scholarly journals A Molecular Mechanics Study of Morphologic Interaction between Graphene and Si Nanowires on a SiO2Substrate

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Zhao Zhang ◽  
Teng Li
Keyword(s):  
Molecular Mechanics ◽  
Material Properties ◽  
Graphene Nanoribbon ◽  
Si Nanowires ◽  
Graphene Flake ◽  
Nanowire Diameter ◽  
Si Nanowire ◽  
Material Systems ◽  
Quantitative Results ◽  
Simulation Results

We study the morphologic interaction between graphene and Si nanowires on a SiO2substrate, using molecular mechanics simulations. Two cases are considered: (1) a graphene nanoribbon intercalated by a single Si nanowire on a SiO2substrate and (2) a blanket graphene flake intercalated by an array of Si nanowires evenly patterned in parallel on a SiO2substrate. Various graphene morphologies emerge from the simulation results of these two cases, which are shown to depend on both geometric parameters (e.g., graphene nanoribbon width, nanowire diameter, and nanowire spacing) and material properties (e.g., graphene-nanowire and graphene-substrate bonding strength). While the quantitative results at the atomistic resolution in this study can be further used to determine the change of electronic properties of graphene under morphologic regulation, the qualitative understandings from this study can be extended to help exploring graphene morphology in other material systems.

scholarly journals Development of Elastoplastic-Damage Model of AlFeSi Phase for Aluminum Alloy 6061

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 954
Author(s):  
Hailong Wang ◽  
Wenping Deng ◽  
Tao Zhang ◽  
Jianhua Yao ◽  
Sujuan Wang
Keyword(s):  
Aluminum Alloy ◽  
Constitutive Model ◽  
Material Properties ◽  
Damage Model ◽  
Scratch Test ◽  
Aluminum Alloy 6061 ◽  
Ultra Precision ◽  
Simulation Results ◽  
Alloy 6061 ◽  
Elastoplastic Damage

Material properties affect the surface finishing in ultra-precision diamond cutting (UPDC), especially for aluminum alloy 6061 (Al6061) in which the cutting-induced temperature rise generates different types of precipitates on the machined surface. The precipitates generation not only changes the material properties but also induces imperfections on the generated surface, therefore increasing surface roughness for Al6061 in UPDC. To investigate precipitate effect so as to make a more precise control for the surface quality of the diamond turned Al6061, it is necessary to confirm the compositions and material properties of the precipitates. Previous studies have indicated that the major precipitate that induces scratch marks on the diamond turned Al6061 is an AlFeSi phase with the composition of Al86.1Fe8.3Si5.6. Therefore, in this paper, to study the material properties of the AlFeSi phase and its influences on ultra-precision machining of Al6061, an elastoplastic-damage model is proposed to build an elastoplastic constitutive model and a damage failure constitutive model of Al86.1Fe8.3Si5.6. By integrating finite element (FE) simulation and JMatPro, an efficient method is proposed to confirm the physical and thermophysical properties, temperature-phase transition characteristics, as well as the stress–strain curves of Al86.1Fe8.3Si5.6. Based on the developed elastoplastic-damage parameters of Al86.1Fe8.3Si5.6, FE simulations of the scratch test for Al86.1Fe8.3Si5.6 are conducted to verify the developed elastoplastic-damage model. Al86.1Fe8.3Si5.6 is prepared and scratch test experiments are carried out to compare with the simulation results, which indicated that, the simulation results agree well with those from scratch tests and the deviation of the scratch force in X-axis direction is less than 6.5%.

FEMLIB: An Object-Oriented Framework for Optimization and Simulation

1995 ◽  
Author(s):  
Michael M. Tiller ◽  
Jonathan A. Dantzig
Keyword(s):  
Material Properties ◽  
Object Oriented ◽  
The Finite Element Method ◽  
Simulation And Optimization ◽  
Gradient Based ◽  
Level Problem ◽  
Simulation Results ◽  
Optimization And Simulation ◽  
High Level ◽  
Simulation Parameters

Abstract In this paper we discuss the design of an object-oriented framework for simulation and optimization. Although oriented around high-level problem solving, the framework defines several classes of problems and includes concrete implementations of common algorithms for solving these problems. Simulations are run by combining these algorithms, as needed, for a particular problem. Included in this framework is the capability to compute the sensitivity of simulation results to the different simulation parameters (e.g. material properties, boundary conditions, etc). This sensitivity information is valuable in performing optimization because it allows the use of gradient-based optimization algorithms. Also included in the system are many useful abstractions and implementations related to the finite element method.

