ORCID Profile
0000-0002-0008-545X
Current Organisations
Zhejiang University
,
Queensland University of Technology
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Nanoscale Characterisation | Mechanical Engineering | Numerical Modelling and Mechanical Characterisation | Ceramics
Expanding Knowledge in Engineering | Expanding Knowledge in Technology |
Publisher: American Chemical Society (ACS)
Date: 03-11-2021
Publisher: Elsevier BV
Date: 05-2021
Publisher: American Chemical Society (ACS)
Date: 14-05-2021
Publisher: Elsevier BV
Date: 03-2016
Publisher: Emerald
Date: 25-10-2018
Abstract: Metal plates are usually used as protective shields of engineering structures, which probably undergo multiple projectile impacts resulting from gunshot and blast. Though a large number of studies have been conducted on the performance of metal plates under a single projectile impact, few studies have explored their performance under multiple projectile impacts. This paper aims to explore the performance of Weldox 460 E steel plates against multiple projectile impacts through numerical simulation. A three-dimensional coupled finite element (FE) and smoothed particle hydrodynamics (SPH) model was developed to simulate the perforation of a 12-mm-thick Weldox 460 E steel plate by an ogival projectile. The model was verified by existing experimental data. Then, it was extended to investigate the same target plate subjected to impacts with multiple projectiles. Simultaneous impacts with different number of projectiles, as well as sequential impacts with two projectiles, were considered. Effects of spacing between projectiles on residual velocity of projectile, ballistic limit and failure mode of target were revealed for simultaneous impacts. Effects of spacing and axial distance between projectiles on residual velocity of projectile were explored for sequential impacts. This work developed an advanced FE–SPH model to simulate perforation of steel plates by multiple projectiles, and revealed the effects of multiple impacts on ballistic performance of steel plates. It provides guidance for the design of protective structures/shields in various engineering applications.
Publisher: American Chemical Society (ACS)
Date: 16-01-2015
DOI: 10.1021/JP5117905
Publisher: Elsevier BV
Date: 12-2011
Publisher: IOP Publishing
Date: 03-12-2014
Publisher: Springer Science and Business Media LLC
Date: 17-03-2017
DOI: 10.1038/NCOMMS14863
Abstract: Carbon fibres have attracted interest from both the scientific and engineering communities due to their outstanding physical properties. Here we report that recently synthesized ultrathin diamond nanothread not only possesses excellent torsional deformation capability, but also excellent interfacial load-transfer efficiency. Compared with (10,10) carbon nanotube bundles, the flattening of nanotubes is not observed in diamond nanothread bundles, which leads to a high-torsional elastic limit that is almost three times higher. Pull-out tests reveal that the diamond nanothread bundle has an interface transfer load of more than twice that of the carbon nanotube bundle, corresponding to an order of magnitude higher in terms of the interfacial shear strength. Such high load-transfer efficiency is attributed to the strong mechanical interlocking effect at the interface. These intriguing features suggest that diamond nanothread could be an excellent candidate for constructing next-generation carbon fibres.
Publisher: American Chemical Society (ACS)
Date: 12-10-2020
Publisher: Elsevier BV
Date: 04-2012
Publisher: Wiley
Date: 15-08-2022
Abstract: A compact, stable, sustainable, and high‐energy density power supply system is crucial for the engineering deployment of mobile electromechanical devices/systems either at the small‐ or large‐scale. This work proposes a spiral‐based mechanical energy storage scheme utilizing the newly synthesized 2D diamane. Atomistic simulations show that diamane spiral can achieve a high theoretical gravimetric energy density of about 564 Wh kg −1 , about 14 500 times the steel spring. The interlayer friction between diamane is found to cause a strong stick–slip effect that results in local stress/strain concentration. As such, the energy storage capacity of the diamane spiral can be tuned by suppressing the influence from the interlayer friction. Simulations affirm that higher gravimetric energy density can be achieved by reducing the turn number or adopting a low friction contact pair. The fundamental principles that dominate the energy storage capacity of the spiral spring are theoretically analyzed, respectively. The obtained insights suggest that the 2D vdW solids can be promising candidates to construct spiral structures with a high gravimetric energy density. This work should be beneficial for the design of reliable, stable, and sustainable nanoscale mechanical energy storage schemes that can be used as an alternative low‐carbon footage energy supplier for novel micro‐/nanoscale devices or systems.
Publisher: MDPI AG
Date: 24-02-2022
DOI: 10.3390/NANO12050760
Abstract: Carbon nanotube (CNT) bundles/fibers possess promising applications in broad fields, such as artificial muscles and flexible electronics, due to their excellent mechanical properties. The as-prepared CNT bundles contain complex structural features (e.g., different alignments and components), which makes it challenging to predict their mechanical performance. Through in silico studies, this work assessed the torsional performance of CNT bundles with randomly packed CNTs. It is found that CNT bundles with varying constituent CNTs in terms of chirality and diameter exhibit remarkably different torsional properties. Specifically, CNT bundles consisting of CNTs with a relatively large diameter ratio possess lower gravimetric energy density and elastic limit than their counterpart with a small diameter ratio. More importantly, CNT bundles with the same constituent CNTs but different packing morphologies can yield strong variation in their torsional properties, e.g., up to 30%, 16% and 19% difference in terms of gravimetric energy density, elastic limit and elastic constants, respectively. In addition, the separate fracture of the inner and outer walls of double-walled CNTs is found to suppress the gravimetric energy density and elastic limit of their corresponding bundles. These findings partially explain why the experimentally measured mechanical properties of CNT bundles vary from each other, which could benefit the design and fabrication of high-performance CNT bundles.
