Determination of mechanical properties of two-phase and hybrid nanocomposites: experimental determination and multiscale modeling

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Haghighi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi
Keyword(s):  
Mechanical Properties ◽  
Ultimate Strength ◽  
Multiscale Modeling ◽  
Filler Content ◽  
Hybrid Nanocomposites ◽  
Dynamics Simulation ◽  
Strength Increase ◽  
Two Phase ◽  
Macro Scale ◽  
Elongation To Failure

Abstract In this paper, the effects of filler content and the use of hybrid nanofillers on agglomeration and nanocomposite mechanical properties such as elastic moduli, ultimate strength and elongation to failure are investigated experimentally. In addition, thermoset epoxy-based two-phase and hybrid nanocomposites are simulated using multiscale modeling techniques. First, molecular dynamics simulation is carried out at nanoscale considering the interphase. Next, finite element method and micromechanical modeling are used for micro and macro scale modeling of nanocomposites. Nanocomposite samples containing carbon nanotubes, graphene nanoplatelets, and hybrid nanofillers with different filler contents are prepared and are tested. Also, field emission scanning electron microscopy is used to take micrographs from samples’ fracture surfaces. The results indicate that in two-phase nanocomposites, elastic modulus and ultimate strength increase while nanocomposite elongation to failure decreases with reinforcement weight fraction. In addition, nanofiller agglomeration occurred at high nanofiller contents especially higher than 0.75 wt% in the two-phase nanocomposites. Nanofiller agglomeration was observed to be much lower in the hybrid nanocomposite samples. Therefore, using hybrid nanofillers delays/prevents agglomeration and improves mechanical properties of nanocomposite at the same total filler content.

Two modified multiscale modeling approaches for determination of two-phase and hybrid nanocomposite properties

2021 ◽  
pp. 095440622110303
Author(s):  
Ali Khodadadi ◽  
Hossein Golestanian ◽  
Farshid Aghadavoudi
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Multiscale Modeling ◽  
Md Simulations ◽  
Hybrid Nanocomposites ◽  
Hybrid Nanocomposite ◽  
Fiber Volume ◽  
Two Phase ◽  
Epoxy Nanocomposite ◽  
Modeling Approaches

In this paper, mechanical properties of thermoset epoxy based two-phase and hybrid nanocomposites containing carbon nanotubes (CNTs), and carbon nano diamond particles (CNPs) are determined using two different multiscale modeling approaches. The effects of resin crosslinking, interphase mechanical properties, and filler agglomeration on nanocomposite mechanical properties are investigated. First, the crosslinking between Diglycidyl ether of bisphenol A (DGEBA) resin and Diethylenetriamine (DETA) hardener is modeled considering different crosslinking forms and ratios using molecular dynamics (MD) simulations. Results indicate that resin elastic modulus increases with increasing the crosslinking ratio especially above 75%, but crosslinking form has an insignificant effect on resin modulus. Next, different nanofillers and their interphases are modeled using MD simulations to determine the representative volume element (RVE) and the effective fiber sizes and mechanical properties. The thickness of the interphase for each nano filler type is determined from the radial distribution function (RDF) diagram in order to determine the effective fiber volume more realistically. Then, the general Halpin-Tsai model is modified by adding an interphase volume factor and is used to determine two-phase and hybrid nanocomposite mechanical properties using effective nano filler properties. In addition, a new numerical multiscale modeling technique was developed which uses the MD-determined effective filler properties along with finite element method (FEM) to determine nanocomposite mechanical properties. Nanocomposites reinforced with aligned and randomly oriented reinforcements are modeled. Good agreement is observed between the two multiscale modeling techniques for the two-phase nanocomposite mechanical properties. Finally, the effect of filler agglomeration on nanocomposite properties is investigated. The results indicate that agglomeration decreases elastic modulus of CNT/epoxy nanocomposite. However, agglomeration does not have a significant effect on elastic modulus of CNP/epoxy nanocomposite.

scholarly journals Preparation and mechanical properties of Nanoclay-MWCNT/Epoxy hybrid nanocomposites

