scholarly journals Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1422
Author(s):  
Daniela A. Damasceno ◽  
R.K.N.D. Nimal Rajapakse ◽  
Euclides Mesquita
Keyword(s):  
Mechanical Properties ◽  
Electronic Properties ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Graphene Nanoribbons ◽  
Topological Defects ◽  
Device Fabrication ◽  
Pristine Graphene ◽  
Size Dependent ◽  
Complex Dependency

Cove-edged graphene nanoribbons (CGNR) are a class of nanoribbons with asymmetric edges composed of alternating hexagons and have remarkable electronic properties. Although CGNRs have attractive size-dependent electronic properties their mechanical properties have not been well understood. In practical applications, the mechanical properties such as tensile strength, ductility and fracture toughness play an important role, especially during device fabrication and operation. This work aims to fill a gap in the understanding of the mechanical behaviour of CGNRs by studying the edge and size effects on the mechanical response by using molecular dynamic simulations. Pristine graphene structures are rarely found in applications. Therefore, this study also examines the effects of topological defects on the mechanical behaviour of CGNR. Ductility and fracture patterns of CGNR with divacancy and topological defects are studied. The results reveal that the CGNR become stronger and slightly more ductile as the width increases in contrast to normal zigzag GNR. Furthermore, the mechanical response of defective CGNRs show complex dependency on the defect configuration and distribution, while the direction of the fracture propagation has a complex dependency on the defect configuration and position. The results also confirm the possibility of topological design of graphene to tailor properties through the manipulation of defect types, orientation, and density and defect networks.

Mechanical Response of Laminate (Glass/Epoxy) at Different Periods of Environmental Conditioning (Saturation and Ageing)

2010 ◽  
Vol 34-35 ◽  
pp. 1015-1018
Author(s):  
A. Naceri
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Glass Fiber ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Laminate Glass ◽  
Moisture Concentration ◽  
Environmental Conditioning ◽  
Hygrothermal Ageing ◽  
Fiber Fabric

This paper considers the analysis of the mechanical behaviour of a laminate constituted of 12 layers of glass fiber fabric/epoxy resin conditioned at different relative humidities of 0, 60 and 96% at 60 °C. The analysing of the experimental results obtained of hygrothermal ageing on the mechanical response has permited to show that the influence of the moisture concentration on the ultimate mechanical properties becomes significant and important for the composite conditioned at relative humidity of 96% to the periods I and II (state of saturation and ageing).

scholarly journals Multiscale Modeling of Epoxy-Based Nanocomposites Reinforced with Functionalized and Non-Functionalized Graphene Nanoplatelets

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1958
Author(s):  
Hashim Al Mahmud ◽  
Matthew S. Radue ◽  
Sorayot Chinkanjanarot ◽  
Gregory M. Odegard
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Aspect Ratio ◽  
Mechanical Response ◽  
Nanocomposite Materials ◽  
Graphene Nanoplatelets ◽  
Pristine Graphene ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
The Impact

The impact on the mechanical properties of an epoxy resin reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and functionalized graphene oxide (FGO) has been investigated in this study. Molecular dynamics (MD) using a reactive force field (ReaxFF) has been employed in predicting the effective mechanical properties of the interphase region of the three nanocomposite materials at the nanoscale level. A systematic computational approach to simulate the reinforcing nanoplatelets and probe their influence on the mechanical properties of the epoxy matrix is established. The modeling results indicate a significant degradation of the in-plane elastic Young’s (decreased by ~89%) and shear (decreased by ~72.5%) moduli of the nanocomposite when introducing large amounts of oxygen and functional groups to the robust sp2 structure of the GNP. However, the wrinkled morphology of GO and FGO improves the nanoplatelet-matrix interlocking mechanism, which produces a significant improvement in the out-of-plane shear modulus (increased by 2 orders of magnitudes). The influence of the nanoplatelet content and aspect ratio on the mechanical response of the nanocomposites has also been determined in this study. Generally, the predicted mechanical response of the bulk nanocomposite materials demonstrates an improvement with increasing nanoplatelet content and aspect ratio. The results show good agreement with experimental data available from the literature.

Size-dependent non-linear mechanical properties of graphene nanoribbons

2011 ◽  
Vol 50 (7) ◽  
pp. 2057-2062 ◽  
Author(s):  
S.K. Georgantzinos ◽  
G.I. Giannopoulos ◽  
D.E. Katsareas ◽  
P.A. Kakavas ◽  
N.K. Anifantis
Keyword(s):  
Mechanical Properties ◽  
Graphene Nanoribbons ◽  
Size Dependent ◽  
Non Linear

Size Dependent Mechanical Properties of Graphene Nanoribbons: Molecular Dynamics Simulation

2013 ◽  
Vol 749 ◽  
pp. 456-460 ◽  
Author(s):  
Yun Jin Sun ◽  
Fei Ma ◽  
K.W. Xu
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Mechanical Stability ◽  
Graphene Nanoribbons ◽  
Md Simulations ◽  
Strain Engineering ◽  
Dynamics Simulation ◽  
Size Dependent ◽  
Key Issues ◽  
Strain Stress

