Structural instability and mechanical properties of MoS2toroidal nanostructures

2015 ◽  
Vol 17 (48) ◽  
pp. 32425-32435 ◽  
Author(s):  
Jianyang Wu ◽  
Gaosheng Nie ◽  
Jun Xu ◽  
Jianying He ◽  
Qingchi Xu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Structural Stability ◽  
Md Simulation ◽  
Young's Modulus ◽  
Hierarchical Structures ◽  
Structural Instability ◽  
High Tensile Strength

Classic molecular dynamics (MD) simulation of hypothetical MoS2NT nanorings and their woven hierarchical structures shows a strong dimension-dependent structural stability, and reveals that the hierarchical structures with 4-in-1 weaves exhibit high tensile strength and Young's modulus.

scholarly journals Modeling the Mechanical Properties of Functionalized Carbon Nanotubes and Their Composites: Design at the Atomic Level

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qing-Sheng Yang ◽  
Bing-Qi Li ◽  
Xiao-Qiao He ◽  
Yiu-Wing Mai
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Atomic Level ◽  
Functionalized Carbon Nanotubes ◽  
Buckling Stress ◽  
Compressive Buckling

This investigation focuses on the design of functionalization configuration at the atomic level to determine the influence of atomic structure on the mechanical properties of functionalized carbon nanotubes (F-CNTs) and their composites. Tension and compressive buckling behaviors of different configurations of CNTs functionalized by H atoms are studied by a molecular dynamics (MD) method. It is shown that H-atom functionalization reduces Young’s modulus of CNTs, but Young’s modulus is not sensitive to the functionalization configuration. The configuration does, however, affect the tensile strength and critical buckling stress of CNTs. Further, the stress-strain relations of composites reinforced by nonfunctionalized and various functionalized CNTs are analyzed.

Development of Changeable Young's Modulus with Good Mechanical Properties in β-Type Ti-Cr-O Alloys

2013 ◽  
Vol 575-576 ◽  
pp. 453-460
Author(s):  
Hui Hong Liu ◽  
Mitsuo Niinomi ◽  
Masaaki Nakai ◽  
Junko Hieda ◽  
Ken Cho
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Potential Candidate ◽  
Spinal Fixation ◽  
High Tensile Strength ◽  
Cold Rolled

A novel β-type titanium alloy with a changeable Youngs modulus, that is, with a low Young's modulus to prevent the stress-shielding effect for patients and a high Young's modulus to suppress springback for surgeons, should be developed in order to satisfy the conflicting requirements of both the patients and surgeons in spinal fixation operations. In this study, the oxygen content in ternary Ti-11Cr-O alloys was optimized in order to achieve a large changeable Young's modulus with good mechanical properties for spinal fixation applications. The increase in Youngs moduli of all the examined alloys by cold rolling is attributed to the deformation-induced ω-phase transformation which is suppressed by oxygen. Among the examined alloys, the Ti-11Cr-0.2O alloy exhibits the largest changeable Youngs modulus and a high tensile strength with an acceptable plasticity under both solution-treated (ST) and cold-rolled (CR) conditions. Therefore, the Ti-11Cr-0.2O alloy, which shows a good balance among a changeable Youngs modulus, high tensile strength and good plasticity, is considered a potential candidate for spinal fixation applications.

scholarly journals Effects of temperature and intrinsic structural defects on mechanical properties and thermal conductivities of InSe monolayers

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Van-Trung Pham ◽  
Te-Hua Fang
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Fracture Strain ◽  
Young's Modulus ◽  
Vacancy Defect ◽  
Structural Defects ◽  
Effects Of Temperature ◽  
Dynamics Simulations

