scholarly journals Effect of Stone-Wales Defect on Mechanical Properties of Gr/epoxy Nanocomposites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1116 ◽  
Author(s):  
Maoyuan Li ◽  
Peng Chen ◽  
Bing Zheng ◽  
Tianzhengxiong Deng ◽  
Yun Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
High Performance ◽  
Volume Fraction ◽  
Epoxy Nanocomposites ◽  
Dynamic Simulations ◽  
Plane Shear ◽  
High Performance Polymer ◽  
Superior Mechanical Properties ◽  
Perfect Graphene

Due to its superior mechanical properties, graphene (Gr) has the potential to achieve high performance polymer-based nanocomposites. Previous studies have proved that defects in the Gr sheets could greatly reduce the mechanical properties of Gr, while the Stone-Wales (SW) defect was found to enhance the interfacial mechanical strength between Gr and epoxy. However, the combined effects of defects on the overall mechanical properties of Gr/epoxy nanocomposites have not been well understood. In this paper, the effect of the SW defect on the mechanical properties of Gr/epoxy nanocomposites was systematically investigated by using molecular dynamic simulations. The simulation results showed that the SW defect would degrade the mechanical properties of nanocomposites, including the Young’s modulus and in-plane shear modulus. Surprisingly, the transverse shear modulus could be remarkably enhanced with the existence of SW. The reinforcing mechanisms were mainly due to two aspects: (1) the SW defect could increase the surface roughness of the Gr, preventing the slippage between Gr and epoxy during the transverse shea; and (2) the nanocomposite with defective Gr enables a higher interaction energy than that with perfect graphene. Additionally, the effects of temperature, the dispersion and volume fraction of Gr were also investigated.

Macroprobe Mode for the Study of Segregation in Steels

1990 ◽  
Vol 48 (2) ◽  
pp. 260-261
Author(s):  
Auclair Gilles ◽  
Benoit Danièle
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
High Performance ◽  
Volume Fraction ◽  
Sheet Steel ◽  
Acquisition Time ◽  
Chemical Information ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Optical Micrographs

During these last 10 years, high performance correction procedures have been developed for classical EPMA, and it is nowadays possible to obtain accurate quantitative analysis even for soft X-ray radiations. It is also possible to perform EPMA by adapting this accurate quantitative procedures to unusual applications such as the measurement of the segregation on wide areas in as-cast and sheet steel products.The main objection for analysis of segregation in steel by means of a line-scan mode is that it requires a very heavy sampling plan to make sure that the most significant points are analyzed. Moreover only local chemical information is obtained whereas mechanical properties are also dependant on the volume fraction and the spatial distribution of highly segregated zones. For these reasons we have chosen to systematically acquire X-ray calibrated mappings which give pictures similar to optical micrographs. Although mapping requires lengthy acquisition time there is a corresponding increase in the information given by image anlysis.

Impact of Steel Fibers on Workability and Properties of UHPC

2016 ◽  
Vol 249 ◽  
pp. 57-61 ◽  
Author(s):  
Milan Rydval ◽  
Tomáš Bittner ◽  
Jiří Kolísko ◽  
Šárka Nenadálová
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Fresh Concrete ◽  
Mixture Design ◽  
Steel Fibers ◽  
Hardened Concrete ◽  
Hardened Cement ◽  
The Impact

This paper is focused on properties of fresh and hardened cement-based composite Ultra-High Performance Concrete with regard to different volume fraction of short brass coated steel fibers BASF MASTERFIBER® 482. Workability of fresh concrete and basic mechanical properties (tensile strength in bending, compressive strength) of hardened UHPC were found out. The workability of fresh concrete was measured by small mortar Haegermann cone. Percentage differences at cost were obtained at hardened concrete, too. The aim of the first experimental part of the research was the impact of volume fraction of steel fibers according to workability of fresh concrete and also according to mechanical properties of hardened UHPC with the same volume fraction of each component of the mixture, only the volume fraction of the steel fibers was different at each mixture. The mixture design of UHPC was changed to maintaining the workability of fresh concrete at the second part of the research. The workability at mixture with dosage of steel fibers of 300 kg/m3 measured by Haegermann cone was around 300 mm. In the framework of grant project GAČR 15-05791S the basic mechanical properties of hardened fine-grained cementitious composite material UHPC at small beams size of 160/40/40 mm and beams size 300/70/70 mm were determined. The aim of the research project was not only the determination of basic mechanical properties for each mixture design but also workability assessment and costs linked with higher amount of the volume fracture of steel fibers.

