Nanotechnology Future and Present in Construction Industry

2016 ◽  
pp. 141-179
Author(s):  
Umair Hasan ◽  
Amin Chegenizadeh ◽  
Hamid Nikraz
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Natural Hazards ◽  
Finite Element Methods ◽  
Material Behavior ◽  
Concrete Pavements ◽  
Metallic Oxides ◽  
Subgrade Stabilization

After the introduction of nanotechnology, it has been widely researched in geotechnical engineering field. This chapter aims to study these advancements with specific focus on geotechnical applications. In-situ probing of soil and rock masses through nanomaterials may help in providing better safeguards against natural hazards. The molecular dynamics and finite element methods may also be used for the modelling of the nanostructures to better understand the material behavior, causing a bottom-up approach from nano to macroscopic simulations. Nanoclays, nano-metallic oxides and fibers (carbon nanotubes) can enhance the mechanical characteristics of weak, reactive and soft soils. Nanomaterials may also be used for improving the performance of reinforced concrete pavements by enhancing the thermal, mechanical and electrical characteristics of the concrete mixes. The chapter presents a review of the current researches and practices in the nano-probing, nanoscale modelling and application of nanomaterials for soil, pavement concrete mortar and subgrade stabilization.

Modelling in situ shear strength testing of asphalt concrete pavements using the finite element method

2001 ◽  
Vol 28 (3) ◽  
pp. 541-544 ◽  
Author(s):  
Wael Bekheet ◽  
Yasser Hassan ◽  
AO Abd El Halim
Keyword(s):  
Finite Element ◽  
Shear Strength ◽  
Traffic Safety ◽  
Asphalt Concrete ◽  
Material Properties ◽  
Fundamental Property ◽  
Analytical Models ◽  
Strength Testing ◽  
Concrete Pavements

Rutting is one of the well-recognized road surface distresses in asphalt concrete pavements that can affect the pavement service life and traffic safety. Previous studies have shown that the shear strength of asphalt concrete pavements is a fundamental property in resisting rutting. Laboratory investigation has shown that improving the shear strength of the asphalt concrete mix can reduce surface rutting by more than 30%, and the SUPERPAVE mix design method has acknowledged the importance of the shear resistance of asphalt mixes as a fundamental property in resisting deformation of the pavement. An in situ shear strength testing facility was developed at Carleton University, and a more advanced version of this facility is currently under development in cooperation with the Transportation Research Board and the Ontario Ministry of Transportation. In using this facility, a circular area of the pavement surface is forced to rotate about a normal axis by applying a torque on a circular plate bonded to the surface. The pavement shear strength is then related to the maximum torque. This problem has been solved mathematically in the literature for a linear, homogeneous, and isotropic material. However, the models for other material properties are mathematically complicated and are not applicable to all cases of material properties. Therefore, developing a model that can accurately analyze the behaviour of asphalt concrete pavements during the in situ shear test has proven pivotal. This paper presents the development of a three-dimensional finite element model that can simulate the forces applied while measuring the shear strength of the asphalt concrete pavement. A comparison between the model results and those obtained from available analytical models and field measurements proved the accuracy of the developed model.Key words: shear strength, in situ testing, finite element, asphalt, pavement, modelling.

Multiscale Model to Study the Effect of Interfaces in Carbon Nanotube-Based Composites

2005 ◽  
Vol 127 (2) ◽  
pp. 222-232 ◽  
Author(s):  
S. Namilae ◽  
N. Chandra
Keyword(s):  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Finite Element ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Interfacial Region ◽  
Model Parameters ◽  
Zone Model ◽  
Pullout Tests ◽  
Nanoscale Interfaces

In order to fully harness the outstanding mechanical properties of carbon nanotubes (CNT) as fiber reinforcements, it is essential to understand the nature of load transfer in the fiber matrix interfacial region of CNT-based composites. With controlled experimentation on nanoscale interfaces far off, molecular dynamics (MD) is evolving as the primary method to model these systems and processes. While MD is capable of simulating atomistic behavior in a deterministic manner, the extremely small length and time scales modeled by MD necessitate multiscale approaches. To study the atomic scale interface effects on composite behavior, we herein develop a hierarchical multiscale methodology linking molecular dynamics and the finite element method through atomically informed cohesive zone model parameters to represent interfaces. Motivated by the successful application of pullout tests in conventional composites, we simulate fiber pullout tests of carbon nanotubes in a given matrix using MD. The results of the pullout simulations are then used to evaluate cohesive zone model parameters. These cohesive zone models (CZM) are then used in a finite element setting to study the macroscopic mechanical response of the composites. Thus, the method suggested explicitly accounts for the behavior of nanoscale interfaces existing between the matrix and CNT. The developed methodology is used to study the effect of interface strength on stiffness of the CNT-based composite.

scholarly journals Continuous Finite Element Methods of Molecular Dynamics Simulations

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
Qiong Tang ◽  
Luohua Liu ◽  
Yujun Zheng
Keyword(s):  
Molecular Dynamics ◽  
Finite Element ◽  
Molecular Dynamics Simulations ◽  
Finite Element Methods ◽  
Molecular System ◽  
Classical Trajectory ◽  
Dynamics Simulation ◽  
Long Time ◽  
Motion Characteristics ◽  
Dynamics Simulations

Molecular dynamics simulations are necessary to perform very long integration times. In this paper, we discuss continuous finite element methods for molecular dynamics simulation problems. Our numerical results aboutABdiatomic molecular system andA2Btriatomic molecules show that linear finite element and quadratic finite element methods can better preserve the motion characteristics of molecular dynamics, that is, properties of energy conservation and long-term stability. So finite element method is also a reliable method to simulate long-time classical trajectory of molecular systems.

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