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  • Open Access


    Recent Advances in Numerical Simulation Technologies for Various Dynamic Fracture Phenomena

    Toshihisa Nishioka 1,

    CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.3, pp. 209-216, 2005, DOI:10.3970/cmes.2005.010.209

    Abstract Recent Advances in Numerical Simulation Technologies for Various Dynamic Fracture Phenomena are summarized. First, the basic concepts of fracture simulations are explained together with pertinent simulation results. Next, Examples of dynamic fracture simulations are presented. More >

  • Open Access


    The Core Structure and Energy of the 90° Partial Dislocation in Si

    Karin Lin1, D. C. Chrzan2

    CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.2, pp. 201-212, 2002, DOI:10.3970/cmes.2002.003.201

    Abstract The 90° partial dislocation in Si is studied using a combination of Tersoff potentials and isotropic elasticity theory. Both periodic supercells and cylindrical cells are employed and the results compared. The dislocation core radius is extracted by fitting the results of atomic scale calculations to an expression for the elastic energy of the dislocation. The energy differences between two proposed reconstructions of the dislocation core are computed and found to depend systematically on the stress field imposed on the dislocation. It is suggested that hydrostatic stresses may introduce a core transformation. More >

  • Open Access


    Lateral Plastic Collapse of Cylinders: Experiments and Modeling

    K. Nesnas1, A. Abdul-Latif2

    CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.3, pp. 373-388, 2001, DOI:10.3970/cmes.2001.002.373

    Abstract Large plastic collapse of an identical pair of cylinders of various geometries having the same length and volume is studied under lateral compressive load. Superplastic material is employed as a representative material to simulate the classical engineering material behavior under high strain rate. The effects of the strain rate and the geometry of cylinders on the plastic collapse are taken into account. The experimental study is conducted using a structure in which one cylinder is superplastic and the other is steel (referred to as deformable and non-deformable situation "DND''). The actual structure (DND) and that one investigated experimentally by Abdul-Latif… More >

  • Open Access


    Non-Linear Rigid Body Dynamics: Energy and Momentum Conserving Algorithm

    Fernando A. Rochinha1, Rubens Sampaio2

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.2, pp. 7-18, 2000, DOI:10.3970/cmes.2000.001.167

    Abstract The dynamics of flexible systems, such as robot manipulators, mechanical chains or cables, is becoming increasingly important in engineering. The main question arising from the numerical modelling of large overall motions of multibody systems is an appropriate treatment for the large rotations. In the present work an alternative approach is proposed leading to a time-stepping numerical algorithm which achieves stable solutions combined with high precision. In particular, in order to check the performance of the proposed approach, two examples having preserved constants of the motion are presented. More >

  • Open Access


    A Comparative Study of Phase Changing Characteristics of Granular Phase Change Materials Using DSC and T-History Methods

    Mohamed Rady1, Eric Arquis2

    FDMP-Fluid Dynamics & Materials Processing, Vol.6, No.2, pp. 137-152, 2010, DOI:10.3970/fdmp.2010.006.137

    Abstract In the present article, differential scanning calorimetry (DSC) and a modified T-history method have been used to study the phase changing behavior of granular composites. Further modifications and improvements of the two methods are employed to handle granular materials undergoing phase change over a temperature range. A simple procedure has been advised to obtain accurate results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. The concept of enthalpy and its relationship with temperature has been employed in the T-history analysis to obtain enthalpy-temperature and apparent heat capacity curves similar to… More >

  • Open Access


    Predicting The Onset of Asphaltene Precipitation by Virial EOS

    S. Sabbaghi1, M. Shariaty-Niassar2, Sh. Ayatollahi1, A. Jahanmiri1

    FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 113-124, 2008, DOI:10.3970/fdmp.2008.004.113

