scholarly journals Preparation, Characterization, and Modeling of Carbon Nanofiber/Epoxy Nanocomposites

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Lan-Hui Sun ◽  
Zoubeida Ounaies ◽  
Xin-Lin Gao ◽  
Casey A. Whalen ◽  
Zhen-Guo Yang
Keyword(s):  
Electrical Properties ◽  
Young’S Modulus ◽  
Carbon Nanofiber ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Alternate Current ◽  
Epoxy Nanocomposites ◽  
Mechanical And Electrical Properties ◽  
Depth Study ◽  
Matrix Nanocomposites

There is a lack of systematic investigations on both mechanical and electrical properties of carbon nanofiber (CNF)-reinforced epoxy matrix nanocomposites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nanocomposites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nanocomposites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nanocomposite with a 1.0 wt% CNFs. The alternate-current (AC) electrical properties of the CNF/epoxy nanocomposites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt% (0.058 vol%) CNFs and by ten orders of magnitude for nanocomposites with CNF volume fractions higher than 1.0 wt% (0.578 vol%). The percolation threshold (i.e., the critical CNF volume fraction) is found to be at 0.057 vol%.

Evaluation of Decalcification Induced Changes in Bone Strength Using Electrical Conductivity Measurements

2014 ◽  
Author(s):  
Vladislav Sevostianov
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Cortical Bone ◽  
Young’S Modulus ◽  
Bone Strength ◽  
Acid Treatment ◽  
Bending Strength ◽  
Young's Modulus ◽  
Testing Machine ◽  
Mechanical And Electrical Properties

The paper focuses on the effect of decalcification on microstructure and the mechanical and electrical properties of cortical bone. Decalcification is produced by placing the specimens into 5% vinegar acid for 72 hours. This acid treatment leads to a decrease in mass of the specimens 7.78 % (averaged over ten acid treated specimens). Microstructure of natural bone and acid treated bone is then compared using confocal microscopy. To estimate effect of acid treatment on electrical resistivity of bone, the specimens are rinsed and saturated with 0.9% NaCl solution for ten minutes. Then electrical resistance is measured by the four-point method and electrical resistivity is calculated. Averaging over ten acid treated specimens and ten control specimens show that decalcification lead to increase of electrical resistivity 5.85 times. Comparison of mechanical properties of natural and acid treated bones is done by three point bending using Instron 5882 testing machine. It is observed that 7.78 % mass loss in cortical bone yields reduction of the Young’s modulus about 2.7 times and bending strength of the specimens by 35%. A positive correlation between change in strength and Young’s modulus and electrical resistivity of the individual specimens is observed. The obtained results allows one to estimate changes in mechanical and electrical properties of bone from known losses in bone mass and, thus, non-destructively evaluate the decrease in bone strength through changes in electrical resistivity.

scholarly journals Mechanical and Electrical Properties of Epoxy Composites Modified by Functionalized Multiwalled Carbon Nanotubes

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3325
Author(s):  
Paweł Smoleń ◽  
Tomasz Czujko ◽  
Zenon Komorek ◽  
Dominik Grochala ◽  
Anna Rutkowska ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Strength ◽  
Electrical Properties ◽  
Young’S Modulus ◽  
Multiwalled Carbon Nanotubes ◽  
Young's Modulus ◽  
Epoxy Composites ◽  
Multiwalled Carbon ◽  
Mechanical And Electrical Properties ◽  
Functionalized Multiwalled Carbon Nanotubes

This paper investigates the effect of multiwalled carbon nanotubes on the mechanical and electrical properties of epoxy resins and epoxy composites. The research concerns multiwalled carbon nanotubes obtained by catalytic chemical vapor deposition, subjected to purification processes and covalent functionalization by depositing functional groups on their surfaces. The study included the analysis of the change in DC resistivity, tensile strength, strain, and Young’s modulus with the addition of carbon nanotubes in the range of 0 to 2.5 wt.%. The effect of agents intended to increase the affinity of the nanomaterial to the polymer on the aforementioned properties was also investigated. The addition of functionalized multiwalled carbon nanotubes allowed us to obtain electrically conductive materials. For all materials, the percolation threshold was obtained with 1% addition of multiwalled carbon nanotubes, and filling the polymer with a higher content of carbon nanotubes increased its conductivity. The use of carbon nanotubes as polymer reinforcement allows higher values of tensile strength and a higher strain percentage to be achieved. In contrast, Young’s modulus values did not increase significantly, and higher nanofiller percentages resulted in a drastic decrease in the values of the abovementioned properties.

