S. Gerace¹, K. Erhart¹, E. Divo^1,2, A. Kassab¹

CMES-Computer Modeling in Engineering & Sciences, Vol.81, No.1, pp. 35-68, 2011, DOI:10.3970/cmes.2011.081.035

Abstract The focus of this work is to demonstrate a novel approach to true CFD automation based on an adaptive Cartesian point distribution process coupled with a Meshless flow solution algorithm. As Meshless method solutions require only an underlying nodal distribution, this approach works well even for complex flow geometries with non-aligned domain boundaries. Through the addition of a so-called shadow layer of body-fitted nodes, application of boundary conditions is simplified considerably, eliminating the stair-casing issues of typical Cartesian-based techniques. This paper describes the approach taken to automatically generate the Meshless nodal distribution, along with the details of an automatic local… More >

V.G.Yakhno¹, T.M. Yakhno²

CMES-Computer Modeling in Engineering & Sciences, Vol.80, No.3&4, pp. 233-250, 2011, DOI:10.3970/cmes.2011.080.233

Abstract The time-dependent Maxwell's equations in non-dispersive homogeneous bi-anisotropic materials are considered in the paper. These equations are written as a symmetric hyperbolic system. A new method of the computation of the electric and magnetic fields arising from electric current is suggested in the paper. This method consists of the following. The Maxwell's equations are written in terms of the Fourier transform with respect to the space variables. The Fourier image of the obtained system is a system of ordinary differential equations whose coefficients depend on the 3D Fourier parameter. The formula for the solution of the obtained system is derived… More >

K.I. Silva¹, J.C.F. Telles², F.C. Araújo³

CMES-Computer Modeling in Engineering & Sciences, Vol.78, No.3&4, pp. 209-224, 2011, DOI:10.3970/cmes.2011.078.209

Abstract In this work the boundary element method is applied to solve 2D elastoplastic problems. In elastoplastic boundary element analysis, domain integrals have to be calculated to introduce the contribution of yielded zones. Traditionally, the use of internal integration cells have been adopted to evaluate such domain integrals. The present work, however, proposes an alternative cell free strategy based on the OMLS (Orthogonal Moving Least Squares) interpolation, typically adopted in meshless methods. In this approach the definition of points to compute the interpolated value of a function at a given location only depends on their relative distance, without need to define… More >

H.F.Qiang¹, F.Z.Chen¹, W.R. Gao¹

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.3&4, pp. 239-262, 2011, DOI:10.3970/cmes.2011.077.239

Abstract Based on smoothed particle hydrodynamics (SPH) method with surface tension proposed by Morris, this paper is intended to modify equations for surface tension by modifying normal and curvature with corrective smoothing particle method (CSPM). Compared with the continuum surface force (CSF) model for surface tension employed in the traditional SPH method, the accuracy in the present paper is much higher in terms of handling the problems with large deformation and surface tension. The reason is that in the traditional SPH method the deficiency of particles is near the boundary and sharp-angled areas, and it causes gross errors of curvature calculation.… More >

Hsin-Ping Chu¹, Cheng-Ying Lo²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.3&4, pp. 161-172, 2011, DOI:10.3970/cmes.2011.077.161

Abstract This paper presents the application of the differential transform method to solve strongly nonlinear equations with cubic nonlinearities and self-excitation terms. First, the equations are transformed by the differential transform method into the algebra equations in terms of the transformed functions. Secondly, the higher-order transformed functions are calculated in terms of other lower-order transformed functions through the iterative procedure. Finally, the solutions are approximated by the n-th partial sum of the infinite series obtained by the inverse differential transform. Two strongly nonlinear equations with different coefficients and initial conditions are given as illustrative examples. More >

A. Rezaei Mojdehi^1,2, A. Darvizeh³, A. Basti²

CMES-Computer Modeling in Engineering & Sciences, Vol.77, No.1, pp. 1-32, 2011, DOI:10.3970/cmes.2011.077.001

Abstract In this paper, a meshless method based on the local petrov-galerkin approach is proposed for the three dimensional (3D) elasto-plastic problems. Galerkin weak-form formulation is applied to derive the discrete governing equations. A weak formulation for the set of governing equations is transformed into local integral equations on local sub-domains by using a unit test function. Nodal points are distributed in the 3D analyzed domain and each node is surrounded by a cubic sub-domain to which a local integral equation is applied. Three dimensional Moving Least-Square (MLS) approximation is used as shape function to approximate the field variable of scattered… More >

Xiaowei Zeng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.3&4, pp. 183-202, 2011, DOI:10.3970/cmes.2011.074.183

Abstract This paper presents an atomistic field theory and its application in modeling and simulation of nano/micro materials. Atomistic formulation and finite element implementation of the atomistic field theory is briefly introduced. Numerical simulations based on the field theory are performed to investigate the material behaviors of bcc iron at coarse-grained scale and we have obtained the mechanical strength and elastic modulus, which are in good agreement with results by first principles calculations. Also the nanoscale deformation and failure mechanism are revealed in bcc iron nanorods under simple tension. It is interesting to observe that under tensile loading, iron has gone… More >

A. Gakwaya¹, H. Sharifi², M. Guillot¹, M. Souli³, F. Erchiqui⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.3, pp. 209-266, 2011, DOI:10.3970/cmes.2011.073.209

Abstract A mechanical computer aided design and engineering system can be used to reduce the design-to-manufacture cycle time in metal forming process. Such a system could be built upon a solid modeling geometry engine and an efficient finite element (FE) solver. The maintenance of a high-quality mesh throughout the analysis is an essential feature of an efficient finite element simulation of large strain metal forming problems. In this paper, a mesh adaptation technique employing the Arbitrary Lagrangian-Eulerian formulation (ALE) is applied to some industrial metal forming problems. An ACIS boundary representation of the solid model is employed. This type of representation… More >

K. Jayabal¹, A. Menzel^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.2, pp. 183-208, 2011, DOI:10.3970/cmes.2011.073.183

Abstract Naturally evolving Voronoi discretisation of two-dimensional plane domains renders representative microstructures that turn out to be useful for the modelling and simulation of polycrystalline materials. Hybrid finite element approaches are employed on such polygonal discretisations to solve, for instance, mechanical and electromechanical problems within a finite element context. In view of solving mechanical problems, varying order of polynomial functions are suggested in the literature to sufficiently approximate stresses within the polygonal finite elements. These are, in addition to the order of the approximation functions for the displacements, characterised by the number of edges in the polygonal elements. It appears, as… More >

K. Wang¹, S.J. Zhou^2,3, Z.F. Nie⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.1, pp. 77-102, 2011, DOI:10.3970/cmes.2011.073.077

Abstract The natural neighbour Galerkin method is tailored to solve boundary value problems of the couple-stress elasticity to model the size dependent behaviour of materials. This method is based on the displacement-based Galerkin approach, and the calculation of the global stiffness matrix is performed using gradient smoothing technique combined with the non-Sibsonian partition of unity approximation scheme. This method possesses the following properties: the complex C1-continuous approximation scheme is avoided without using either Lagrange multipliers or penalty parameters; no domain integrals involved in the assembly of the global stiffness matrix; and the imposition of essential boundary conditions is straightforward. The validity… More >