    Abstract In this study, the Onset of Asphaltene Precipitation is predicted by a modified Virial equation of state. The bases of quantum mechanics and statistical thermodynamics are used to evaluate the potential energy and intermolecular forces related to asphaltene molecules. The Virial equation of state is modified using group-contribution-methods for asphaltenes, which are assumed to be polymeric-like compounds consisting of aggregates of monodisperse asphaltene monomers. It is shown how the modified Virial equation of state with the Peneloux correction leads to estimate the molar volume and solubility parameter. These parameters are also compared successfully with results provided by the Soave-Redlich-Kwong equation… More >

  • Open Access


    Computer Modelling of the Energy Distribution within Wood throughout Microwave Processing

    M. Daian1, A. Taube2, G. Torgovnikov3, G. Daian4, Y. Shramkov5

    CMC-Computers, Materials & Continua, Vol.8, No.3, pp. 165-172, 2008, DOI:10.3970/cmc.2008.008.165

    Abstract Microwave wood modification and treatment technologies become more and more essential within the wood industry due to their technical and economical advantages. Microwave processing of wood involves many complicated physical phenomena and requires a very careful control of variables (such as intensity of microwave power, loading period, maximum temperature, etc.) in order to reduce structural deformations of the processed wood. To optimise and minimise the project design engineers' work, modelling and simulation of the microwave energy-wood interaction represents an indispensable tool.
    This research work has been undertaken with the aim to design and optimise microwave applicators for microwave pre-drying… More >

  • Open Access


    Evaluations of the BGA Solder Ball Shape by Using Energy Method

    Heng Cheng Lin1,2, Chieh Kung3, Rong Sheng Chen2

    CMC-Computers, Materials & Continua, Vol.6, No.1, pp. 43-50, 2007, DOI:10.3970/cmc.2007.006.043

    Abstract Presented herein are the evaluation results of the BGA solder ball shape using energy method, two types of solder, viz. Sn37Pb and Sn80Pb, are selected .The geometry of the solder bump is firstly estimated using free computer software, the Surface Evolver, an interactive program which is an energy-based approach for the study of liquid droplet surfaces shaped by surface tension and other energies. The solder bump is then numerically constructed in a finite element model that simulates a BGA package. The influences of both upper and bottom solder pad radii, the surface tension on the balls, and the external load… More >

  • Open Access


    Multi-Rate Polling: Improve the Performance of Energy Harvesting Backscatter Wireless Networks

    Yu Han1,*, Wenxian Zheng2, Guangjun Wen1, Chu Chu1, Jian Su3, Yibo Zhang4

    CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 795-812, 2019, DOI:10.32604/cmc.2019.05719

    Abstract In recent years, Researchers have proposed the concept of Energy Harvesting Backscatter Wireless Networks (EHBWN). EHBWN usually consists of one sink and several backscatter nodes. Backscatter nodes harvest energy from their environment and communicate with sink through backscattering the carrier wave transmitted by sink. Although a certain amount of access protocols for Energy Harvesting Wireless Networks have been present, they usually do not take the sink’s receiver sensitivity into account, which makes those protocols unsuitable in practice. In this paper, we first give an analysis of the backscatter channel link budget and the relationship between the effective communication range and… More >

  • Open Access


    An Energy-Efficient Protocol Using an Objective Function & Random Search with Jumps for WSN

    Mohammed Kaddi1,3,*, Khelifa Benahmed2, Mohammed Omari3

    CMC-Computers, Materials & Continua, Vol.58, No.3, pp. 603-624, 2019, DOI:10.32604/cmc.2019.05341

    Abstract Wireless Sensor Networks (WSNs) have hardware and software limitations and are deployed in hostile environments. The problem of energy consumption in WSNs has become a very important axis of research. To obtain good performance in terms of the network lifetime, several routing protocols have been proposed in the literature. Hierarchical routing is considered to be the most favorable approach in terms of energy efficiency. It is based on the concept parent-child hierarchy where the child nodes forward their messages to their parent, and then the parent node forwards them, directly or via other parent nodes, to the base station (sink).… More >

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