Mark Andrew Bradford¹, Yong-Lin Pi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.5, pp. 389-416, 2012, DOI:10.3970/cmes.2012.089.389

Abstract This paper is devoted to the development of a finite composite beam element for the nonlinear elastic-plastic analysis of composite high strength steel and geopolymer concrete members. For this, geometric nonlinearity is derived using a special orthogonal rotation matrix, so that scalar product of vectors is preserved during rotation from the initial configuration to a deformed configuration and rigid body movements are excluded from the finite strains. The material nonlinearities of the geopolymer concrete are based on constitutive models in association with its axial stress-strain relationship that is consistent with the experimental results. To consider the slip due to possible… More >

A.R.Ervilha^1,2, F.A.Sousa¹, J.M.C.Pereira¹, J.C.F.Pereira¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.5, pp. 361-387, 2012, DOI:10.3970/cmes.2012.089.361

Abstract Faster than real time stochastic fire spread predictions are reported using a Non-Intrusive Spectral Projection (NISP) method based on Polynomial Chaos expansion and Graphic Processing Units (GPUs). The fireLib BEHAVE model together with a raster surface fire growth algorithm was implemented using the Compute Unified Device Architecture (CUDA) programming language. The uncertainty generated by the four random variables considered (wind speed, wind direction, fuel moisture, and fuel load) is quantified in the stochastic solution. Stochastic simulation of an idealized vegetation fire in a realistic complex terrain is obtained with speed-ups as high as 176 when compared to Central Processing Unit… More >

D.-A. An-Vo¹, C.-D. Tran¹, N. Mai-Duy¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 303-359, 2012, DOI:10.3970/cmes.2012.089.303

Abstract Many important engineering problems have multiple-scale solutions. Thermal conductivity of composite materials, flow in porous media, and turbulent transport in high Reynolds number flows are examples of this type. Direct numerical simulations for these problems typically require extremely large amounts of CPU time and computer memory, which may be too expensive or impossible on the present supercomputers. In this paper, we develop a high order computational method, based on multiscale basis function approach and integrated radialbasis- function (IRBF) approximant, for the solution of multiscale elliptic problems with reduced computational cost. Unlike other methods based on multiscale basis function approach, sets… More >

Ashraf Balabel¹,

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 283-301, 2012, DOI:10.3970/cmes.2012.089.283

Abstract This paper presents a novel numerical method for solving the twophase flow problems with moving interfaces in either laminar or turbulent flow regimes. The developed numerical method is based on the solution of the Reynolds- Averaged Navier Stokes equations in both phases separately with appropriate boundary conditions located at the interface separating the two fluids. The solution algorithm is performed on a regular and structured two-dimensional computational grid using the control volume approach. The complex shapes as well as the geometrical quantities of the interface are determined via the level set method. The numerical method is firstly validated against the… More >

Max de Castro Magalhaes¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.4, pp. 263-281, 2012, DOI:10.3970/cmes.2012.089.263

Abstract The main objective is to develop a 'hybrid' numerical method for predicting sound power radiated from honey-comb panels and analyze the sensitivity and variability of it to different boundary conditions. The honey-comb panels are mainly used on the aerospace, mechanical and civil engineering design. The method used herein is a combination of the Finite Element Method and the Jinc Function Approach. The original contribution of this paper is therefore to show the sensitivity of sound power radiated from a honey-comb panel using a 'hybrid' method which is simple and efficient on tackling sound radiation problems for complex orthotropic panels, especially… More >

Y.J. Ning^1,2,3, Z.Y. Zhao³, J.P. Sun³, W.F. Yuan^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.3, pp. 221-262, 2012, DOI:10.3970/cmes.2012.089.221

Abstract In this paper, wave propagations in jointed rock masses are modeled by the discontinuous deformation analysis (DDA) method. The selection of the numerical control parameters in the DDA for wave propagation modeling is discussed in detail, and the effects of the joint stiffness, the seismic loading frequency, the joint strength, and the incident angle on the propagations of stress waves in a jointed rock mass are modeled and analyzed. Two nonreflecting boundary conditions including the viscous boundary condition (VBC) and the superposition boundary condition (SBC) are coupled into the DDA. The applicability of the two nonreflecting boundary conditions for simple… More >

N. Thai-Quang¹, N. Mai-Duy¹, C.-D Tran¹, T. Tran-Cong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.3, pp. 189-220, 2012, DOI:10.3970/cmes.2012.089.189

Abstract In this paper, the alternating direction implicit (ADI) method reported in [You(2006)] for the convection-diffusion equation is implemented in the context of compact integrated radial basis function (CIRBF) approximations. The CIRBF approximations are constructed over 3-point stencils, where extra information is incorporated via two forms: only nodal second-order derivative values (Scheme 1), and both nodal first- and second-order derivative values (Scheme 2). The resultant algebraic systems are sparse, especially for Scheme 2 (tridiagonal matrices). Several steady and non-steady problems are considered to verify the present schemes and to compare their accuracy with some other ADI schemes. Numerical results show that… More >

D.M. Zhang^1,2, L.X. Ma^1,2, H.W. Huang^1,2, J. Zhang^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.3, pp. 163-188, 2012, DOI:10.3970/cmes.2012.089.163

Abstract This paper suggests a new set of analytical solutions for predicting leakage-induced seepage field and ground settlement in saturated clay. A unique feature of the solutions presented is considering the effect of the tunnel lining through the relative permeability between the tunnel and the soil. Through the superposition method, the proposed method can be easily extended to twin parallel tunnels. The accuracy of the analytical solutions are verified with numerical simulations. Parametric studies reveal that the decrease of pore pressure and the consequent settlements of ground and tunnel is proportional to the relative permeability. Over 20% of the initial hydrostatic… More >

Deli Gao^1,2, Lianzhong Sun^1,3, Hongshu Wei⁴, Shunwen Wang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 143-162, 2012, DOI:10.3970/cmes.2012.089.143

Abstract Due to the complexity of forces acting on the down-hole tubular strings in extended reach drilling (ERD), the factors which influence the process should be taken into account as much as possible, in order to predict the down-hole drag & torque more accurately. This can help us to identify and prevent the problems related to downhole drag & torque in ERD. The effects of such factors, as the tubular buckling, the buoyancy, the mechanical resistance and the friction reducer, on down-hole drag & torque, are taken into account in this paper, in order to improve the accuracy of the prediction… More >

Yongsheng An¹, Xiaodong Wu¹, Deli Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.2, pp. 123-142, 2012, DOI:10.3970/cmes.2012.089.123

Abstract The accuracy of numerical simulation of a two-phase (oil and water) flow in a fractured horizontal well depends greatly upon the types of grids used in the computation. Cartesian grids have been widely used in recent years, but they have some disadvantages in describing complex structural wells, such as fractured horizontal wells. For example, Cartesian grids are not efficient in describing the main wellbores and the fractures of fractured horizontal wells, and the results can frequently suffer from grid orientation effects, even though a grid-refinement is often introduced to enhance the adaptability of a Cartesian grid. The PEBI (Perpendicular Bisector)… More >