix Material ◽  
Dc Conductivity ◽  
Critical Volume ◽  
Matrix Structure ◽  
Electrical Measurements ◽  
Conducting Component ◽  
Critical Volume Fraction ◽  
The Matrix

The microstructures of binary (conductor-insulator) composites, containing nanoparticles, will usually have one of two basic structures. The first is the matrix structure where the nanoparticles (granules) are embedded in and always coated by the matrix material and there are no particle-particle contacts. The AC and DC conductivity of this microstructure is usually described by the Maxwell-Wagner/Hashin-Shtrikman or Bricklayer model. The second is a percolation structure, which can be thought to be made up by randomly packing the two types of granules (not necessarily the same size) together. In percolation systems, there exits a critical volume fraction below which the electrical properties are dominated by the insulating component and above which the conducting component dominates. Such percolation systems are best analyzed using the two-exponent phenomenological percolation equation (TEPPE). This paper discusses all of the above and addresses the problem of how to distinguish among the microstructures using electrical measurements.

Effect of Mo microstructure on the critical volume fraction for conduction in Mo-alumina cermets

1997 ◽  
Vol 12 (3) ◽  
pp. 738-744 ◽  
Author(s):  
J. F. Kelso ◽  
R. R. Higgins ◽  
F. J. Krivda
Keyword(s):  
Volume Fraction ◽  
Critical Volume ◽  
Glass Content ◽  
Alumina Powder ◽  
Particle Sizes ◽  
Initial Particle ◽  
Electrical Percolation ◽  
Metal Contents ◽  
Critical Volume Fraction ◽  
The Matrix

The microstructure of Mo in an alumina/frit matrix was found to be dependent on the initial particle sizes of the alumina and Mo powders, the glass content in the matrix ceramic, and the amount of moisture in the firing atmosphere. The Mo microstructure had a significant influence on the critical volume fraction for conductivity in these cermets. Coarser alumina powder, finer Mo powder, and higher glass content promoted coalescence of Mo into conductive networks at lower metal contents. Drier firing atmospheres produced a more coarsened Mo microstructure with a slight decrease in the amount of network contiguity, causing an increase in the amount required for electrical percolation.

scholarly journals Predictive Computational Model for Damage Behavior of Metal-Matrix Composites Emphasizing the Effect of Particle Size and Volume Fraction

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2143
Author(s):  
Shaimaa I. Gad ◽  
Mohamed A. Attia ◽  
Mohamed A. Hassan ◽  
Ahmed G. El-Shafei
Keyword(s):  
Finite Element ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Particulate Composites ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Zone Method ◽  
Stress Strain ◽  
The Matrix

In this paper, an integrated numerical model is proposed to investigate the effects of particulate size and volume fraction on the deformation, damage, and failure behaviors of particulate-reinforced metal matrix composites (PRMMCs). In the framework of a random microstructure-based finite element modelling, the plastic deformation and ductile cracking of the matrix are, respectively, modelled using Johnson–Cook constitutive relation and Johnson–Cook ductile fracture model. The matrix-particle interface decohesion is simulated by employing the surface-based-cohesive zone method, while the particulate fracture is manipulated by the elastic–brittle cracking model, in which the damage evolution criterion depends on the fracture energy cracking criterion. A 2D nonlinear finite element model was developed using ABAQUS/Explicit commercial program for modelling and analyzing damage mechanisms of silicon carbide reinforced aluminum matrix composites. The predicted results have shown a good agreement with the experimental data in the forms of true stress–strain curves and failure shape. Unlike the existing models, the influence of the volume fraction and size of SiC particles on the deformation, damage mechanism, failure consequences, and stress–strain curve of A359/SiC particulate composites is investigated accounting for the different possible modes of failure simultaneously.

Constitutive Equations of Power-Law Composites and Failure of Materials Having Multiple Cracks

1994 ◽  
Vol 116 (3) ◽  
pp. 359-366 ◽  
Author(s):  
S. C. Lin ◽  
Y. Hirose ◽  
T. Mura
Keyword(s):  
Power Law ◽  
Constitutive Equations ◽  
Fracture Criterion ◽  
Volume Fraction ◽  
Piecewise Linear ◽  
Pure Shear ◽  
Failure Criteria ◽  
Multiple Cracks ◽  
Critical Volume Fraction ◽  
The Matrix

Based upon the Mori-Tanaka method, the constitutive equations of power-law materials and the failure criteria of multiple cracks materials are investigated. The piecewise linear incremental approach is also employed to analyze the effective stress and strain of the power-law materials. Results are presented for the case of pure shear where the matrix is a power-law material with rigid or void inhomogeneities. For the multiple cracked materials, the Griffith fracture criterion is applied to determine the critical volume fraction which causes the catastrophic failure of a material. The failure criteria of penny shaped, flat ellipsoidal, and slit-like cracked materials are examined and it is found that the volume fraction of cracks and critical applied stress are in linear relation.

scholarly journals Microstructural Modeling and Strengthening Mechanism of TiB/Ti-6Al-4V Discontinuously-Reinforced Titanium Matrix Composite

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 827 ◽  
Author(s):  
Shuai Zhao ◽  
Yangjian Xu ◽  
Changliang Pan ◽  
Lihua Liang ◽  
Xiaogui Wang
Keyword(s):  
Finite Element ◽  
Matrix Composite ◽  
Distribution Density ◽  
Volume Fraction ◽  
Element Model ◽  
Titanium Matrix ◽  
Titanium Matrix Composite ◽  
Finite Element Software ◽  
Multiple User ◽  
Thiessen Polygon