Abstract We conduct molecular dynamics simulations to study the mechanical and thermal properties of monolayer indium selenide (InSe) sheets. The influences of temperature, intrinsic structural defect on the tensile properties were assessed by tensile strength, fracture strain, and Young’s modulus. We found that the tensile strength, fracture strain, and Young’s modulus reduce as increasing temperature. The results also indicate that with the existence of defects, the stress is concentrated at the region around the vacancy leading to the easier destruction. Therefore, the mechanical properties were considerably decreased with intrinsic structural defects. Moreover, Young’s modulus is isotropy in both zigzag and armchair directions. The point defect almost has no influence on Young’s modulus but it strongly influences the ultimate strength and fracture strain. Besides, the effects of temperature, length size, vacancy defect on thermal conductivity (κ) of monolayer InSe sheets were also studied by using none-equilibrium molecular dynamics simulations. The κ significantly arises as increasing the length of InSe sheets. The κ of monolayer InSe with infinite length at 300 K in armchair direction is 46.18 W/m K, while in zigzag direction is 45.87 W/m K. The difference of κ values in both directions is very small, indicating the isotropic properties in thermal conduction of this material. The κ decrease as increasing the temperature. The κ goes down with the number of atoms vacancy defect increases.

Mechanical Properties of Vacancy-containing Graphene and Graphite Estimated by Molecular Dynamics Simulations

2011 ◽  
Vol 1362 ◽  
Author(s):  
Akihiko Ito ◽  
Shingo Okamoto
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Molecular Dynamics Simulations ◽  
Young’S Modulus ◽  
Md Simulation ◽  
Pristine Graphene ◽  
Cluster Type ◽  
Slip Deformation ◽  
Dynamics Simulations

ABSTRACTUsing molecular dynamics (MD) simulation, we investigated the mechanical properties of graphene and graphite, which contain cluster-type vacancies. We found that as the vacancy size increases, the tensile strength drastically decreases to at least 56% of that of pristine graphene, whereas Young’s modulus hardly changes. In vacancy-containing graphene, we also found that slip deformation followed by fracture occurs under zigzag tension. In general, tensile strength decreases as the size of cluster-type vacancies increases. However, the tensile strength of graphene with a clustered sextuple vacancy increases as the vacancy disappears because slip deformation proceeds. Furthermore, we found that slip deformation by vacancies in graphite occurs less easily than in graphene.Our results suggest that the shape of vacancies affects the strengths of graphene and graphite.

A molecular dynamics study on thermal and mechanical properties of graphene–paraffin nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (101) ◽  
pp. 82638-82644 ◽  
Author(s):  
Yu Wang ◽  
Chunhui Yang ◽  
Yuan Cheng ◽  
Yingyan Zhang
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Thermal Transport ◽  
Young's Modulus ◽  
Thermal And Mechanical Properties

Hydrogenation enhances thermal transport across graphene–paraffin interfaces, but it deteriorates the Young’s modulus and tensile strength of the composites.

scholarly journals Molecular Dynamics Simulations of the Tensile Mechanical Responses of Selective Laser-Melted Aluminum with Different Crystalline Forms

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1388
Author(s):  
Qiang Zeng ◽  
Lijuan Wang ◽  
Wugui Jiang
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Grain Orientation ◽  
Young's Modulus ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Columnar Grains ◽  
Columnar Grain

The mechanical deformation of cellular structures in the selective laser melting (SLM) of aluminum was investigated by performing a series of molecular dynamics (MD) simulations of uniaxial tension tests. The effects of crystalline form, temperature, and grain orientation of columnar grains on the mechanical properties of SLM aluminum were examined. The MD results showed that the tensile strength of SLM aluminum with columnar grains at different temperatures was lower than that of single-crystal aluminum, but greater than that of aluminum with equiaxed grains. The tensile strength and Young’s modulus both decreased approximately linearly upon increasing the temperature. The deformation mechanisms of equiaxed and columnar grains included dislocation slip, grain boundary migration, and torsion, while the deformation mechanisms of single crystals included stacking fault formation and amorphization. Finally, the influence of the columnar grain orientation on the mechanical properties was studied, and it was found that the Young’s modulus was almost independent of the grain orientation. The tensile strength was greatly affected by the columnar grain orientation. Reasonable control of the grain orientation can improve the tensile strength of SLM aluminum.