Publisher: SAGE Publications
Date: 13-05-2014
Abstract: The majority of the current research on the mounting system has emphasised on the low/medium power engine, rare work has been reported for the high-speed and heavy-duty engine, the vibration characteristics of which exhibits significantly increased complexity and uncertainty. In this work, a general dynamics model was firstly established to describe the dynamic properties of a mounting system with various numbers of mounts. Then, this model was employed for the optimization of the mounting system. A modified Powell conjugate direction method was developed to improve the optimization efficiency. Basing on the optimization results obtained from the theoretical model, a mounting system was constructed for a V6 diesel engine. The experimental measurement of the vibration intensity of the mounting systems shows excellent agreement with the theoretical calculations, indicating the validity of the model. This dynamics model opens a new avenue in assessing and designing the mounting system for a high-speed and heavy-duty engine. On the other hand, the delineated dynamics model, and the optimization algorithm should find wide applications for other mounting systems, such as the power transmission system which usually has various uncertain mounts.
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.582
Abstract: A theoretical model is developed for the analysis of piston secondary motion. Based on this model, the slap force of a specific L6 diesel engine was compared when considering different boundary conditions, such as lubricating oil on cylinder liner, surface roughness, deformation of cylinder liner and piston skirt. It is concluded that it is necessary to consider the secondary motion of piston in the analysis of the inner excitation for an internal combustion engine. A more comprehensive consideration of the boundary condition (i.e., more close to the actual condition) will lead to a smaller maximum slap force, and among all boundary conditions considered in this paper, the structural deformation of the piston skirt and cylinder liner is the most influential factor. The theoretical model developed and findings obtained in this study will benefit the future analysis and design of advanced internal combustion engine structures.
Publisher: American Scientific Publishers
Date: 07-2014
Publisher: Elsevier BV
Date: 06-2021
Publisher: American Chemical Society (ACS)
Date: 26-03-2018
Publisher: Trans Tech Publications, Ltd.
Date: 05-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMM.553.3
Abstract: Doping as one of the popular methods to manipulate the properties of nanomaterials has received extensive application in deriving different types of graphene derivates, while the understanding of the resonance properties of dopant graphene is still lacking in literature. Based on the large-scale molecular dynamics simulation, reactive empirical bond order potential, as well as the tersoff potential, the resonance properties of N-doped graphene were studied. The studied s les were established according to previous experiments with the N atom’s percentage ranging from 0.38%-2.93%, including three types of N dopant locations, i.e., graphitic N, pyrrolic N and pyridinic N. It is found that different percentages of N-dopant exert different influence to the resonance properties of the graphene, while the amount of N-dopant is not the only factor that determines its impact. For all the considered cases, a relative large percentage of N-dopant (2.65% graphitic N-dopant) is observed to introduce significant influence to the profile of the external energy, and thus lead to an extremely low Q-factor comparing with that of the pristine graphene. The most striking finding is that the natural frequency of the defective graphene with N-dopant’s percentage higher than 0.89% appears larger than its pristine counterpart. For the perfect graphene, the N-dopant shows larger influence to its natural frequency. This study will enrich the current understanding of the influence of dopants on graphene, which will eventually shed lights on the design of different molecules-doped graphene sheet.
Publisher: World Scientific Pub Co Pte Lt
Date: 03-2012
DOI: 10.1142/S0219876212400038
Abstract: Based on the molecular dynamics (MD) method, the single-crystalline copper nanowire with different surface defects is investigated through tension simulation. For comparison, the MD tension simulations of perfect nanowire are first carried out under different temperatures, strain rates, and sizes. It has concluded that the surface–volume ratio significantly affects the mechanical properties of nanowire. The surface defects on nanowires are then systematically studied in considering different defect orientation and distribution. It is found that the Young's modulus is the insensitive of surface defects. However, the yield strength and yield point show a significant decrease due to the different defects. Different defects are observed to serve as a dislocation source.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2NR03084E
Abstract: The mechanical performance of degraded polycaprolactone is closely related to the nonaffine displacement of the polymer chains.
Publisher: IOP Publishing
Date: 26-10-2012
Publisher: Wiley
Date: 08-09-2020
Publisher: American Chemical Society (ACS)
Date: 15-10-2021
Publisher: Trans Tech Publications, Ltd.
Date: 09-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.328-330.1239
Abstract: Molecular dynamics (MD) simulations have been carried out to investigate the defect’s effect on the mechanical properties of copper nanowire with different crystallographic orientations, under tensile deformation. Three different crystallographic orientations have been considered. The deformation mechanism has been carefully discussed. It is found that the Young’s modulus is insensitive to the defect, even when the nanowire’s crystallographic orientation is different. However, due to the defect’s effect, the yield strength and yield strain appear a large decrease. The defects have played a role of dislocation sources, the slips or stacking faults are first generated around the locations of the defects. The necking locations have also been affected by different defects. Due to the surface defect, the plastic deformation has received a large influence for the and orientated nanowires, and a relative small influence is seen for the nanowire.
