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- A New Meshless Interpolation Scheme for MLPG_R Method
- CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.2, pp. 75-90, 2008, DOI:10.3970/cmes.2008.023.075
- Abstract In the MLPG_R (Meshless Local Petrove-Galerkin based on Rankine source solution) method, one needs a meshless interpolation scheme for an unknown function to discretise the governing equation. The MLS (moving least square) method has been used for this purpose so far. The MLS method requires inverse of matrix or solution of a linear algebraic system and so is quite time-consuming. In this paper, a new scheme, called simplified finite difference interpolation (SFDI), is devised. This scheme is generally as accurate as the MLS method but does not need matrix inverse and consume less CPU time to evaluate. Although this scheme…
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- Consolidation of a Soft Clay Composite: Experimental Results and Computational Estimates
- CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.1, pp. 53-74, 2008, DOI:10.3970/cmes.2008.023.053
- Abstract This paper deals with the problem of the consolidation of a composite consisting of alternate layers of soft clay and a granular material. A series of experiments were conducted on components to develop the constitutive models that can be implemented in a computational approach. The constitutive response of the soft clay is represented by a poro-elasto-plastic Cam clay-based model and the granular medium by an elasto-plastic model with a Drucker-Prager type failure criterion and a non-associated flow rule. The computational poro-elasto-plastic model is used to calibrate the experimental results derived from the one-dimensional tests and to establish the influence of…
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- Investigation of Multi Geometric Uncertainties by Different Polynomial Chaos Methodologies Using a Fictitious Domain Solver
- CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.1, pp. 29-52, 2008, DOI:10.3970/cmes.2008.023.029
- Abstract In this paper different Polynomial Chaos methods coupled to Fictitious Domain approach have been applied to one- and two- dimensional elliptic problems with multi uncertain variables in order to compare the accuracy and convergence of the methodologies. Both intrusive and non-intrusive methods have been considered, with particular attention to their employment for quantification of geometric uncertainties. A Fictitious Domain approach with Least-Squares Spectral Element approximation has been employed for the analysis of differential problems with uncertain boundary domains. Its main advantage lies in the fact that only a Cartesian mesh, that represents the enclosure, needs to be generated. Excellent accuracy…
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- Analysis of EDL Effect for Pressure-Driven 3D Developing Micro-Scale Flow
- CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.1, pp. 13-28, 2008, DOI:10.3970/cmes.2008.023.013
- Abstract Microchannels have been recognized as a very effective chemical separation and heat transfer device. The electrical double layer (EDL) effect in a micro-scale flow is however anticipated to be critical. In this paper, Nernst-Planck model (NPM), is used to predict the ion concentration distribution as it is reported to be a more appropriate model for developing microchannel flow. The governing equations are discretised for developing rectangular microchannel flows in Cartesians coordinate. An additional body force source term that is relating to the electric potential, resulted from the EDL effect is introduced in the conventional z-axis momentum equation as a body…
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- A Class of Wavelet-based Flat Shell Elements Using B-spline Wavelet on the Interval and Its applications
- CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.1, pp. 1-12, 2008, DOI:10.3970/cmes.2008.023.001
- Abstract A class of flat shell elements is constructed by using the scaling functions of two-dimensional tensor product B-spline wavelet on the interval (BSWI). Unlike the process of direct wavelets adding in the wavelet Galerkin method, the element displacement field represented by the coefficients of wavelets expansions was transformed from wavelet space into physical space via the constructed two-dimensional transformation matrix. Then, the BSWI flat shell element is constructed by the assembly of BSWI plane elastomechanics and Mindlin plate elements. Because of the good character of BSWI scaling functions, the BSWI flat shell element combine the accuracy of B-spline functions approximation…
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- Perfectly matched layer for acoustic waveguide modeling --- benchmark calculations and perturbation analysis
- CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 235-248, 2007, DOI:10.3970/cmes.2007.022.235
- Abstract The perfectly matched layer (PML) is a widely used technique for truncating unbounded domains in numerical simulations of wave propagation problems. In this paper, the PML technique is used with a standard one-way model to solve a benchmark problem for underwater acoustics modeling. Accurate solutions are obtained with a PML layer with a thickness of only a quarter of the wavelength. The effect of a PML is analyzed in a perturbation analysis for waveguides.
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- Application of the MLPG to Thermo-Piezoelectricity
- CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 217-234, 2007, DOI:10.3970/cmes.2007.022.217
- Abstract A meshless method based on the local Petrov-Galerkin approach is proposed for the solution of boundary value problems for coupled thermo-electro-mechanical fields. Transient dynamic governing equations are considered here. To eliminate the time-dependence in these equations, the Laplace-transform technique is applied. Material properties of piezoelectric materials are influenced by a thermal field. It is leading to an induced nonhomogeneity and the governing equations are more complicated than in a homogeneous counterpart. Two-dimensional analyzed domain is subdivided into small circular subdomains surrounding nodes randomly spread over the whole domain. A unit step function is used as the test functions in the…
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- Lattice Boltzmann Method Simulation of Channel Flow with Square Pillars inside by the Field Synergy Principle
- CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 203-216, 2007, DOI:10.3970/cmes.2007.022.203
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Abstract In this study, the channel flow is discussed by the LBM simulations. In the cases of channel with obstacles inside, the square pillars play the role of causing interruption within the fluid field, and hence change the direction of fluid flow. The recirculation region is formed behind the obstacles and influences the fluid passed through not only in the velocity field but also in the temperature field. Therefore, heat transfer is enhanced in local region.
The field synergy principle is applied in the research to demonstrate that the increased interruption within the fluid increases the synergistic level between the… - More
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- Effect of Interface Modification on the Mechanical Behavior of Carbon Nanotube Reinforced Composites Using Parallel Molecular Dynamics Simulations
- CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 189-202, 2007, DOI:10.3970/cmes.2007.022.189
- Abstract Molecular dynamics (MD) simulations play an important predictive role in understanding the behavior of nanoscale systems. In this paper, parallel MD simulations are used to understand the mechanical behavior of interfaces in CNT based composites. We present an algorithm for parallel implementation of MD simulations of carbon nanotube (CNT) based systems using reactive bond order potentials. We then use that algorithm to model the CNT-polymer interfaces with various levels of interaction as (a) described only by long range Van Der Waals interactions (b) chemically bonded with fixed matrix and (c) chemically bonded with matrix explicitly modeled. It is shown that…
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- A Meshless Local Petrov-Galerkin Method for Magnetic Diffusion in Non-magnetic Conductors
- CMES-Computer Modeling in Engineering & Sciences, Vol.22, No.3, pp. 165-188, 2007, DOI:10.3970/cmes.2007.022.165
- Abstract In this paper, we propose a Meshless Local Petrov-Galerkin method for studying the diffusion of a magnetic field within a non-magnetic (μ = μ0) conducting medium with non-homogeneous and anisotropic electrical resistivity. We derive a local weak form for the magnetic diffusion equation and discuss the effects of different trial/test functions and nodal spacings on its solution. We then demonstrate that the method produces convergent results for several relevant one-dimensional test problems for which solutions are known. This method has the potential to be combined with other mesh-free methods such as Smoothed Particle Hydrodynamics (SPH) to solve problems in resistive…
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