2021 ◽  
Vol 2 (1) ◽  
pp. 17
Author(s):  
Sunil Kumar ◽  
Arun Gupta
Keyword(s):  
Mechanical Properties ◽  
Epoxy Resin ◽  
Filler Content ◽  
Hybrid Composites ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Polymer Composite Material ◽  
Hybrid Nanocomposites ◽  
Content Increase ◽  
Carbon Nano Tubes

<p>Among the various kinds of reinforcing element, Multi Wall Carbon Nano-tubes (MWCNT) and Nanoclay have found much more attention as a filler element to upgrade the mechanical properties of polymer composite material. In this paper, production of hybrid nanocomposites and the effect of MWCNT and nanoclay on mechanical properties of hybrid nanocomposites have been evaluated. In hybrid nanocomposites, MWCNT and nanoclay are embedded in epoxy resin. The processing of hybrid nanocomposite is always been a difficult task for researcher to prepare defects free samples. Here, the processing of Epoxy/Nanoclay-MWCNT hybrid composites has been done by using homogenizer and ultrasonic techniques for complete dispersion of nanoparticles into epoxy resin. The MWCNT and nanoclay were embedded into epoxy resin in different weight fractions and mixtures were used for tensile test and hardness specimen production. The tensile modulus and tensile strength values have been calculated via tensile tests. The test result shows that tensile modulus of samples increases as the filler content increase up to certain extent but then start decreasing. Also the elongation reduces as the filler content rises in the epoxy which shows the brittleness present in the samples. Rockwell hardness on B-scale was conducted on Nanocomposite samples and found that increasing the filler content excessively does not improve hardness as much.</p>

scholarly journals Effect of the Ti6Al4V Alloy Track Trajectories on Mechanical Properties in Direct Metal Deposition

Machines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 79
Author(s):  
Ivan Erdakov ◽  
Lev Glebov ◽  
Kirill Pashkeev ◽  
Vitaly Bykov ◽  
Anastasia Bryk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Ultimate Strength ◽  
Ti6al4v Alloy ◽  
Laser Deposition ◽  
Laser Alloying ◽  
Laser Melting ◽  
Two Phase ◽  
Phase Condition ◽  
Direct Laser ◽  
First Time

The TiAl6V4 alloy is widely used in selective laser melting and direct laser melting. In turn, works devoted to the issue of how the track stacking scheme affects the value of mechanical properties is not enough. The influence of the Ti6Al4V alloy track trajectories on the microstructure and mechanical properties during direct laser deposition is studied in this article for the first time. The results were obtained on the influence of «parallel» and «perpendicular» technique of laying tracks in direct laser synthesis. All studied samples have a microstructure typical of the hardened two-phase condition titanium. Here, it is shown that the method of laying tracks and the direction of load application during compression testing relative to the location of the tracks leads to a change in the ultimate strength of the Ti-6Al-4V alloy from 1794 to 1910 MPa. The plasticity of the Ti-6Al-4V alloy obtained by direct laser alloying can vary from 21.3 to 33.0% depending on the direction of laying the tracks and the direction of the compression test. The hardness of alloys varies in the range from 409 to 511 HV and depends on the method of laying the tracks and the direction of hardness measurements.

scholarly journals Effect of Angle, Temperature and Vacancy Defects on Mechanical Properties of PSI-Graphene

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 238 ◽  
Author(s):  
Lu Xie ◽  
Tingwei Sun ◽  
Chenwei He ◽  
Haojie An ◽  
Qin Qin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Ultimate Strength ◽  
Fracture Morphology ◽  
Dynamics Simulation ◽  
Dimensional Structure ◽  
Two Dimensional ◽  
Carbon Allotrope ◽  
Vacancy Defects ◽  
Carbon Structures

The PSI-graphene, a two-dimensional structure, was a novel carbon allotrope. In this paper, based on molecular dynamics simulation, the effects of stretching direction, temperature and vacancy defects on the mechanical properties of PSI-graphene were studied. We found that when PSI-graphene was stretched along 0° and 90° at 300 K, the ultimate strength reached a maximum of about 65 GPa. And when stretched along 54.2° and 155.2° at 300 K, the Young’s modulus had peaks, which were 1105 GPa and 2082 GPa, respectively. In addition, when the temperature was raised from 300 K to 900 K, the ultimate strength in all directions was reduced. The fracture morphology of PSI-graphene stretched at different angles was also shown in the text. In addition, the number of points removed from PSI-graphene sheet also seriously affected the tensile properties of the material. It was found that, compared with graphene, PSI-graphene didn’t have the negative Poisson’s ratio phenomenon when it was stretched along the direction of 0°, 11.2°, 24.8° and 34.7°. Our results provided a reference for studying the multi-angle stretching of other carbon structures at various temperatures.

