Lagrangian Functions
Mostrando 1-12 de 19 artigos, teses e dissertações.
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1. A simple spline finite strip for buckling analysis of composite cylindrical panel with cutout
Abstract In this study, a new sub-parametric strip element is developed to simulate the axially loaded composite cylindrical panel with arbitrary cutout. For this purpose, a code called SSFSM is developed in FORTRAN to analyze the buckling of panels. The first order shear deformation theory is used to form the strain-displacement relations. Spline and Lagran
Lat. Am. j. solids struct.. Publicado em: 30/09/2019
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2. Physical and geometric non-linear analysis using the finite difference method for one-dimensional consolidation problem
Abstract This article presents a numerical model based on the finite difference method for the physical and geometric non-linear analysis of a one-dimensional consolidation problem regarding a saturated, homogeneous and isotropic soil layer with low permeability and high compressibility. The problem is formulated by adopting the void ratio as the primary var
REM, Int. Eng. J.. Publicado em: 2019-06
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3. A Unified Approach to the Timoshenko Geometric Stiffness Matrix Considering Higher-Order Terms in the Strain Tensor
Abstract Nonlinear analyses using an updated Lagrangian formulation considering the Euler-Bernoulli beam theory have been developed with consistency in the literature, with different geometric matrices depending on the nonlinear displacement parts considered in the strain tensor. When performing this type of analysis using the Timoshenko beam theory, in gene
Lat. Am. j. solids struct.. Publicado em: 25/04/2019
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4. Numerical modeling of contact problems with the finite element method utilizing a B-Spline surface for contact surface smoothing
Abstract The basic aim of this work is to present a method to treat structural mechanics problems dealing with tridimensional contact and large elastic deformations. The formulation presented in this article offers a B-Spline based discretization for the contact surface, which solves the continuity problems presented by the classic Lagrangian contact element
Lat. Am. j. solids struct.. Publicado em: 23/07/2018
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5. Prediction of Modal Damping of FRP-Honeycomb Sandwich Panels with Arbitrary Geometries
Abstract In this work, the modal characteristics, including modal damping, of FRP composite skin, honeycomb core sandwich panels with arbitrary geometries are computed using a mixed finite element-meshless method. By using the meshless node distribution scheme in conjunction with the lagrangian quadrilateral interpolating functions, the continuity of inter-e
Lat. Am. j. solids struct.. Publicado em: 2017-01
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6. A shell finite element formulation to analyze highly deformable rubber-like materials
Abstract: In this paper, a shell finite element formulation to analyze highly deformable shell structures composed of homogeneous rubber-like materials is presented. The element is a triangular shell of any-order with seven nodal parameters. The shell kinematics is based on geometrically exact Lagrangian description and on the Reissner-Mindlin hypothesis. Th
Lat. Am. j. solids struct.. Publicado em: 2013-11
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7. Empacotamento em quadráticas / Packing on quadrics
Neste trabalho, serão propostos modelos matemáticos para problemas de empacotamento não reticulado de esferas em regiões limitadas por quadráticas no plano e no espaço. Uma técnica para construir representações ou parametrizações será introduzida, mediante a qual será possível encontrar um sistema de desigualdades que determinam o empacotamento
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/03/2012
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8. Diferenciação automática de matrizes Hessianas / Automatic differentiation of hessian matrices
In the context of nonlinear programming, many algorithms boil down to the application of Newton s method to the system constituted by the first order Lagrangian conditions. The calculation of Hessian matrices is necessary in this class of solvers. Our focus is on the exact calculation, within machine precision, of Hessian matrices through automatic different
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/04/2011
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9. Sobre o acoplamento fluido-casca utilizando o método dos elementos finitos / On fluid-shell coupling using the finite element method
This work consists of the development of computational tools for nonlinear geometric fluid-shell interaction analysis using the Finite Element Method (FEM). The fluid solver is explicit and its time integration based on characteristics. The computational code is able to simulate the Navier-Stokes equations for compressible flows written in the Eulerian descr
Publicado em: 2011
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10. Um metodo do tipo lagrangiano aumentado com região de confiança / On augmented lagrangian methods with trust-region
Ao resolver problemas de programação não linear usando métodos do tipo Lagrangiano Aumentado, um fenômeno chamado voracidade pode ocorrer. Quando este fenômeno ocorre, o método busca pontos muito infactíveis com valor de função objetivo muito pequeno. Tais fatos ocorrem, em geral, na primeiras iterações e então, o parâmetro de penalidade precis
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 17/06/2009
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11. Metodo lagrangiano aumentado regularizado para problemas com voracidade / Regularized augmented lagrangian method for problems with greediness
Quando resolvemos problemas de programação não linear por meio de algoritmos que utilizam o Lagrangiano Aumentado, um fenômeno chamado voracidade pode ocorrer. Quando isto ocorre o método busca pontos muito infactíveis com valores de função muito pequenos, em geral, nas primeiras iterações, assim o parâmetro de penalidade cresce excessivamente, de
Publicado em: 2009
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12. Local and global symmetries in gauge theories / Simetrias globais e locais em teorias de calibre
This thesis deals with the geometric formulation of classical gauge theories, or Yang-Mills theories, regarded as an important class of models that must be included in any attempt to establish a general mathematical framework for classical field theory. Such a formulation must come in (at least) two variants: the hamiltonian version which has gone through a
Publicado em: 2007