Low-Energy Ion Irradiated Silicon Nanowires: Anomalous Plastic Deformation

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Chu Rainer Kwang-Hua
Keyword(s):  
Plastic Deformation ◽  
Silicon Nanowires ◽  
Room Temperature ◽  
Transition State Theory ◽  
State Theory ◽  
Si Nanowires ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Si Nanowire ◽  
Dependent Viscosity

We adopted the verified transition state theory, which originates from the quantum chemistry approach to explain the anomalous plastic flow or plastic deformation for Si nanowires irradiated with 100 keV (at room temperature regime) Ar+ ions as well as the observed amorphization along the Si nanowire (Johannes, et al. 2015, “Anomalous Plastic Deformation and Sputtering of Ion Irradiated Silicon Nanowires,” Nano Lett., 15, pp. 3800–3807). We shall illustrate some formulations which can help us calculate the temperature-dependent viscosity of flowing Si in nanodomains.

Development of Parametric Kelvin Structures will Closed Cells

2016 ◽  
Vol 254 ◽  
pp. 49-54 ◽  
Author(s):  
Dan Andrei Şerban ◽  
Emanoil Linul ◽  
Sorin Sărăndan ◽  
Liviu Marşavina
Keyword(s):  
Mechanical Properties ◽  
Cell Wall ◽  
Relative Density ◽  
Material Properties ◽  
Cell Diameter ◽  
Rigid Polyurethane Foam ◽  
Loading Direction ◽  
Convergence Study ◽  
Simulation Results ◽  
Mesh Convergence

This work presents the design of a parametric Kelvin structure in which the relative density of the geometry can be varied by adjusting three parameters: cell diameter, cell wall thickness and cell chamfer radius, the structure consistsing of a tessellation of hollow truncated octahedral. The developed model was evaluated in terms of compressive stiffness for the case of a rigid polyurethane foam of 0.256 relative density. Three models were analyzed in order to determine the influence of geometric characteristics on mechanical properties: a model that presented no chamfer a model that presented a medium-sized chamfer and a model that presented a large chamfer. A mesh convergence study was performed which analyzed the results in terms of accuracy and time expenses for three element sizes for both linear and quadratic elements. Due to the orthotropic nature of the model, its response on both possible loading directions was investigated. Simulation results were compared with experimental results and yielded accurate results for one loading direction, when using the material properties for solid polyurethane described in literature.

The Numerical Simulation of Effective Elastic Response for WC-Co Cemented Carbide

2015 ◽  
Vol 1096 ◽  
pp. 417-421
Author(s):  
Pei Luan Li ◽  
Zi Qian Huang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Model ◽  
Material Properties ◽  
Cemented Carbide ◽  
Elastic Response ◽  
The Finite Element Method ◽  
Simulation Results ◽  
Element Method

By the use of finite element method, this paper predicts the effects of the shapes of reinforcements with different ductility (Co) on the effective elastic response for WC-Co cemented carbide. This paper conducts a comparative study on the material properties obtained through theoretical model, numerical simulation and experimental observations. Simulation results indicate that the finite element method is more sophisticated than the theoretical prediction.

Computational Design of Microstructures With Stochastic Property Closures

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Pinar Acar
Keyword(s):  
Material Properties ◽  
Computational Design ◽  
Polycrystalline Materials ◽  
Stochastic Property ◽  
Analytical Uncertainty ◽  
Magnetostrictive Strain ◽  
Material Systems ◽  
Stochastic Solution ◽  
Deformation Processes ◽  
Computational Solution

Abstract The present work addresses a stochastic computational solution to define the property closures of polycrystalline materials under uncertainty. The uncertainty in material systems arises from the natural stochasticity of the microstructures as a result of the fluctuations in deformation processes. The microstructural uncertainty impacts the performance of engineering components by causing unanticipated anisotropy in properties. We utilize an analytical uncertainty quantification algorithm to describe the microstructural stochasticity and model its propagation on the volume-averaged material properties. The stochastic solution will be integrated into linear programming to generate the property closure that shows all possible values of the volume-averaged material properties under the uncertainty. We demonstrate example applications for stiffness parameters of α-Titanium, and multi-physics parameters (stiffness, yield strength, magnetostrictive strain) of Galfenol. Significant differences observed between stochastic and deterministic closures imply the importance of considering the microstructural uncertainty when modeling and designing materials.

scholarly journals Experimental and simulation investigation on spring-in deformation for L-shape component

2019 ◽  
Vol 6 (1) ◽  
pp. 169-180 ◽  
Author(s):  
Tushar Gajjar ◽  
Dhaval B. Shah ◽  
S. J. Joshi ◽  
K. M. Patel
Keyword(s):  
Material Properties ◽  
Composite Laminates ◽  
Coefficient Of Thermal Expansion ◽  
Spring Back ◽  
Composite Part ◽  
Autoclave Process ◽  
Temperature Heat ◽  
Testing Techniques ◽  
Simulation Results ◽  
Key Parameter

AbstractThe angular deformation is key parameter in composite manufacturing for curvature surfaces. Process Induced Distortions (PID’s) are a major problem while manufacturing a composite part using autoclave process. Spring-back or spring-in is one of the PID in autoclave process. Spring-in effect either increase or decrease at angled section during curing of composite laminates. In this paper, L-shaped composite part has been manufactured using autoclave process. The material properties like glass transition temperature, heat reaction, crystallization temperature, Coefficient of Thermal Expansion have been measured for the cured component by using various testing techniques. Spring-in angle has been found for various number of layers and layup orientation. The simulation has been performed in ABAQUS software along with the COMPRO plug-in for each component. The variation of spring-in angle has been observed with changing material properties. The experimental results have been compared with simulation results. The percentage variation of spring-in deformation for experimental and simulation results has been found in the range of 5-7%.

