scholarly journals Theoretical Investigation on Failure Strength and Fracture Toughness of Precracked Single-Layer Graphene Sheets

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xin-Liang Li ◽  
Jian-Gang Guo
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Young’S Modulus ◽  
Failure Strain ◽  
Young's Modulus ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Failure Strength ◽  
Griffith Criterion ◽  
Variation Trends

Young’s modulus, failure strength, and failure strain of precracked graphene are investigated via finite element method based on molecular structure mechanics in this research. The influence of distribution, length, and orientation of precrack and graphene sizes on these mechanical properties is analyzed. The ratio of precrack length and graphene width is defined as P value, and its particular value Pc can be found, at which the variation trends of Young’s modulus, failure strength, and strain have changes with increasing P value. In addition, the fracture toughness of precracked graphene is investigated, and the stress intensity factor (SIF) is calculated according to the Griffith criterion in classical fracture mechanics. The numerical values of the SIF are about 3.20-3.37 MPa√m, which are compared with the experimental results, and the simulations verify the applicability of the classical fracture mechanics to graphene.

Mechanical and thermal properties of graphene–carbon nanotube-reinforced metal matrix composites: A molecular dynamics study

2016 ◽  
Vol 51 (23) ◽  
pp. 3299-3313 ◽  
Author(s):  
Sumit Sharma ◽  
Pramod Kumar ◽  
Rakesh Chandra
Keyword(s):  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Single Layer ◽  
Dynamics Simulation ◽  
Single Layer Graphene ◽  
Graphene Sheets ◽  
Layer Graphene

Single layer graphene sheets and carbon nanotubes have resulted in the development of new materials for a variety of applications. Though there are a large number of experimental and numerical studies related to these nanofillers, still there is a lack of understanding of the effect of geometrical characteristics of these nanofillers on their mechanical properties. In this study, molecular dynamics simulation has been used to assess this issue. Two different computational models, single layer graphene sheets–copper and carbon nanotube–copper composites have been examined to study the effect of nanofiller geometry on Young’s modulus and thermal conductivity of these nanocomposites. Effect of increase in temperature on Young’s modulus has also been predicted using molecular dynamics. The effect of nanofiller volume fraction ( Vf) on Young’s modulus and thermal conductivity has also been studied. Results of thermal conductivity obtained using molecular dynamics have been compared with theoretical models. Results show that with increase in Vf the Young’s modulus as well as thermal conductivity of single layer graphene sheets–Cu composites increases at a faster rate than that for carbon nanotube–Cu composite. For the same Vf, the Young’s modulus of single layer graphene sheets–Cu composite is higher than carbon nanotube–Cu composite.

scholarly journals Effects of CNT Addition on Mechanical Properties, Electric Conductivity and Oxidation Resistance of Al2O3-TiC Composite

2013 ◽  
Vol 761 ◽  
pp. 83-86
Author(s):  
Hideaki Sano ◽  
Junichi Morisaki ◽  
Guo Bin Zheng ◽  
Yasuo Uchiyama
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Electric Conductivity ◽  
Young’S Modulus ◽  
Oxidation Resistance ◽  
Young's Modulus ◽  
Tic Particle

Effects of carbon nanotubes (CNT) addition on mechanical properties, electric conductivity and oxidation resistance of CNT/Al2O3-TiC composite were investigated. It was found that flexural strength, Young’s modulus and fracture toughness of the composites were improved by addition of more than 2 vol%-CNT. In the composites with more than 3 vol%-CNT, the oxidation resistance of the composite was degraded. In comparison with Al2O3-26vol%TiC sample as TiC particle-percolated sample, the Al2O3-12vol%TiC-3vol%CNT sample, which is not TiC particle-percolated sample, shows almost the same mechanical properties and electric conductivity, and also shows thinner oxidized region after oxidation at 1200°C due to less TiC in the composite.

Two-Stage Sintering of Alumina-Y-TZP (Al2O3/Y-TZP) Composites

2019 ◽  
Vol 814 ◽  
pp. 12-18 ◽  
Author(s):  
Sivakumar Sivanesan ◽  
Teow Hsien Loong ◽  
Satesh Namasivayam ◽  
Mohammad Hosseini Fouladi
Keyword(s):  
Fracture Toughness ◽  
Young’S Modulus ◽  
Heating Rate ◽  
Vickers Hardness ◽  
Young's Modulus ◽  
Two Stage ◽  
Dwelling Time ◽  
Microstructure Density

Alumina-Y-TZP composites between 0 to 25 vol% Y-TZP content produced via conventional two-stage sintering with T1 ranging between 1400°C and 1550°C, heating rate of 20°C/min, followed by T2 of 1350°C and 12 hours dwelling time. The microstructure, density, Vickers hardness (HV), Young’s modulus (E) and fracture toughness (KIC) of the sintered samples were then evaluated. It is observed that all samples up to 10 vol% Y-TZP achieved > 98% T.D. as the T1 increases. Samples with Y-TZP content above 10 vol% resulted in a significant decrease in density and hardness. Samples with ≤ 10 vol% Y-TZP sintered at T1 of 1450°C was able to achieve density > 98% T.D., Vickers hardness > 18 GPa and Young’s modulus > 380 GPa and fracture toughness > 6 MPam1/2 when compared to pure Al2O3 ceramics.