Publisher: American Chemical Society (ACS)
Date: 21-05-2015
Publisher: Elsevier BV
Date: 10-2016
Publisher: World Scientific Pub Co Pte Lt
Date: 12-2013
DOI: 10.1142/S2047684113500206
Abstract: Graphene has been reported with record-breaking properties which have opened up huge potential applications. A considerable research has been devoted to manipulate or modify the properties of graphene to target a more smart nanoscale device. Graphene and carbon nanotube hybrid structure (GNHS) is one of the promising graphene derivative, whose mechanical properties have been rarely discussed in literature. Therefore, the mechanical properties of GNHS is studied in this paper based on the large-scale molecular dynamics simulation. The target GNHS is constructed by considering two separate graphene layers that are being connected by single-wall carbon nanotubes (SWCNTs) according to the experimental observations. It is found that the GNHSs exhibit much lower yield strength, Young's modulus, and earlier yielding compared to bilayer graphene sheet. Fracture of GNHSs is found to initiate at the connecting region between carbon nanotubes (CNTs) and graphene. After failure, monatomic chains are normally observed at the front of the failure region, and the two graphene layers at the failure region without connecting CNTs will adhere to each other, generating a bilayer graphene sheet scheme (with a layer distance about 3.4 Å). This study will enrich the current understanding of the mechanical performance of GNHS, which will guide the design of GNHS and shed light on its various applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1NR00356A
Abstract: Polymer nanocomposites with regularly aligned and evenly distributed carbon nanothreads exhibit better thermal conductivity than their counterparts with randomly dispersed nanofillers or nanofillers with functional groups.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR31545A
Abstract: The elastic properties of 1D nanostructures such as nanowires are often measured experimentally through actuation of nanowires at their resonance frequency, and then relating the resonance frequency to the elastic stiffness using the elementary beam theory. In the present work, we utilize large scale molecular dynamics simulations to report a novel beat phenomenon in [110] oriented Ag nanowires. The beat phenomenon is found to arise from the asymmetry of the lattice spacing in the orthogonal elementary directions of [110] nanowires, i.e. the [110] and [001] directions, which results in two different principal moments of inertia. Because of this, actuations imposed along any other direction are found to decompose into two orthogonal vibrational components based on the actuation angle relative to these two elementary directions, with this phenomenon being generalizable to FCC nanowires of different materials (Cu, Au, Ni, Pd and Pt). The beat phenomenon is explained using a discrete moment of inertia model based on the hard sphere assumption the model is utilized to show that surface effects enhance the beat phenomenon, while effects are reduced with increasing nanowire cross-sectional size or aspect ratio. Most importantly, due to the existence of the beat phenomena, we demonstrate that in resonance experiments only a single frequency component is expected to be observed, particularly when the d ing ratio is relatively large or very small. Furthermore, for a large range of actuation angles, the lower frequency is more likely to be detected than the higher one, which implies that experimental predictions of the Young's modulus obtained from resonance may in fact be under-predictions. The present study therefore has significant implications for experimental interpretations of the Young's modulus as obtained via resonance testing.
Publisher: Wiley
Date: 24-05-2016
Publisher: AIP Publishing
Date: 15-04-2012
DOI: 10.1063/1.3703673
Abstract: Several studies of the surface effect on bending properties of a nanowire (NW) have been conducted. However, these analyses are mainly based on theoretical predictions, and there is seldom integration study in combination between theoretical predictions and simulation results. Thus, based on the molecular dynamics (MD) simulation and different modified beam theories, a comprehensive theoretical and numerical study for bending properties of nanowires considering surface/intrinsic stress effects and axial extension effect is conducted in this work. The discussion begins from the Euler-Bernoulli beam theory and Timoshenko beam theory augmented with surface effect. It is found that when the NW possesses a relatively small cross-sectional size, these two theories cannot accurately interpret the true surface effect. The incorporation of axial extension effect into Euler-Bernoulli beam theory provides a nonlinear solution that agrees with the nonlinear-elastic experimental and MD results. However, it is still found inaccurate when the NW cross-sectional size is relatively small. Such inaccuracy is also observed for the Euler-Bernoulli beam theory augmented with both contributions from surface effect and axial extension effect. A comprehensive model for completely considering influences from surface stress, intrinsic stress, and axial extension is then proposed, which leads to good agreement with MD simulation results. It is thus concluded that, for NWs with a relatively small cross-sectional size, a simple consideration of surface stress effect is inappropriate, and a comprehensive consideration of the intrinsic stress effect is required.
