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Descripción
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| In this work we present a formulation for the dynamics of discrete elements that exhibit an elasto- plastic behaviour with significant temperature effects, that may be useful in many different ap- plications. One of these applications could be the dynamic analysis of passive safety devices in vehicles, designed to dissipate large amounts of energy when subjected to rapid loads. In this situations mechanical energy is typically dissipated by plastic deformation in form of heat. Part of this heat may modify the temperature of the device, changing its mechanical properties, and part of it may go to the environment. Other possible application is the analysis of the dynamical failure of certain type of mechanisms. These mechanisms can incorporate flexible parts that experience large movements and small strains in normal operation, but may experience permanent strains and significant temperature effects under abnormal conditions prior to failure. The discrete element proposed in this work is a one-dimensional truss embedded in a three- dimensional environment, incorporating a classic plasticity model with hardening and thermo- mechanical coupling. The numerical solution of its dynamical behaviour has to face two main difficulties. The first one is related to the non-Hamiltonian structure of the underlying mathemati- cal model; the second one is the non-smoothness in the constitutive plastic response. The proposed time-stepping scheme is the Energy-Entropy-Momentum (EEM) method, originally proposed in [2] for smooth problems and recently extended in [1] to non-smooth ones. The main feature of this second-order scheme is that guarantees exact satisfaction of the laws of thermo- dynamics in the discrete setting; namely the energy balance and the entropy production, while improving the numerical stability in the nonlinear regime. A problem posed by the the EEM method, when applied to a classic elastoplastic model, is the fact that it algorithmically imposes the constitutive relation at midpoint, violating the plastic constraint at each discrete time step. Two methods will be analyzed in this work in order to solve this problem; a method based in a energy-conserving, entropy-producing projection as proposed in [1], and a new method based in a modified radial return. These methods will be implemented and compared with a representative numerical example. Finally, the incorporation of this type of elements in a multibody framework (with rigid, de- formable bodies and kinematical constraints) will be explored with additional examples, illus- trating the applicability and benefits of this approach in more complex problems. | |
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Internacional
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Si |
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Nombre congreso
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IUTAM Symposium on Intelligent Multibody Systems - Dynamics, Control, Simulation |
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Tipo de participación
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960 |
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Lugar del congreso
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Sozopol, Bulgaria |
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Revisores
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Si |
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ISBN o ISSN
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9783030005269 |
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DOI
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Fecha inicio congreso
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11/09/2017 |
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Fecha fin congreso
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15/09/2017 |
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Desde la página
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1 |
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Hasta la página
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20 |
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Título de las actas
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IUTAM Symposium on Intelligent Multibody Systems - Dynamics, Control, Simulation |