Showing papers by "YuanTong Gu published in 2006"

Meshless techniques for convection dominated problems

Abstract: In this paper, the stability problem in the analysis of the convection dominated problems using meshfree methods is first discussed through an example problem of steady state convection-diffusion. Several techniques are then developed to overcome the instability issues in convection dominated phenomenon simulated using meshfree collocation methods. These techniques include: the enlargement of the local support domain, the upwind support domain, the adaptive upwind support domain, the biased support domain, the nodal refinement, and the adaptive analysis. These techniques are then demonstrated in one- and two-dimensional problems. Numerical results for example problems demonstrate the techniques developed in this paper are effective to solve convection dominated problems, and in these techniques, using adaptive local support domain is the most effective method. Comparing with the conventional finite difference method (FDM) and the finite element method (FEM), the meshfree method has found some attractive advantages in solving the convection dominated problems, because it easily overcomes the instability issues.

A Concurrent Multiscale Method Based on the Meshfree Method and Molecular Dynamics Analysis

Abstract: This paper presents a concurrent simulation technique for analyzing the deformation of systems that need the integration of material properties from nanoscopic to macroscopic dimensional scales. In the continuum subdomain, a weak‐form based meshfree method using the radial basis function interpolation was employed, but in the atomic subdomain, molecular dynamics analysis was used. The transition from the atomic to continuum domains was realized by transition particles which are independent of either the nodes in the continuum subdomain or the atoms in the atomic subdomain. A simple penalty method was used to ensure the compatibility of displacements and their gradients in the transition. A virtual cell algorithm was developed using a local quasi‐continuum approach to obtain the equivalent continuum strain energy density based on the atomic potentials and Cauchy–Born rule. Numerical examples showed that the present method is very accurate and stable, and has a promising potential to a wide class of multisc...

A concurrent multiscale method based on the meshfree method and molecular dynamics analysis

Abstract: This paper presents a concurrent simulation technique for analysing the deformation of systems that need the integration of material properties from nanoscopic to macroscopic dimensional scales. In the continuum sub-domain, a weak-form meshfree based method using the radial basis function interpolation was employed, but in the atomic sub-domain, molecular dynamics analysis was used. The transition from the atomic to continuum domains was realized by transition particles which are independent of either the nodes in the continuum sub-domain or the atoms in the atomic sub-domain. A simple penalty method was used to ensure the compatibility of displacements and their gradients in the transition. A virtual cell algorithm was developed using a local quasi-continuum approach to obtain the equivalent continuum strain energy density based on the atomic potentials and Cauchy-Born rule. Numerical examples showed that the present method is very accurate and stable, and has a promising potential to a wide class of multiscale systems.

JKMRC Mineral Liberation Analyser — A modern tool for ore characterisation and plant optimisation

Abstract: The Mineral Liberation Analyser (MLA) employs the technologies of scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The use of backscattered electron images to define phase boundaries produces very high resolution image analysis and subsequently detailed and accurate particle images and data output. The mineralogy, elemental deportment, grain size, liberation characteristics and mineral associations of a large number of samples can be described.

Deformation characterization of a nanoelectromechanical switch

Abstract: This paper analyses the deformation of a double-walled nanotube-based nanoelectromechanical switch. The product of Young's modulus and moment of inertia of the tube is determined by a molecular dynamics simulation with a linear deflection approximation. The switch is simplified to a beam system, and the loading is calculated from three coupled energy domains: the electrostatic energy domain, the elastostatic energy domain, and the van der Waals energy domain. A meshless formulation is then used to discretize the switch to establish the non-linear system of equations for analysis. A parametric comparison with the results in the literature showed that the method developed in this paper is very effective.

A simple method for analysing the deformation of nanoelectromechanical switches based on carbon nanotubes

Abstract: This paper developed an effective multiscale method for analysing the deformation of NanoElectroMechanical (NEM) switches based on carbon nanotubes. The switches were simplified to beam systems with loads calculated from three-coupled energy domains: the electrostatic energy domain, the elastostatic energy domain, and the van der Waals energy domain. A meshless formulation was then used to discretise the switches to establish the non-linear system of equations for solution. The pull-in voltage characteristics of the fixed-fixed and cantilever nanoswitches based on the single-walled nanotube and the double-walled nanotube are analysed. A parametric comparison with the results in the literature showed that the method developed in this paper is very effective.