Fabrication and Mechanical Properties of Glass Fiber/Epoxy Nanocomposites

2006 ◽  
Vol 505-507 ◽  
pp. 37-42 ◽  
Author(s):  
Jia Lin Tsai ◽  
Jui Ching Kuo ◽  
Shin Ming Hsu
Keyword(s):  
Mechanical Properties ◽  
Shear Stress ◽  
Shear Strength ◽  
Glass Fiber ◽  
Shear Failure ◽  
Epoxy Nanocomposites ◽  
Plane Shear ◽  
Epoxy Nanocomposite ◽  
Transverse Normal Stress ◽  
Mechanical Mixer

This research is aimed to fabricate glass fiber/epoxy nanocomposites containing organoclay as well as to understand the organoclay effect on the in-plane shear strength of the nanocomposites. To demonstrate the organoclay effect, three different loadings of organoclay, were dispersed in the epoxy resin using mechanical mixer followed by sonication. The corresponding glass/epoxy nanocomposites were prepared by impregnating the organoclay epoxy mixture into the dry glass fiber through a vacuum hand lay-up process. Off-axis block glass/epoxy nanocomposites were tested in compression to produce in-plane shear failure. It is noted only the specimens showing in-plane shear failure mode were concerned in this study. Through coordinate transformation law, the uniaxial failure stresses were then converted to a plot of shear stress versus transverse normal stress from which the in-plane shear strength was obtained. Experimental results showed that the fiber/epoxy nanocomposite exhibit higher in-plane shear strength than the conventional composites. This increased property could be ascribed to the enhanced fiber/matrix adhesion promoted by the organoclay.

Moisture Effect on Mechanical Properties of Graphene/Epoxy Nanocomposites

2016 ◽  
Vol 32 (6) ◽  
pp. 673-682 ◽  
Author(s):  
H.-K. Liu ◽  
Y.-C. Wang ◽  
T.-H. Huang
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Moisture Absorption ◽  
Graphene Nanosheets ◽  
Salt Water ◽  
Testing Machine ◽  
Weight Fraction ◽  
Epoxy Nanocomposites ◽  
Moisture Effect ◽  
Superior Mechanical Properties

Abstract2-D graphene nanosheets (GNS) not only have superior mechanical properties, but stacking of GNS in composites is expected to inhibit moisture absorption. In this paper, moisture effect on tensile strength of graphene/epoxy nanocomposites is investigated. Two kinds of graphene reinforcements are used including graphene oxide (GO) and reduced graphene oxide (RGO) with reinforcement weight fraction WGO or WRGO in the range of 0.5 to 3.0wt%. A dispersion agent acetone is added in nanocomposites to enhance graphene dispersion. To evaluate moisture influence, those nanocomposites are soaked in two kinds of liquid including deionized water (DIW) and salt water (saline solution) for seven kinds of soaking periods of time including 24, 48, 72, 100, 400 hours, 30 days, and 60 days. After soaking test, diffusion coefficients of various composites are evaluated; besides tensile strengths of composites are measured by microforce testing machine. In order to correlate the strength with microstructure evolution, several techniques are adopted to analyze morphologies and functionalities of reinforcements and fracture surface of composites. They include Raman spectroscope, X-ray photoelectron spectroscope, and SEM. 2-D GNS are found to effectively enhance nanocomposites by moisture attack, and their corresponding reinforcing mechanisms are proposed.

The effect of bis allyl benzoxazine on the thermal, mechanical and dielectric properties of bismaleimide–cyanate blend polymers

RSC Advances ◽  
2015 ◽  
Vol 5 (72) ◽  
pp. 58821-58831 ◽  
Author(s):  
Yiqun Wang ◽  
Kaichang Kou ◽  
Guanglei Wu ◽  
Ailing Feng ◽  
Longhai Zhuo
Keyword(s):  
Mechanical Properties ◽  
Dielectric Properties ◽  
Polymer Composite ◽  
High Performance ◽  
Cross Linking ◽  
Thermal And Mechanical Properties ◽  
High Performance Polymer ◽  
The Cross

A high-performance polymer composite was fabricated using Bz-allyl/BMI/BADCy resin, in which the BMI/BADCy resin was modified with Bz-allyl to improve its dielectric, thermal and mechanical properties and the cross-linking degree after curing.

scholarly journals Nanocellulose and nanoclay as reinforcement materials in polymer composites: A review

2020 ◽  
Vol 16 (2) ◽  
pp. 145-153
Author(s):  
Fathin Najihah Nor Mohd Hussin ◽  
Roswanira Abdul Wahab ◽  
Nursyafreena Attan
Keyword(s):  
Mechanical Properties ◽  
Thermal Properties ◽  
Environmental Impact ◽  
Polymer Composites ◽  
Polymer Nanocomposites ◽  
High Performance ◽  
Reinforced Polymer ◽  
Low Weight ◽  
High Performance Polymer ◽  
Strength And Stiffness

The advancement of nanotechnology has opened a new opportunity to develop nanocomposites using nanocellulose (NC) and nanoclay (NCl). Researchers have regarded these nanocomposites as promising substitutes for conventional polymers because of their characteristic and useful features, which include exceptional strength and stiffness, low weight, and low environmental impact. These features of NC and NCl explain their multifarious applications across many sectors. Here we review NC and NCl as well as various reinforced polymer composites that are made up of either of the two nanomaterials. The structural and physicochemical properties of NC and NCl are highlighted, along with the mechanical behavior and thermal properties of NC. Current nanomaterial hybrid biopolymers for the production of novel high-performance polymer nanocomposites are also discussed with respect to their mechanical properties.

