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  • Open Access

    ARTICLE

    A Real-Coded Hybrid Genetic Algorithm to Determine Optimal Resin Injection Locations in the Resin Transfer Molding Process

    R. Mathur1, S. G. Advani2, B. K. Fink3

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 587-602, 2003, DOI:10.3970/cmes.2003.004.587

    Abstract Real number-coded hybrid genetic algorithms for optimal design of resin injection locations for the resin transfer molding process are evaluated in this paper. Resin transfer molding (RTM) is widely used to manufacture composite parts with material and geometric complexities, especially in automotive and aerospace sectors. The sub-optimal location of the resin injection locations (gates) can leads to the formation of resin starved regions and require long mold fill times, thus affecting the part quality and increasing manufacturing costs. There is a need for automated design algorithms and software that can determine the best gate and vent locations for a composite… More >

  • Open Access

    ARTICLE

    A Conservative Time Integration Scheme for Dynamics of Elasto-damaged Thin Shells

    L. Briseghella1, C. Majorana1, P. Pavan1

    CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.2, pp. 273-286, 2003, DOI:10.3970/cmes.2003.004.273

    Abstract Some aspects of the application of a conservative time integration scheme to the non-linear dynamics of elasto-damaged thin shells are presented. The main characteristic of the scheme is to be conservative, in the sense that it allows the time-discrete system to preserve the basic laws of continuum, namely the balance of the linear and angular momenta as well as the fulfilment of the second law of thermodynamic. Here the method is applied to thin shells under large displacements and rotations. The constitutive model adopted is built coupling the linear elastic model of De Saint Venant-Kirchhoff with a scalar damage function… More >

  • Open Access

    ARTICLE

    Solving Rolling Contact Problems Using Boundary Element Method and Mathematical Programming Algorithms

    José A. González, Ramón Abascal1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 141-150, 2000, DOI:10.3970/cmes.2000.001.443

    Abstract In this work an approach to the two-dimensional steady-state rolling contact problem, with and without force transmission, is presented. The problem is solved by the combination of the Boundary Element Method with a formulation of the variational inequalities that govern the problem in the contact area, producing finally a mathematical programming problem. This formulation avoids the direct use of the contact constrains, but it drives to the minimisation of a non-differentiable function, being necessary the use of an specific numerical tool as the modified Newton's method. More >

  • Open Access

    ARTICLE

    An Inverse Boundary Element Method for Determining the Hydraulic Conductivity in Anisotropic Rocks

    R. Mustata1, S. D. Harris2, L. Elliott1, D. Lesnic1, D. B. Ingham1

    CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 107-116, 2000, DOI:10.3970/cmes.2000.001.409

    Abstract An inverse boundary element method is developed to characterise the components of the hydraulic conductivity tensor K of anisotropic materials. Surface measurements at exposed boundaries serve as additional input to a Genetic Algorithm (GA) using a modified least squares functional that minimises the difference between observed and BEM-predicted boundary pressure and/or hydraulic flux measurements under current hydraulic conductivity tensor component estimates. More >

  • Open Access

    ARTICLE

    Optimizing the Design of PV Solar Reverse Osmosis Unit (RO/PV) by using Genetic Algorithms for Abu Dhabi Climate

    K. Bououni1, T. Jaber1, S. Elbehissy1

    FDMP-Fluid Dynamics & Materials Processing, Vol.13, No.2, pp. 127-141, 2017, DOI:10.3970/fdmp.2017.013.127

    Abstract The economic progress in the United Arab Emirates (UAE) induces to a significant increase in the demand for agricultural development. In Emirates the majority of the farms are irrigated by underground water, characterized by a high level of salinity. Liwa, Al Ain and Al Khatem areas are suffering from high water well salinity that exceeds 20,000 ppm. This work focuses on this problem and suggests a suitable solution allowing the use of renewable energy (Solar Photovoltaic) to drive RO desalination units. An optimal design of RO/PV unit adapted to a typical farm in Abu Dhabi was suggested using a model… More >

  • Open Access

    ARTICLE

    Convergence Properties of Genetic Algorithmsin a Wide Variety of Noisy Environments

    TakehikoNakama1

    CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 35-60, 2009, DOI:10.3970/cmc.2009.014.035

    Abstract Random noise perturbs objective functions in practical optimization problems, and genetic algorithms (GAs) have been proposed as an effective optimization tool for dealing with noisy objective functions. In this paper, we investigate GAs in a variety of noisy environments where fitness perturbation can occur in any form-for example, fitness evaluations can be concurrently disturbed by additive and multiplicative noise. We reveal the convergence properties of GAs by constructing and analyzing a Markov chain that explicitly models the evolution of the algorithms in noisy environments. We compute the one-step transition probabilities of the Markov chain and show that the chain has… More >

  • Open Access

    ARTICLE

    Relaxation of Alternating Iterative Algorithms for the Cauchy Problem Associated with the Modified Helmholtz Equation

    B. Tomas Johansson1, Liviu Marin2

    CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 153-190, 2009, DOI:10.3970/cmc.2009.013.153

    Abstract We propose two algorithms involving the relaxation of either the given Dirichlet data or the prescribed Neumann data on the over-specified boundary, in the case of the alternating iterative algorithm of Kozlov, Maz'ya and Fomin(1991) applied to Cauchy problems for the modified Helmholtz equation. A convergence proof of these relaxation methods is given, along with a stopping criterion. The numerical results obtained using these procedures, in conjunction with the boundary element method (BEM), show the numerical stability, convergence, consistency and computational efficiency of the proposed methods. More >

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