Publisher: American Scientific Publishers
Date: 07-2012
Publisher: Elsevier BV
Date: 08-2017
Publisher: American Chemical Society (ACS)
Date: 02-03-2017
Abstract: Construction of nanoarchitectures requires techniques like joint formation and trimming. For ceramic materials, however, it is extremely difficult to form nanojoints by conventional methods like merging. In this work, we demonstrate that ceramic titanate nanowires (NWs) can be joined by spot melting under electron beam (e-beam) irradiation (EBI). The irradiation fuses the contacted spot of titanate NWs yielding an intact nanojoint. Nanojoints with different morphologies can be produced. The joint structures consist of titanium dioxide (TiO
Publisher: Elsevier BV
Date: 12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C6NR02414A
Abstract: As a potential building block for the next generation of devices/multifunctional materials that are spreading in almost every technology sector, one-dimensional (1D) carbon nanomaterial has received intensive research interests. Recently, a new ultra-thin diamond nanothread (DNT) has joined this palette, which is a 1D structure with poly-benzene sections connected by Stone-Wales (SW) transformation defects. Using large-scale molecular dynamics simulations, we found that this sp(3) bonded DNT can transition from brittle to ductile behaviour by varying the length of the poly-benzene sections, suggesting that DNT possesses entirely different mechanical responses than other 1D carbon allotropes. Analogously, the SW defects behave like a grain boundary that interrupts the consistency of the poly-benzene sections. For a DNT with a fixed length, the yield strength fluctuates in the vicinity of a certain value and is independent of the "grain size". On the other hand, both yield strength and yield strain show a clear dependence on the total length of DNT, which is due to the fact that the failure of the DNT is dominated by the SW defects. Its highly tunable ductility together with its ultra-light density and high Young's modulus makes diamond nanothread ideal for the creation of extremely strong three-dimensional nano-architectures.
Publisher: Elsevier BV
Date: 12-2023
Publisher: American Chemical Society (ACS)
Date: 13-04-2020
Publisher: American Chemical Society (ACS)
Date: 10-2019
Publisher: Elsevier BV
Date: 02-2023
Publisher: American Scientific Publishers
Date: 04-2011
Publisher: AIP Publishing
Date: 15-06-2012
DOI: 10.1063/1.4729485
Abstract: Based on the molecular dynamics (MD) simulation and the classical Euler-Bernoulli beam theory, a fundamental study of the vibrational performance of the Ag nanowire (NW) is carried out. A comprehensive analysis of the quality (Q)-factor, natural frequency, beat vibration, as well as high vibration mode is presented. Two excitation approaches, i.e., velocity excitation and displacement excitation, have been successfully implemented to achieve the vibration of NWs. Upon these two kinds of excitations, consistent results are obtained, i.e., the increase of the initial excitation litude will lead to a decrease to the Q-factor, and moderate plastic deformation could increase the first natural frequency. Meanwhile, the beat vibration driven by a single relatively large excitation or two uniform excitations in both two lateral directions is observed. It is concluded that the nonlinear changing trend of external energy magnitude does not necessarily mean a non-constant Q-factor. In particular, the first order natural frequency of the Ag NW is observed to decrease with the increase of temperature. Furthermore, comparing with the predictions by Euler-Bernoulli beam theory, the MD simulation provides a larger and smaller first vibration frequencies for the cl ed-cl ed and cl ed-free thin Ag NWs, respectively. Additionally, for thin NWs, the first order natural frequency exhibits a parabolic relationship with the excitation magnitudes. The frequencies of the higher vibration modes tend to be low in comparison to Euler-Bernoulli beam theory predictions. A combined initial excitation is proposed which is capable to drive the NW under a multi-mode vibration and arrows the coexistence of all the following low vibration modes. This work sheds lights on the better understanding of the mechanical properties of NWs and benefits the increasing utilities of NWs in erse nano-electronic devices.
Publisher: Elsevier BV
Date: 04-2016
Publisher: MDPI AG
Date: 18-07-2022
DOI: 10.3390/NANO12142456
Abstract: 2D Titanium carbide MXenes with a structural formula recognized as Tin+1Cn have attracted attention from both the academic and industry fields due to their intriguing mechanical properties and appealing potential in a variety of areas such as nano-electronic circuits/devices, bio sensors, energy storage and reinforcing material for composites. Based on mutli-body comb3 (third-generation Charge-Optimized Many-Body) potential, this work investigated the impact resistance of monolayer Tin+1Cn nanosheets (namely, Ti2C Ti3C2 and Ti4C3) under hypervelocity up to 7 km/s. The deformation behavior and the impact resist mechanisms of Tin+1Cn nanosheets were assessed. Penetration energy is found to positively correlate with the number of titanium atom layer (n). However, in tracking atomic Von Mises stress distribution, Ti2C exhibits the most significant elastic wave propagation velocity among the examined nanosheets, suggesting the highest energy delocalization rate and stronger energy dissipation via deformation prior to bond break. Consistently, Ti2C presents superior specific penetration energy due its Young’s-modulus-to-density ratio, followed by Ti3C2 and Ti4C3, suggesting an inverse correlation between the titanium atom layer number and specific penetration energy. This study provides a fundamental understanding of the deformation and penetration mechanisms of titanium carbide MXene nanosheets under impact, which could be beneficial to facilitating their emerging impact protection applications.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7NR07449B
Abstract: Mechanical resonance of GaAs nanowires allows for measurement of the effect of stacking faults on Young's modulus and quality factor.
Publisher: American Chemical Society (ACS)
Date: 02-12-2015
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR04882G
Abstract: 2D material based nanosprings break down Hooke's law at the nanoscale.