Effect of Castor Oil Impregnation on the Physical and Mechanical Properties of Bacterial Cellulose

2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Scanning Electron Micrographs ◽  
Elongation At Break ◽  
Acetone Water

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.

scholarly journals Regulation Mechanism of Graphene Oxide on the Structure and Mechanical Properties of Bio-Based Gel-Spun Lignin/Poly (Vinyl Alcohol) Fibers

2021 ◽  
Author(s):  
Yanhong Jin ◽  
Yuanyuan Jing ◽  
Wenxin Hu ◽  
Jiaxian Lin ◽  
Yu Cheng ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Young’S Modulus ◽  
Vinyl Alcohol ◽  
Young's Modulus ◽  
Lignin Content ◽  
Poly Vinyl Alcohol ◽  
Regulation Mechanism ◽  
Composite Fibers

Abstract Lignin has been used as a sustainable and eco-friendly filler in composite fibers. However, lignin aggregation occurred at high lignin content, which significantly hindered the further enhancement of fiber performance. The incorporation of graphene oxide (GO) enhanced the mechanical properties of the lignin/poly(vinyl alcohol) (PVA) fibers and affected their structure. With the GO content increasing from 0 to 0.2%, the tensile strength of 5% lignin/PVA fibers increased from 491 MPa to 631 MPa, and Young's modulus increased from 5.91 GPa to 6.61 GPa. GO reinforced 30% lignin/PVA fibers also showed the same trend. The tensile strength increased from 455 MPa to 553 MPa, and Young's modulus increased from 5.39 GPa to 7 GPa. The best mechanical performance was observed in PVA fibers containing 5% lignin and 0.2% GO, which had an average tensile strength of 631 MPa and a Young’s modulus of 6.61 GPa. The toughness values of these fibers are between 9.9-15.6 J/g, and the fibrillar and ductile fracture microstructure were observed. Structure analysis of fibers showed that GO reinforced 5% lignin/PVA fibers had higher crystallinity, and evidence of hydrogen bonding among GO, lignin, and PVA in the gel fibers was revealed. Further, water resistance and swelling behavior of composite PVA fibers were studied to further evidence the structure change of composite fibers.

scholarly journals Physical and mechanical rock properties of a heterogeneous volcano; the case of Mount Unzen, Japan

2020 ◽  
Author(s):  
Jackie E. Kendrick ◽  
Lauren N. Schaefer ◽  
Jenny Schauroth ◽  
Andrew F. Bell ◽  
Oliver D. Lamb ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Acoustic Emission ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
B Value ◽  
Coda Wave ◽  
Damage Accrual ◽  
The Impact

