Home / Advanced Search

  • Title/Keywords

  • Author/Affliations

  • Journal

  • Article Type

  • Start Year

  • End Year

Update SearchingClear
  • Articles
  • Online
Search Results (1,019)
  • Open Access

    ARTICLE

    A New Application of the Panel Clustering Method for 3D SGBEM

    A. Aimi1, M. Diligenti1, F. Lunardini1, A. Salvadori2

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.1, pp. 31-50, 2003, DOI:10.3970/cmes.2003.004.031

    Abstract This paper is devoted to the study of a new application of the Panel Clustering Method [Hackbusch and Sauter (1993); Hackbusch and Nowak (1989)]. By considering a classical 3D Neumann screen problem in its boundary integral formulation discretized with the Galerkin BEM, which requires the evaluation of double integrals with hypersingular kernel, we recall and use some recent results of analytical evaluation of the inner hypersingular integrals. Then we apply the Panel Clustering Method (PCM) for the evaluation of the outer integral. For this approach error estimate is shown. Numerical examples and comparisons with classical More >

  • Open Access

    ARTICLE

    Development of a Nanoelectronic 3-D (NEMO 3-D ) Simulator for Multimillion Atom Simulations and Its Application to Alloyed Quantum Dots

    Gerhard Klimeck1,2, 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… More >

  • Open Access

    ARTICLE

    Select Applications of Carbon Nanotubes: Field-Emission Devices and Electromechanical Sensors

    Amitesh Maiti1

    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 589-600, 2002, DOI:10.3970/cmes.2002.003.589

    Abstract Atomistic modeling and simulations are becoming increasingly important in the design of new devices at the nanoscale. In particular, theoretical modeling of carbon nanotubes have provided useful insight and guidance to many experimental efforts. To this end, we report simulation results on the electronic, structural and transport properties for two different applications of carbon nanotube-based devices: (1) effect of adsorbates on field emission; and (2) effect of mechanical deformation on the electronic transport. The reported simulations are based on First Principles Density Functional Theory (DFT), classical molecular mechanics, and tight-binding transport based on the recursive More >

  • Open Access

    ARTICLE

    Multiscale Modeling of Laser Ablation: Applications to Nanotechnology

    Leonid V. Zhigilei1, Avinash M. Dongare1

    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.5, pp. 539-556, 2002, DOI:10.3970/cmes.2002.003.539

    Abstract Computational modeling has a potential of making an important contribution to the advancement of laser-driven methods in nanotechnology. In this paper we discuss two computational schemes developed for simulation of laser coupling to organic materials and metals and present a multiscale model for laser ablation and cluster deposition of nanostructured materials. In the multiscale model the initial stage of laser ablation is reproduced by the classical molecular dynamics (MD) method. For organic materials, the breathing sphere model is used to simulate the primary laser excitations and the vibrational relaxation of excited molecules. For metals, the… More >

  • Open Access

    ARTICLE

    An Improved Contact Algorithm for the Material Point Method and Application to Stress Propagation in Granular Material

    S.G. Bardenhagen1, J.E. Guilkey2, K.M. Roessig3, J.U. Brackbill4, W.M. Witzel5, J.C.Foster6

    CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 509-522, 2001, DOI:10.3970/cmes.2001.002.509

    Abstract Contact between deformable bodies is a difficult problem in the analysis of engineering systems. A new approach to contact has been implemented using the Material Point Method for solid mechanics, Bardenhagen, Brackbill, and Sulsky (2000a). Here two improvements to the algorithm are described. The first is to include the normal traction in the contact logic to more appropriately determine the free separation criterion. The second is to provide numerical stability by scaling the contact impulse when computational grid information is suspect, a condition which can be expected to occur occasionally as material bodies move through… More >

  • Open Access

    ARTICLE

    Application of Multi-Region Trefftz Method to Elasticity

    J. Sladek1, V. Sladek1, V. Kompis2, R. Van Keer3

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.4, pp. 1-8, 2000, DOI:10.3970/cmes.2000.001.453

    Abstract This paper presents an application of a direct Trefftz method with domain decomposition to the two-dimensional elasticity problem. Trefftz functions are substituted into Betti's reciprocity theorem to derive the boundary integral equations for each subdomain. The values of displacements and tractions on subdomain interfaces are tailored by continuity and equilibrium conditions, respectively. Since Trefftz functions are regular, much less requirements are put on numerical integration than in the traditional boundary integral method. Then, the method can be utilized to analyse also very narrow domains. Linear elements are used for modelling of the boundary geometry and More >

  • Open Access

    ARTICLE

    General Application of Numerical Green's Functions for SIF Computations With Boundary Elements

    S. Guimarães1, J.C.F. Telles2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 131-139, 2000, DOI:10.3970/cmes.2000.001.433

    Abstract The paper discusses further applications of the hyper-singular boundary integral equation to obtain the Green's function solution to general geometry fracture mechanics problems, such as curved multifracture crack simulation, static and transient dynamic in 2-D, 3-D and plate bending problems. This numerical Green's function (NGF) is implemented into alternative boundary element computer programs, as the fundamental solution, to enhance the scope of alternative applications of the NGF procedure.
    The results to some typical linear fracture mechanics problems are presented. More >

  • Open Access

    ARTICLE

    A Numerical Method for Schwarz-Christoffel Conformal Transformation with Application to Potential Flow in Channels with Oblique Sub-channels

    P.M.J. Trevelyan1, L. Elliott1, D.B. Ingham1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 117-122, 2000, DOI:10.3970/cmes.2000.001.419

    Abstract The potential flow in a semi-infinite channel with multiple semi-infinite oblique sub-channels is determined using the Schwarz-Christoffel transformation and complex potential theory. The standard iterative technique, i.e. the Newton-Raphson method with the Jacobian matrix approximated by a finite-difference quotient matrix, was employed with an alternative integration region to that found elsewhere in the literature is employed after integrating across the boundaries to determine the Schwarz-Christoffel transformation parameters which solely depend on the dimensions of the region being considered. Each semi-infinte channel permits integration at infinity perpendicularly across the channel and sub-channels, yielding some analytical relationships… More >

  • Open Access

    ARTICLE

    Porous Metals with Developing Anisotropy: Constitutive Models, Computational Issues and Applications to Deformation Processing

    M. Kailasam1, N. Aravas2, P. Ponte Castañeda3

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.2, pp. 105-118, 2000, DOI:10.3970/cmes.2000.001.265

    Abstract A constitutive model for a porous metal subjected to general three-dimensional finite deformations is presented. The model takes into account the evolution of porosity and the development of anisotropy due to changes in the shape and the orientation of the voids during deformation. A methodology for the numerical integration of the elastoplastic constitutive model is developed. Finally, some sample applications to plane strain extrusion and compaction of a porous disk are considered using the finite element method. More >

Displaying 1011-1020 on page 102 of 1019. Per Page