Publisher: Elsevier BV
Date: 2014
Publisher: American Chemical Society (ACS)
Date: 11-2019
Publisher: Beilstein Institut
Date: 20-03-2014
DOI: 10.3762/BJNANO.5.37
Abstract: Doping is an effective approach that allows for the intrinsic modification of the electrical and chemical properties of nanomaterials. Recently, a graphene and carbon nanotube hybrid structure (GNHS) has been reported, which extends the excellent properties of carbon-based materials to three dimensions. In this paper, we carried out a first-time investigation on the tensile properties of the hybrid structures with different dopants. It is found that with the presence of dopants, the hybrid structures usually exhibit lower yield strength, Young’s modulus, and earlier yielding compared to that of a pristine hybrid structure. For dopant concentrations below 2.5% no significant reduction of Young’s modulus or yield strength could be observed. For all considered s les, the failure is found to initiate at the region where the nanotubes and graphene sheets are connected. After failure, monatomic chains are normally observed around the failure region. Dangling graphene layers without the separation of a residual CNT wall are found to adhere to each other after failure with a distance of about 3.4 Å. This study provides a fundamental understanding of the tensile properties of the doped graphene–nanotube hybrid structures, which will benefit the design and also the applications of graphene-based hybrid materials.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3NA00622K
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4RA11753K
Abstract: We report on the mechanical properties of sodium titanate nanowires (Na 2 Ti 3 O 7 NW) through a combination of bending experiments and theoretical analysis.
Publisher: Elsevier BV
Date: 11-2022
Publisher: World Scientific Pub Co Pte Ltd
Date: 13-04-2017
DOI: 10.1142/S0219876217500232
Abstract: For smoothed particle hydrodynamics (SPH), homogeneous particle distribution is important to ensure the computational accuracy and stability, but it is hard to achieve this for complex geometries. In this paper, a new particle generation method is developed to generate particles for arbitrary 2D geometries. In the method, the geometry required for generating particles is orthogonally partitioned into a series of sub-domains. Among the resultant sub-domains, the most ones having standard area are directly converted into particles. The others are iteratively meshed into elements with nearly standard area and particles are placed according to these elements. The present method is implemented based on Abaqus. Ex les of particle generation are given to compare various particle generation methods. It is found that the present method shows advantages over some existing methods in the approximation of geometric boundary as well as the regularity and homogeneity of particle distribution. Several physical problems are adopted to examine the influence of initial particle distribution on SPH solution. The calculated results show that particle distributions generated by the present method can lead to better accuracy and stability than those created by some existing methods.
Publisher: Elsevier BV
Date: 07-2017
Publisher: American Chemical Society (ACS)
Date: 08-03-2021
Publisher: American Chemical Society (ACS)
Date: 20-12-2014
DOI: 10.1021/JP4109442
Publisher: MDPI AG
Date: 16-08-2016
DOI: 10.3390/MA9080697
Publisher: Elsevier BV
Date: 12-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0NA00284D
Abstract: Three-point bending tests of a pristine rutile TiO 2 NW.
Publisher: MDPI AG
Date: 24-11-2019
DOI: 10.3390/MA12233884
Abstract: The poor surface performance of titanium alloys substantially limits their application in many fields, such as the petrochemical industry. To overcome this weakness, the Cu and Ni double layers were deposited on the surface of TC4 alloy by the electroplating method, and the isothermal diffusion process was performed at 700 °C to enhance the binding ability between Cu and Ni layers. The isothermal diffusion behavior and microstructure of the coating were systematically analyzed, and tribological property and corrosion resistance of the coating were also evaluated to reveal the influence of isothermal diffusion on the surface performance. It was shown that multiple diffusion layers appeared on the Cu/Ni and Ni/Ti interface, and that NixTiy and CuxTiy phases were formed in the coating with the increase of diffusion time. More importantly, Kirkendall diffusion occurred when the diffusion time increased, which led to the formation of continuous microvoids and cracks in the diffusion layer, weakening the surface performance of the Cu/Ni coatings. This paper unveils the relationship between the microstructure of the Cu/Ni coatings and isothermal diffusion behavior, providing guidelines in preparing high performance surface coatings.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 08-2017
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 08-2023
Publisher: Trans Tech Publications, Ltd.
Date: 09-2011
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.335-336.498
Abstract: Molecular dynamics (MD) simulations have been carried out to investigate the defect’s effect on the mechanical properties of single-crystal copper nanowire with different surface defects, under torsion deformation. The torsional rigidity is found insensitive to the surface defects and the critical angle appears an obvious decrease due to the surface defects, the largest decrease is found for the nanowire with surface horizon defect. The deformation mechanism appears different degrees of influence due to surface defects. The surface defects play a role of dislocation sources. Comparing with single intrinsic stacking faults formation for the perfect nanowire, much affluent deformation processes have been activated because of surface defects, for instance, we find the twins formation for the nanowire with a surface 45 o defect.
Publisher: IOP Publishing
Date: 17-07-2015
DOI: 10.1088/0957-4484/26/31/315501
Abstract: The capabilities of the mechanical resonator-based nanosensors in detecting ultra-small mass or force shifts have driven a continuing exploration of the palette of nanomaterials for such application purposes. Based on large-scale molecular dynamics simulations, we have assessed the applicability of a new class of carbon nanomaterials for nanoresonator usage, i.e. the single-wall carbon nanotube (SWNT) network. It is found that SWNT networks inherit excellent mechanical properties from the constituent SWNTs, possessing a high natural frequency. However, although a high quality factor is suggested from the simulation results, it is hard to obtain an unambiguous Q-factor due to the existence of vibration modes in addition to the dominant mode. The nonlinearities resulting from these extra vibration modes are found to exist uniformly under various testing conditions including different initial actuations and temperatures. Further testing shows that these modes can be effectively suppressed through the introduction of axial strain, leading to an extremely high quality factor in the order of 10(9) estimated from the SWNT network with 2% tensile strain. Additional studies indicate that the carbon rings connecting the SWNTs can also be used to alter the vibrational properties of the resulting network. This study suggests that the SWNT network can be a good candidate for applications as nanoresonators.