Manufacturing and Measuring Mechanical Properties of Continuous Functionally Graded Beam

2021 ◽  
Vol 21 (2) ◽  
pp. 7-11
Author(s):  
Ahmed Mansoor Abbood ◽  
Haider K. Mehbes ◽  
Abdulkareem. F. Hasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Functionally Graded ◽  
High Concentration ◽  
Functionally Graded Beam ◽  
Low Concentration ◽  
Graded Material ◽  
Vertical Gravity

In this study, glass-filled epoxy functionally graded material (FGM) was prepared by adopting the hand lay-up method. The vertical gravity casting was used to produce a continuous variation in elastic properties. A 30 % volume fraction of glass ingredients that have mean diameter 90 μm was spread in epoxy resin (ρ = 1050 kg/m3). The mechanical properties of FGM were evaluated according to ASTM D638. Experimental results showed that a gradually relationship between Young’s modulus and volume fraction of glass particles, where the value of Young’s modulus at high concentration of glass particles was greater than that at low concentration, while the value of Poisson’s ratio at high concentration of glass particles was lower than that at low concentration. The manufacture of this FG beam is particularly important and useful in order to benefit from it in the field of various fracture tests under dynamic or cyclic loads.

Cellulose Whiskers Micro-Fibers Effect in the Mechanical Proprieties of PP and PLA Composites Fibers Obtained by Spinning Process

2011 ◽  
Vol 146 ◽  
pp. 12-26 ◽  
Author(s):  
A. Gherissi ◽  
R.Ben Cheikh ◽  
E. Dévaux ◽  
Fethi Abbassi
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Tensile Tests ◽  
Advanced Materials ◽  
Uniaxial Tensile ◽  
Failure Resistance ◽  
Cellulose Whiskers ◽  
Limit Strength

In this study, we present the manufacturing process of two new composites materials in the form of long fibers of polylactic-acid (PLA) or polypropylene (PP), reinforced by cellulose whiskers micro-fibers loads. In order to evaluate the mechanical properties of these advanced materials, a several uniaxial tensile tests were carried out. The PP and the PLA have initially been spinning without the addition of cellulose whiskers micro-fibers. In order to study the effects of cellulose whiskers micro-fibers reinforcements in the Mechanical behavior of the PLA and PP filaments, we determinate the proprieties of these advanced material from the tensile results. For the PP composite filaments material case, the whiskers reinforcement increases Young's modulus and failure resistance, but it reduces the limit strength failure. For the PLA composites the addition of 1% wt of cellulose whiskers from the total volume fraction of the material, increase the Young’s modulus more than 50% and a decrease of the failure resistance and the limit strength of composite. The obtained composites fibers are very rigid and brittle. What follows, that the addition of cellulose whiskers micro fibers in PP matrix, provides mechanical properties more convenient compared to the PLA matrix.

Determination of mechanical properties of FFF 3D printed material by assessing void volume fraction, cooling rate and residual thermal stresses

2019 ◽  
Vol 25 (10) ◽  
pp. 1661-1683 ◽  
Author(s):  
Rafael Quelho de Macedo ◽  
Rafael Thiago Luiz Ferreira ◽  
Kuzhichalil Jayachandran
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Young’S Modulus ◽  
Thermal Stresses ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Void Volume Fraction ◽  
Void Volume ◽  
Temperature Fields ◽  
Content Type

Purpose This paper aims to present experimental and numerical analyses of fused filament fabrication (FFF) printed parts and show how mechanical characteristics of printed ABS-MG94 (acrylonitrile butadiene styrene) are influenced by the void volume fraction, cooling rate and residual thermal stresses. Design/methodology/approach Printed specimens were experimentally tested to evaluate the mechanical properties for different printing speeds, and micrographs were taken. A thermo-mechanical finite element model, able to simulate the FFF process, was developed to calculate the temperature fields in time, cooling rate and residual thermal stresses. Finally, the experimental mechanical properties and the microstructure distribution could be explained by the temperature fields in time, cooling rate and residual thermal stresses. Findings Micrographs revealed the increase of void volume fraction with the printing speed. The variations on voids were associated to the temperature fields in time: when the temperatures remained high for longer periods, less voids were generated. The Young's Modulus of the deposited filament varied according to the cooling rate: it decreased when the cooling rate increased. The influence of the residual thermal stresses and void volume fraction on the printed parts failure was also investigated: in the worst scenarios evaluated, the void volume fraction reduced the strength in 9 per cent, while the residual thermal stresses reduced it in 3.8 per cent. Originality/value This work explains how the temperature fields can affect the void volume fraction, Young's Modulus and failure of printed parts. Experimental and numerical results are shown. The presented research can be used to choose printing parameters to achieve desired mechanical properties of FFF printed parts.

scholarly journals Mechanical and Electrical Properties of Glass and Carbon Fiber-Reinforced Composites