Abstract. Volcanoes represent one of the most critical geological settings for hazard modelling due to their propensity to both unpredictably erupt and collapse, even in times of quiescence. Volcanoes are heterogeneous at multiple scales, from porosity which is variably distributed and frequently anisotropic to strata that are laterally discontinuous and commonly pierced by fractures and faults. Due to variable and, at times, intense stress and strain conditions during and post-emplacement, volcanic rocks span an exceptionally wide range of physical and mechanical properties. Understanding the constituent materials' attributes is key to improving the interpretation of hazards posed by the diverse array of volcanic complexes. Here, we examine the spectrum of physical and mechanical properties presented by a single dome-forming eruption at a dacitic volcano, Mount Unzen (Japan) by testing a number of isotropic and anisotropic lavas in tension and compression and using monitored acoustic emission (AE) analysis. The lava dome was erupted as a series of 13 lobes between 1991–1995, and its ongoing instability means much of the volcano and its surroundings remain within an exclusion zone today. During a field campaign in 2015, we selected 4 representative blocks as the focus of this study. The core samples from each block span range in porosity from 9.14 to 42.81 %, and permeability ranges from 1.54 × 10−14 to 2.67 × 10−10 m2 (from 1065 measurements). For a given porosity, sample permeability varies by > 2 orders of magnitude is lower for macroscopically anisotropic samples than isotropic samples of similar porosity. An additional 379 permeability measurements on planar block surfaces ranged from 1.90 × 10−15 to 2.58 × 10−12 m2, with a single block having higher standard deviation and coefficient of variation than a single core. Permeability under confined conditions showed that the lowest permeability samples, whose porosity largely comprises microfractures, are most sensitive to effective pressure. The permeability measurements highlight the importance of both scale and confinement conditions in the description of permeability. The uniaxial compressive strength (UCS) ranges from 13.48 to 47.80 MPa, and tensile strength (UTS) using the Brazilian disc method ranges from 1.30 to 3.70 MPa, with crack-dominated lavas being weaker than vesicle-dominated materials of equivalent porosity. UCS is lower in saturated conditions, whilst the impact of saturation on UTS is variable. UCS is between 6.8 and 17.3 times higher than UTS, with anisotropic samples forming each end member. The Young's modulus of dry samples ranges from 4.49 to 21.59 GPa and is systematically reduced in water-saturated tests. The interrelation of porosity, UCS, UTS and Young's modulus was modelled with good replication of the data. Acceleration of monitored acoustic emission (AE) rates during deformation was assessed by fitting Poisson point process models in a Bayesian framework. An exponential acceleration model closely replicated the tensile strength tests, whilst compressive tests tended to have relatively high early rates of AEs, suggesting failure forecast may be more accurate in tensile regimes, though with shorter warning times. The Gutenberg-Richter b-value has a negative correlation with connected porosity for both UCS and UTS tests which we attribute to different stress intensities caused by differing pore networks. b-value is higher for UTS than UCS, and typically decreases (positive Δb) during tests, with the exception of cataclastic samples in compression. Δb correlates positively with connected porosity in compression, and negatively in tension. Δb using a fixed sampling length may be a more useful metric for monitoring changes in activity at volcanoes than b-value with an arbitrary starting point. Using coda wave interferometry (CWI) we identify velocity reductions during mechanical testing in compression and tension, the magnitude of which is greater in more porous samples in UTS but independent of porosity in UCS, and which scales to both b-value and Δb. Yet, saturation obscures velocity changes caused by evolving material properties, which could mask damage accrual or source migration in water-rich environments such as volcanoes. The results of this study highlight that heterogeneity and anisotropy within a single system not only add uncertainty but also have a defining role in the channelling of fluid flow and localisation of strain that dictate a volcano's hazards and the geophysical indicators we use to interpret them.

scholarly journals Preliminary Study on Mechanical Properties of 3D Printed Multimaterials ABS/PC Parts: Effect of Printing Parameters

2021 ◽  
Vol 32 (2) ◽  
pp. 87-104
Author(s):  
Pui-Voon Yap ◽  
Ming-Yeng Chan ◽  
Seong-Chun Koay
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Flexural Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Flexural Modulus ◽  
Nozzle Diameter ◽  
Fused Deposition ◽  
Printing Parameters ◽  
Printing Speed

This research work highlights the mechanical properties of multi-material by fused deposition modelling (FDM). The specimens for tensile and flexural test have been printed using polycarbonate (PC) material at different combinations of printing parameters. The effects of varied printing speed, infill density and nozzle diameter on the mechanical properties of specimens have been investigated. Multi-material specimens were fabricated with acrylonitrile butadiene styrene (ABS) as the base material and PC as the reinforced material at the optimum printing parameter combination. The specimens were then subjected to mechanical testing to observe their tensile strength, Young’s modulus, percentage elongation, flexural strength and flexural modulus. The outcome of replacing half of ABS with PC to create a multi-material part has been examined. As demonstrated by the results, the optimum combination of printing parameters is 60 mm/s printing speed, 15% infill density and 0.8 mm nozzle diameter. The combination of ABS and PC materials as reinforcing material has improved the tensile strength (by 38.46%), Young’s modulus (by 23.40%), flexural strength (by 23.90%) and flexural modulus (by 37.33%) while reducing the ductility by 14.31% as compared to pure ABS. The results have been supported by data and graphs of the analysed specimens.

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