scholarly journals An Augmented Reality Facility to Run Hybrid Physical-Numerical Flood Models

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3290
Author(s):  
Jerónimo Puertas ◽  
Luis Hernández-Ibáñez ◽  
Luis Cea ◽  
Manuel Regueiro-Picallo ◽  
Viviana Barneche-Naya ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Graphical User Interface ◽  
Overland Flow ◽  
Digital Terrain Model ◽  
Entire System ◽  
Terrain Model ◽  
Digital Terrain ◽  
Physical Scale ◽  
Quantitative Results ◽  
Simulation Results

This article presents a novel installation for the development of hybrid physical-numerical flood models in an augmented reality environment. This installation extends the concept introduced by the well-known Augmented Reality-SandBox (AR-Sandbox) module, which presents a more educational, and less research-based and professional application. It consists of a physical scale topography built in a sandbox into which other elements (such as buildings, roads or dikes) can be incorporated. A scanner generates, in real time, a Digital Terrain Model (DTM) from the sandbox topography, which serves as a basis for the simulation of overland flow using professional hydraulic software (Iber+). The hydraulic and hydrological parameters (surface roughness, inlet discharges, boundary conditions) are entered with a simple Graphical User Interface (GUI) developed specifically for this project, as indeed was the entire system that allows the visualization of the simulation results. This allows us to obtain quantitative results of flood extension and magnitude, which are represented directly over the physical topography, yielding a realistic visual effect. This installation is conceived for both educational and professional uses. An example of its use is presented, through which its accuracy can be appreciated, and which also illustrates its potential.

scholarly journals Iterative Analysis of Dielectric Constant of Patch Antenna Substrate at UHF Band

2018 ◽  
Vol 7 (2.16) ◽  
pp. 7
Author(s):  
Amish Kumar Jha ◽  
Bharti Gupta Gupta ◽  
Preety D Swami
Keyword(s):  
Dielectric Constant ◽  
Material Properties ◽  
Patch Antenna ◽  
Dielectric Materials ◽  
Substrate Material ◽  
Frequency Range ◽  
Shape Model ◽  
Iterative Analysis ◽  
Working Frequency ◽  
Simulation Results

This paper presents an investigation of effect of substrate material properties on the performance of antenna. The simulations are tested for 30 different dielectric materials on the basic RPA antenna model as well as on the most common U shape model using CST Microwave Studio. Two designs are proposed. On the basis of simulation results it has been concluded that for the first design the best material is which has a dielectric constant of 2.7 (𝜀r = 2.7) with bandwidth improvements of around 69.33% to 88.6% as compared to the most frequently used materials at present. For the second design the best result is obtained for the material that has dielectric constant in the range 2.0 to 2.7.  For a material having dielectric constant of 2.1 (𝜀r = 2.1) bandwidth improvement of around 11.74% with respect to RT Duroid was observed. For the second design, radiations from all other materials were not available in the working frequency range of 1GHz to 6GHz.  

Prediction of elastic properties of carbon nanotube reinforced composites

2005 ◽  
Vol 461 (2058) ◽  
pp. 1685-1710 ◽  
Author(s):  
N Hu ◽  
H Fukunaga ◽  
C Lu ◽  
M Kameyama ◽  
B Yan
Keyword(s):  
Finite Element ◽  
Carbon Nanotube ◽  
Molecular Mechanics ◽  
Elastic Properties ◽  
Polymer Matrix ◽  
Material Properties ◽  
Transition Layer ◽  
Beam Model ◽  
Reinforced Composites ◽  
Computational Structural Mechanics

In this paper, the macroscopic elastic properties of carbon nanotube reinforced composites are evaluated through analysing the elastic deformation of a representative volume element (RVE) under various loading conditions. This RVE contains three components, i.e. a carbon nanotube, a transition layer between the nanotube and polymer matrix and an outer polymer matrix body. First, based on the force field theory of molecular mechanics and computational structural mechanics, an equivalent beam model is constructed to model the carbon nanotube effectively. The explicit relationships between the material properties of the equivalent beam element and the force constants have been set-up. Second, to describe the interaction between the nanotube and the outer polymer matrix at the level of atoms, the molecular mechanics and molecular dynamics computations have been performed to obtain the thickness and material properties of the transition layer. Moreover, an efficient three-dimensional eight-noded brick finite element is employed to model the transition layer and the outer polymer matrix. The macroscopic behaviours of the RVE can then be evaluated through the traditional finite element method. In the numerical simulations, the influences of various important factors, such as the stiffness of transition layer and geometry of RVE, on the final macroscopic material properties of composites have been investigated in detail.

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