Listagem por temas:
Escolhendo um título você terá acesso ao arquivo original em Post-Script.
COB81 ELEMENTOS FINITOS TRI-LINEARES COM INTEGRAÇÃO REDUZIDA NA ANÁLISE DE PLACAS E CASCAS / TRI-LINEAR FINITE ELEMENTS WITH REDUCED INTEGRATION IN THE ANALYSIS OF PLATES AND SHELLS
Sérgio Luiz Schulz & Armando Miguel Awruch
Curso de Pós-Graduação em Engenharia Civil – CPGEC / UFRGS - Av. Osvaldo Aranha, 99 – 3o andar
CEP 90035-190 Porto Alegre, RS, Brasil – E-mail: slschulz@uepg.br ; awruch@nutecnet.com.br
The static and dynamic finite element analysis of plates, shells and other structural systems using eight nodes three-dimensional linear isoparametric elements is presented in this work. Some important features are: (a) the element matrices are obtained using reduced integration with control of hourglass modes; (b) an explicit Taylor-Galerkin scheme is used to carry out the dynamic analysis, solving the corresponding equations in terms of velocity components; (c) advantages of vector processors facilities, existing in modern super-computers, were considered. Good results were obtained in terms of accuracy and computational performance.
Keywords: Placas, cascas, elementos finitos, integração reduzida, supercomputação / Plates, shells, finite element method, reduced integration, supercomputing
COB172 FREE VIBRATION STUDIES IN CLAMPED PLATES AND SHELLS USING FINITE ELEMENTS
André R. G. de Oliviera & Maher Nasr Bismarck-Nasr
Instituto Tecnológico de Aeronáutica – Divisão de Engenharia de Aeronáutica, 12228-900 – São José dos Campos, SP,Brasil
The present work deals with a parametric study of free vibration analysis of clamped plates and shells using various finite element models. The different element formulations used are compared in terms of convergence, accuracy, ease of implementation and computational efficiencies. The results obtained are compared with other analytical formulations and experimental findings.
Keywords: Plates and Shells, Dynamics, Free vibrations, Finite Element Method.
COB173 FINITE ELEMENT BUCKLING ANALYSIS OF DOUBLY CURVED SHALLOW SHELLS
Juliano Casarin Ozores & Maher Nasr Bismarck-Nasr
Instituto Tecnológico de Aeronáutica – Divisão de Engenharia Aeronáutica, 12228-900 – São José dos Campo, SP, Brasil
The present work deals with linear elastic stability analysis of doubly curved isotropic shallow shells. The shell analysis uses a two-field variable variational principle with the transverse displacement and Airy stress function as field variables. A finite element formulation that preserves C1 continuity is used for the solution of the problem. Several numerical results are presented and the results obtained are discussed and are compared with previous solutions whenever available.
Keywords: Plates and Shells, Buckling, Linear Elastic Stability, Finite Element Method.
COB206 ELASTIC SOLUTIONS IN THE COMPUTATION OF LIMIT LOAD FOR PRESSURE VESSELS / SOLUÇÕES ELÁSTICAS PARA O CÁLCULO DA CARGA LIMITE EM VASOS DE PRESSÃO
José Ricardo Queiroz Franco & Felício Brüzzi Barros
Departamento de Engenharia de Estruturas, Escola de Engenharia da UFMG
Av. Contorno, 842/2-Belo Horizonte 30110-060- Brasil - E-mail:franco@dees.ufmg.br
Elastic solutions for thin shells are shown to be a very good alternative for the calculation of limit loads on axisymmetrical pressure vessels in a displacement formulation for the finite element method. In this paper the fundamental relations for the new formulation is presented, followed by the procedure on how to implement them in a technique for limit analysis. The procedure consists of substituting the direct load by its general forces on the calculation of the external work for the Koiter's theorem. The structural problem is reduced to an optimization problem and solved using standard linear programming. The results are presented as 3D collapse mechanisms and upper bounds on the limit load.
Keywords: Finite Element, Pressure Vessels, Optimization
Elementos Finitos, Vasos de Pressão, Optimização.
COB224 UM ELEMENTO FINITO MULTICAMADAS ADAPTADO A ESTRUTURAS ESPESSAS DO TIPO CASCA / A MULTILAYER FINITE ELEMENT ADAPTABLE TO THICK SHELL STRUCTURES
J. C. Pereira* & P. Swider**
* Centro Técnico Aeroespacial, Instituto de Aeronáutica e Espaço, Divisão de Sistemas Espaciais
12228-904 S. J. Campos, Brasil - E-mail: jcarlos@ase2.iae.cta.br
* * Laboratoire de Génie Mécanique de Toulouse, 31077 Toulouse, França
A multilayer finite element associated with a model to provide damping in thick shell structures is presented. The displacement components, which are linear by layer, allow a better representation of the shear transverse effects. The validation of the model, based on the comparison with the Classical Laminated Theory , is made on an orthotropic square plate with different ply orientations and different boundary conditions.
