Approximation Theory
Mostrando 13-24 de 199 artigos, teses e dissertações.
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13. Estimating the Impact of an All-Electron Basis Set and Scalar Relativistic Effects on the Structure, Stability, and Reactivity of Small Copper Clusters
Basis sets of valence double and quadruple zeta qualities and the Douglas-Kroll-Hess (DKH) approximation are used to estimate the impact of an all-electron basis set and scalar relativistic effects on the structure, stability, and electronic properties of small neutral copper clusters (Cun, n ≤ 8). At the Becke three-parameter for exchange and Perdew-Wang
J. Braz. Chem. Soc.. Publicado em: 2016-01
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14. Elastic analysis of pressurized thick FGM cylinders with exponential variation of material properties using TSDT
AbstractIn this research, the general governing set of differential equations for axisymmetric thick FG pressurized cylinders with exponential function of material properties is derived based on third order shear deformation theory. Afterwards, a general analytical solution of governing equations based on Eigen values problems is conducted for cylinders unde
Lat. Am. j. solids struct.. Publicado em: 2015-06
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15. Comparative Analysis of Ck- and C0-GFEM Applied to Two-dimensional Problems of Confined Plasticity
AbstractFor many practical applications in engineering, a complex structure shows linear elastic behavior over almost all its extension, but exhibits confined plasticity contained in some small critical regions, e.g. stress concentrations in fillets and sharp internal corners. The behavior of C0- and Ck-GFEM is investigated in this class of problems. The fir
Lat. Am. j. solids struct.. Publicado em: 2015-05
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16. Low-velocity Impact Response of a Nanocomposite Beam Using an Analytical Model
AbstractLow-velocity impact of a nanocomposite beam made of glass/epoxy reinforced with multi-wall carbon nanotubes and clay nanoparticles is investigated in this study. Exerting modified rule of mixture (MROM), the mechanical properties of nanocomposite including matrix, nanoparticles or multi-wall carbon nanotubes (MWCNT), and fiber are attained. In order
Lat. Am. j. solids struct.. Publicado em: 2015-04
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17. Application of nonlocal elasticity and DQM to dynamic analysis of curved nanobeams
In this paper, a new numerical technique, the differential quadrature method (DQM) has been developed for dynamic analysis of the nanobeams in the polar coordinate system. DQ approximation of the required partial derivatives is given by a weighted linear sum of the function values at all grid points. A semicircular arch with small-scale effects is investigat
Lat. Am. j. solids struct.. Publicado em: 2014-10
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18. Ab. initio study of the structural, elastic, electronic and optical properties of Cu3N
Electronic, optical, elastic, properties of Copper nitride (Cu3N) in cubic anti- ReO3 phase have been studied using the full-potential augmented plane waves (FP-LAPW) within density functional theory (DFT) framework. Generalized gradient approximation (GGA), local density approximation (LDA), Perdew - Burke - Ernzerhof generalized parameterization of gradien
Mat. Res.. Publicado em: 01/04/2014
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19. Active vibration control of an arbitrary thick piezolaminated beam with imperfectly integrated sensor and actuator layers
A spatial state-space formulation based on the linear twodimensional piezoelasticity theory and involving local/global transfer matrices is applied to investigate the active vibration suppression of a simply supported, arbitrarily thick, orthotropic elastic beam, imperfectly integrated with spatially distributed piezoelectric actuator and sensor layers on it
Lat. Am. j. solids struct.. Publicado em: 2014
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20. Algumas contribuições na teoria de aproximação e otimização com variáveis fuzzy / Some contributions on theory of approximation and optimization with fuzzy variables
É apresentada uma nova formalização do conceito de número fuzzy poligonal junto com uma extensão do conceito para dimensão n. Esta abordagem unificada permite obter generalizações e versões simplificadas de resultados relevantes sobre números fuzzy poligonais e sobre aproximação de quantidades fuzzy n-dimensionais. Consideramos o problema da melh
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/04/2012
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21. Aeroelastic stability analysis using linear matrix inequalities
The present work describes an alternative methodology for identification of aeroelastic stability in a range of varying parameters. Analysis is performed in time domain based on Lyapunov stability and solved by convex optimization algorithms. The theory is outlined and simulations are carried out on a benchmark system to illustrate the method. The classical
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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22. Construction of Lyapunov functions for the estimation of basins of attraction
Technical systems are often modeled through systems of differential equations in which the parameters and initial conditions are subject to uncertainties. Usually, special solutions of the differential equations like equilibrium positions and periodic orbits are of importance and frequently the corresponding equations are only set up with the intent to descr
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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23. Dynamics of rotating non-linear thin-walled composite beams: analysis of modeling uncertainties
In this article a non-linear model for dynamic analysis of rotating thin-walled composite beams is introduced. The theory is deduced in the context of classic variational principles and the finite element method is employed to discretize and furnish a numerical approximation to the motion equations. The model considers shear flexibility as well as non-linear
J. Braz. Soc. Mech. Sci. & Eng.. Publicado em: 2012
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24. Esquemas de aproximação em multinível e aplicações / Multilevel approximation schemes and applications
O objetivo desta tese é desenvolver algoritmos baseados em malhas e bases funcionais inovadoras usando técnicas de multiescala para aproximação de funções e resolução de problemas de equações diferenciais. Para certas classes de problemas, é possível incrementar a eficiência dos algoritmos de multiescala usando bases adaptativas, associadas a ma
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/12/2011