Microstructural and Mechanical Properties of Al 7003 Alloy Processed by Dual Equal Channel Lateral Extrusion

2014 ◽  
Vol 852 ◽  
pp. 214-218
Author(s):  
Zhao Hua Liu ◽  
Hua Rong Qi ◽  
Xiao Wang ◽  
Shi Qi ◽  
Nan Qing
Keyword(s):  
Mechanical Properties ◽  
Tensile Yield Strength ◽  
Strength Increase ◽  
Deformation Bands ◽  
Lateral Extrusion ◽  
Elongation To Failure ◽  
Dislocation Cells ◽  
Average Size ◽  
Tensile Strength Increase ◽  
Ultimate Tensile Strength Increase

In this paper, the Al 7003 alloy in the as-annealed condition was processed by dual equal channel lateral extrusion (DECLE) at room temperature. The microstructure and mechanical properties of the as-annealed and DECLEed alloys were examined. The results showed that the microstructure of as-annealed Al 7003 alloys was refined by the formation of deformation bands, with dislocation cells and subgrains inside these bands. The final grains with an average size of about 250nm are observed. Due to DECLE, tensile yield strength and ultimate tensile strength increase by 84.5%, 35.4%, respectively. Meanwhile, elongation to failure decreases by 40.4%. The fracture was characterized by ductile fracture due to existence of a large number of dimples.

Particle Redistribution and Grain Refinement during Processing by Hydrostatic Extrusion

2008 ◽  
Vol 584-586 ◽  
pp. 541-546 ◽  
Author(s):  
Kinga Wawer ◽  
Małgorzata Lewandowska ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Grain Refinement ◽  
Hydrostatic Extrusion ◽  
Strength Increase ◽  
Two Phase ◽  
Size Refinement ◽  
Cast Alloys ◽  
Tensile Strength Increase

In this study particle redistribution and grain size refinement induced by hydrostatic extrusion (HE) have been studied in two Al-Si cast alloys (Al-9%Si and Al-11%Si). It has been found that HE results in a significant changes in particle shape, size and distribution which was revealed by SEM observations and quantified using stereological parameters. At the same time, significant grain refinement down to ~100 nm in diameter takes place in aluminium phase. Such a microstructure evolution affects substantially the mechanical properties of two-phase alloys. The yield strength and tensile strength increase over two times whereas the plasticity only slightly decreases.

scholarly journals Piezoresistive Characteristics of Nanocarbon Composite Strain Sensor by Its Longitudinal Pattern Design

2021 ◽  
Vol 11 (13) ◽  
pp. 5760
Author(s):  
Sung-Yong Kim ◽  
Baek-Gyu Choi ◽  
Gwang-Won Oh ◽  
Chan-Jung Kim ◽  
Young-Seok Jung ◽  
...  
Keyword(s):  
Axial Load ◽  
Filler Content ◽  
Factor Model ◽  
Strain Sensor ◽  
Gauge Factor ◽  
Geometric Pattern ◽  
Pattern Design ◽  
Macro Scale ◽  
Composite Strain ◽  
Longitudinal Pattern

For an engineering feasibility study, we studied a simple design to improve NCSS (nanocarbon composite strain sensor) sensitivity by using its geometric pattern at a macro scale. We fabricated bulk- and grid-type sensors with different filler content weights (wt.%) and different sensor lengths and investigated their sensitivity characteristics. We also proposed a unit gauge factor model of NCSS to find a correlation between sensor length and its sensitivity. NCSS sensitivity was improved proportional to its length incremental ratio and we were able to achieve better linear and consistent data from the grid type than the bulk type one. We conclude that the longer sensor length results in a larger change of resistance due to its piezoresistive unit summation and that sensor geometric pattern design is one of the important issues for axial load and deformation measurement.

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