Publisher: MDPI AG
Date: 27-06-2022
DOI: 10.3390/NANO12132203
Abstract: Metallic nanowires (NWs) are essential building blocks for flexible electronics, and experience different deformation modes due to external mechanical loading. Using atomistic simulations, this work investigated the deformation behavior of copper nanowire under coupled tension–torsion loading. A transition in both yielding pattern and dislocation pattern were observed with varying torsion/tension strain ratios. Specifically, increasing the torsion/tension strain ratio (with larger torsional strain) triggered the nucleation of different partial dislocations in the slip system. At low torsion/tension strain ratios, plastic deformation of the nanowire was dominated by stacking faults with trailing partial dislocations pinned at the surface, shifting to two partial dislocations with stacking faults as the strain ratio increases. More interestingly, the NW under tension-dominated loading exhibited a stacking fault structure after yielding, whereas torsion-dominated loading resulted in a three-dimensional dislocation network within the structure. This work thus suggests that the deformation behavior of the NW varies depending on the coupled mechanical loading, which could be beneficial for various engineering applications.
Publisher: MDPI AG
Date: 21-09-2021
DOI: 10.3390/NANO11092456
Abstract: 3D Printed biodegradable polymeric scaffolds are critical to repair a bone defect, which can provide the in idual porous and network microenvironments for cell attachment and bone tissue regeneration. Biodegradable PCL/HA composites were prepared with the blending of poly(ε-caprolactone) (PCL) and hydroxyapatite nanoparticles (HA). Subsequently, the PCL/HA scaffolds were produced by the melting deposition-forming method using PCL/HA composites as the raw materials in this work. Through a serial of in vitro assessments, it was found that the PCL/HA composites possessed good biodegradability, low cell cytotoxicity, and good biocompatibility, which can improve the cell proliferation of osteoblast cells MC3T3-E1. Meanwhile, in vivo experiments were carried out for the rats with skull defects and rabbits with bone defects. It was observed that the PCL/HA scaffolds allowed the adhesion and penetration of bone cells, which enabled the growth of bone cells and bone tissue regeneration. With a composite design to load an anticancer drug (doxorubicin, DOX) and achieve sustained drug release performance, the multifunctional 3D printed PCL/HA/DOX scaffolds can enhance bone repair and be expected to inhibit probably the tumor cells after malignant bone tumor resection. Therefore, this work signifies that PCL/HA composites can be used as the potential biodegradable scaffolds for bone repairing.
Publisher: Elsevier BV
Date: 2015
Publisher: MDPI AG
Date: 24-05-2022
DOI: 10.3390/NANO12111785
Abstract: Through atomistic simulations, this work investigated the permeability of hexagonal diamond nanochannels for NaCl solution. Compared with the multilayer graphene nanochannel (with a nominal channel height of 6.8 Å), the diamond nanochannel exhibited better permeability. The whole transportation process can be ided into three stages: the diffusion stage, the transition stage and the flow stage. Increasing the channel height reduced the transition nominal pressure that distinguishes the diffusion and flow stages, and improved water permeability (with increased water flux but reduced ion retention rate). In comparison, channel length and solution concentration exerted ignorable influence on water permeability of the channel. Further simulations revealed that temperature between 300 and 350 K remarkably increased water permeability, accompanied by continuously decreasing transition nominal pressure. Additional investigations showed that the permeability of the nanochannel could be effectively tailored by surface functionalization. This work provides a comprehensive atomic insight into the transportation process of NaCl solution in a diamond nanochannel, and the established understanding could be beneficial for the design of advanced nanofluidic devices.
Publisher: MDPI AG
Date: 21-04-2023
DOI: 10.3390/MA16083270
Abstract: The combination of spinel Li4Ti5O12 (LTO) with carbon nanostructures, such as graphene (G) and carbon nanotubes (CNTs), provides all of the required properties for modern chemical power sources such as Li-ion batteries (LIBs) and supercapacitors (SCs). G/LTO and CNT/LTO composites demonstrate a superior reversible capacity, cycling stability, and good rate performances. In this paper, an ab initio attempt to estimate the electronic and capacitive properties of such composites was made for the first time. It was found that the interaction between LTO particles and CNTs was higher than that with graphene due to the larger amount of transfer charge. Increasing the graphene concentration raised the Fermi level and enhanced the conductive properties of G/LTO composites. For CNT/LTO s les, the radius of CNT did not affect the Fermi level. For both G/LTO and CNT/LTO composites, an increase in the carbon ratio resulted in a similar reduction in quantum capacitance (QC). It was observed that during the charge cycle in the real experiment, the non-Faradaic process prevailed during the charge cycle, while the Faradaic process prevailed during the discharge cycle. The obtained results confirm and explain the experimental data and improve the understanding of the processes occurring in G/LTO and CNT/LTO composites for their usages in LIBs and SCs.
