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  • Open Access


    Numerical Simulation of Fatigue Crack Growth in Microelectronics Solder Joints

    K. Kaminishi1, M. Iino2, H. Bessho2, M. Taneda3

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 107-110, 2000, DOI:10.3970/cmes.2000.001.107

    Abstract An FEA (finite element analysis) program employing a new scheme for crack growth analysis is developed and a prediction method for crack growth life is proposed. The FEA program consists of the subroutines for the automatic element re-generation using the Delaunay Triangulation technique, the element configuration in the near-tip region being provided by a super-element, elasto-inelastic stress analyses, prediction of crack extension path and calculation of fatigue life. The FEA results show that crack extension rate and path are controlled by a maximum opening stress range, Δσθmax, at a small radial distance of r = d, where More >

  • Open Access


    Cracking of GSO Single Crystal Induced by Thermal Stress

    N. Miyazaki1, T. Tamura2, K. Yamamoto1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 99-106, 2000, DOI:10.3970/cmes.2000.001.099

    Abstract Quantitative estimation of the failure of a gadolinium orthosilicate (Gd2SiO5, hereafter abbreviated as GSO) single crystal induced by thermal stress was investigated. A GSO cylindrical test specimen was heated in a silicone oil bath, then subjected to large thermal stress by room temperature silicone oil. Cracking occurred during cooling. The transient heat conduction analysis was performed to obtain temperature distribution in the test specimen at the time of cracking, using the surface temperatures measured in the test. Then the thermal stress was calculated using the temperature profile of the test specimen obtained from the heat conduction… More >

  • Open Access


    Strength Evaluation of Electronic Plastic Packages Using Stress Intensity Factors of V-Notch

    Toru Ikeda1, Isao Arase, Yuya Ueno, Noriyuki Miyazaki

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 91-98, 2000, DOI:10.3970/cmes.2000.001.091

    Abstract In electronic devices, the corners of joined dissimilar materials exist between plastic resin and a die pad or a chip. Failure of the plastic resin is often caused from these corners during the assembly process or the operation of products. The strength evaluation of the corner is important to protect the failure of plastic packages. To evaluate the singular stress field around a corner, we utilize the stress intensity factors of the asymptotic solution for a corner of joined dissimilar materials. We show that the accurate stress intensity factor can be analyzed by the displacement More >

  • Open Access


    Effect of Growth Direction on Twin Formation in GaAs Crystals Grown by the Vertical Gradient Freeze Method

    A.N. Gulluoglu1, C.T. Tsai2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 85-90, 2000, DOI:10.3970/cmes.2000.001.085

    Abstract Twins in growing crystals are due to excessive thermal stresses induced by the temperature gradients developed during the growth process. Twinning is an important defect in advanced semiconductor crystals such as GaAS and InP. The objective of this study is to develop a computational model to predict the twin formation in the Gallium Arsenide (GaAs) crystals grown by the vertical gradient freeze method (VGF). A quantitative quasi-steady state thermal stress model is developed here for predicting the twinning formation in GaAs grown by VGF. The thermoelastic stresses in VGF grown crystal are calculated from a More >

  • Open Access


    Modelling and Validation of Contribions to Stress in the Shallow Trench Isolation Process Sequence

    K. Garikipati1, V.S. Rao2, M.Y. Hao3, E. Ibok4, I. de Wolf5, R. W. Dutton6

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 65-84, 2000, DOI:10.3970/cmes.2000.001.065

    Abstract This work is based upon a careful rendering of mechanics and mathematics to describe the phenomena that influence the stress engendered by the Shallow Trench Isolation process. The diffusion-reaction problem is posed in terms of fundamental mass balance laws. Finite strain kinematics is invoked to model the large expansion of SiO2, dielectrics are modelled as viscoelastic solids and annealing-induced density relaxation of SiO2 is incorporated as a history-dependent process. A levelset framework is used to describe the moving Si/SiO2 interface. Sophisticated finite element methods are employed to solve the mathematical equations posed for each phenomenon. These include More >

