Gerhard Klimeck^1,2, Fabiano Oyafuso², Timothy B. Boykin³, R. Chris Bowen², Paul von Allmen⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 601-642, 2002, DOI:10.3970/cmes.2002.003.601

Abstract Material layers with a thickness of a few nanometers are common-place in today's semiconductor devices. Before long, device fabrication methods will reach a point at which the other two device dimensions are scaled down to few tens of nanometers. The total atom count in such deca-nano devices is reduced to a few million. Only a small finite number of "free'' electrons will operate such nano-scale devices due to quantized electron energies and electron charge. This work demonstrates that the simulation of electronic structure and electron transport on these length scales must not only be fundamentally quantum mechanical, but it must… More >

Y.C. Shiah¹, C. L. Tan², C.Y. Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.1, pp. 1-22, 2012, DOI:10.3970/cmes.2012.087.001

Abstract The fundamental solution, or Green's function, for 3D anisotropic elastostatics as derived by Ting and Lee (1997) [Q.J. Mech. Appl. Math.; 50: 407-426] is one that is fully explicit and algebraic in form. It has, however, only been utilized in boundary element method (BEM) formulations quite recently even though it is relatively straightforward and direct to implement. This Green's function and its derivatives are necessary items in this numerical analysis technique. By virtue of the periodic nature of the angles when it is expressed in the spherical coordinate system, the present authors have very recently represented the Green's function as… More >

L. Chen¹ J. H. Lee¹, C.-f. Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.3, pp. 199-224, 2012, DOI:10.3970/cmes.2012.086.199

Abstract This paper presents a numerical procedure to model surface tension using the Generalized Interpolation Material Point (GIMP) method which employs a background mesh in solving the equations of motion. The force due to surface tension is formulated at the mesh grid points by using the continuum surface force (CSF) model and then added to the equations of motion at each grid point. In GIMP, we use the grid mass as the color function in CSF and apply a moving average smoothing scheme to the grid mass to improve the accuracy in calculating the surface interface. The algorithm, named as GIMP-CSF,… More >

Hong-Hua Dai^1,2, Matt Schnoor², Satya N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.5, pp. 459-498, 2012, DOI:10.3970/cmes.2012.084.459

Abstract In this study, the harmonic and 1/3 subharmonic oscillations of a single degree of freedom Duffing oscillator with large nonlinearity and large damping are investigated by using a simple point collocation method applied in the time domain over a period of the periodic solution. The relationship between the proposed collocation method and the high dimensional harmonic balance method (HDHB), proposed earlier by Thomas, Dowell, and Hall (2002), is explored. We demonstrate that the HDHB is not a kind of "harmonic balance method" but essentially a cumbersome version of the collocation method. In using the collocation method, the collocation-resulting nonlinear algebraic… More >

Kazuhiko Kakuda¹, Shunsuke Obara¹, Jun Toyotani¹, Mitsuhiko Meguro¹, Masakazu Furuichi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.1, pp. 57-72, 2012, DOI:10.3970/cmes.2012.083.057

Abstract The application of a particle method to incompressible viscous fluid flow problem and its physics-based computer graphics are presented. The method is based on the MPS (Moving Particle Semi-implicit) scheme using logarithmic weighting function to stabilize the spurious oscillatory solutions for the pressure fields which are governed by Poisson equation. The physics-based computer graphics consist of the POV-Ray (Persistence of Vision Raytracer) rendering using marching cubes algorithm as polygonization. The standard MPS scheme is widely utilized as a particle strategy for the free surface flow, the problem of moving boundary, multi-physics/multi-scale ones, and so forth. Numerical results demonstrate the workability… 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 >

Yi W. Wan¹, Huan J. Keh²

CMES-Computer Modeling in Engineering & Sciences, Vol.74, No.2, pp. 109-138, 2011, DOI:10.3970/cmes.2011.074.109

Abstract The steady rotation of an axially symmetric particle about its axis of revolution normal to two plane walls at an arbitrary position between them in a viscous fluid is studied theoretically in the limit of small Reynolds number. The fluid is allowed to slip at the surface of the particle. A method of distribution of a set of spherical singularities along the axis of revolution inside a prolate particle or on the fundamental disk within an oblate particle is used to find the general solution for the fluid velocity distribution that satisfies the boundary conditions at the confining walls and… More >

B.T. Tang^1,2, X.Y. Lu¹, H. Xie²

CMES-Computer Modeling in Engineering & Sciences, Vol.73, No.2, pp. 171-182, 2011, DOI:10.3970/cmes.2011.073.171

Abstract The Traditional Inverse Analysis Method (TIAM) of sheet metal stamping has the shortcoming of neglecting the effects of deformation history on stress prediction. An Updated Inverse Analysis Method (UIAM) is proposed based on the final workpiece in Euler coordinate system. The UIAM uses the constitutive equation based on pseudo flow theory of plasticity to consider the loading history. In order to avoid numerous iterations to ensure the numerical stability in Newton-Raphson scheme to obtain plastic multiplier ∆λ, the equation in unknown stress vectors is transformed into a scalar equation using the notion of the equivalent stress. Thus a scalar equation… More >

Duning Li¹, Yufeng Nie^1,2, Xuemei Zhou¹, Li Cai¹

CMES-Computer Modeling in Engineering & Sciences, Vol.72, No.2, pp. 149-166, 2011, DOI:10.3970/cmes.2011.072.149

Abstract In this study, the efficient discrete model including the resin infusion and the fiber compaction is developed to simulate the RFI (resin film infusion) process. The non-linear governing equations are derived by the Darcy's law, the Terzaghi's law and the continuity equations. The finite element method and the finite difference method are used to discretize the proposed equations, and the VOF method is used to track the filling front. Compared with the analytical results of Park, our numerical results agree well with them. Furthermore, we analyze the RFI process of BMI/G0814, and simulate the resin pressure, the fiber volume fraction… More >

Jin Yeon Cho¹, Min Hwan Oh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.66, No.3, pp. 187-214, 2010, DOI:10.3970/cmes.2010.066.187

Abstract In this work, a sample-reusable sequential approximate optimization (SAO) procedure is suggested. The suggested sequential approximate optimization procedure utilizes a newly proposed sample-reusable meta-model along with the trust region algorithm. Domain of design is sequentially updated to search for the optimal solution through the trust region algorithm, and the system response in the updated design region at each sequential stage is approximated by the proposed sample-reusable meta-model. The proposed sample-reusable meta-model is based on the moving least squares(MLS) approximation scheme. Thanks to the merits of moving least squares scheme, the proposed meta-model can fully utilize the previously sampled responses as… More >