1991 ◽  
Vol 113 (3) ◽  
pp. 176-181 ◽  
Author(s):  
G. R. Headifen ◽  
E. P. Fahrenthold
Keyword(s):  
Electrical Properties ◽  
Volume Fraction ◽  
High Energy ◽  
Composite Fiber ◽  
Pulsed Power ◽  
High Energy Density ◽  
Fiber Reinforced ◽  
Dynamics Modeling ◽  
Mechanical And Electrical Properties ◽  
Strength And Stiffness

The design of composite rotors for high-energy density pulsed power supplies demands accurate characterization of both the mechanical and electrical properties of fiber-reinforced epoxy. The mechanical properties of S-2 glass-epoxy, IM6 graphite-epoxy, and hybrid graphite-glass epoxy composites were measured in tension and torsion tests, providing strength and stiffness parameters for rotor dynamics modeling. Variable frequency electrical resistivity tests were conducted to allow estimation of eddy current losses arising in carbon-reinforced materials. Volume fraction measurements using electron microscopy and analysis by digestion allow for normalization of the test results with respect to composite fiber content. The experimental results were used to evaluate the micromechanical rule of mixtures and Halpin-Tsai correlations.

The Mechanical and Electrical Properties of a Single Carbon Nanofiber Induced by Applying Tensile Strain

2015 ◽  
Vol 15 (11) ◽  
pp. 8711-8715 ◽  
Author(s):  
Sang Koo Jeon ◽  
Hoon-Sik Jang ◽  
Nam Hee Lee ◽  
Oh Heon Kwon ◽  
Seung Hoon Nahm
Keyword(s):  
Electrical Properties ◽  
Tensile Strain ◽  
Carbon Nanofiber ◽  
Mechanical And Electrical Properties

Fibers of Bamboo and Hem Palm Tree

2001 ◽  
Vol 702 ◽  
Author(s):  
Shigeyasu Amada
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Volume Fraction ◽  
Young's Modulus ◽  
Simple Procedure ◽  
High Strength ◽  
Tensile Tests ◽  
Palm Tree ◽  
Bamboo Fibers ◽  
The One

ABSTRACTBamboo is a typical composite material which is axially reinforced by very strong fibers. So that, the fibers play an important role for the bamboo structure. The elastic properties of the bamboo culm have been measured only by tensile test so far, which needs a large specimen. Recently ultra-sonic technique, which has a simple procedure and uses a small specimen, has been applied to woods as well as metals. This report reviews about the elastic properties of bamboo and Hemp palm fibers. The Young's modulus and Poisson's ratio of the bamboo fibers are measured by ultra-sonic method with a transmitting wave. On the other hand, the strength of the bamboo and Hemp palm fibers are measured by the tensile tests. Using the volume fraction of fibers in the specimen and mixture principle, the Young's modulus and strength of the fibers and parenchyma were obtained. The fiber has a high strength up to 1GPa and an strong anisotropic property because its axial Young's modulus has 7 times higher than the one in the transverse direction.

Design Optimization of Material Properties in a Particle-Filled Composite Material System

2008 ◽  
Author(s):  
Siva P. Gurrum ◽  
Jie-Hua Zhao ◽  
Darvin R. Edwards
Keyword(s):  
Composite Material ◽  
Young’S Modulus ◽  
Material Properties ◽  
Poisson’S Ratio ◽  
Volume Fraction ◽  
Filler Content ◽  
Young's Modulus ◽  
Random Packing ◽  
Poisson's Ratio ◽  
Analytical Models

This work presents a methodology implementing random packing of spheres combined with commercial finite element method (FEM) software to optimize the material properties, such as Young’s modulus, Poisson’s ratio, coefficient of thermal expansion (CTE) of two-phase materials used in electronic packaging. The methodology includes an implementation of a numerical algorithm of random packing of spheres and a technique for creating conformal FEM mesh of a large aggregate of particles embedded in a medium. We explored the random packing of spheres with different diameters using particle generation algorithms coded in MATLAB. The FEM meshes were generated using MATLAB and TETGEN. After importing the nodes and elements databases into commercial FEM software ANSYS, the composite materials with spherical fillers and the polymer matrix were modeled using ANSYS. The effective Young’s modulus, Poisson’s ratio, and CTE along different axes were calculated using ANSYS by applying proper loading and boundary conditions. It was found that the composite material was virtually isotropic. The Young’s modulus and Poisson’s ratio calculated by FEM models were compared to a number of analytical solutions in the literature. For low volume fraction of filler content, the FEM results and analytical solutions agree well. However, for high volume fraction of filler content, there is some discrepancy between FEM and analytical models and also among the analytical models themselves.

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