Publisher: Elsevier BV
Date: 12-2015
Publisher: American Chemical Society (ACS)
Date: 26-04-2017
Publisher: American Chemical Society (ACS)
Date: 15-09-2020
Publisher: American Chemical Society (ACS)
Date: 23-12-2020
Publisher: Wiley
Date: 08-07-2021
Abstract: Low‐dimensional carbon nanostructures are ideal nanofillers to reinforce the mechanical performance of polymer nanocomposites due to their excellent mechanical properties. Through molecular dynamics simulations, the mechanical performance of poly(vinyl alchohol) (PVA) nanocomposites reinforced with a single‐layer diamond – diamane is investigated. It is found the PVA/diamane exhibits similar interfacial strengths and pull‐out characteristics with the PVA/bilayer‐graphene counterpart. Specifically, when the nanofiller is fully embedded in the nanocomposite, it is unable to deform simultaneously with the PVA matrix due to the weak interfacial load transfer efficiency, thus the enhancement effect is not significant. In comparison, diamane can effectively promote the tensile properties of the nanocomposite when it has a laminated structure as it deforms simultaneously with the matrix. With this configuration, the interlayer sp 3 bonds endows diamane with a much higher resistance under compression and shear tests, thus the nanocomposite can reach very high compressive and shear stress. Overall, enhancement on the mechanical interlocking at the interface as triggered by surface functionalization is only effective for the fully embedded nanofiller. This work provides a fundamental understanding of the mechanical properties of PVA nanocomposites reinforced by diamane, which can shed lights on the design and preparation of next generation high‐performance nanocomposites.
Publisher: Pan Stanford Publishing
Date: 08-04-2013
DOI: 10.1201/B14795-24
Publisher: American Chemical Society (ACS)
Date: 15-10-2019
DOI: 10.1021/ACS.NANOLETT.9B02685
Abstract: It is challenging but important to understand the mechanical properties of one-dimensional (1D) nanomaterials for their design and integration into nanodevices. Generally, brittle ceramic nanowires (NWs) cannot withstand a large bending strain. Herein,
Publisher: Elsevier BV
Date: 10-2014
Publisher: American Chemical Society (ACS)
Date: 22-09-2021
Publisher: AIP Publishing
Date: 13-10-2014
DOI: 10.1063/1.4898578
Abstract: We reported the thermal conductivity of the two-dimensional carbon nanotube (CNT)-based architecture, which can be constructed through welding of single-wall CNTs by electron beam. Using large-scale nonequilibrium molecular dynamics simulations, the thermal conductivity is found to vary with different junction types due to their different phonon scatterings at the junction. The strong length and strain dependence of the thermal conductivity suggests an effective avenue to tune the thermal transport properties of the CNT-based architecture, benefiting the design of nanoscale thermal rectifiers or phonon engineering.
Publisher: Elsevier
Date: 2017
Publisher: IOP Publishing
Date: 03-2018
Publisher: MDPI AG
Date: 20-11-2022
DOI: 10.3390/MET12111989
Abstract: Titanium carbides attract attention from both academic and industry fields because of their intriguing mechanical properties and proven potential as appealing candidates in the variety of fields such as nanomechanics, nanoelectronics, energy storage and oil/water separation devices. A recent study revealed that the presence of Ti8C5 not only improves the impact strength of composites as coatings, but also possesses significant strengthening performance as an interlayer material in composites by forming strong bonding between different matrices, which sheds light on the design of impact protection composite materials. To further investigate the impact resistance and strengthening mechanism of Ti8C5, a pilot Molecular Dynamics (MD) study utilizing comb3 potential is carried out on a Ti8C5 nanosheet by subjecting it to hypervelocity impacts. The deformation behaviour of Ti8C5 and the related impact resist mechanisms are assessed in this research. At a low impact velocity ~0.5 km/s, the main resonance frequency of Ti8C5 is 11.9 GHz and its low Q factor (111.9) indicates a decent energy d ing capability, which would eliminate the received energy in an interfacial reflection process and weaken the shock waves for Ti8C5 strengthened composites. As the impact velocity increases above the threshold of 1.8 km/s, Ti8C5 demonstrates brittle behaviour, which is signified by its insignificant out-of-plane deformation prior to crack initiation. When tracking atomic Von Mises stress distribution, the elastic wave propagation velocity of Ti8C5 is calculated to be 5.34 and 5.90 km/s for X and Y directions, respectively. These figures are inferior compared with graphene and copper, which indicate slower energy delocalization rates and thus less energy dissipation via deformation is expected prior to bond break. However, because of its relatively small mass density comparing with copper, Ti8C5 presents superior specific penetration. This study provides a fundamental understanding of the deformation and penetration mechanisms of titanium carbide nanosheets under impact, which is crucial in order to facilitate emerging impact protection applications for titanium carbide-related composites.
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5RA05584A
Abstract: A numerical study of the tuning of the thermal conductivity of three-dimensional CNT-based nanotubes.
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR02082A
Abstract: Layered sodium titanate nanowires exhibit ultra-large bending strain, which is accompanied by dislocation motion.
Publisher: MDPI AG
Date: 28-10-2022
DOI: 10.3390/NANO12213807
Abstract: Nanomaterials and nanostructures are continuously driving technology revolutions in broad engineering fields, such as defense [...]