scholarly journals Bone-inspired microarchitectures achieve enhanced fatigue life

2019 ◽  
Vol 116 (49) ◽  
pp. 24457-24462 ◽  
Author(s):  
Ashley M. Torres ◽  
Adwait A. Trikanad ◽  
Cameron A. Aubin ◽  
Floor M. Lambers ◽  
Marysol Luna ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fatigue Life ◽  
Cancellous Bone ◽  
High Performance ◽  
Mechanical Performance ◽  
Lattice Structures ◽  
Structural Elements ◽  
Naturally Occurring ◽  
Superior Mechanical Properties ◽  
The Cost

Microarchitectured materials achieve superior mechanical properties through geometry rather than composition. Although ultralightweight microarchitectured materials can have high stiffness and strength, application to durable devices will require sufficient service life under cyclic loading. Naturally occurring materials provide useful models for high-performance materials. Here, we show that in cancellous bone, a naturally occurring lightweight microarchitectured material, resistance to fatigue failure is sensitive to a microarchitectural trait that has negligible effects on stiffness and strength—the proportion of material oriented transverse to applied loads. Using models generated with additive manufacturing, we show that small increases in the thickness of elements oriented transverse to loading can increase fatigue life by 10 to 100 times, far exceeding what is expected from the associated change in density. Transversely oriented struts enhance resistance to fatigue by acting as sacrificial elements. We show that this mechanism is also present in synthetic microlattice structures, where fatigue life can be altered by 5 to 9 times with only negligible changes in density and stiffness. The effects of microstructure on fatigue life in cancellous bone and lattice structures are described empirically by normalizing stress in traditional stress vs. life (S-N) curves by √ψ, where ψ is the proportion of material oriented transverse to load. The mechanical performance of cancellous bone and microarchitectured materials is enhanced by aligning structural elements with expected loading; our findings demonstrate that this strategy comes at the cost of reduced fatigue life, with consequences to the use of microarchitectured materials in durable devices and to human health in the context of osteoporosis.

scholarly journals Compressive Behavior Characteristics of High-Performance Slurry-Infiltrated Fiber-Reinforced Cementitious Composites (SIFRCCs) under Uniaxial Compressive Stress

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 159 ◽  
Author(s):  
Seungwon Kim ◽  
Seungyeon Han ◽  
Cheolwoo Park ◽  
Kyong-Ku Yun
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Compressive Stress ◽  
High Performance ◽  
Volume Fraction ◽  
Fiber Reinforced Concrete ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Fiber Volume ◽  
Behavior Characteristics

The compressive stress of concrete is used as a design variable for reinforced concrete structures in design standards. However, as the performance-based design is being used with increasing varieties and strengths of concrete and reinforcement bars, mechanical properties other than the compressive stress of concrete are sometimes used as major design variables. In particular, the evaluation of the mechanical properties of concrete is crucial when using fiber-reinforced concrete. Studies of high volume fractions in established compressive behavior prediction equations are insufficient compared to studies of conventional fiber-reinforced concrete. Furthermore, existing prediction equations for the mechanical properties of high-performance fiber-reinforced cementitious composite and high-strength concrete have limitations in terms of the strength and characteristics of contained fibers (diameter, length, volume fraction) even though the stress-strain relationship is determined by these factors. Therefore, this study developed a high-performance slurry-infiltrated fiber-reinforced cementitious composite that could prevent the fiber ball phenomenon, a disadvantage of conventional fiber-reinforced concrete, and maximize the fiber volume fraction. Then, the behavior characteristics under compressive stress were analyzed for fiber volume fractions of 4%, 5%, and 6%.

scholarly journals Development of Graphene Reinforced Metal Matrix Composite by Spark Plasma Sintering

2018 ◽  
Vol 7 (3.32) ◽  
pp. 76
Author(s):  
Fei Gao ◽  
Yongbum Choi ◽  
Yosuke Dobashi ◽  
Kazuhiro Matsugi
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Spark Plasma Sintering ◽  
High Performance ◽  
Volume Fraction ◽  
Applied Pressure ◽  
Ceramic Particle ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Dispersed Aluminum

In order to obtain the high performance materials with high thermal conductivity, high　electrical conductivity, low thermal expansion, good mechanical properties and low density, Graphene has higher thermal conductivity comparison with other ceramic particle. In this study, graphene dispersed aluminum (Al) composites was developed by spark plasma sintering. Volume fraction of graphene were 10, 20 and 30 vol.%. Fabrication conditions of graphene dispersed aluminum (Al) composites were temperature of 813K and applied pressure of 80 MPa. As composite properties are affected by the dispersibility and volume fraction of the graphene particles, the relationship among the dispersibility of dispersant and the thermal conductivity and mechanical properties was investigated.  

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