A novel modeling method was proposed to provide an improved representation of the actual microstructure of TiB/Ti-6Al-4V discontinuously-reinforced titanium matrix composite (DRTMC). Based on the Thiessen polygon structure, the representative volume element (RVE) containing the complex microstructures of the DRTMC was first generated. Thereafter, by using multiple user-defined subroutines in the commercial finite element software ABAQUS, the application of asymmetric mesh periodic boundary conditions on the RVE was realized, and the equivalent elastic modulus of the DRTMC was determined according to the homogenization method. Through error analyses on the experimental and calculated results regarding the equivalent elastic parameters of the DRTMC, the rationality of generating the DRTMC finite element model by using the present method was validated. Finally, simulations based on four types of network-like models revealed that the present simplifications to the particle shape of the reinforcement phase had less of an influence on the overall composite strength. Moreover, the present study demonstrates that the DRTMC enhancement is mainly attributed to the matrix strengthening, rather than the load-transferring mechanism. The strengthening influences of the distribution forms of the reinforcement phases, including their distribution density and orientation, were studied further. It was found that both the higher distribution density and limited distribution orientation of the particles would increase the probability of overlapping and merging between particles, and; therefore, higher strength could be yielded when the volume fraction of the reinforcement phase reached a certain threshold. Owing to the versatility of the developed methods and programs, this work can provide a useful reference for the characterization of the mechanical properties of other composites types.

scholarly journals Effects of Bentonite Nanoclay and Cetyltrimethyl Ammonium Bromide Modified Bentonite Nanoclay on Phase Inversion of Water-in-Oil Emulsions

2020 ◽  
Vol 4 (1) ◽  
pp. 2
Author(s):  
Sileola B. Ogunlaja ◽  
Rajinder Pal
Keyword(s):  
Contact Angle ◽  
Aqueous Phase ◽  
Phase Inversion ◽  
Volume Fraction ◽  
Critical Volume ◽  
Ammonium Bromide ◽  
Cetyltrimethyl Ammonium Bromide ◽  
Modified Bentonite ◽  
Critical Volume Fraction ◽  
Cetyltrimethyl Ammonium

The effects of unmodified and modified bentonite nanoclays (with various degrees of surfactant modification) on the catastrophic phase inversion from water-in-oil (W/O) emulsion to oil-in-water (O/W) emulsion were determined experimentally. The bentonite nanoclay (NC-Bt) was suspended in the aqueous phase, and the critical volume fraction of water where phase inversion from W/O to O/W emulsion took place was determined through conductivity measurements. Cetyltrimethyl ammonium bromide (CTAB) was used as a surfactant to modify the nanoclay. The adsorption of CTAB onto nanoclay had a strong influence on the contact angle and the critical volume fraction of water where phase inversion took place. The modification of the nanoclay brought about by the adsorption of CTAB increased the three-phase contact angle (measured through the aqueous phase), thereby making it more hydrophobic, and prolonged the phase inversion point. CTAB alone and CTAB-modified nanoclay delayed the phase inversion process in a similar manner, showing a strong dependence on the CTAB concentration.

scholarly journals Finite Element Simulation of the Thermo-mechanical Response of Graphene Reinforced Nanocomposites

2018 ◽  
Vol 188 ◽  
pp. 01016
Author(s):  
Androniki S. Tsiamaki ◽  
Nick K. Anifantis
Keyword(s):  
Finite Element ◽  
Mechanical Behavior ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Matrix Material ◽  
Continuum Theory ◽  
Element Model ◽  
Multilayer Graphene ◽  
Temperature Changes ◽  
The Matrix

The research for new materials that can withstand extreme temperatures and present good mechanical behavior is of great importance. The interest is highly focused on the utilization of composites reinforced by nanomaterials. To cope with this goal the present work studies the mechanical response of graphene reinforced nanocomposite structures subjected to temperature changes. A computational finite element model has been developed that accounts for both the reinforcement and the matrix material phases. The model developed is based on both the continuum theory and the molecular mechanics theory, for the simulation of the three different material phases of the composite, respectively, i.e. the matrix, the intermediate transition phase and the reinforcement. Considering this model, the mechanical response of an appropriate representative volume element of the nanocomposite is simulated under various temperature changes. The study involves different types of reinforcement composed from either monolayer or multilayer graphene sheets. Apart from the investigation of the behavior of a nanocomposite with each particular type of the reinforcement, comparisons are also presented between them in order to reveal optimized material combinations. The principal parameters taken into consideration, which contribute also to the mechanical behavior of the nanocomposite, are its size, the sheet multiplicity as well as the volume fraction.

Optimization Analysis for Radial Support by Finite Elements Method

2012 ◽  
Vol 466-467 ◽  
pp. 734-738
Author(s):  
Cheng Ming Li ◽  
Yi Fan Wang
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Optimal Solution ◽  
Support Point ◽  
Mirror Surface ◽  
Optimization Analysis ◽  
Primary Mirror ◽  
Finite Element Software ◽  
The Relationship ◽  
Surface Figure

Primary mirror’ surface figure is affected by supporting structure obviously. Especially for large-aperture telescope, the surface figure is significant because of primary mirror’ self-weight. For the requirement of the usage, it’s necessary to minimize the surface figure from self-weight by reasonable supporting scheme. The text optimized support point and force of radial support to minimize the surface figure by finite-element software. At the same time, it studied the relationship between support point and counterweight to reduce the weight of support structure. At last, it gave the optimal solution.

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