Publisher: Springer Science and Business Media LLC
Date: 13-09-2016
DOI: 10.1038/SREP33139
Abstract: The excellent mechanical properties of graphene have enabled it as appealing candidate in the field of impact protection or protective shield. By considering a monolayer graphene membrane, in this work, we assessed its deformation mechanisms under hypervelocity impact (from 2 to 6 km/s), based on a serial of in silico studies. It is found that the cracks are formed preferentially in the zigzag directions which are consistent with that observed from tensile deformation. Specifically, the boundary condition is found to exert an obvious influence on the stress distribution and transmission during the impact process, which eventually influences the penetration energy and crack growth. For similar s le size, the circular shape graphene possesses the best impact resistance, followed by hexagonal graphene membrane. Moreover, it is found the failure shape of graphene membrane has a strong relationship with the initial kinetic energy of the projectile. The higher kinetic energy, the more number the cracks. This study provides a fundamental understanding of the deformation mechanisms of monolayer graphene under impact, which is crucial in order to facilitate their emerging future applications for impact protection, such as protective shield from orbital debris for spacecraft.
Publisher: American Chemical Society (ACS)
Date: 17-09-2018
DOI: 10.1021/ACS.JPCLETT.8B02349
Abstract: In situ tensile tests show atypical defect motions in the brittle Na
Publisher: IOP Publishing
Date: 11-2020
Abstract: The excellent mechanical properties of Graphdiyne (GDY) family has enabled it as an appealing candidate in the field of impact protection. In this in silico study, Monolayer GDY nanosheets of different morphology including GDY, GY-3, GY-4, GY-5 and GY-6 are assessed under hypervelocity impacts (from 1 to 6 km s −1 ). Tracking the deformation mechanisms under impacts as well as the Probability density function based on atomic Von Mises stress distribution, the length of acetylenic chain clearly alters ductile behavior as well as the energy dissipation/delocalization rate of GDY family during the impact. Results also suggest the penetration energy is not only determined by the energy delocalization rate but also sensitive to impact velocity for nanosheet with various acetylenic chain length. GY-5 with a much lower energy delocalization rate presents a close penetration energy comparing with GDY at a low impact at ∼2.0 km s −1 , its superior ductility granted by long acetylenic chain not only dissipates kinetic energy of projectile via deformation, but also extends time for acceleration during the contact with projectile. Considering the impact resist performance of GDY family in terms of Specific penetration energy, GY-5 with the perfect balance between material density, ductility and Young’s modulus makes it the superior anti-ballistic material for impact velocity at km s −1 . For impact velocity km s −1 , it induces severer local deformation, and leaves no time for a well-developed distributed pattern as observed in a lower impact velocity scenario. As such, extensive elastic deformation of the nanosheet is not captured under impact, nanosheets with shorter acetylenic chains and hence greater material strength demonstrates superior impact resist. This study provides a fundamental understanding of the deformation and penetration mechanisms of monolayer GDY nanosheets under impact, which is crucial in order to facilitate their emerging applications for impact protection.
Publisher: Springer Science and Business Media LLC
Date: 20-04-2020
DOI: 10.1038/S41467-020-15807-7
Abstract: The excellent mechanical properties of carbon nanofibers bring promise for energy-related applications. Through in silico studies and continuum elasticity theory, here we show that the ultra-thin carbon nanothreads-based bundles exhibit a high mechanical energy storage density. Specifically, the gravimetric energy density is found to decrease with the number of filaments, with torsion and tension as the two dominant contributors. Due to the coupled stresses, the nanothread bundle experiences fracture before reaching the elastic limit of any in idual deformation mode. Our results show that nanothread bundles have similar mechanical energy storage capacity compared to (10,10) carbon nanotube bundles, but possess their own advantages. For instance, the structure of the nanothread allows us to realize the full mechanical energy storage potential of its bundle structure through pure tension, with a gravimetric energy density of up to 1.76 MJ kg −1 , which makes them appealing alternative building blocks for energy storage devices.
Publisher: Wiley
Date: 22-07-2022
Abstract: To facilitate the biomedical applications of biocomposites, researchers have used different types of fillers to enhance their mechanical properties. However, the addition of fillers not only changes the mechanical performance of the biocomposites, but also affects their printability, that is, their rheological properties. With the aid of atomistic simulations, this work investigates the influence of graphene size and aggregation on the rheological properties of polycaprolactone (PCL) composites. For the same weight ratio, increasing the graphene size causes the viscosity of the PCL composite to increase until a threshold edge length equal to PCL's average radius of gyration. After this threshold value, the viscosity decreases with increasing edge length. The PCL composite with multilayered graphene exhibits a lower viscosity compared with its counterpart with monolayer graphene. Specifically, the addition of graphene is shown to augment the shear‐thinning effect. The findings in this work provide a fundamental understanding of the rheological property of PCL composites with the addition of 2D nanofillers, which shed light on the ink design for bioprinting.
Publisher: IEEE
Date: 08-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C8CP05408H
Abstract: Generally existing flexural mode doublets in silicon nanowires.
Publisher: Elsevier BV
Date: 03-2014
Start Date: 2020
End Date: 2022
Funder: Australian Research Council
View Funded ActivityStart Date: 2015
End Date: 2015
Funder: Department of Education, Australian Governement
View Funded ActivityStart Date: 2017
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 2017
End Date: 04-2020
Amount: $415,500.00
Funder: Australian Research Council
View Funded ActivityStart Date: 05-2020
End Date: 12-2023
Amount: $410,000.00
Funder: Australian Research Council
View Funded Activity