Keywords: Casca, multicamadas, material composto, elementos finitos, shell, multilayer, composite materials, finite elements.
COB225 ANÁLISE ESTÁTICA NÃO LINEAR DO ENVELOPE BOBINADO DE UM PROPULSOR / THE NON LINEAR STATIC BEHAVIOUR OF A MOTOR’S CASE
J. C. Pereira & A. F. Palmerio
Centro Técnico Aeroespacial, Instituto de Aeronáutica e Espaço, Divisão de Sistemas Espaciais
12228-904 S. J. Campos, Brasil - E-mail: jcarlos@ase2.iae.cta.br
The non linear static behaviour of a motor’s case in Aramid/Epoxy is analyzed. The cure process of the Epoxy resine is analyzed numerically and compared with the measurements taken after the fabrication of the envelope. In the non linear analysis, an additional stiffness matrix is considered as a function of the in-plane stresses state.
Keywords: Análise não linear, estrutura bobinada, material composto, elementos finitos, non linear behaviour, wound structure, composite materials, finite elements.
COB811 ANÁLISE ELASTOPLÁSTICA DE PLACAS SEMI-ESPESSAS COM NÃO-LINEARIDADES GEOMÉTRICA E MATERIAL UTILIZANDO O MÉTODO DOS ELEMENTOS FINITOS / ELASTIC-PLASTIC ANALYSIS OF THICK PLATES UNDERGOING LARGE DEFLECTIONS USING THE FINITE ELEMENT METHOD
José Aguiomar Foggiatto & Carlos Alberto de Campos Selke
NUPES Núcleo de Pesquisas em Engenharia Simultânea / NUPEM Núcleo de Pesquisas em Engenharia Mecânica - Departamento de Mecânica - CEFET-PR Centro Federal de Educação Tecnológica do Paraná
CEP 80230-901 Curitiba, Paraná, Brasil - E-mail: foggiatt@damec.cefetpr.br
GRANTE Grupo de Análise de Tensões - Departamento de Engenharia Mecânica - UFSC Universidade Federal de Santa Catarina CEP 88040-900 Florianópolis, Santa Catarina, Brasil - E-mail:carlos_selke@sirius.cnpq.br
The finite element method is used to solve elastic-plastic problems of thick plates undergoing large deflections. Hill’s variational principle, in its updated lagrangian form, is adopted in the formulation of the problem, since it has show to be efficient in the modelling of elastic-plastic materials, with isotropic hardening. The behavior of the elastic-plastic plates is modelled using the von Mises yield function and the flow rule associated with von Mises yield function. Due to its invariance with the rigid body rotation and displacements and because its leads to a symmetric stiffness matrix, the co-rotacional rate of Kirchhoff stress tensor is used in the formulation. The element obtained from this formulation is the nine node isoparametric quadrilateral Lagrangian finite element. The integration through the thickness of the element is numerically performed by the Gauss-Lobatto quadrature rule, which allows a better representation of the plastic process. This thick plate finite element is used to solve several non-linear elastic-plastic problems of plates and the results obtained are compared with analytical and numerical solutions available in the literature.
Keywords:Finite elements, plasticity, thick plates, quadrature rule, nonlinearities Elementos finitos, plasticidade, placas semi-espessas, regra de quadratura, não-linearidades.
COB823 ANÁLISE DE CARGAS CRÍTICAS DE CHAPAS PELO MÉTODO DOS ELEMENTOS FINITOS/ANALYSIS OF CRÍTICAL LOADS OF PLATES BY THE FINITE ELEMENTS METHODS
Paulo Shigueme Ide, Reyolando M. L. R. F. Brasil & Henrique de Britto Costa
Departamento de Engenharia Mecânica, Escola Federal de Engenharia de Itajubá - EFEI
CEP 37.500-000 Itajubá- MG, Brasil - E-Mail: shigueme@iem.efei.rmg.br
This paper presents a determination of crítical loads of compression of plates under several conditions of boundary. However, it will be necessary a formulation geometrically nonlinear to obtain diferential equations of equilibrium.
The numerical solution of diferential equations of equilibrium is obtained by Finite Elements Method(through Weighted Residual). The problem of eigenvalues is solved through the Jacobi Method and the solution of nonlinear system through the Newton-Raphson Method. Several examples are analysed varying boundary geometric parameters. Where possible, comparisons are presented with published results or obtained by commercial program.
Keywords: Cargas Críticas, Autovalores, Flambagem de Placas e Chapas, Método dos Elementos Finitos.
Crítical Loads, Eigenvalues, Plates and Shells of Buckiling, Finite Elements Methods.