Microbridge Testing of Silicon Oxide/Silicon Nitride Bilayer Films

2000 ◽  
Vol 657 ◽  
Author(s):  
C.-F. Qian ◽  
Y.-J. Su ◽  
M.-H. Zhao ◽  
T.-Y. Zhang
Keyword(s):  
Residual Stress ◽  
Silicon Nitride ◽  
Young’S Modulus ◽  
Silicon Oxide ◽  
Young's Modulus ◽  
Single Layer ◽  
Bilayer Films ◽  
Silicon Nitride Films ◽  
Small Deflection ◽  
Equivalent Bending Stiffness

ABSTRACTThe present work further develops the microbridge testing method to characterize mechanical properties of bilayer thin films. A closed-form formula for deflection versus load under small deflection is derived with consideration of the substrate deformation and residual stress in each layer. The analysis shows that the solution for bending a bilayer beam is equivalent to that for bending a single-layer beam with an equivalent bending stiffness, an equivalent residual force and a residual moment. One can estimate the Young's modulus and residual stress in a layer if the corresponding values in the other layer are known. The analytic results are confirmed by finite element calculations. The microbridge tests are conducted on low-temperature-silicon oxide (LTO)/silicon nitride bilayer films as well as on silicon nitride single-layer films. All microbridge specimens are prepared by the microfabricating technique. The tests on the single-layer films provide the material properties of the silicon nitride films. Then, applying the proposed method for bilayer films under small deflection yields the Young's modulus of 37 GPa and the residual stress of -148 MPa for LTO films.

Influence of B4C, SiC and Si3N4 Additions on Microstructures and Selected Properties of Titanium Nitride Matrix Materials Obtained by HPHT Method

2014 ◽  
Vol 89 ◽  
pp. 109-114
Author(s):  
Jolanta Cyboroń ◽  
Piotr Klimczyk ◽  
Pawel Figiel ◽  
Małgorzata Karolus
Keyword(s):  
Fracture Toughness ◽  
High Pressure ◽  
Phase Composition ◽  
High Temperature ◽  
Titanium Nitride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Ceramic Phase ◽  
Ultra High Temperature Ceramics

The paper presents the results of the High Pressure and High Temperature (HP-HT) sintering and investigation of Ultra High Temperature Ceramics (UHTC) composites of titanium nitride matrix. The aim of this studies were to determine the influence of additives on the ceramic phase composition, microstructure and selected properties. Three different kind of mixtures were prepared. 8 to 22 wt% B4C, SiC and Si3N4were added. Composites were sintered under high-pressure high-temperature conditions (HP-HT) using a Bridgman-type apparatus under pressure about 6 GPa. Materials were sintered at the range of 1450 to 1690 ° C, duration of sintering was 60s. The phase composition, microstructure, and the apparent density, Young's modulus, hardness and fracture toughness KIC (HV), using the Vickers indentation method were examined. Sintered titanium nitride with the 22 wt% silicon carbide participation was characterized the best physical and mechanical properties. For this material the relative density is 99%, the Young's modulus 435 GPa, Vickers hardness 18.3 GPa HV1 and fracture toughness 5.5 MPa∙m1/2.

Self-Assembled Patterns and Young’s Modulus of Single-Layer Naphthalocyanine Molecules on Ag(111)

2015 ◽  
Vol 119 (15) ◽  
pp. 8208-8212 ◽  
Author(s):  
Rongting Wu ◽  
Linghao Yan ◽  
Yanfang Zhang ◽  
Junhai Ren ◽  
Deliang Bao ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Single Layer ◽  
Self Assembled

Determination of hardness, Young's modulus and fracture toughness of lanthanum tungstates as novel proton conductors

2011 ◽  
Vol 37 (5) ◽  
pp. 1593-1599 ◽  
Author(s):  
J.J. Roa ◽  
A. Magrasó ◽  
M. Morales ◽  
P. Núñez ◽  
M. Segarra
Keyword(s):  
Fracture Toughness ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Proton Conductors
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