A. Vukovic¹, P. Sewell¹, T. M. Benson¹

CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.2, pp. 171-190, 2010, DOI:10.3970/cmes.2010.055.171

Abstract A fast and accurate method is developed for the analysis of a class of metal three-dimensional resonators with rotational symmetry. The analysis is formulated using the Body of Revolution approach and the Method of Analytical Regularization. This development is motivated by the need for three-dimensional analytical solvers that could enable fast and accurate analysis of photonic resonant structures which support very high Q whispering gallery modes and which are computationally challenging for numerical simulations. The paper outlines the formulation of the method and demonstrates the stability and the source of computation errors of the method. As a practical illustration, the… More >

M. Irízar, L. D. Câmara, A. J. Silva Neto, O. Llanes

CMES-Computer Modeling in Engineering & Sciences, Vol.54, No.1, pp. 1-14, 2009, DOI:10.3970/cmes.2009.054.001

Abstract Modeling of Chromatography allows a better understanding and development of new techniques to be applied at industrial level, although it's relatively complex. The models of this process are represented by systems of partial differential equations with non linear parameters difficult to estimate generally, which constitutes an inverse problem. In general there aren't analytical solutions and therefore numerical methods should be used for their direct solutions. Frequently typical boundary conditions are considered, but it's convenient to study different approaches for those. Evolutionary Computation has been used successfully in many problems of diverse areas for searching in complex spaces. Considering previous works… More >

Yi W. Wan¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.53, No.1, pp. 73-94, 2009, DOI:10.3970/cmes.2009.053.073

Abstract The problem of the rotation of a rigid particle of revolution about its axis in a viscous fluid is studied theoretically in the steady limit of low Reynolds number. The fluid is allowed to slip at the surface of the particle. A singularity method based on the principle of distribution of a set of spherical singularities along the axis of revolution within a prolate particle or on the fundamental plane within an oblate particle is used to find the general solution for the fluid velocity field that satisfies the boundary condition at infinity. The slip condition on the surface of… More >

B.R.Kim¹ and H.K.Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.47, No.3, pp. 253-282, 2009, DOI:10.3970/cmes.2009.047.253

Abstract Damage characteristic of particulated ductile composites is a complex evolutionary phenomenon that includes particle debonding and void evolution with the accumulation of the plastic straining of the ductile matrix. In this paper, a micromechanical elastoplastic damage model for ductile matrix composites considering gradually incremental damage (particle debonding and void evolution) is proposed to predict the overall elastoplastic behavior and damage evolution in the composites. The constitutive damage model proposed in an earlier work by the authors [Kim and Lee (2009)] considering particle debonding is extended to accommodate the gradually incremental damage and elastoplastic behavior of the composites. On the basis… More >

Hossein M. Shodja^1,2,3, Alireza Hashemian^1,4

CMES-Computer Modeling in Engineering & Sciences, Vol.32, No.1, pp. 17-34, 2008, DOI:10.3970/cmes.2008.032.017

Abstract Gradient reproducing kernel particle method (GRKPM) is a meshless technique which incorporates the first gradients of the function into the reproducing equation of RKPM. Therefore, in two-dimensional space GRKPM introduces three types of shape functions rather than one. The robustness of GRKPM's shape functions is established by reconstruction of a third-order polynomial. To enforce the essential boundary conditions (EBCs), GRKPM's shape functions are modified by transformation technique. By utilizing the modified shape functions, the weak form of the nonlinear evolutionary Buckley-Leverett (BL) equation is discretized in space, rendering a system of nonlinear ordinary differential equations (ODEs). Subsequently, Gear's method is… More >

Z. Chen^1,2, Y. Gan¹, J.K. Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.2, pp. 123-138, 2008, DOI:10.3970/cmes.2008.026.123

Abstract A coupled thermo-mechanical constitutive model with decohesion is proposed to simulate the material failure evolution due to localized heating. A discontinuous bifurcation analysis is performed based on a thermoviscoplasticity relation to identify the transition from continuous to discontinuous failure modes as well as the orientation of the discontinuous failure. The thermo-mechanical model is then implemented within the framework of the Material Point Method (MPM) so that the different gradient and divergence operators in the governing differential equations could be discretized in a single computational domain and that continuous remeshing is not required with the evolution of failure. The proposed model-based… More >

S. Sabchevski¹, I. Zhelyazkov², M. Thumm³, S. Illy⁴, B. Piosczyk⁵, T.-M. Tran^6,7, J. Gr. Pagonakis⁸

CMES-Computer Modeling in Engineering & Sciences, Vol.20, No.3, pp. 203-220, 2007, DOI:10.3970/cmes.2007.020.203

Abstract Computer aided design of powerful gyrotrons for electron cyclotron resonance heating and current drive of fusion plasmas requires adequate physical models and efficient software packages for analysis, comparison and optimization of their electron-optical systems through numerical experiments. In this paper, we present and discuss the current status of the simulation tools available to the researchers involved in the development of multi-megawatt gyrotrons for the ITER project, review some of their recent upgrades and formulate directions for further modifications and improvements. Illustrative examples used represent results from recent numerical investigations of real constructions. Some physical problems that are outside of the… More >

Sharnappa¹, N. Ganesan², Raju Sethuraman³

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.2, pp. 121-144, 2007, DOI:10.3970/cmes.2007.018.121

Abstract This article presents the study on buckling and free vibration behavior of sandwich general shells of revolution under thermal environment using Wilkins theory. The temperature assumes to be uniform over the shell structure. The numerical analysis is based on the semi-analytical finite element method applicable to thick shells. The analysis is carried out for different geometry such as truncated conical and hemispherical shells with various facing and core materials under clamped-clamped boundary condition. The parametric study is carried out for different core to facing (t_c / t_f) thickness ratio by considering the temperature dependent and independent material properties of the… More >

Z. Chen¹, W. Hu¹, E.P. Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.4, pp. 57-62, 2000, DOI:10.3970/cmes.2000.001.509

Abstract To simulate the dynamic failure evolution without using nonlocal terms in the strain-stress space, a damage diffusion equation is formulated with the use of a combined damage/plasticity model that was primarily applied to the case of rock fragmentation. A vectorized model solver is developed for large-scale simulation. Two-dimensional sample problems are considered to illustrate the features of the proposed solution procedure. It appears that the proposed approach is effective in simulating the evolution of localization, with parallel computing, in a single computational domain involving different lower-order governing differential equations. More >

A. Behjatian¹, A. Esmaeeli¹

FDMP-Fluid Dynamics & Materials Processing, Vol.10, No.3, pp. 299-317, 2014, DOI:10.3970/fdmp.2014.010.299

Abstract Computational studies are performed to explore the underlying physics behind the evolution of the flow field in an around a liquid jet that is immersed in another liquid and is exposed to a uniform electric field. Here the focus is on finite Reynolds and O(1) Ohnesorge number flows. This is achieved by solving the full Navier-Stokes and electric field equations using a front tracking/finite difference technique in the framework of Taylor's leaky dielectric theory. It is shown that the evolution of the flow field is determined by the relative magnitude of the ratio of the electric conductivity R = σ_i/σ_o… More >