  • Open Access


    A Methodology and Associated CAD Tools for Support of Concurrent Design of MEMS

    B. F. Romanowicz1, M. H. Zaman1, S. F. Bart1, V. L. Rabinovich1, I. Tchertkov1, S. Zhang1, M. G. da Silva1, M. Deshpande1, K. Greiner1, J. R. Gilbert1, Shawn Cunningham2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 45-64, 2000, DOI:10.3970/cmes.2000.001.045

    Abstract Development of micro-electro-mechanical systems (MEMS) products is currently hampered by the need for design aids, which can assist in integration of all domains of the design. The cross-disciplinary character of microsystems requires a top-down approach to system design which, in turn, requires designers from many areas to work together in order to understand the effects of one sub-system on another. This paper describes current research on a methodology and tool-set which directly support such an integrated design process. More >

  • Open Access


    Accurate Modelling and Simulation of Thermomechanical Microsystem Dynamics

    S. Taschini1, J. Müller2, A. Greiner2, M. Emmenegger1, H. Baltes1, J.G. Korvink2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 31-44, 2000, DOI:10.3970/cmes.2000.001.031

    Abstract We present three techniques to accurately model the thermomechanical response of microsystem components: a new, accurate and stable Kirchhoff-Love multi-layered plate model implemented as an Argyris finite element, a model for the amplitude fluctuations of vibrational modes in micro-mechanical structures within a gaseous environment, and the consistent refinement of a finite element mesh in order to maximize the computational accuracy for a given mesh size. We have implemented these techniques in our in-house MEMS finite element program and accompanying Monte Carlo simulator. We demonstrate our approach to dynamic modeling by computing the thermomechanical response of More >

  • Open Access


    Analysis of Realistic Large MEMS Devices

    Per Ljung1, Martin Bächtold2, Mirko Spasojevic2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 21-30, 2000, DOI:10.3970/cmes.2000.001.021

    Abstract This paper presents AutoMEMS®, a numerical simulation environment to efficiently analyze the behavior of large real-world MEMS designs. By automating surface-based model generation, meshing and field solver tools, it is possible to rapidly model large complex MEMS devices. More >

  • Open Access


    Simulation of Anisotropic Crystalline Etching using a Continuous Cellular Automata Algorithm

    Zhenjun Zhu, Chang Liu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 11-20, 2000, DOI:10.3970/cmes.2000.001.011

    Abstract We present results on the development of an anisotropic crystalline etching simulation (ACES) program based on a new continuous Cellular Automata (CA) model, which provides improved spatial resolution and accuracy compared with the conventional and the stochastic CA \mbox{methods}. Implementation of a dynamic CA technique provides increased simulation speed and reduced memory requirement (5x). A first ACES software based on common personal computer platforms has been realized. Simulated results of etching match well with experiments. We have developed a new methodology to obtain the etch-rate diagram of anisotropic etching efficiently using both experimental and numerical More >

  • Open Access


    Modeling of the Electronic Properties of Vertical Quantum Dots by the Finite Element Method

    Philippe Matagne1, Jean-Pierre Leburton2, Jacques Destine, Guy Cantraine3

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.1, pp. 1-10, 2000, DOI:10.3970/cmes.2000.001.001

    Abstract We investigate the quantum mechanical properties and single-electron charging effects in vertical semiconductor quantum dots by solving the Schrödinger and Poisson (SP) equations, self-consistently. We use the finite element method (FEM), specifically the Bubnov-Galerkin technique to discretize the SP equations. Owing to the cylindrical symmetry of the structure, the mesh is generated from hexahedral volume elements. The fine details of the electron spectrum and wavefunctions in the quantum dot are obtained as a function of macroscopic parameters such as the gate voltage, device geometry and doping level. The simulations provide comprehensive data for the analysis More >

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