1,721,148 research outputs found
A collocation meshless method based in local optimal point interpolation
Full text linkThis paper deals with the use of the local optimal point interpolating (LOPI) formula in solving partial differential equations (PDEs) with a collocation method. LOPI is an interpolating formula constructed by localization of optimal point interpolation formulas that reproduces polynomials and verifies the delta Kronecker property. This scheme results in a truly meshless method that produces high quality output and accurate solutions.Fil: Zuppa, Carlos. Universidad Nacional de San Luis; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Superelements Modelling in Flexible Multibody Dynamics
Full text linkWe present a new implementation of substructuring methods for flexible multibody analysis. In previous developed formulations, we fixed the local axes of the superelement to one node. In this formulation, the reference frame is floating and close, in some sense, to the body center. The local frame is selected based on the positions of the interface nodes of the superelement, and completely independent of the order in which the nodes of the superelement are given. Therefore, the superelement itself depends only on the nodes positions, and on the mass and stiffness properties, thus allowing a very easy interfacing between the finite element program which computed the superelement and the mechanism analysis program.Fil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Design of bistable compliant mechanisms using precision-position and rigid-body replacement methods
Full text linkA systematic approach to the synthesis of compliant mechanisms starting from the problem requirements is proposed. The method uses as topological solution space several atlases of compliant mechanisms specialized from rigid kinematic chains. Graph Theory is used to solve the type synthesis stage, while the rigid analytical synthesis combined with the well-known process of rigid-body replacement synthesis is used to synthesize the flexible members. Using these tools, we show that the initial and final equilibrium positions of partially compliant mechanisms can be designed from simple topological and kinematic considerations.Fil: Pucheta, Martín Alejo. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
An augmented lagrangian method to solve three-dimensional nonlinear contact problems
No full textA finite element formulation to deal with the friction contact problem between an elastic body and a rigid foundation is presented. An augmented Lagrangian method, which incorporates two Lagrange multipliers and a slack variable in the constraint equation, is developed. In this method, the solution is achieved through a Newton-Raphson monolithic iterative strategy and leads to simple implementation. Examples are provided to demonstrate the accuracy of the proposed algorithm.Fil: Cavalieri, Federico José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Energy Preserving Time Integration for Constrained Multibody Systems
Full text linkThis paper describes an energy preserving integration method for the dynamic analysis of nonlinear multibody systems in the presence of nonlinear constraints. The aspects of finite rotation incrementation, discrete energy conservation and the most common constraint types are examined in detail. The application is made to several rigid body examples, including an intermittent contact problem.Fil: Lens, Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Gerardin, Michel. Université de Liège; Bélgic
An energy preserving/decaying scheme for nonlinearly constrained multibody systems
No full textSeveral numerical time integration methods for multibody system dynamics are described: an energy preserving scheme and three energy decaying ones, which introduce high-frequency numerical dissipation in order to annihilate the nondesired high-frequency oscillations. An exhaustive analysis of these four schemes is done, including their formulation, and energy preserving and decaying properties by taking into account the presence of nonlinear algebraic constraints and the incrementation of finite rotations. A new energy preserving/decaying scheme is developed, which is well suited for either stiff or nonstiff nonlinearly constrained multibody systems. Examples on a series of test cases show the performance of the algorithms.Fil: Lens, Elisabet. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentin
Simulation and Control in Nonlinear Fluid / Structure Coupling Problems with Application to Wind Turbines
Full text linkFil: Cardona, Alberto. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas; Argentina.Se desarrollarán herramientas de simulación numérica para el análisis y el modelado por computadora de sistemas mecánicos complejos, con acoplamiento fluido estructural, en un entorno de cosimulación mediante HPC. Se considerarán efectos de dinámica no lineal introducidos por impacto entre componentes. Se desarrollarán además algoritmos de control y de simulación de sistemas dinámicos complejos, como los que se requieren en el control de generadores eólicos, vehículos y máquinas. Los paquetes de software actuales para el análisis de estos sistemas mecánicos tienen gran flexibilidad y permiten modelar con precisión estos fenómenos, pero poseen deficiencias en cuanto al elevado costo computacional y a la falta de desarrollo y conocimiento del modelado computacional de ciertos fenómenos de interacción. Se analizarán esquemas de acoplamiento entre dominios, y de cosimulación entre softwares, en entornos de trabajo de HPC. La aplicación principal será para el modelado de turbinas eólicas de generación de energía.Numerical simulation tools for the analysis and computer modelling of complex mechanical systems will be developed, with fluid / structure coupling, in a cosimulation HPC environment. Nonlinear dynamics effects introduced by impact between components will be considered. Control algorithms for complex dynamics systems will be considered, as those required for instance to control wind turbines, vehicles and machines. Current software packages for the analysis of these systems have great flexibility and allow to model with accuracy these phenomena, but have deficiencies concerning the high computational cost and lack of development and knowledge in the computational modeling of certain interaction phenomena. Different coupling schemes between domains and for software cosimulation, in HPC environments, will be analyzed. The main application will be modelling of wind turbines for energy generation
Numerical solutions for frictional contact problems based on a mortar algorithm with an augmented Lagrangian technique
Full text linkThis work presents a frictional contact formulation to solve three-dimensional contact problems with large finite displacements. The kinematic description of the contacting bodies is defined by using a mortar approach. The regularization of the variational frictional contact problem is solved with a mixed dual penalty approach based on an augmented Lagrangian technique. In this method, the numerical results do not depend on the definition of any user defined penalty parameter affecting the normal or tangential component of forces. The robustness and performance of the proposed algorithm are studied and validated by solving a series of numerical examples with finite displacements and large slip.Fil: Cavalieri, Federico José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones En Metodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones En Metodos Computacionales; ArgentinaFil: Cardona, Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones En Metodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones En Metodos Computacionales; Argentin
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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