Strain engineering is an effective method to tune the band gap and electronic transport properties of graphene nanoribbons (GNRs). However, strain/stress field may promote the system deviating from the equilibrium state, and the mechanical stability will become one of the key issues for reliable services of relevant devices. In this paper, the size-dependent mechanical properties of GNRs under tensile loading were studied by Molecular Dynamics (MD) simulations. The results indicate that the yield stress of both zigzag and armchair GNRs decreases with the ribbon length changing from 240 Å to 30 Å. However, the ductility of armchair GNRs was significantly improved. Radial Distribution Function (RDF) was employed to analyze the evolution of atomic configurations. It showed that lattice shearing is the main mechanism for the ductility of armchair GNRs.

scholarly journals Atomic Insights into Fracture Characteristics of Twisted Tri-Layer Graphene

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1202
Author(s):  
Hassan Shoaib ◽  
Qing Peng ◽  
Abduljabar Q. Alsayoud
Keyword(s):  
Mechanical Properties ◽  
Crack Length ◽  
Electronic Properties ◽  
Fracture Strain ◽  
Twist Angle ◽  
Critical Stress Intensity Factor ◽  
Dynamics Simulation ◽  
Monolayer Graphene ◽  
Pristine Graphene ◽  
Trilayer Graphene

Graphene twistronics have recently gained significant attention due their superconductive behavior as a consequence of their tunable electronic properties. Although the electronic properties of twisted graphene have been extensively studied, the mechanical properties and integrity of twisted trilayer graphene (tTLG) under loading is still elusive. We investigated the fracture mechanics of tTLG with a twist angle of ±1.53° utilizing molecular dynamics simulation. This twist angle was chosen because it is known to exhibit highly superconductive behavior. The results indicate that tTLG does not preserve the excellent mechanical properties typically associated with graphene, with toughness and fracture strain values much lower in comparison. The Young’s modulus was an exception with values relatively close to pristine graphene, whereas the tensile strength was found to be roughly half of the intrinsic strength of graphene. The fracture toughness, fracture strain and strength converge as the crack length increases, reaching 0.26 J/m3, 0.0217 and 39.9 GPa at a crack length of 8 nm, respectively. The Griffth critical strain energy is 19.98 J/m2 and the critical stress intensity factor Kc is 4.47 MPa M1/2, in good agreement with that of monolayer graphene in the experiment. Our atomic insights might be helpful in the material design of twisted trilayer graphene-based electronics.

Influence of Residual Stresses and Particle Properties on Mechanical Response of the Material in Particulate Ceramic Composites

2016 ◽  
Vol 713 ◽  
pp. 212-215 ◽  
Author(s):  
Kateřina Štegnerová ◽  
Luboš Náhlík ◽  
Pavel Hutař ◽  
Pavel Pokorný ◽  
Zdeněk Majer
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Mechanical Behaviour ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Ceramic Composites ◽  
Particle Properties ◽  
Three Dimensional Models

The contribution deals with the issue of mechanical response of the particulate ceramic composites used in microelectronic. Mechanical properties and behaviour of composites are highly influenced by residual stresses which are developed in material during cooling in manufacturing process due to the different coefficients of thermal expansions of individual constituents. The main aim of this paper is to estimate the elastic constants and strength of the selected particulate ceramic composites with considering the residual stresses. Three dimensional models and finite element method are used for numerical simulations. Results contribute to determination and better understanding of mechanical behaviour of the particulate ceramic composites.

Graphene Nanoribbons: Towards Graphitic Materials with Predefined Dimensions and Electronic Properties

2015 ◽  
Vol 19 (18) ◽  
pp. 1850-1871 ◽  
Author(s):  
Eleftherios K. Pefkianakis ◽  
Georgios Sakellariou ◽  
Georgios C. Vougioukalakis
Keyword(s):  
Electronic Properties ◽  
Graphene Nanoribbons

scholarly journals Evolution of the viscoelastic properties of painting stratigraphies: a moisture weathering and nanoindentation approach

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Mathilde Tiennot ◽  
Davide Iannuzzi ◽  
Erma Hermens
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Cultural Heritage ◽  
Mechanical Behaviour ◽  
Viscoelastic Properties ◽  
Viscoelastic Behaviour ◽  
Storage And Loss Moduli ◽  
Heritage Studies ◽  
Paint Films ◽  
The Impact

AbstractIn this investigation on the mechanical behaviour of paint films, we use a new ferrule-top nanoindentation protocol developed for cultural heritage studies to examine the impact of repeated relative humidity variations on the viscoelastic behaviour of paint films and their mechanical properties in different paint stratigraphies through the changes in their storage and loss moduli. We show that the moisture weathering impact on the micromechanics varies for each of these pigment-oil systems. Data from the nanoindentation protocol provide new insights into the evolution of the viscoelastic properties dsue to the impact of moisture weathering on paint films.

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